National Library of Energy BETA

Sample records for micrometer-sized magnetic thin

  1. THE STICKINESS OF MICROMETER-SIZED WATER-ICE PARTICLES

    SciTech Connect (OSTI)

    Gundlach, B.; Blum, J.

    2015-01-01

    Water ice is one of the most abundant materials in dense molecular clouds and in the outer reaches of protoplanetary disks. In contrast to other materials (e.g., silicates), water ice is assumed to be stickier due to its higher specific surface energy, leading to faster or more efficient growth in mutual collisions. However, experiments investigating the stickiness of water ice have been scarce, particularly in the astrophysically relevant micrometer-sized region and at low temperatures. In this work, we present an experimental setup to grow aggregates composed of ?m-sized water-ice particles, which we used to measure the sticking and erosion thresholds of the ice particles at different temperatures between 114 K and 260 K. We show with our experiments that for low temperatures (below ?210 K), ?m-sized water-ice particles stick below a threshold velocity of 9.6 m s{sup 1}, which is approximately 10times higher than the sticking threshold of ?m-sized silica particles. Furthermore, erosion of the grown ice aggregates is observed for velocities above 15.3 m s{sup 1}. A comparison of the experimentally derived sticking threshold with model predictions is performed to determine important material properties of water ice, i.e., the specific surface energy and the viscous relaxation time. Our experimental results indicate that the presence of water ice in the outer reaches of protoplanetary disks can enhance the growth of planetesimals by direct sticking of particles.

  2. A micrometer-size movable light emitting area in a resonant tunneling light emitting diode

    SciTech Connect (OSTI)

    Pettinari, G., E-mail: giorgio.pettinari@cnr.it [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); National Research Council (CNR), Institute for Photonics and Nanotechnologies (IFN-CNR), Via Cineto Romano 42, 00156 Roma (Italy); Balakrishnan, N.; Makarovsky, O.; Campion, R. P.; Patan, A. [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom)] [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Polimeni, A.; Capizzi, M. [CNISM-Dipartimento di Fisica, Sapienza Universit di Roma, P.le A. Moro 2, 00185 Roma (Italy)] [CNISM-Dipartimento di Fisica, Sapienza Universit di Roma, P.le A. Moro 2, 00185 Roma (Italy)

    2013-12-09

    We report on the fabrication of a micrometer-size movable light emitting area in a GaAs/AlAs quantum well resonant tunneling p-i-n diode. The spatial position of the micrometer-size light emitting area shifts linearly with increasing applied bias, up to 30??m for a bias increment of 0.2?V. Also, the simultaneous resonant tunneling injection of both electrons and holes into the quantum well states is achieved at specific positions of the diode, thus resulting in a tenfold increase of the electroluminescence intensity.

  3. Thin film superconductor magnetic bearings

    DOE Patents [OSTI]

    Weinberger, Bernard R.

    1995-12-26

    A superconductor magnetic bearing includes a shaft (10) that is subject to a load (L) and rotatable around an axis of rotation, a magnet (12) mounted to the shaft, and a stator (14) in proximity to the shaft. The stator (14) has a superconductor thin film assembly (16) positioned to interact with the magnet (12) to produce a levitation force on the shaft (10) that supports the load (L). The thin film assembly (16) includes at least two superconductor thin films (18) and at least one substrate (20). Each thin film (18) is positioned on a substrate (20) and all the thin films are positioned such that an applied magnetic field from the magnet (12) passes through all the thin films. A similar bearing in which the thin film assembly (16) is mounted on the shaft (10) and the magnet (12) is part of the stator (14) also can be constructed.

  4. Magnetic Vortex Core Reversal by Low-Field Excitations

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Magnetic Vortex Core Reversal by Low-Field Excitations Print In micrometer-sized magnetic thin films, the magnetization typically adopts an in-plane, circular configuration known as a magnetic vortex. At the vortex core, the magnetization turns sharply out of the plane, pointing either up or down. Magnetic data storage based on this binary phenomenon is an intriguing concept, but it would require the ability to flip the vortex cores on demand. Because these structures are highly stable, very

  5. Magnetic Vortex Core Reversal by Low-Field Excitations

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Magnetic Vortex Core Reversal by Low-Field Excitations Print In micrometer-sized magnetic thin films, the magnetization typically adopts an in-plane, circular configuration known as a magnetic vortex. At the vortex core, the magnetization turns sharply out of the plane, pointing either up or down. Magnetic data storage based on this binary phenomenon is an intriguing concept, but it would require the ability to flip the vortex cores on demand. Because these structures are highly stable, very

  6. Magnetic Vortex Core Reversal by Low-Field Excitations

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Magnetic Vortex Core Reversal by Low-Field Excitations Print In micrometer-sized magnetic thin films, the magnetization typically adopts an in-plane, circular configuration known as a magnetic vortex. At the vortex core, the magnetization turns sharply out of the plane, pointing either up or down. Magnetic data storage based on this binary phenomenon is an intriguing concept, but it would require the ability to flip the vortex cores on demand. Because these structures are highly stable, very

  7. Magnetic Vortex Core Reversal by Low-Field Excitations

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Magnetic Vortex Core Reversal by Low-Field Excitations Print In micrometer-sized magnetic thin films, the magnetization typically adopts an in-plane, circular configuration known as a magnetic vortex. At the vortex core, the magnetization turns sharply out of the plane, pointing either up or down. Magnetic data storage based on this binary phenomenon is an intriguing concept, but it would require the ability to flip the vortex cores on demand. Because these structures are highly stable, very

  8. Magnetic Vortex Core Reversal by Low-Field Excitations

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Magnetic Vortex Core Reversal by Low-Field Excitations Print In micrometer-sized magnetic thin films, the magnetization typically adopts an in-plane, circular configuration known as a magnetic vortex. At the vortex core, the magnetization turns sharply out of the plane, pointing either up or down. Magnetic data storage based on this binary phenomenon is an intriguing concept, but it would require the ability to flip the vortex cores on demand. Because these structures are highly stable, very

  9. Magnetic Vortex Core Reversal by Low-Field Excitations

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Magnetic Vortex Core Reversal by Low-Field Excitations Print In micrometer-sized magnetic thin films, the magnetization typically adopts an in-plane, circular configuration known as a magnetic vortex. At the vortex core, the magnetization turns sharply out of the plane, pointing either up or down. Magnetic data storage based on this binary phenomenon is an intriguing concept, but it would require the ability to flip the vortex cores on demand. Because these structures are highly stable, very

  10. Magnetic Vortex Core Reversal by Low-Field Excitations

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Magnetic Vortex Core Reversal by Low-Field Excitations Print In micrometer-sized magnetic thin films, the magnetization typically adopts an in-plane, circular configuration known as a magnetic vortex. At the vortex core, the magnetization turns sharply out of the plane, pointing either up or down. Magnetic data storage based on this binary phenomenon is an intriguing concept, but it would require the ability to flip the vortex cores on demand. Because these structures are highly stable, very

  11. Magnetic Vortex Core Reversal by Low-Field Excitations

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Magnetic Vortex Core Reversal by Low-Field Excitations Magnetic Vortex Core Reversal by Low-Field Excitations Print Wednesday, 28 March 2007 00:00 In micrometer-sized magnetic thin films, the magnetization typically adopts an in-plane, circular configuration known as a magnetic vortex. At the vortex core, the magnetization turns sharply out of the plane, pointing either up or down. Magnetic data storage based on this binary phenomenon is an intriguing concept, but it would require the ability to

  12. Low Temperature Chemical Vapor Deposition Of Thin Film Magnets

    DOE Patents [OSTI]

    Miller, Joel S.; Pokhodnya, Kostyantyn I.

    2003-12-09

    A thin-film magnet formed from a gas-phase reaction of tetracyanoetheylene (TCNE) OR (TCNQ), 7,7,8,8-tetracyano-P-quinodimethane, and a vanadium-containing compound such as vanadium hexcarbonyl (V(CO).sub.6) and bis(benzene)vanalium (V(C.sub.6 H.sub.6).sub.2) and a process of forming a magnetic thin film upon at least one substrate by chemical vapor deposition (CVD) at a process temperature not exceeding approximately 90.degree. C. and in the absence of a solvent. The magnetic thin film is particularly suitable for being disposed upon rigid or flexible substrates at temperatures in the range of 40.degree. C. and 70.degree. C. The present invention exhibits air-stable characteristics and qualities and is particularly suitable for providing being disposed upon a wide variety of substrates.

  13. Quantum states of neutrons in magnetic thin films

    SciTech Connect (OSTI)

    Radu, F.; Zabel, H.; Leiner, V.; Wolff, M.; Ignatovich, V.K.

    2005-06-01

    We have studied experimentally and theoretically the interaction of polarized neutrons with magnetic thin films and magnetic multilayers. In particular, we have analyzed the behavior of the critical edges for total external reflection in both cases. For a single film we have observed experimentally and theoretically a simple behavior: the critical edges remain fixed and the intensity varies according to the angle between the polarization axis and the magnetization vector inside the film. For the multilayer case we find that the critical edges for spin-up and spin-down polarized neutrons move toward each other as a function of the angle between the magnetization vectors in adjacent ferromagnetic films. Although the results for multilayers and single thick layers appear to be different, in fact, the same spinor method explains both results. An interpretation of the critical edges behavior for the multilyers as a superposition of ferromagnetic and antifferomagnetic states is given.

  14. AXISYMMETRIC SCATTERING OF p MODES BY THIN MAGNETIC TUBES

    SciTech Connect (OSTI)

    Hindman, Bradley W.; Jain, Rekha

    2012-02-10

    We examine the scattering of acoustic p-mode waves from a thin magnetic fibril embedded in a gravitationally stratified atmosphere. The scattering is mediated through the excitation of slow sausage waves on the magnetic tube, and only the scattering of the monopole component of the wave field is considered. Since such tube waves are not confined by the acoustic cavity and may freely propagate along the field lines removing energy from the acoustic wave field, the excitation of fibril oscillations is a source of acoustic wave absorption as well as scattering. We compute the mode mixing that is achieved and the absorption coefficients and phase shifts. We find that for thin tubes the mode mixing is weak and the absorption coefficient is small and is a smooth function of frequency over the physically relevant band of observed frequencies. The prominent absorption resonances seen in previous studies of unstratified tubes are absent. Despite the relatively small absorption, the phase shift induced can be surprisingly large, reaching values as high as 15 Degree-Sign for f modes. Further, the phase shift can be positive or negative depending on the incident mode order and the frequency.

  15. High-field magnets using high-critical-temperature superconducting thin films

    DOE Patents [OSTI]

    Mitlitsky, F.; Hoard, R.W.

    1994-05-10

    High-field magnets fabricated from high-critical-temperature superconducting ceramic (HTSC) thin films which can generate fields greater than 4 Tesla are disclosed. The high-field magnets are made of stackable disk-shaped substrates coated with HTSC thin films, and involves maximizing the critical current density, superconducting film thickness, number of superconducting layers per substrate, substrate diameter, and number of substrates while minimizing substrate thickness. The HTSC thin films are deposited on one or both sides of the substrates in a spiral configuration with variable line widths to increase the field. 4 figures.

  16. High-field magnets using high-critical-temperature superconducting thin films

    DOE Patents [OSTI]

    Mitlitsky, Fred; Hoard, Ronald W.

    1994-01-01

    High-field magnets fabricated from high-critical-temperature superconducting ceramic (HTSC) thin films which can generate fields greater than 4 Tesla. The high-field magnets are made of stackable disk-shaped substrates coated with HTSC thin films, and involves maximizing the critical current density, superconducting film thickness, number of superconducting layers per substrate, substrate diameter, and number of substrates while minimizing substrate thickness. The HTSC thin films are deposited on one or both sides of the substrates in a spiral configuration with variable line widths to increase the field.

  17. CONDITIONS FOR TRANSVERSE WAVES PROPAGATION ALONG THIN MAGNETIC FLUX TUBES ON THE SUN

    SciTech Connect (OSTI)

    Lopin, Igor; Nagorny, Ivan

    2013-09-10

    The propagation of kink waves in the thin gravity stratified flux tubes with a generalized magnetic field distribution model is considered in cylindrical geometry. The new kink wave equations for both wave variables are obtained. It is shown that the inclusion of the radial component of an unperturbed tube magnetic field sufficiently transforms the conditions for the propagation of transverse waves. It is demonstrated that, for the models of isothermal and polytropic atmosphere in the tube and its environment, the propagation of kink waves along thin magnetic flux tubes is cutoff-free.

  18. Engineering Gilbert damping by dilute Gd doping in soft magnetic Fe thin films

    SciTech Connect (OSTI)

    Zhang, W. Jiang, S.; Sun, L.; Wang, Y. K.; Zhai, Y.; Wong, P. K. J.; Wang, K.; Jong, M. P. de; Wiel, W. G. van der; Laan, G. van der

    2014-05-07

    By analyzing the ferromagnetic resonance linewidth, we show that the Gilbert damping constant in soft magnetic Fe thin films can be enhanced by ?6 times with Gd doping of up to 20%. At the same time, the magnetic easy axis remains in the film plane while the coercivity is strongly reduced after Gd inclusion. X-ray magnetic circular dichroism measurements reveal a strong increase in the orbital-to-spin moment ratio of Fe with increasing Gd concentration, in full agreement with the increase in the Gilbert damping obtained for these thin films. Combined with x-ray diffraction and vibrating sample magnetometry, the results demonstrate that the FeGd thin films with dilute Gd doping of up to 20% are promising candidates for spin-transfer-torque applications in soft magnetic devices, in which an enhanced damping is required.

  19. Noncircular skyrmion and its anisotropic response in thin films of chiral magnets under a tilted magnetic field

    SciTech Connect (OSTI)

    Lin, Shi-Zeng; Saxena, Avadh

    2015-11-03

    Here we study the equilibrium and dynamical properties of skyrmions in thin films of chiral magnets with oblique magnetic field. The shape of an individual skyrmion is non-circular and the skyrmion density decreases with the tilt angle from the normal of films. As a result, the interaction between two skyrmions depends on the relative angle between them in addition to their separation. The triangular lattice of skyrmions under a perpendicular magnetic field is distorted into a centered rectangular lattice for a tilted magnetic field. For a low skyrmion density, skyrmions form a chain like structure. Lastly, the dynamical response of the non-circular skyrmions depends on the direction of external currents.

  20. Noncircular skyrmion and its anisotropic response in thin films of chiral magnets under a tilted magnetic field

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lin, Shi-Zeng; Saxena, Avadh

    2015-11-03

    Here we study the equilibrium and dynamical properties of skyrmions in thin films of chiral magnets with oblique magnetic field. The shape of an individual skyrmion is non-circular and the skyrmion density decreases with the tilt angle from the normal of films. As a result, the interaction between two skyrmions depends on the relative angle between them in addition to their separation. The triangular lattice of skyrmions under a perpendicular magnetic field is distorted into a centered rectangular lattice for a tilted magnetic field. For a low skyrmion density, skyrmions form a chain like structure. Lastly, the dynamical response ofmore » the non-circular skyrmions depends on the direction of external currents.« less

  1. Phase formation, thermal stability and magnetic moment of cobalt nitride thin films

    SciTech Connect (OSTI)

    Gupta, Rachana; Pandey, Nidhi; Tayal, Akhil; Gupta, Mukul E-mail: dr.mukul.gupta@gmail.com

    2015-09-15

    Cobalt nitride (Co-N) thin films prepared using a reactive magnetron sputtering process are studied in this work. During the thin film deposition process, the relative nitrogen gas flow (R{sub N{sub 2}}) was varied. As R{sub N{sub 2}} increases, Co(N), Co{sub 4}N, Co{sub 3}N and CoN phases are formed. An incremental increase in R{sub N{sub 2}}, after emergence of Co{sub 4}N phase at R{sub N{sub 2}} = 10%, results in a linear increase of the lattice constant (a) of Co{sub 4}N. For R{sub N{sub 2}} = 30%, a maximizes and becomes comparable to its theoretical value. An expansion in a of Co{sub 4}N, results in an enhancement of the magnetic moment, to the extent that it becomes even larger than pure Co. Such larger than pure metal magnetic moment for tetra-metal nitrides (M{sub 4}N) have been theoretically predicted. Incorporation of N atoms in M{sub 4}N configuration results in an expansion of a (relative to pure metal) and enhances the itinerary of conduction band electrons leading to larger than pure metal magnetic moment for M{sub 4}N compounds. Though a higher (than pure Fe) magnetic moment for Fe{sub 4}N thin films has been evidenced experimentally, higher (than pure Co) magnetic moment is evidenced in this work.

  2. Modified Magnetic Ground State in Nimn (2) O (4) Thin Films

    SciTech Connect (OSTI)

    Nelson-Cheeseman, B.B.; Chopdekar, R.V.; Iwata, J.M.; Toney, M.F.; Arenholz, E.; Suzuki, Y.; /SLAC

    2012-08-23

    The authors demonstrate the stabilization of a magnetic ground state in epitaxial NiMn{sub 2}O{sub 4} (NMO) thin films not observed in their bulk counterpart. Bulk NMO exhibits a magnetic transition from a paramagnetic phase to a collinear ferrimagnetic moment configuration below 110 K and to a canted moment configuration below 70 K. By contrast, as-grown NMO films exhibit a single magnetic transition at 60 K and annealed films exhibit the magnetic behavior found in bulk. Cation inversion and epitaxial strain are ruled out as possible causes for the new magnetic ground state in the as-grown films. However, a decrease in the octahedral Mn{sup 4+}:Mn{sup 3+} concentration is observed and likely disrupts the double exchange that produces the magnetic state at intermediate temperatures. X-ray magnetic circular dichroism and bulk magnetometry indicate a canted ferrimagnetic state in all samples at low T. Together these results suggest that the collinear ferrimagnetic state observed in bulk NMO at intermediate temperatures is suppressed in the as grown NMO thin films due to a decrease in octahedral Mn{sup 4+}, while the canted moment ferrimagnetic ordering is preserved below 60 K.

  3. Brownian motion of massive skyrmions in magnetic thin films

    SciTech Connect (OSTI)

    Troncoso, Roberto E.; Núñez, Álvaro S.

    2014-12-15

    We report on the thermal effects on the motion of current-driven massive magnetic skyrmions. The reduced equation for the motion of skyrmion has the form of a stochastic generalized Thiele’s equation. We propose an ansatz for the magnetization texture of a non-rigid single skyrmion that depends linearly with the velocity. By using this ansatz it is found that the skyrmion mass tensor is closely related to intrinsic skyrmion parameters, such as Gilbert damping, skyrmion-charge and dissipative force. We have found an exact expression for the average drift velocity as well as the mean-square velocity of the skyrmion. The longitudinal and transverse mobility of skyrmions for small spin-velocity of electrons is also determined and found to be independent of the skyrmion mass.

  4. Retrieving spin textures on curved magnetic thin films with full-field soft X-ray microscopies

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Streubel, Robert; Kronast, Florian; Fischer, Peter; Parkinson, Dula; Schmidt, Oliver G.; Makarov, Denys

    2015-07-03

    X-ray tomography is a well-established technique to characterize 3D structures in material sciences and biology; its magnetic analogue—magnetic X-ray tomography—is yet to be developed. We demonstrate the visualization and reconstruction of magnetic domain structures in a 3D curved magnetic thin films with tubular shape by means of full-field soft X-ray microscopies. In the 3D arrangement of the magnetization is retrieved from a set of 2D projections by analysing the evolution of the magnetic contrast with varying projection angle. By using reconstruction algorithms to analyse the angular evolution of 2D projections provides quantitative information about domain patterns and magnetic coupling phenomenamore » between windings of azimuthally and radially magnetized tubular objects. In conclusion, the present approach represents a first milestone towards visualizing magnetization textures of 3D curved thin films with virtually arbitrary shape.« less

  5. Retrieving spin textures on curved magnetic thin films with full-field soft X-ray microscopies

    SciTech Connect (OSTI)

    Streubel, Robert; Kronast, Florian; Fischer, Peter; Parkinson, Dula; Schmidt, Oliver G.; Makarov, Denys

    2015-07-03

    X-ray tomography is a well-established technique to characterize 3D structures in material sciences and biology; its magnetic analogue—magnetic X-ray tomography—is yet to be developed. We demonstrate the visualization and reconstruction of magnetic domain structures in a 3D curved magnetic thin films with tubular shape by means of full-field soft X-ray microscopies. In the 3D arrangement of the magnetization is retrieved from a set of 2D projections by analysing the evolution of the magnetic contrast with varying projection angle. By using reconstruction algorithms to analyse the angular evolution of 2D projections provides quantitative information about domain patterns and magnetic coupling phenomena between windings of azimuthally and radially magnetized tubular objects. In conclusion, the present approach represents a first milestone towards visualizing magnetization textures of 3D curved thin films with virtually arbitrary shape.

  6. Non-linear radial spinwave modes in thin magnetic disks

    SciTech Connect (OSTI)

    Helsen, M. De Clercq, J.; Vansteenkiste, A.; Van Waeyenberge, B.; Weigand, M.

    2015-01-19

    We present an experimental investigation of radial spin-wave modes in magnetic nano-disks with a vortex ground state. The spin-wave amplitude was measured using a frequency-resolved magneto-optical spectrum analyzer, allowing for high-resolution resonance curves to be recorded. It was found that with increasing excitation amplitude up to about 10 mT, the lowest-order mode behaves strongly non-linearly as the mode frequency redshifts and the resonance peak strongly deforms. This behavior was quantitatively reproduced by micromagnetic simulations. Micromagnetic simulations showed that at higher excitation amplitudes, the spinwaves are transformed into a soliton by self-focusing, and collapse onto the vortex core, dispersing the energy in short-wavelength spinwaves. Additionally, this process can lead to switching of the vortex polarization through the injection of a Bloch point.

  7. Composition dependence of electronic, magnetic, transport and morphological properties of mixed valence manganite thin films

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Singh, Surendra; Freeland, J. W.; Fitzsimmons, Michael R.; Jeen, H.; Biswas, A.

    2016-07-27

    Mixed-valence manganese oxides present striking properties like the colossal magnetoresistance, metal-insulator transition (MIT) that may result from coexistence of ferromagnetic, metallic and insulating phases. Percolation of such phase coexistence in the vicinity of MIT leads to first-order transition in these manganites. However the length scales over which the electronic and magnetic phases are separated across MIT which appears compelling for bulk systems has been elusive in (La1-yPry)1-xCaxMnO3 films. Here we show the in-plane length scale over which charge and magnetism are correlated in (La0.4Pr0.6)1-xCaxMnO3 films with x = 0.33 and 0.375, across the MIT temperature. We combine electrical transport (resistance)more » measurements, x-ray absorption spectroscopy (XAS), x-ray magnetic circular dichroism (XMCD), and specular/off-specular x-ray resonant magnetic scattering (XRMS) measurements as a function of temperature to elucidate relationships between electronic, magnetic and morphological structure of the thin films. Using off-specular XRMS we obtained the charge-charge and charge-magnetic correlation length of these LPCMO films across the MIT. We observed different charge-magnetic correlation length for two films which increases below the MIT. The different correlation length shown by two films may be responsible for different macroscopic (transport and magnetic) properties.« less

  8. Structural controlled magnetic anisotropy in Heusler L1{sub 0}-MnGa epitaxial thin films

    SciTech Connect (OSTI)

    Wang Kangkang; Lu Erdong; Smith, Arthur R.; Knepper, Jacob W.; Yang Fengyuan

    2011-04-18

    Ferromagnetic L1{sub 0}-MnGa thin films have been epitaxially grown on GaN, sapphire, and MgO substrates using molecular beam epitaxy. Using diffraction techniques, the epitaxial relationships are determined. It is found that the crystalline orientation of the films differ due to the influence of the substrate. By comparing the magnetic anisotropy to the structural properties, a clear correlation could be established indicating that the in-plane and out-of-plane anisotropy is directly determined by the crystal orientation of the film and could be controlled via selection of the substrates. This result could be helpful in tailoring magnetic anisotropy in thin films for spintronic applications.

  9. Tunable giant magnetic anisotropy in amorphous SmCo thin films

    SciTech Connect (OSTI)

    Magnus, F.; Moubah, R.; Roos, A. H.; Kapaklis, V.; Hjoervarsson, B.; Andersson, G.; Kruk, A.; Hase, T.

    2013-04-22

    SmCo thin films have been grown by magnetron sputtering at room temperature with a composition of 2-35 at. % Sm. Films with 5 at. % or higher Sm are amorphous and smooth. A giant tunable uniaxial in-plane magnetic anisotropy is induced in the films which peaks in the composition range 11-22 at. % Sm. This cross-over behavior is not due to changes in the atomic moments but rather the local configuration changes. The excellent layer perfection combined with highly tunable magnetic properties make these films important for spintronics applications.

  10. Direct evidence of anomalous interfacial magnetization in metamagnetic Pd doped FeRh thin films

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bennett, S. P.; Ambaye, H.; Lee, H.; LeClair, P.; Mankey, G. J.; Lauter, V.

    2015-03-16

    Palladium doped iron rhodium is a magnetic material of significant interest for it’s close to room temperature magnetostructural phase transition from antiferromagnetic (AF) to ferromagnetic (FM) ordering. Here we report on the peculiarities of the magnetization distribution in thin films of FeRh(Pd) probed by Polarized Neutron Reflectometry. Remarkably, we’ve found thin interfacial regions with strong magnetization that have unique thermomagnetic properties as compared to the rest of the system. These regions exist at the top and bottom interfaces of the films while the central regions behave similarly to the bulk with a clear AF-FM order transition. Further we explore themore » impact of an additional Pt interlayer introduced in the middle of the FeRh(Pd) film and reveal that it serves to replicate the strong interfacial magnetization found at the top and bottom interfaces. In conclusion, these results are of great value both in understanding the fundamental physics of such an order transition, and in considering FeRh(Pd) for magnetic media and spintronics applications.« less

  11. Simultaneous measurement of the surface and bulk magnetization in thin magnetic films

    SciTech Connect (OSTI)

    Teplin, Charles W.; Rogers, Charles T.

    2001-06-01

    We describe an apparatus for the simultaneous measurement of the transverse and longitudinal linear magneto-optic Kerr effects and the transverse second-harmonic magneto-optic Kerr effect. We have used this system to study low frequency bulk and surface magnetization loops, and high frequency response to 100 ps impulse fields for 70 nm thick Ni{sub 80}Fe{sub 20} films. Magnetization loops show that the surface and bulk magnetization fields in these films respond essentially identically to external fields. Similarly, the dynamic response of the films to 100 ps magnetic field impulses also shows simultaneous rotation of the surface and bulk magnetization. Finally, we use the system to produce 8 {mu}m resolution (at the diffraction limit for our ellipsometric optical geometry) images of the magnetization spatial and temporal response. {copyright} 2001 American Institute of Physics.

  12. Atomic moments in Mn{sub 2}CoAl thin films analyzed by X-ray magnetic circular dichroism

    SciTech Connect (OSTI)

    Jamer, M. E.; Assaf, B. A.; Heiman, D.; Sterbinsky, G. E.; Arena, D. A.

    2014-12-07

    Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The magnetic properties of Mn{sub 2}CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the atomic-specific magnetic moments of Mn and Co atoms measured through X-ray magnetic circular dichroism as a function of annealing and the consequent structural ordering. The results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value.

  13. Atomic moments in Mn2CoAl thin films analyzed by X-ray magnetic circular dichroism

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jamer, M. E.; Assaf, B. A.; Sterbinsky, G. E.; Arena, D. A.; Heiman, D.

    2014-12-05

    Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The magnetic properties of Mn2CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the atomic-specific magnetic moments of Mn and Co atoms measured through X-ray magnetic circular dichroism as a function of annealing and the consequent structural ordering. Results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value.

  14. Magnetic thin-film split-domain current sensor-recorder

    DOE Patents [OSTI]

    Hsieh, Edmund J.

    1979-01-01

    A sensor-recorder for recording a representation of the direction and peak amplitude of a transient current. A magnetic thin film is coated on a glass substrate under the influence of a magnetic field so that the finished film is magnetically uniaxial and anisotropic. The film is split into two oppositely magnetized contiguous domains with a central boundary by subjecting adjacent portions of the film simultaneously to magnetic fields that are opposed 180.degree.. With the split-domain sensor-recorder placed with the film plane and domain boundary either perpendicular or parallel to the expected conductive path of a transient current, the occurrence of the transient causes switching of a portion of one domain to the direction of the other domain. The amount of the switched domain portion is indicative of the amplitude of the peak current of the transient, while the particular domain that is switched is indicative of the direction of the current. The resulting domain patterns may be read with a passive magnetic tape viewer.

  15. Structural, magnetic, and transport properties of Fe-doped CoTiSb epitaxial thin films

    SciTech Connect (OSTI)

    Sun, N. Y.; Zhang, Y. Q.; Che, W. R.; Shan, R.; Qin, J.

    2015-11-07

    Epitaxial intrinsic and Fe-doped CoTiSb thin films with C1{sub b} structure were grown on MgO(100) substrates by magnetron sputtering. The semiconducting-like behavior in both intrinsic and Fe-doped thin films was demonstrated by temperature dependence of longitudinal resistivity. The Fe-doped CoTiSb films with a wide range of doping concentrations can maintain semiconducting-like and magnetic properties simultaneously, while the semiconducting behavior is weakening with the increasing Fe concentration. For 21 at. % Fe-doped film, low lattice magnetic moment (around 0.65 μ{sub B}) and high resistivity (larger than 800 μΩ cm) are beneficial to its application as a magnetic electrode in spintronic devices. Anomalous Hall effect of 21 at. % Fe-doped film was also investigated and its behaviors can be treated well by recent-reported anomalous Hall scaling including the contribution of spin-phonon skew scattering.

  16. Magnetism and transport properties of epitaxial Fe-Ga thin films on GaAs(001)

    SciTech Connect (OSTI)

    Duong Anh Tuan; Shin, Yooleemi; Cho, Sunglae; Dang Duc Dung; Vo Thanh Son

    2012-04-01

    Epitaxial Fe-Ga thin films in disordered bcc {alpha}-Fe crystal structure (A2) have been grown on GaAs(001) by molecular beam epitaxy. The saturated magnetization (M{sub S}) decreased from 1371 to 1105 kA/m with increasing Ga concentration from 10.5 to 24.3 % at room temperature. The lattice parameter increased with the increase in Ga content because of the larger atomic radius of Ga atom than that of Fe. The increase in carrier density with Ga content caused in lower resistivity.

  17. Magnetic domain structure in nanocrystalline Ni-Zn-Co spinel ferrite thin films using off-axis electron holography

    SciTech Connect (OSTI)

    Zhang, D.; Ray, N. M.; Petuskey, W. T.; Smith, D. J.; McCartney, M. R.

    2014-08-28

    We report a study of the magnetic domain structure of nanocrystalline thin films of nickel-zinc ferrite. The ferrite films were synthesized using aqueous spin-spray coating at low temperature (?90?C) and showed high complex permeability in the GHz range. Electron microscopy and microanalysis revealed that the films consisted of columnar grains with uniform chemical composition. Off-axis electron holography combined with magnetic force microscopy indicated a multi-grain domain structure with in-plane magnetization. The correlation between the magnetic domain morphology and crystal structure is briefly discussed.

  18. Goos-Hänchen effect and bending of spin wave beams in thin magnetic films

    SciTech Connect (OSTI)

    Gruszecki, P. Krawczyk, M.; Romero-Vivas, J.; Dadoenkova, Yu. S.; Dadoenkova, N. N.; Lyubchanskii, I. L.

    2014-12-15

    For magnon spintronic applications, the detailed knowledge of spin wave (SW) beam dispersion, transmission (reflection) of SWs passing through (reflected from) interfaces, or borders or the scattering of SWs by inhomogeneities is crucial. These wave properties are decisive factors on the usefulness of a particular device. Here, we demonstrate, using micromagnetic simulations supported by an analytical model, that the Goos-Hänchen (GH) shift exists for SW reflecting from thin film edge and that with the effect becomes observable. We show that this effect will exist for a broad range of frequencies in the dipole-exchange range, with the magnetization degree of pinning at the film edge as the crucial parameter, whatever its nature. Moreover, we have also found that the GH effect can be accompanied or even dominating by a bending of the SW beam due to the inhomogeneity of the internal magnetic field. This inhomogeneity, created by demagnetizing field taking place at the film edge, causes gradual change of SWs refractive index. The refraction of the SW beams by the non-uniformity of the magnetic field enables the exploration of graded index magnonics and metamaterial properties for the transmission and processing of information at nanoscale.

  19. The magnetic ordering in high magnetoresistance Mn-doped ZnO thin films

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Venkatesh, S.; Baras, A.; Lee, J. -S.; Roqan, I. S.

    2016-03-24

    Here, we studied the nature of magnetic ordering in Mn-doped ZnO thin films that exhibited ferromagnetism at 300 K and superparamagnetism at 5 K. We directly inter-related the magnetisation and magnetoresistance by invoking the polaronpercolation theory and variable range of hopping conduction below the metal-to-insulator transition. By obtaining a qualitative agreement between these two models, we attribute the ferromagnetism to the s-d exchange-induced spin splitting that was indicated by large positive magnetoresistance (~40 %). Low temperature superparamagnetism was attributed to the localization of carriers and non-interacting polaron clusters. This analysis can assist in understanding the presence or absence of ferromagnetismmore » in doped/un-doped ZnO.« less

  20. Thin film deposition by electric and magnetic crossed-field diode sputtering

    DOE Patents [OSTI]

    Welch, Kimo M.

    1977-01-01

    Applying a thin film coating to the surface of a workpiece, in particular, applying a coating of titanium nitride to a klystron window by means of a crossed-field diode sputtering array. The array is comprised of a cohesive group of numerous small hollow electrically conducting cylinders and is mounted so that the open ends of the cylinders on one side of the group are adjacent a titanium cathode plate. The workpiece is mounted so as to face the open ends of the other side of the group. A magnetic field is applied to the array so as to be coaxial with the cylinders and a potential is applied across the cylinders and the cathode plate, the cylinders as an anode being positive with respect to the cathode plate. The cylinders, the cathode plate and the workpiece are situated in an atmosphere of nitrogen which becomes ionized such as by field emission because of the electric field between the cylinders and cathode plate, thereby establishing an anode-cathode discharge that results in sputtering of the titanium plate. The sputtered titanium coats the workpiece and chemically combines with the nitrogen to form a titanium nitride coating on the workpiece. Gas pressure, gas mixtures, cathode material composition, voltages applied to the cathode and anode, the magnetic field, cathode, anode and workpiece spacing, and the aspect ratio (ratio of length to inner diameter) of the anode cylinders, all may be controlled to provide consistent optimum thin film coatings of various compositions and thicknesses. Another facet of the disclosure is the coating of microwave components per se with titanium nitride to reduce multipactoring under operating conditions of the components.

  1. Thin film deposition by electric and magnetic crossed-field diode sputtering

    DOE Patents [OSTI]

    Welch, Kimo M.

    1980-01-01

    Applying a thin film coating to the surface of a workpiece, in particular, applying a coating of titanium nitride to a klystron window by means of a crossed-field diode sputtering array. The array is comprised of a cohesive group of numerous small hollow electrically conducting cylinders and is mounted so that the open ends of the cylinders on one side of the group are adjacent a titanium cathode plate. The workpiece is mounted so as to face the open ends of the other side of the group. A magnetic field is applied to the array so as to be coaxial with the cylinders and a potential is applied across the cylinders and the cathode plate, the cylinders as an anode being positive with respect to the cathode plate. The cylinders, the cathode plate and the workpiece are situated in an atmosphere of nitrogen which becomes ionized such as by field emission because of the electric field between the cylinders and cathode plate, thereby establishing an anode-cathode discharge that results in sputtering of the titanium plate. The sputtered titanium coats the workpiece and chemically combines with the nitrogen to form a titanium nitride coating on the workpiece. Gas pressure, gas mixtures, cathode material composition, voltages applied to the cathode and anode, the magnetic field, cathode, anode and workpiece spacing, and the aspect ratio (ratio of length to inner diameter) of the anode cylinders, all may be controlled to provide consistent optimum thin film coatings of various compositions and thicknesses. Another facet of the disclosure is the coating of microwave components per se with titanium nitride to reduce multipactoring under operating conditions of the components.

  2. Exponentially decaying magnetic coupling in sputtered thin film FeNi/Cu/FeCo trilayers

    SciTech Connect (OSTI)

    Wei, Yajun Akansel, Serkan; Thersleff, Thomas; Brucas, Rimantas; Lansaker, Pia; Leifer, Klaus; Svedlindh, Peter; Harward, Ian; Celinski, Zbigniew; Ranjbar, Mojtaba; Dumas, Randy K.; Jana, Somnath; Pogoryelov, Yevgen; Karis, Olof; Åkerman, Johan

    2015-01-26

    Magnetic coupling in trilayer films of FeNi/Cu/FeCo deposited on Si/SiO{sub 2} substrates have been studied. While the thicknesses of the FeNi and FeCo layers were kept constant at 100 Å, the thickness of the Cu spacer was varied from 5 to 50 Å. Both hysteresis loop and ferromagnetic resonance results indicate that all films are ferromagnetically coupled. Micromagnetic simulations well reproduce the ferromagnetic resonance mode positions measured by experiments, enabling the extraction of the coupling constants. Films with a thin Cu spacer are found to be strongly coupled, with an effective coupling constant of 3 erg/cm{sup 2} for the sample with a 5 Å Cu spacer. The strong coupling strength is qualitatively understood within the framework of a combined effect of Ruderman-Kittel-Kasuya-Yosida and pinhole coupling, which is evidenced by transmission electron microscopy analysis. The magnetic coupling constant surprisingly decreases exponentially with increasing Cu spacer thickness, without showing an oscillatory thickness dependence. This is partially connected to the substantial interfacial roughness that washes away the oscillation. The results have implications on the design of multilayers for spintronic applications.

  3. Interface driven magnetic interactions in nanostructured thin films of iron nanocrystallites embedded in a copper matrix

    SciTech Connect (OSTI)

    Desautels, R. D. Lierop, J. van; Shueh, C.; Lin, K.-W.; Freeland, J. W.

    2015-05-07

    We have fabricated thin films of iron nanocrystallites embedded in a copper matrix using a dual ion beam assisted deposition technique. A secondary End-Hall ion beam bombarded the iron atoms during deposition altering significantly the morphology of the films and allowing for control of the intermixing between iron and copper components. Cross-sectional transmission electron microscopy and x-ray reflectometry experiments indicated that the morphology of the films was that of iron nanocrystallites embedded in a copper matrix. Rietveld refinements of the diffraction pattern identified fcc-copper and amorphous iron. An increased amount of disorder was observed with a reduction in the amount of deposited iron from a 1:1 Fe:Cu ratio to 0.25:0.75 Fe:Cu ratio. Interfacial copper-iron alloys were identified by DC susceptibility experiments through their reduced T{sub C,Alloy} (370, 310, and 280 K) compared with that of bulk iron (∼1000 K). Element specific x-ray absorption and x-ray magnetic circular dichroism experiments were performed to identify the contributions to the magnetism from the iron and the copper-iron alloy.

  4. Thin film deposition by electric and magnetic crossed-field diode sputtering. [Patent application

    DOE Patents [OSTI]

    Welch, K.M.

    1975-04-04

    Applying a coating of titanium nitride to a klystron window by means of a cross-field diode sputtering array is described. The array is comprised of a cohesive group of numerous small hollow electrically conducting cylinders and is mounted so that the open ends of the cylinders on one side of the group are adjacent to a titanium cathode plate. The workpiece is mounted so as to face the open ends of the other side of the group. A magnetic field is applied to the array so as to be coaxial with the cylinders and a potential is applied across the cylinders and the cathode plate, the cylinders as an anode being positive with respect to the cathode plate. The cylinders, the cathode plate, and the workpiece are situated in an atmosphere of nitrogen which becomes ionized such as by field emission because of the electric field between the cylinders and cathode plate, thereby establishing an anode-cathode discharge that results in sputtering of the titanium plate. The sputtered titanium coats the workpiece and chemically combines with the nitrogen to form a titanium nitride coating on the workpiece. Gas pressure, gas mixtures, cathode material composition, voltages applied to the cathode and anode, the magnetic field, cathode, anode and workpiece spacing, and the aspect ratio (ratio of length to inner diameter) of the anode cylinders, all may be controlled to provide consistent optimum thin film coatings of various compositions and thickness. Another facet of the disclosure is the coating of microwave components per se with titanium nitride to reduce multifactoring under operating conditions of the components.

  5. Depth-dependent magnetism in epitaxial MnSb thin films: effects of surface passivation and cleaning

    SciTech Connect (OSTI)

    Aldous J. D.; Sanchez-Hanke C.; Burrows, C.W.; Maskery, I.; Brewer, M.S.; Hase, T.P.A.; Duffy, J.A.; Lees, M. Rs; Decoster, T.; Theis, W.; Quesada, A.; Schmid, A.K.; Bell, G.R.

    2012-03-15

    Depth-dependent magnetism in MnSb(0001) epitaxial films has been studied by combining experimental methods with different surface specificities: polarized neutron reflectivity, x-ray magnetic circular dichroism (XMCD), x-ray resonant magnetic scattering and spin-polarized low energy electron microscopy (SPLEEM). A native oxide {approx}4.5 nm thick covers air-exposed samples which increases the film's coercivity. HCl etching efficiently removes this oxide and in situ surface treatment of etched samples enables surface magnetic contrast to be observed in SPLEEM. A thin Sb capping layer prevents oxidation and preserves ferromagnetism throughout the MnSb film. The interpretation of Mn L{sub 3,2} edge XMCD data is discussed.

  6. Quantum anomalous Hall effect and a nontrivial spin-texture in ultra-thin films of magnetic topological insulators

    SciTech Connect (OSTI)

    Duong, Le Quy; Das, Tanmoy; Feng, Y. P.; Lin, Hsin

    2015-05-07

    We study the evolution of quantum anomalous Hall (QAH) effect for a Z{sub 2} topological insulator (TI) thin films in a proximity induced magnetic phase by a realistic layered k·p model with interlayer coupling. We examine three different magnetic configurations in which ferromagnetic (FM) layer(s) is added either from one side (FM-TI), from both sides (FM-TI-FM), or homogeneously distributed (magnetically doped) in a TI slab. We map out the thickness-dependent topological phase diagram under various experimental conditions. The critical magnetic exchange energy for the emergence of QAH effect in the latter two cases decreases monotonically with increasing number of quintuple layers (QLs), while it becomes surprisingly independent of the film thickness in the former case. The gap size of the emergent QAH insulator depends on the non-magnetic “parent” gap of the TI thin film and is tuned by the FM exchange energy, opening a versatile possibility to achieve room-temperature QAH insulator in various topological nanomaterials. Finally, we find that the emergent spin-texture in the QAH effect is very unconventional, non-“hedgehog” type; and it exhibits a chiral out-of-plane spin-flip texture within the same valence band which is reminiscent of dynamical “skyrmion” pattern, except our results are in the momentum space.

  7. Atomic moments in Mn2CoAl thin films analyzed by X-ray magnetic circular dichroism

    SciTech Connect (OSTI)

    Jamer, M. E.; Assaf, B. A.; Sterbinsky, G. E.; Arena, D. A.; Heiman, D.

    2014-12-05

    Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The magnetic properties of Mn2CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the atomic-specific magnetic moments of Mn and Co atoms measured through X-ray magnetic circular dichroism as a function of annealing and the consequent structural ordering. Results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value.

  8. Atomic moments in Mn2CoAl thin films analyzed by X-ray magnetic circular dichroism

    SciTech Connect (OSTI)

    Jamer, M.; Sterbinsky, G.; Assaf, B.; Arena, D.; Heiman, D.

    2014-12-05

    Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The magnetic properties of Mn2CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the atomic-specific magnetic moments of Mn and Co atoms measured through X-ray magnetic circular dichroism as a function of annealing and the consequent structural ordering. The results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value. (auth)

  9. Perpendicularly magnetized {tau}-MnAl (001) thin films epitaxied on GaAs

    SciTech Connect (OSTI)

    Nie, S. H.; Zhu, L. J.; Lu, J.; Pan, D.; Wang, H. L.; Yu, X. Z.; Xiao, J. X.; Zhao, J. H.

    2013-04-15

    Perpendicularly magnetized {tau}-MnAl films have been epitaxied on GaAs (001) by molecular-beam epitaxy. Crystalline quality and magnetic properties of the samples were strongly dependent on growth temperature. The highest coercivity of 10.7 kOe, saturation magnetization of 361.4 emu/cm{sup 3}, perpendicular magnetic anisotropy constant of 13.65 Merg/cm{sup 3}, and magnetic energy product of 4.44 MGOe were achieved. These tunable magnetic properties make MnAl films valuable as excellent and cost-effective alternative for not only high density perpendicular magnetic recording storage and spintronics devices but also permanent magnets.

  10. Reactive sputter deposition of pyrite structure transition metal disulfide thin films: Microstructure, transport, and magnetism

    SciTech Connect (OSTI)

    Baruth, A.; Manno, M.; Narasimhan, D.; Shankar, A.; Zhang, X.; Johnson, M.; Aydil, E. S.; Leighton, C. [Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    2012-09-01

    Transition metal disulfides crystallizing in the pyrite structure (e.g., TMS{sub 2}, with TM = Fe, Co, Ni, and Cu) are a class of materials that display a remarkably diverse array of functional properties. These properties include highly spin-polarized ferromagnetism (in Co{sub 1-x}Fe{sub x}S{sub 2}), superconductivity (in CuS{sub 2}), an antiferromagnetic Mott insulating ground state (in NiS{sub 2}), and semiconduction with close to optimal parameters for solar absorber applications (in FeS{sub 2}). Exploitation of these properties in heterostructured devices requires the development of reliable and reproducible methods for the deposition of high quality pyrite structure thin films. In this manuscript, we report on the suitability of reactive sputter deposition from metallic targets in an Ar/H{sub 2}S environment as a method to achieve exactly this. Optimization of deposition temperature, Ar/H{sub 2}S pressure ratio, and total working gas pressure, assisted by plasma optical emission spectroscopy, reveals significant windows over which deposition of single-phase, polycrystalline, low roughness pyrite films can be achieved. This is illustrated for the test cases of the ferromagnetic metal CoS{sub 2} and the diamagnetic semiconductor FeS{sub 2}, for which detailed magnetic and transport characterization are provided. The results indicate significant improvements over alternative deposition techniques such as ex situ sulfidation of metal films, opening up exciting possibilities for all-sulfide heterostructured devices. In particular, in the FeS{sub 2} case it is suggested that fine-tuning of the sputtering conditions provides a potential means to manipulate doping levels and conduction mechanisms, critical issues in solar cell applications. Parenthetically, we note that conditions for synthesis of phase-pure monosulfides and thiospinels are also identified.

  11. Attempt to measure magnetic hyperfine fields in metallic thin wires under spin Hall conditions using synchrotron-radiation Mssbauer spectroscopy

    SciTech Connect (OSTI)

    Mibu, K. Tanaka, M. A.; Mitsui, T.; Masuda, R.; Kitao, S.; Kobayashi, Y.; Seto, M.; Yoda, Y.

    2015-05-07

    Measurement of the magnetic hyperfine fields in metallic thin wires under spin Hall conditions was attempted using the emerging technique, synchrotron-radiation Mssbauer spectroscopy. A Mssbauer probe layer of {sup 57}Fe (0.2?nm), {sup 57}Fe (0.6?nm), or {sup 119}Sn (0.6?nm) was embedded as an electron spin detector near the surfaces of V, Au, Pt, and {sup 56}Fe wires. The magnitudes of the magnetic hyperfine fields at the {sup 57}Fe and {sup 119}Sn nuclear sites that could be enhanced by non-equilibrium conduction-electron spin polarization were measured both without and with the application of an electric current along the wire. Changes in the Mssbauer spectra were not clearly observed, indicating that the magnetic hyperfine field induced by non-equilibrium spin polarization is smaller than the detection limit at least for the measured systems and conditions.

  12. Epitaxial Mn{sub 2.5}Ga thin films with giant perpendicular magnetic anisotropy for spintronic devices

    SciTech Connect (OSTI)

    Wu Feng; Mizukami, Shigemi; Watanabe, Daisuke; Miyazaki, Terunobu; Naganuma, Hiroshi; Oogane, Mikihiko; Ando, Yasuo

    2009-03-23

    We report on epitaxial growth and magnetic properties of Mn{sub 2.5}Ga thin films, which were deposited on Cr/MgO single crystal substrates by magnetron sputtering. X-ray diffraction results revealed the epitaxial relationships as Mn{sub 2.5}Ga(001)[100] parallel Cr(001)[110] parallel MgO(001)[100]. The presence of (002) and (011) superlattice peaks indicates that the films were crystallized into DO{sub 22} ordered structures. The perpendicular magnetic anisotropy (PMA) properties were found to be related to the extent of DO{sub 22} chemical ordering. A giant PMA (K{sub u}{sup eff}=1.2x10{sup 7} erg/cm{sup 3}) and low saturation magnetization (M{sub s}=250 emu/cm{sup 3}) can be obtained for the film with highest chemical ordering parameter (S=0.8)

  13. Microstructure and magnetic properties of FeCo epitaxial thin films grown on MgO single-crystal substrates

    SciTech Connect (OSTI)

    Shikada, Kouhei; Ohtake, Mitsuru; Futamoto, Masaaki; Kirino, Fumiyoshi

    2009-04-01

    FeCo epitaxial films were prepared on MgO(100), MgO(110), and MgO(111) substrates by ultrahigh vacuum molecular beam epitaxy. FeCo thin films with (100), (211), and (110) planes parallel to the substrate surface grow on respective MgO substrates. FeCo/MgO interface structures are studied by high-resolution cross-sectional transmission electron microscopy and the epitaxial growth mechanism is discussed. Atomically sharp boundaries are recognized between the FeCo thin films and the MgO substrates where misfit dislocations are introduced in the FeCo thin films presumably to decrease the lattice misfits. Misfit dislocations are observed approximately every 9 and 1.4 nm in FeCo thin film at the FeCo/MgO(100) and the FeCo/MgO(110) interfaces, respectively. X-ray diffraction analysis indicates that the lattice spacing measured parallel to the single-crystal substrate surfaces are in agreement within 0.1% with those of the respective bulk values of Fe{sub 50}Co{sub 50} alloy crystal, showing that the FeCo film strain is very small. The magnetic anisotropies of these epitaxial films basically reflect the magnetocrystalline anisotropy of bulk FeCo alloy crystal.

  14. The scattering of f- and p-modes from ensembles of thin magnetic flux tubes: an analytical approach

    SciTech Connect (OSTI)

    Hanson, Chris S.; Cally, Paul S.

    2014-08-20

    Motivated by the observational results of Braun, we extend the model of Hanson and Cally to address the effect of multiple scattering of f and p modes by an ensemble of thin vertical magnetic flux tubes in the surface layers of the Sun. As in the observational Hankel analysis, we measure the scatter and phase shift from an incident cylindrical wave in a coordinate system roughly centered in the core of the ensemble. It is demonstrated that although thin flux tubes are unable to interact with high-order fluting modes individually, they can indirectly absorb energy from these waves through the scatters of kink and sausage components. It is also shown how the distribution of absorption and phase shift across the azimuthal order m depends strongly on the tube position as well as on the individual tube characteristics. This is the first analytical study into an ensembles multiple-scattering regime that is embedded within a stratified atmosphere.

  15. Technique to quantitatively measure magnetic properties of thin structures at <10 NM spatial resolution

    DOE Patents [OSTI]

    Bajt, Sasa

    2003-07-08

    A highly sensitive and high resolution magnetic microscope images magnetic properties quantitatively. Imaging is done with a modified transmission electron microscope that allows imaging of the sample in a zero magnetic field. Two images from closely spaced planes, one in focus and one slightly out of focus, are sufficient to calculate the absolute values of the phase change imparted to the electrons, and hence obtain the magnetization vector field distribution.

  16. Influence of defects on the structural and magnetic properties of multifunctional La2NiMnO6 thin films

    SciTech Connect (OSTI)

    Guo, HZ; Burgess, J; Ada, E; Street, S; Gupta, A.; Iliev, M N; Kellock, A J; Magen Dominguez, Cesar; Varela del Arco, Maria; Pennycook, Stephen J

    2008-01-01

    Thin films of the double perovskite La2NiMnO6 (LNMO) have been grown on various lattice-matched substrates (SrTiO3, LaAlO3, NdGaO3 and MgO) by pulsed laser deposition under varying oxygen background pressure (25 - 800 mTorr). The out-of-plane lattice constant of the LNMO film initially decreases with increasing pressure, likely caused by a reduction in the defect concentration and improved structural ordering, before leveling off at higher pressures. Scanning transmission electron microscopy results show that the films are epitaxial, and the interface is sharp and coherent. While very few defects are observed by STEM in a film grown at high oxygen pressure (800 mTorr), a film grown at a lower pressure (100 mTorr) shows the formation of defects that extend throughout the thickness except for a very thin layer near the interface. The Raman spectra of the films are dominated by two broad peaks at around 540 cm-1 and 685 cm-1, which are assigned to the antisymmetric stretching (AS) and symmetric stretching (S) modes of MnO6 and NiO6 octahedra, respectively. The Raman peaks of the LNMO thin films grown in 800 mTorr background O2 are blue shifted in comparison to those of LNMO bulk, and the shift increases with decreasing film thickness, indicating the increased influence of strain. The critical thickness for strain relaxation as determined from the Raman spectra is between 40 - 80 nm. The strain is observed to have a negligible influence on the magnetic properties for films grown at high oxygen pressures. However, films grown at low pressures exhibit degraded magnetic properties, which can be attributed to a combination of B-site cation disorder and an increase in the concentration of Mn3+ and Ni3+ Jahn-Teller ions caused by oxygen defects. With increasing oxygen pressure during growth, the paramagnetic-ferromagnetic transition temperature (~280 K) gets sharper and the saturation magnetization at low temperatures is enhanced. Based on electron energy loss spectroscopy

  17. The high-efficiency jets magnetically accelerated from a thin disk in powerful lobe-dominated FRII radio galaxies

    SciTech Connect (OSTI)

    Li, Shuang-Liang

    2014-06-10

    A maximum jet efficiency line R ? 25 (R = L {sub jet}/L {sub bol}), found in FRII radio galaxies by Fernandes et al., was extended to cover the full range of jet power by Punsly. Recent general relativistic magnetohydrodynamic simulations of jet formation have mainly focused on the enhancement of jet power. In this work, we suggest that the jet efficiency could be very high even for conventional jet power if the radiative efficiency of disks was much smaller. We adopt the model of a thin disk with magnetically driven winds to investigate the observational high-efficiency jets in FRII radio galaxies. It is found that the structure of a thin disk can be significantly altered by the feedback of winds. The temperature of a disk gradually decreases with increasing magnetic field; the disk density, surface density, and pressure also change enormously. The lower temperature and higher surface density in the inner disk result in the rapid decrease of radiative efficiency. Thus, the jet efficiency is greatly improved even if the jet power is conventional. Our results can explain the observations quite well. The theoretical maximum jet efficiency of R ? 1000 suggested by our calculations is large enough to explain all of the high jet efficiency in observations, even considering the episodic activity of jets.

  18. Change in the magnetic structure of (Bi,Sm)FeO{sub 3} thin films at the morphotropic phase boundary probed by neutron diffraction

    SciTech Connect (OSTI)

    Maruyama, Shingo; Anbusathaiah, Varatharajan; Takeuchi, Ichiro; Fennell, Amy; Enderle, Mechthild; Ratcliff, William D.

    2014-11-01

    We report on the evolution of the magnetic structure of BiFeO{sub 3} thin films grown on SrTiO{sub 3} substrates as a function of Sm doping. We determined the magnetic structure using neutron diffraction. We found that as Sm increases, the magnetic structure evolves from a cycloid to a G-type antiferromagnet at the morphotropic phase boundary, where there is a large piezoelectric response due to an electric-field induced structural transition. The occurrence of the magnetic structural transition at the morphotropic phase boundary offers another route towards room temperature multiferroic devices.

  19. FePtCu alloy thin films: Morphology, L1{sub 0} chemical ordering, and perpendicular magnetic anisotropy

    SciTech Connect (OSTI)

    Brombacher, C.; Schletter, H.; Daniel, M.; Matthes, P.; Joehrmann, N.; Makarov, D.; Hietschold, M.; Albrecht, M.; Maret, M.

    2012-10-01

    Rapid thermal annealing was applied to transform sputter-deposited Fe{sub 51}Pt{sub 49}/Cu bilayers into L1{sub 0} chemically ordered ternary (Fe{sub 51}Pt{sub 49}){sub 100-x}Cu{sub x} alloys with (001) texture on amorphous SiO{sub 2}/Si substrates. It was found that for thin film samples, which were processed at 600 Degree-Sign C for 30 s, the addition of Cu strongly favors the L1{sub 0} ordering and (001) texture formation. Furthermore, it could be revealed by transmission electron microscopy and electron backscatter diffraction that the observed reduction of the ordering temperature with Cu content is accompanied by an increased amount of nucleation sites forming L1{sub 0} ordered grains. The change of the structural properties with Cu content and annealing temperature is closely related to the magnetic properties. While an annealing temperature of 800 Degree-Sign C induces strong perpendicular magnetic anisotropy (PMA) in binary Fe{sub 51}Pt{sub 49} films, the addition of Cu systematically reduces the PMA. However, due to the enhancement of both the A1-L1{sub 0} phase transformation and the development of the (001) texture with increasing Cu content, lowering of the annealing temperature leads to a shift of the maximum perpendicular magnetic anisotropy towards alloys with higher Cu content. Thus, for an annealing temperature of 600 Degree-Sign C, the highest perpendicular magnetic anisotropy energy is found for the (Fe{sub 51}Pt{sub 49}){sub 91}Cu{sub 9} alloy. The smooth surface morphology, adjustable PMA, and high degree of intergranular exchange coupling make these films suitable for post-processing required for specific applications such as for sensorics or magnetic data storage.

  20. Imaging magnetic domain structure in sub-500 nm thin film elements

    SciTech Connect (OSTI)

    Kirk, K. J.; McVitie, S.; Chapman, J. N.; Wilkinson, C. D. W.

    2001-06-01

    Magnetic imaging in the transmission electron microscope (TEM) has been used to examine submicron elements with the aim of discovering down to what element size complex domain patterns can form. The elements were squares, circles, triangles, and pentagons in the size range 100{endash}500 nm and were made from 36 nm Co films or 8 nm Ni{sub 80}Fe{sub 20} (NiFe) with in-plane magnetization. The magnetic domain structures in these elements were imaged at high resolution using the differential phase contrast imaging mode in a TEM. Nonuniform magnetization structures were seen in the images. Vortices were present at remanence in all shapes of 36-nm-thick Co elements down to 100 nm size and in circular NiFe elements down to 116 nm diameter. Triangular NiFe elements did not have a vortex state at remanence, instead the magnetization curved round within the element but did not achieve complete flux closure. In simulations of square and circular NiFe elements, it was found that defects at the edges of the elements encouraged reversal by a vortex mechanism, whereas for simulated elements with no defects, reversal was by rotation and occurred at much lower fields. {copyright} 2001 American Institute of Physics.

  1. Structural and magnetic properties of magnetron sputtered Ni-Mn-Sn ferromagnetic shape memory alloy thin films

    SciTech Connect (OSTI)

    Vishnoi, Ritu; Kaur, Davinder

    2010-05-15

    In the present study, structural and magnetic properties of Mn-rich, off-stoichiometric, nanocrystalline Ni-Mn-Sn ferromagnetic shape memory alloy thin films, grown on Si (100) substrates at 550 deg. C by dc magnetron sputtering have been systematically investigated. The crystallization, surface morphology, and structural features were studied using x-ray diffraction, atomic force microscopy, and field emission scanning electron microscopy. The structural transition from austenite to martensite was observed with an increase of Mn content. Austenitic phase with mixed L2{sub 1}/A2+B2 structure has been observed at room temperature in Ni{sub 52.6}Mn{sub 23.7}Sn{sub 23.6} (S{sub 1}) and Ni{sub 51.5}Mn{sub 26.1}Sn{sub 22.2} (S{sub 2}) films, while those with composition of Ni{sub 58.9}Mn{sub 28.0}Sn{sub 13.0} (S{sub 3}) and Ni{sub 58.3}Mn{sub 29.0}Sn{sub 12.6} (S{sub 4}) show martensitic phase with 14M modulated monoclinic structures. Field induced martensite-austenite transformation has been observed in magnetization studies using superconducting quantum interference device magnetometer. Temperature dependent magnetization measurements demonstrate the influence of magnetic field on the structural phase transition temperature. The investigations reveal an increase of martensitic transformation temperature (T{sub M}) with corresponding increase in substitution of Mn. The films exhibit ferromagnetic behavior at low temperatures below Curie temperature (T{sub C}). The decrease in saturation moment with increasing Mn content, indicates the existence of antiferromagnetic correlations within ferromagnetic matrix.

  2. Electric and magnetic behaviors observed in NiO-based thin films under light-irradiation

    SciTech Connect (OSTI)

    Luo, Yi-Dong; Song, Kenan; Shun, Li; Gao, Junqi; Xu, Ben, E-mail: xuben@mail.tsinghua.edu.cn, E-mail: linyh@mail.tsinghua.edu.cn; Lin, Yuan-Hua, E-mail: xuben@mail.tsinghua.edu.cn, E-mail: linyh@mail.tsinghua.edu.cn; Nan, Ce-Wen; Liu, Wei [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2014-09-07

    We report the room-temperature ferromagnetic properties that can be tuned by light irradiation in the Li and Mn co-doped NiO films (LMNO) grown by the spinning coating. The optical tunable magnetic behavior is enhanced by the increase of the Li doping concentration. First-principle calculations reveal that the Li doping plays key roles in the optical tuned magnetic behavior, which brings a 3d-like impurity state to enhance a significant hybridization between the Mn{sup 3+} 3d state and the impurity band, thus strengthening the ferromagnetic coupling effects. Additionally, it can tune the band gap of the LMNO films and produce more holes under the light irradiation, enhancing the optical tuned magnetic behavior.

  3. Ferromagnetism of magnetically doped topological insulators in Cr{sub x}Bi{sub 2−x}Te{sub 3} thin films

    SciTech Connect (OSTI)

    Ni, Y.; Zhang, Z. Hadimani, R. L.; Tuttle, G.; Jiles, D. C.; Nlebedim, I. C.

    2015-05-07

    We investigated the effect of magnetic doping on magnetic and transport properties of Bi{sub 2}Te{sub 3} thin films. Cr{sub x}Bi{sub 2−x}Te{sub 3} thin films with x = 0.03, 0.14, and 0.29 were grown epitaxially on mica substrate with low surface roughness (∼0.4 nm). It is found that Cr is an electron acceptor in Bi{sub 2}Te{sub 3} and increases the magnetization of Cr{sub x}Bi{sub 2−x}Te{sub 3}. When x = 0.14 and 0.29, ferromagnetism appears in Cr{sub x}Bi{sub 2−x}Te{sub 3} thin films, where anomalous Hall effect and weak localization of magnetoconductance were observed. The Curie temperature, coercivity, and remnant Hall resistance of thin films increase with increasing Cr concentration. The Arrott-Noakes plot demonstrates that the critical mechanism of the ferromagnetism can be described better with 3D-Heisenberg model than with mean field model. Our work may benefit for the practical applications of magnetic topological insulators in spintronics and magnetoelectric devices.

  4. Process For Direct Integration Of A Thin-Film Silicon P-N Junction Diode With A Magnetic Tunnel Junction

    DOE Patents [OSTI]

    Toet, Daniel; Sigmon, Thomas W.

    2005-08-23

    A process for direct integration of a thin-film silicon p-n junction diode with a magnetic tunnel junction for use in advanced magnetic random access memory (MRAM) cells for high performance, non-volatile memory arrays. The process is based on pulsed laser processing for the fabrication of vertical polycrystalline silicon electronic device structures, in particular p-n junction diodes, on films of metals deposited onto low temperature-substrates such as ceramics, dielectrics, glass, or polymers. The process preserves underlayers and structures onto which the devices are typically deposited, such as silicon integrated circuits. The process involves the low temperature deposition of at least one layer of silicon, either in an amorphous or a polycrystalline phase on a metal layer. Dopants may be introduced in the silicon film during or after deposition. The film is then irradiated with short pulse laser energy that is efficiently absorbed in the silicon, which results in the crystallization of the film and simultaneously in the activation of the dopants via ultrafast melting and solidification. The silicon film can be patterned either before or after crystallization.

  5. Process for direct integration of a thin-film silicon p-n junction diode with a magnetic tunnel junction

    DOE Patents [OSTI]

    Toet, Daniel; Sigmon, Thomas W.

    2003-01-01

    A process for direct integration of a thin-film silicon p-n junction diode with a magnetic tunnel junction for use in advanced magnetic random access memory (MRAM) cells for high performance, non-volatile memory arrays. The process is based on pulsed laser processing for the fabrication of vertical polycrystalline silicon electronic device structures, in particular p-n junction diodes, on films of metals deposited onto low temperature-substrates such as ceramics, dielectrics, glass, or polymers. The process preserves underlayers and structures onto which the devices are typically deposited, such as silicon integrated circuits. The process involves the low temperature deposition of at least one layer of silicon, either in an amorphous or a polycrystalline phase on a metal layer. Dopants may be introduced in the silicon film during or after deposition. The film is then irradiated with short pulse laser energy that is efficiently absorbed in the silicon, which results in the crystallization of the film and simultaneously in the activation of the dopants via ultrafast melting and solidification. The silicon film can be patterned either before or after crystallization.

  6. Process for direct integration of a thin-film silicon p-n junction diode with a magnetic tunnel junction

    DOE Patents [OSTI]

    Toet, Daniel; Sigmon, Thomas W.

    2004-12-07

    A process for direct integration of a thin-film silicon p-n junction diode with a magnetic tunnel junction for use in advanced magnetic random access memory (MRAM) cells for high performance, non-volatile memory arrays. The process is based on pulsed laser processing for the fabrication of vertical polycrystalline silicon electronic device structures, in particular p-n junction diodes, on films of metals deposited onto low temperature-substrates such as ceramics, dielectrics, glass, or polymers. The process preserves underlayers and structures onto which the devices are typically deposited, such as silicon integrated circuits. The process involves the low temperature deposition of at least one layer of silicon, either in an amorphous or a polycrystalline phase on a metal layer. Dopants may be introduced in the silicon film during or after deposition. The film is then irradiated with short pulse laser energy that is efficiently absorbed in the silicon, which results in the crystallization of the film and simultaneously in the activation of the dopants via ultrafast melting and solidification. The silicon film can be patterned either before or after crystallization.

  7. Anisotropy of electrical and magnetic transport properties of epitaxial SrRuO{sub 3} thin films

    SciTech Connect (OSTI)

    Ning, X. K.; Wang, Z. J. Zhang, Z. D.

    2015-03-07

    SrRuO{sub 3} (SRO) thin films with different thickness (2–70 nm) have been grown on (001), (110), and (111) SrTiO{sub 3} substrates. The (001)-SRO films (2–8 nm) exhibited smooth flat surfaces whereas the (110)- and (111)-SRO films featured a faceted island structure. Room temperature resistivity and residual resistivity are the lowest for the (111)-SRO films (30–70 nm). Over all thicknesses, we observed enhanced magnetization in the (111)-SRO films (∼4 μ{sub B}/Ru) compared with that for the (001)- and (110)-SRO films (∼2 μ{sub B}/Ru and ∼3 μ{sub B}/Ru, respectively), suggesting a low-spin state t{sub 2g}(3↑,1↓), high-spin state t{sub 2g}(3↑)e{sub g}(1↑), and mixed low- and high-spin states for the (001)-, (111)-, and (110)-SRO films, respectively. The dependence of resistivity on temperatures near T{sub C} follows a power law with exponent β = 0.312 and β = 0.363 for the (110)- and (111)-SRO films, respectively. These critical exponents are consistent with magnetic data with scaling law M = C (T{sub C} − T){sup β}. At low temperatures, dM/dT and dρ/dT show a linear relationship in the temperature range for the Fermi liquid. These results suggest that the intrinsic electrical and magnetic transport properties are coupled.

  8. Structural, magnetic, and transport properties of sputtered hexagonal MnNiGa thin films

    SciTech Connect (OSTI)

    Li, Yueqing; Liu, E. K.; Wu, G. H.; Wang, Wenhong; Liu, Zhongyuan

    2014-12-14

    We report on a systematical study of the structure, magnetism, and magnetotransport behavior of the hexagonal MnNiGa films deposited on thermally oxidized Si (001) substrates by magnetron sputtering. X-ray diffractions reveal that all the films deposited at different temperatures crystallized in hexagonal Ni{sub 2}In-type structure (space group P6{sub 3}/mmc). Scanning electron microscopy observations show that the surface morphology of the films varies with deposition temperature, and energy dispersive spectroscopy analysis shows compositions of the films remain nearly unchanged, independent of the deposition temperature. Magnetic measurements indicate that all films are ferromagnetic and exhibit a magnetic anisotropy behavior. The magnetoresistance (MR) exhibits a negative temperature- and field-dependent behavior. The possible origin of the negative MR is discussed. Furthermore, we found that the Hall effect is dominated by an anomalous Hall effect (AHE) only due to skew scattering independent of the deposition temperature of films. Moreover, the anomalous Hall resistivity presents a non-monotonously temperature-dependent behavior.

  9. Evidence of martensitic phase transitions in magnetic Ni-Mn-In thin films

    SciTech Connect (OSTI)

    Sokolov, A.; Zhang, Le; Dubenko, I.; Samanta, T.; Ali, N.; Stadler, S.

    2013-02-18

    Ni{sub 50}Mn{sub 35}In{sub 15} Heusler alloy thin films (with thicknesses of about 10 nm) have been grown on single crystal MgO and SrTiO{sub 3} (STO) (100) substrates using a laser-assisted molecular beam epitaxy method. Films of mixed austenitic and martensitic phases and of pure martensitic phase have been detected for those grown on MgO and STO substrates, respectively. Thermomagnetic curves were measured using a SQUID magnetometer and are consistent with those of off-stoichiometric In-based bulk Heusler alloys, including a martensitic transition at T = 315 K for films grown on MgO. The differences in the properties of the films grown on MgO and STO are discussed.

  10. Mechanism of tailored magnetic anisotropy in amorphous Co{sub 68}Fe{sub 24}Zr{sub 8} thin films

    SciTech Connect (OSTI)

    Fu, Yu E-mail: cangcangzhulin@gmail.com; Meckenstock, R.; Farle, M.; Barsukov, I.; Lindner, J.; Raanaei, H.; Hjörvarsson, B.

    2014-02-17

    The mechanism of tailored magnetic anisotropy in amorphous Co{sub 68}Fe{sub 24}Zr{sub 8} thin films was investigated by ferromagnetic resonance (FMR) on samples deposited without an applied magnetic field, with an out-of-plane field and an in-plane field. Analysis of FMR spectra profiles, high frequency susceptibility calculations, and statistical simulations using a distribution of local uniaxial magnetic anisotropy reveal the presence of atomic configurations with local uniaxial anisotropy, of which the direction can be tailored while the magnitude remains at an intrinsically constant value of 3.0(2) kJ/m{sup 3}. The in-plane growth field remarkably sharpens the anisotropy distribution and increases the sample homogeneity. The results benefit designing multilayer spintronic devices based on highly homogeneous amorphous layers with tailored magnetic anisotropy.

  11. Magnetic properties of in-plane oriented barium hexaferrite thin films prepared by direct current magnetron sputtering

    SciTech Connect (OSTI)

    Zhang, Xiaozhi; Yue, Zhenxing Meng, Siqin; Yuan, Lixin

    2014-12-28

    In-plane c-axis oriented Ba-hexaferrite (BaM) thin films were prepared on a-plane (112{sup }0) sapphire (Al{sub 2}O{sub 3}) substrates by DC magnetron sputtering followed by ex-situ annealing. The DC magnetron sputtering was demonstrated to have obvious advantages over the traditionally used RF magnetron sputtering in sputtering rate and operation simplicity. The sputtering power had a remarkable influence on the Ba/Fe ratio, the hematite secondary phase, and the grain morphology of the as-prepared BaM films. Under 80?W of sputtering power, in-plane c-axis highly oriented BaM films were obtained. These films had strong magnetic anisotropy with high hysteresis loop squareness (M{sub r}/M{sub s} of 0.96) along the in-plane easy axis and low M{sub r}/M{sub s} of 0.03 along the in-plane hard axis. X-ray diffraction patterns and pole figures revealed that the oriented BaM films grew via an epitaxy-like growth process with the crystallographic relationship BaM (101{sup }0)//?-Fe{sub 2}O{sub 3}(112{sup }0)//Al{sub 2}O{sub 3}(112{sup }0)

  12. Strain relaxation and enhanced perpendicular magnetic anisotropy in BiFeO{sub 3}:CoFe{sub 2}O{sub 4} vertically aligned nanocomposite thin films

    SciTech Connect (OSTI)

    Zhang, Wenrui; Jiao, Liang; Li, Leigang; Jian, Jie; Khatkhatay, Fauzia; Chu, Frank; Chen, Aiping; Jia, Quanxi; MacManus-Driscoll, Judith L.; Wang, Haiyan

    2014-02-10

    Self-assembled BiFeO{sub 3}:CoFe{sub 2}O{sub 4} (BFO:CFO) vertically aligned nanocomposite thin films have been fabricated on SrTiO{sub 3} (001) substrates using pulsed laser deposition. The strain relaxation mechanism between BFO and CFO with a large lattice mismatch has been studied by X-ray diffraction and transmission electron microscopy. The as-prepared nanocomposite films exhibit enhanced perpendicular magnetic anisotropy as the BFO composition increases. Different anisotropy sources have been investigated, suggesting that spin-flop coupling between antiferromagnetic BFO and ferrimagnetic CFO plays a dominant role in enhancing the uniaxial magnetic anisotropy.

  13. Multi-jump magnetic switching in ion-beam sputtered amorphous Co{sub 20}Fe{sub 60}B{sub 20} thin films

    SciTech Connect (OSTI)

    Raju, M.; Chaudhary, Sujeet; Pandya, D. K.

    2013-08-07

    Unconventional multi-jump magnetization reversal and significant in-plane uniaxial magnetic anisotropy (UMA) in the ion-beam sputtered amorphous Co{sub 20}Fe{sub 60}B{sub 20}(5–75 nm) thin films grown on Si/amorphous SiO{sub 2} are reported. While such multi-jump behavior is observed in CoFeB(10 nm) film when the magnetic field is applied at 10°–20° away from the easy-axis, the same is observed in CoFeB(12.5 nm) film when the magnetic field is 45°–55° away from easy-axis. Unlike the previous reports of multi-jump switching in epitaxial films, their observance in the present case of amorphous CoFeB is remarkable. This multi-jump switching is found to disappear when the films are crystallized by annealing at 420 °C. The deposition geometry and the energy of the sputtered species appear to intrinsically induce a kind of bond orientation anisotropy in the films, which leads to the UMA in the as-grown amorphous CoFeB films. Exploitation of such multi-jump switching in amorphous CoFeB thin films could be of technological significance because of their applications in spintronic devices.

  14. The role of cobalt doping on magnetic and optical properties of indium oxide nanostructured thin film prepared by sol–gel method

    SciTech Connect (OSTI)

    Baqiah, H.; Ibrahim, N.B.; Halim, S.A.; Flaifel, Moayad Husein; Abdi, M.H.

    2015-03-15

    Highlights: • Cobalt doped indium oxide thin films have been prepared by a sol–gel method. • The films have a thickness less than 100 nm and grain size less than 10 nm. • The lattice parameters and grain size of films decrease as Co content increase. • The optical band gap of films increases as the grain size decrease. • The films' magnetic behaviour is sensitive to ratio of oxygen defects per Co ions. - Abstract: The effect of Co doping concentration, (x = 0.025–0.2), in In{sub 2−x}Co{sub x}O{sub 3} thin film was investigated by X-rays diffraction (XRD), transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), Ultraviolet visible spectrophotometer (UV–vis) and vibrating sample magnetometer (VSM). All films were prepared by sol–gel technique followed by spin coating process. The XRD and XPS measurements indicate that Co{sup +2} has been successfully substituted in In{sup +3} site. The TEM measurement shows nanostructure morphology of the films. The doping of Co in indium oxide resulted in a decrease in the lattice parameters and grain size while the band gap increased with increasing Co concentration. Further, by comparing VSM and XPS results, the magnetic behaviour of the films were found to be sensitive to Co concentrations, oxygen vacancies and ratio of oxygen defects to Co concentrations. The magnetic behaviour of the prepared films was explained using bound magnetic polaron (BMP) model.

  15. Magnetic structures of FeTiO{sub 3}-Fe{sub 2}O{sub 3} solid solution thin films studied by soft X-ray magnetic circular dichroism and ab initio multiplet calculations

    SciTech Connect (OSTI)

    Hojo, H. E-mail: fujita@dipole7.kuic.kyoto-u.ac.jp; Fujita, K. E-mail: fujita@dipole7.kuic.kyoto-u.ac.jp; Matoba, T.; Tanaka, K.; Ikeno, H.; Mizoguchi, T.; Tanaka, I.; Nakamura, T.; Takeda, Y.; Okane, T.

    2014-03-17

    The solid solutions between ilmenite (FeTiO{sub 3}) and hematite (α-Fe{sub 2}O{sub 3}) have recently attracted considerable attention as a spintronic material due to their interesting magnetic and electrical properties. In this study, the electronic and magnetic structures of epitaxially grown 0.6FeTiO{sub 3}·0.4Fe{sub 2}O{sub 3} solid solution thin films were investigated by combining x-ray absorption near-edge structure (XANES), x-ray magnetic circular dichroism (XMCD) for two different crystallographic projections, and first-principles theoretical calculations. The Fe L-edge XANES and XMCD spectra reveal that Fe is in the mixed-valent Fe{sup 2+}–Fe{sup 3+} states while Fe{sup 2+} ions are mainly responsible for the magnetization. Moreover, the experimental Fe L-edge XANES and XMCD spectra change depending on the incident x-ray directions, and the theoretical spectra explain such spectral features. We also find a large orbital magnetic moment, which can originate the magnetic anisotropy of this system. On the other hand, although the valence state of Ti was interpreted to be 4+ from the Ti L-edge XANES, XMCD signals indicate that some electrons are present in the Ti-3d orbital, which are coupled antiparallel to the magnetic moment of Fe{sup 2+} ions.

  16. Imaging the magnetic nanodomains in Nd2Fe14B

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Huang, Lunan; Taufour, Valentin; Lamichhane, T. N.; Schrunk, Benjamin; Bud'ko, Sergei L.; Canfield, P. C.; Kaminski, Adam

    2016-03-08

    Here, we study magnetic domains in Nd2Fe14B single crystals using high resolution magnetic force microscopy (MFM). Previous MFM studies and small angle neutron scattering experiments suggested the presence of nanoscale domains in addition to optically detected micrometer-scale ones. We find, in addition to the elongated, wavy nanodomains reported by a previous MFM study, that the micrometer-sized, star-shaped fractal pattern is constructed of an elongated network of nanodomains ~20 nm in width, with resolution-limited domain walls thinner than 2 nm. While the microscopic domains exhibit significant resilience to an external magnetic field, some of the nanodomains are sensitive to the magneticmore » field of the MFM tip.« less

  17. Nanodomain induced anomalous magnetic and electronic transport properties of LaBaCo{sub 2}O{sub 5.5+?} highly epitaxial thin films

    SciTech Connect (OSTI)

    Ruiz-Zepeda, F.; Ma, C.; Bahena Uribe, D.; Cantu-Valle, J.; Wang, H.; Xu, Xing; Yacaman, M. J.; Ponce, A.; Chen, C.; Lorenz, B.; Jacobson, A. J.; Chu, P. C. W.

    2014-01-14

    A giant magnetoresistance effect (?46% at 20?K under 7?T) and anomalous magnetic properties were found in a highly epitaxial double perovskite LaBaCo{sub 2}O{sub 5.5+?} (LBCO) thin film on (001) MgO. Aberration-corrected Electron Microscopy and related analytical techniques were employed to understand the nature of these unusual physical properties. The as-grown film is epitaxial with the c-axis of the LBCO structure lying in the film plane and with an interface relationship given by (100){sub LBCO} || (001){sub MgO} and [001]{sub LBCO} || [100]{sub MgO} or [010]{sub MgO}. Orderly oxygen vacancies were observed by line profile electron energy loss spectroscopy and by atomic resolution imaging. Especially, oxygen vacancy and nanodomain structures were found to have a crucial effect on the electronic transport and magnetic properties.

  18. Structural, magnetic, and electronic properties of GdTiO{sub 3} Mott insulator thin films grown by pulsed laser deposition

    SciTech Connect (OSTI)

    Grisolia, M. N.; Bruno, F. Y.; Sando, D.; Jacquet, E.; Barthlmy, A.; Bibes, M.; Zhao, H. J.; Chen, X. M.; Bellaiche, L.

    2014-10-27

    We report on the optimization process to synthesize epitaxial thin films of GdTiO{sub 3} on SrLaGaO{sub 4} substrates by pulsed laser deposition. Optimized films are free of impurity phases and are fully strained. They possess a magnetic Curie temperature T{sub C}?=?31.8?K with a saturation magnetization of 4.2??{sub B} per formula unit at 10?K. Transport measurements reveal an insulating response, as expected. Optical spectroscopy indicates a band gap of ?0.7?eV, comparable to the bulk value. Our work adds ferrimagnetic orthotitanates to the palette of perovskite materials for the design of emergent strongly correlated states at oxide interfaces using a versatile growth technique such as pulsed laser deposition.

  19. Influence of Mn concentration on magnetic topological insulator MnxBi2−xTe3 thin-film Hall-effect sensor

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ni, Y.; Zhang, Z.; Nlebedim, I. C.; Hadimani, R. L.; Jiles, D. C.

    2015-06-11

    Hall-effect (HE) sensors based on high-quality Mn-doped Bi2Te3 topological insulator (TI) thin films have been systematically studied in this paper. Improvement of Hall sensitivity is found after doping the magnetic element Mn into Bi2Te3. The sensors with low Mn concentrations, MnxBi2-xTe3, x = 0.01 and 0.08 show the linear behavior of Hall resistance with sensitivity about 5 Ω/T. And their Hall sensitivity shows weak dependence on temperature. For sensors with high Mn concentration (x = 0.23), the Hall resistance with respect to magnetic field shows a hysteretic behavior. Moreover, its sensitivity shows almost eight times as high as that ofmore »the HE sensors with low Mn concentration. The highest sensitivity can reach 43 Ω/T at very low magnetic field. This increase of Hall sensitivity is caused by the occurrence of anomalous HE (AHE) after ferromagnetic phase transition. Our work indicates that the magnetic-element-doped TIs with AHE are good candidates for HE sensors.« less

  20. Influence of Mn concentration on magnetic topological insulator MnxBi2−xTe3 thin-film Hall-effect sensor

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ni, Y.; Zhang, Z.; Nlebedim, I. C.; Hadimani, R. L.; Jiles, D. C.

    2015-06-11

    Hall-effect (HE) sensors based on high-quality Mn-doped Bi2Te3 topological insulator (TI) thin films have been systematically studied in this paper. Improvement of Hall sensitivity is found after doping the magnetic element Mn into Bi2Te3. The sensors with low Mn concentrations, MnxBi2-xTe3, x = 0.01 and 0.08 show the linear behavior of Hall resistance with sensitivity about 5 Ω/T. And their Hall sensitivity shows weak dependence on temperature. For sensors with high Mn concentration (x = 0.23), the Hall resistance with respect to magnetic field shows a hysteretic behavior. Moreover, its sensitivity shows almost eight times as high as that ofmore » the HE sensors with low Mn concentration. The highest sensitivity can reach 43 Ω/T at very low magnetic field. This increase of Hall sensitivity is caused by the occurrence of anomalous HE (AHE) after ferromagnetic phase transition. Our work indicates that the magnetic-element-doped TIs with AHE are good candidates for HE sensors.« less

  1. Electronic and magnetic properties of manganite thin films with different compositions and its correlation with transport properties: An X-ray resonant magnetic scattering study

    SciTech Connect (OSTI)

    Singh, Surendra; Freeland, J. W.; Fitzsimmons, M. R.; Jeen, H.; Biswas, A.

    2014-12-14

    Here, we present x-ray resonant magnetic dichroism and x-ray resonant magnetic scattering measurements of the temperature dependence of magnetism in Pr-doped La-Ca-Mn-O films grown on (110) NdGaO{sub 3} substrates. We observed thermal hysteresis of the ferromagnetism in one film that also showed large thermal hysteresis of ?18?K in transport measurements. While in a second film of a different nominal chemistry, which showed very small thermal hysteresis ?3?K in transport measurements, no thermal hysteresis of the ferromagnetism was observed. These macroscopic properties are correlated with evolution of surface magnetization across metal insulator transition for these films as observed by soft x-ray resonant magnetic scattering measurements.

  2. Electronic and magnetic properties of manganite thin films with different compositions and its correlation with transport properties: An X-ray resonant magnetic scattering study

    SciTech Connect (OSTI)

    Singh, Surendra; Freeland, J. W.; Fitzsimmons, M. R.; Jeen, H.; Biswas, A.

    2014-12-08

    Here, we present x-ray resonant magnetic dichroism and x-ray resonant magnetic scattering measurements of the temperature dependence of magnetism in Pr-doped La-Ca-Mn-O films grown on (110) NdGaO3 substrates. We observed thermal hysteresis of the ferromagnetism in one film that also showed large thermal hysteresis of ~18K in transport measurements. While in a second film of a different nominal chemistry, which showed very small thermal hysteresis ~3K in transport measurements, no thermal hysteresis of the ferromagnetism was observed. As a result, these macroscopic properties are correlated with evolution of surface magnetization across metal insulator transition for these films as observed by soft x-ray resonant magnetic scattering measurements.

  3. Electronic and magnetic properties of manganite thin films with different compositions and its correlation with transport properties: An X-ray resonant magnetic scattering study

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Singh, Surendra; Freeland, J. W.; Fitzsimmons, M. R.; Jeen, H.; Biswas, A.

    2014-12-08

    Here, we present x-ray resonant magnetic dichroism and x-ray resonant magnetic scattering measurements of the temperature dependence of magnetism in Pr-doped La-Ca-Mn-O films grown on (110) NdGaO3 substrates. We observed thermal hysteresis of the ferromagnetism in one film that also showed large thermal hysteresis of ~18K in transport measurements. While in a second film of a different nominal chemistry, which showed very small thermal hysteresis ~3K in transport measurements, no thermal hysteresis of the ferromagnetism was observed. As a result, these macroscopic properties are correlated with evolution of surface magnetization across metal insulator transition for these films as observed bymore » soft x-ray resonant magnetic scattering measurements.« less

  4. Passive micromechanical tags. An investigation into writing information at nanometer resolution on micrometer size objects

    SciTech Connect (OSTI)

    Schmieder, R.W.; Bastasz, R.J.

    1995-01-01

    The authors have completed a 3-year study of the technology related to the development of micron-sized passive micromechanical tags. The project was motivated by the discovery in 1990 by the present authors that low energy, high charge state ions (e.g., Xe{sup +44}) can produce nanometer-size damage sites on solid surfaces, and the realization that a pattern of these sites represents information. It was envisioned that extremely small, chemically inert, mechanical tags carrying a large label could be fabricated for a variety of applications, including tracking of controlled substances, document verification, process control, research, and engineering. Potential applications exist in the data storage, chemical, food, security, and other industries. The goals of this project were fully accomplished, and they are fully documented here. The work was both experimental and developmental. Most of the experimental effort was a search for appropriate tag materials. Several good materials were found, and the upper limits of information density were determined (ca. 10{sup 12} bit/cm{sup 2}). Most of the developmental work involved inventing systems and strategies for using these tags, and compiling available technologies for implementing them. The technology provided herein is application-specific: first, the application must be specified, then the tag can be developed for it. The project was not intended to develop a single tag for a single application or for all possible applications. Rather, it was meant to provide the enabling technology for fabricating tags for a range of applications. The results of this project provide sufficient information to proceed directly with such development.

  5. X-ray magnetic spectroscopy of MBE-grown Mn-doped Bi{sub 2}Se{sub 3} thin films

    SciTech Connect (OSTI)

    Collins-McIntyre, L. J.; Watson, M. D.; Zhang, S. L.; Coldea, A. I.; Hesjedal, T.; Baker, A. A.; Harrison, S. E.; Pushp, A.; Kellock, A. J.; Parkin, S. S. P.; Laan, G. van der

    2014-12-15

    We report the growth of Mn-doped Bi{sub 2}Se{sub 3} thin films by molecular beam epitaxy (MBE), investigated by x-ray diffraction (XRD), atomic force microscopy (AFM), SQUID magnetometry and x-ray magnetic circular dichroism (XMCD). Epitaxial films were deposited on c-plane sapphire substrates by co-evaporation. The films exhibit a spiral growth mechanism typical of this material class, as revealed by AFM. The XRD measurements demonstrate a good crystalline structure which is retained upon doping up to ?7.5 atomic-% Mn, determined by Rutherford backscattering spectrometry (RBS), and show no evidence of the formation of parasitic phases. However an increasing interstitial incorporation of Mn is observed with increasing doping concentration. A magnetic moment of 5.1 ?{sub B}/Mn is obtained from bulk-sensitive SQUID measurements, and a much lower moment of 1.6 ?{sub B}/Mn from surface-sensitive XMCD. At ?2.5 K, XMCD at the Mn L{sub 2,3} edge, reveals short-range magnetic order in the films and indicates ferromagnetic order below 1.5 K.

  6. Pauli-limited effect in the magnetic phase diagram of FeSe{sub x}Te{sub 1−x} thin films

    SciTech Connect (OSTI)

    Zhuang, J. C.; Li, Z.; Xu, X.; Wang, L.; Yeoh, W. K.; Wang, X. L.; Du, Y. E-mail: zxshi@seu.edu.cn Dou, S. X. E-mail: zxshi@seu.edu.cn; Xing, X. Z.; Shi, Z. X. E-mail: zxshi@seu.edu.cn

    2015-11-30

    We present a detailed investigation on the doping dependence of the upper critical field H{sub c2}(T) of FeSe{sub x}Te{sub 1−x} thin films (0.18 ≤ x ≤ 0.90) by measuring the electrical resistivity as a function of magnetic field. The H{sub c2}(T) curves exhibit a downturn behavior with decreasing temperature in all the samples, owing to the Pauli-limited effect (spin paramagnetic effect). The Pauli-limited effect on the upper critical field can be monotonically modulated by variation of the Se/Te composition. Our results show that Te-doping induced disorder and excess Fe atoms give rise to enhancement of the Pauli-limited effect.

  7. The effect of strain induced by Ag underlayer on saturation magnetization of partially ordered Fe{sub 16}N{sub 2} thin films

    SciTech Connect (OSTI)

    Yang, Meiyin; Department of Electrical and Computer Engineering, The Center for Micromagnetics and Information Technologies , University of Minnesota, 200 Union St SE, Minneapolis, Minnesota 55455 ; Allard, Lawrence F.; Ji, Nian; Zhang, Xiaowei; Wang, Jian-Ping; Yu, Guang-Hua

    2013-12-09

    Partially ordered Fe-N thin films were grown by a facing target sputtering process on the surface of a (001) Ag underlayer on MgO substrates. It was confirmed by x-ray diffraction that the Ag layer enlarged the in-plane lattice of the Fe-N thin films. Domains of the ordered α″-Fe{sub 16}N{sub 2} phase within an epitaxial (001) α′-Fe{sub x}N phase were identified by electron diffraction and high-resolution aberration-corrected scanning transmission electron microscopy (STEM) methods. STEM dark-field and bright-field images showed the fully ordered structure of the α″-Fe{sub 16}N{sub 2} at the atomic column level. High saturation magnetization(Ms) of 1890 emu/cc was obtained for α″-Fe{sub 16}N{sub 2} on the Ag underlayer, while only 1500 emu/cc was measured for Fe-N on the Fe underlayer. The results are likely due to a tensile strain induced in the α″-Fe{sub 16}N{sub 2} phase by the Ag structure at the interface.

  8. Epitaxial Ni{sub 3}FeN thin films: A candidate for spintronic devices and magnetic sensors

    SciTech Connect (OSTI)

    Loloee, Reza

    2012-07-15

    A new type of epitaxial ferromagnetic nitride (Ni{sub 3} Fe N = permalloy nitride = 'PyN') compound films were grown on Al{sub 2}O{sub 3}(1120) substrates using reactive triode magnetron sputtering. The results of electron back-scattering diffraction and x-ray diffraction techniques indicate a high quality epitaxial crystalline structure with growth normal of (100). Magnetization measurements of epitaxial PyN films revealed several unique results. (1) A textbook square hysteresis loop that suggest existence of single magnetic domain in these films. (2) A coercive field is tunable from a few mOe up to a few Oe by changing the film thickness. (3) A magnetization that switches (rotate) over a very small field range of {delta}H{sub C} {<=} 0.05 Oe, independent of the film thickness. This small {delta}H indicates a very large resistive sensitivity ({delta}R/{delta}H) of the epitaxial PyN. (4) The epitaxial PyN thermal cycling through several cycles between '2 and 800 K' (-271 Degree-Sign C to +527 Degree-Sign C) shows much less degradation only about 2-5% compared to 40% degradation of a simple Py film. Four-probe transport measurements give an anisotropic magnetoresistance of Almost-Equal-To 6%, sufficiently higher than other known ferromagnetic materials. These interesting properties are ideal for a variety of spintronic devices and magnetic sensors.

  9. NMR characterization of thin films

    DOE Patents [OSTI]

    Gerald II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

    2010-06-15

    A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

  10. NMR characterization of thin films

    DOE Patents [OSTI]

    Gerald, II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

    2008-11-25

    A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

  11. Modifying magnetic properties of ultra-thin magnetite films by growth on Fe pre-covered MgO(001)

    SciTech Connect (OSTI)

    Schemme, T. Krampf, A.; Kuepper, K.; Wollschläger, J.; Bertram, F.; Kuschel, T.

    2015-09-21

    Iron oxide films were reactively grown on iron buffer films, which were deposited before on MgO(001) substrates to analyze the influence of the initial iron buffer layers on the magnetic properties of the magnetite films. X-ray photoelectron spectroscopy and low energy electron diffraction showed that magnetite films of high crystalline quality in the surface near region were formed by this two-step deposition procedure. The underlying iron film, however, was completely oxidized as proved by x-ray reflectometry and diffraction. The structural bulk quality of the iron oxide film is poor compared to magnetite films directly grown on MgO(001). Although the iron film was completely oxidized, we found drastically modified magnetic properties for these films using the magnetooptic Kerr effect. The magnetite films had strongly increased coercive fields, and their magnetic in-plane anisotropy is in-plane rotated by 45∘ compared to magnetite films formed directly by one step reactive growth on MgO(001)

  12. Oxygen-vacancy-induced room-temperature magnetization in lamellar V{sub 2}O{sub 5} thin films

    SciTech Connect (OSTI)

    Cezar, A. B.; Graff, I. L. Varalda, J.; Schreiner, W. H.; Mosca, D. H.

    2014-10-28

    In this work, we study the local atomic and electronic structures as well as oxygen-vacancy-induced magnetic properties of electrodeposited V{sub 2}O{sub 5} films. Unlike stoichiometric V{sub 2}O{sub 5}, which is a diamagnetic lamellar semiconductor, our oxygen-defective V{sub 2}O{sub 5} films are ferromagnetic at room-temperature and their saturation magnetization decreases with air exposure time. X-ray absorption spectroscopy was used to monitor the aging effect on these films, revealing that freshly-made samples exhibit only local crystalline order, whereas the aged ones undoubtedly show an enhancement of crystallinity and coordination symmetry. The mean number of oxygen atoms around V tends to increase, indicating a decrease of oxygen vacancies with time. Concurrently with the decrease of oxygen vacancies, a loss of saturation magnetization is also observed. Hence, it can be concluded that the ferromagnetism of the V{sub 2}O{sub 5} films originates from a vacancy-induced mechanism, confirming the universality of this class of ferromagnetism.

  13. Photocatalytic and magnetic behaviors of BiFeO{sub 3} thin films deposited on different substrates

    SciTech Connect (OSTI)

    Xu, Hao-Min; Wang, Huan-Chun; Shen, Yang; Lin, Yuan-Hua Nan, Ce-Wen

    2014-11-07

    Single phase polycrystalline BiFeO{sub 3} thin films were grown on three different substrates via chemical solution deposition. Our results indicate that the band gap of as-prepared BiFeO{sub 3} films can be tuned (2.02–2.67 eV) by the grain size effects caused by the substrates. These BiFeO{sub 3} films show good photocatalytic properties by the degradation of Congo red solution under visible-light irradiation (λ{sub  }> 400 nm). Additionally, weak ferromagnetic behaviors can be observed at room temperature in all the films, which should be correlated to the destruction of the incommensurate cycloid spin structure of BiFeO{sub 3} phase and the coexistence of Fe{sup 3+} and Fe{sup 2+} as confirmed by X-ray photoelectron spectroscopy.

  14. MAGNETS

    DOE Patents [OSTI]

    Hofacker, H.B.

    1958-09-23

    This patent relates to nmgnets used in a calutron and more particularly to means fur clamping an assembly of magnet coils and coil spacers into tightly assembled relation in a fluid-tight vessel. The magnet comprises windings made up of an assembly of alternate pan-cake type coils and spacers disposed in a fluid-tight vessel. At one end of the tank a plurality of clamping strips are held firmly against the assembly by adjustable bolts extending through the adjacent wall. The foregoing arrangement permits taking up any looseness which may develop in the assembly of coils and spacers.

  15. The effect of strain induced by Ag underlayer on saturation magnetization of partially ordered Fe16N2 thin films

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yang, Meiyin; Allard, Lawrence F.; Ji, Nian; Zhang, Xiaowei; Yu, Guang-Hua; Wang, Jian -Ping

    2013-12-12

    Small angle neutron scattering (SANS) and scanning transmission electron microscopy (STEM) were used to study film formation by magnesium alloys AZ31B (Mg-3Al-1Zn base) and ZE10A (Elektron®717, E717: Mg-1Zn + Nd, Zr) in H2O and D2O with and without 1 or 5 wt.% NaCl. No SANS scattering changes were observed after 24 h D2O or H2O exposures compared with as received (unreacted) alloy, consistent with relatively dense MgO-base film formation. However, exposure to 5 wt.% NaCl resulted in accelerated corrosion, with resultant SANS scattering changes detected. The SANS data indicated both particle and rough surface (internal and external) scattering, but withmore » no preferential size features. The films formed in 5 wt.% NaCl consisted of a thin, inner MgO-base layer, and a nano-porous and filamentous Mg(OH)2 outer region tens of microns thick. Chlorine was detected extending to the inner MgO-base film region, with segregation of select alloying elements also observed in the inner MgO, but not the outer Mg(OH)2. Modeling of the SANS data suggested that the outer Mg(OH)2 films had very high surface areas, consistent with loss of film protectiveness. Here, implications for the NaCl corrosion mechanism, and the potential utility of SANS for Mg corrosion, are discussed.« less

  16. Superconducting YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} thin films on polycrystalline ferrite for magnetically tunable microwave components

    SciTech Connect (OSTI)

    Jia, Q.X.; Findikoglu, A.T.; Arendt, P.; Foltyn, S.R.; Roper, J.M.; Groves, J.R.; Coulter, J.Y.; Li, Y.Q.; Dionne, G.F.

    1998-04-01

    Superconducting YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} (YBCO) thin films with a surface resistance of 0.86 m{Omega} at 10 GHz and 76 K have been grown on polycrystalline ferrite yttrium iron garnet (YIG) substrates. The chemical and structural mismatches between YBCO and YIG are solved by using a double buffer layer of biaxially oriented yttria-stabilized zirconia (YSZ) and CeO{sub 2}, where YSZ is deposited by an ion-beam-assisted-deposition technique. The YBCO films are {ital c} axis oriented with an in-plane mosaic spread [full width at half maximum of an x-ray {phi}-scan on (103) reflection] of less than 8{degree}. The films have a superconductive transition temperature above 88 K with a transition width less than 0.3 K, giving a critical current density above 10{sup 6}A/cm{sup 2} in self field at 75 K. At 75 K in an external magnetic field of 1 T perpendicular to the film surface, the films maintain a critical current density over 2{times}10{sup 5}A/cm{sup 2}. {copyright} {ital 1998 American Institute of Physics.}

  17. Structural, Magnetic and Electronic Properties of (110)-OrientedEpitaxial Thin Films of Bilayer Manganite La1.2Sr1.8Mn2O7

    SciTech Connect (OSTI)

    Takamura, Yayoi; Grepstad, Jostein K.; Chopdekar, Rajesh V.; Suzuki, Yuri; Marshall, Ann F.; Zheng, Hong; Mitchell, John F.

    2005-05-09

    We have synthesized (110)-oriented epitaxial thin films of the bilayer (n=2) manganite, La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7}, with the metallic/ferromagnetic a-b planes lying perpendicular to the substrate surface and the c-axis aligned in the plane of the film. X-ray diffraction and transmission electron microscopy confirm the alignment of the a-b planes along the [1{bar 1}0] substrate direction. The films consist primarily of the n=2 phase with a minor component of the n=1 (La,Sr){sub 2}MnO{sub 4} and n={infinity} (La,Sr)MnO{sub 3} phases. A resistivity maximum coincides with a ferromagnet/paramagnet transition at a reduced T{sub c}{approx}90K (vs. 120K for bulk), indicative of the effects of epitaxial strain. The films display similar anisotropic properties to their bulk counterpart with the magnetically easy direction confined to the a-b planes and 20-200 times lower resistivity for current flowing along the a-b planes compared to the c-axis.

  18. Magnetometry of micro-magnets with electrostatically defined Hall bars

    SciTech Connect (OSTI)

    Lachance-Quirion, Dany; Camirand Lemyre, Julien; Bergeron, Laurent; Sarra-Bournet, Christian; Pioro-Ladrière, Michel

    2015-11-30

    Micro-magnets are key components for quantum information processing with individual spins, enabling arbitrary rotations and addressability. In this work, characterization of sub-micrometer sized CoFe ferromagnets is performed with Hall bars electrostatically defined in a two-dimensional electron gas. Due to the ballistic nature of electron transport in the cross junction of the Hall bar, anomalies such as the quenched Hall effect appear near zero external magnetic field, thus hindering the sensitivity of the magnetometer to small magnetic fields. However, it is shown that the sensitivity of the diffusive limit can be almost completely restored at low temperatures using a large current density in the Hall bar of about 10 A/m. Overcoming the size limitation of conventional etched Hall bars with electrostatic gating enables the measurement of magnetization curves of 440 nm wide micro-magnets with a signal-to-noise ratio above 10{sup 3}. Furthermore, the inhomogeneity of the stray magnetic field created by the micro-magnets is directly measured using the gate-voltage-dependent width of the sensitive area of the Hall bar.

  19. Magnetic properties of BaTiO{sub 3}/La{sub 0.7}Sr{sub 0.3}MnO{sub 3} thin films integrated on Si(100)

    SciTech Connect (OSTI)

    Singamaneni, Srinivasa Rao Prater, J. T.; Fan, Wu; Narayan, J.

    2014-12-14

    Two-phase multiferroic heterostructures composed of room-temperature ferroelectric BaTiO{sub 3} (BTO) and ferromagnetic La{sub 0.7}Sr{sub 0.3}MnO{sub 3} (LSMO) epitaxial thin films were grown on technologically important substrate Si (100). Bilayers of BTO/LSMO thin films display ferromagnetic Curie transition temperatures of ?350?K, close to the bulk value, which are independent of BTO films thickness in the range of 25100?nm. Discontinuous magnetization jumps associated with BTO structural transitions were suppressed in M(T) curves, probably due to substrate clamping effect. Interestingly, at cryogenic temperatures, the BTO/LSMO structure with BTO layer thickness of 100?nm shows almost 2-fold higher magnetic coercive field, 3-fold reduction in saturation magnetization, and improved squareness compared to the sample without BTO. We believe that the strong in-plane spin pinning of the ferromagnetic layer induced by BTO layer at BTO/LSMO interface could cause such changes in magnetic properties. This work forms a significant step forward in the integration of two-phase multiferroic heterostructures for CMOS applications.

  20. Change in magnetic and structural properties of FeRh thin films by gold cluster ion beam irradiation with the energy of 1.67?MeV/atom

    SciTech Connect (OSTI)

    Koide, T.; Iwase, A. [Department of Materials Science, Osaka Prefecture University, Sakai, Osaka 599-8531 (Japan); Saitoh, Y. [Japan Atomic Energy Agency, Takasaki, Gunma 370-1292 (Japan); Sakamaki, M.; Amemiya, K. [High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801 (Japan); Matsui, T., E-mail: t-matsui@21c.osakafu-u.ac.jp [Research Organization for the 21st Century, Osaka Prefecture University Sakai, Osaka 599-8531 (Japan)

    2014-05-07

    The effect of energetic cluster ion beam irradiation on magnetic and structural properties of FeRh thin films have been investigated. The cluster ions used in the present studies consist of a few gold atoms with the energy of 1.67?MeV/gold atom. Saturation magnetization of the sample irradiated with Au3 cluster ion beam (280?emu/cc) is larger than that for the irradiated sample with Au1 ion beam (240?emu/cc) for the same irradiation ion fluence. These results can also be confirmed by the X-ray magnetic circular dichroism (XMCD) measurement; the XMCD signal for Au3 cluster ion irradiation is larger than that for Au1 ion irradiation. Since the ion beam irradiation induced magnetization of FeRh is significantly correlated with the amount of the lattice defects in the samples, cluster ion beam irradiation can be considered to effectively introduce the lattice defects in B2-type FeRh rather than the single ion beam. Consequently, cluster ion irradiation is better than single ion irradiation for the viewpoint of saturation magnetization, even if the same irradiation energy is deposited in the samples.

  1. Electronic and magnetic transitions in perovskite SrRu{sub 1-x}Ir{sub x}O{sub 3} thin films

    SciTech Connect (OSTI)

    Biswas, Abhijit; Lee, Yong Woo; Jeong, Yoon Hee

    2015-09-07

    We have investigated the electronic and magnetic properties of perovskite SrRu{sub 1−x}Ir{sub x}O{sub 3} (0.0≤ x ≤ 0.25) thin films grown by pulsed laser deposition on atomically flat (001) SrTiO{sub 3} substrates. SrRuO{sub 3} has the properties of a ferromagnetic metal (resistivity ρ ∼ 200 μΩ · cm at T = 300 K) with Curie temperature T{sub C} ∼ 150 K. Substituting Ir (5d{sup 5+}) for Ru (4d{sup 4+}) in SrRuO{sub 3}, films (0.0 ≤ x ≤ 0.20) showed fully metallic behavior and ferromagnetic ordering, although ρ increased and the ferromagnetic T{sub C} decreased. Films with x = 0.25 underwent the metal-to-insulator transition (T{sub MIT}∼75 K) in ρ, and spin-glass-like ordering (T{sub SG}∼45 K) with the elimination of ferromagnetic long-range ordering caused by the electron localization at the substitution sites. In ferromagnetic films (0.0 ≤ x ≤ 0.20), ρ increased near-linearly with T at T > T{sub C}, but in paramagnetic film (x = 0.25) ρ increased as T{sup 3/2} at T > T{sub MIT}. Moreover, observed spin-glass-like (T{sub SG}) ordering with the negative magnetoresistance at T < T{sub MIT} in film with x = 0.25 validates the hypothesis that (Anderson) localization favors glassy ordering at amply disorder limit. These observations provide a promising approach for future applications and of fundamental interest in 4d and 5d mixed perovskites.

  2. Influence of Mn concentration on magnetic topological insulator MnxBi2−xTe3 thin-film Hall-effect sensor

    SciTech Connect (OSTI)

    Ni, Y.; Zhang, Z.; Nlebedim, I. C.; Hadimani, R. L.; Jiles, D. C.

    2015-06-11

    Hall-effect (HE) sensors based on high-quality Mn-doped Bi2Te3 topological insulator (TI) thin films have been systematically studied in this paper. Improvement of Hall sensitivity is found after doping the magnetic element Mn into Bi2Te3. The sensors with low Mn concentrations, MnxBi2-xTe3, x = 0.01 and 0.08 show the linear behavior of Hall resistance with sensitivity about 5 Ω/T. And their Hall sensitivity shows weak dependence on temperature. For sensors with high Mn concentration (x = 0.23), the Hall resistance with respect to magnetic field shows a hysteretic behavior. Moreover, its sensitivity shows almost eight times as high as that of the HE sensors with low Mn concentration. The highest sensitivity can reach 43 Ω/T at very low magnetic field. This increase of Hall sensitivity is caused by the occurrence of anomalous HE (AHE) after ferromagnetic phase transition. Our work indicates that the magnetic-element-doped TIs with AHE are good candidates for HE sensors.

  3. Structural, electrical and magnetic properties of (Bi{sub 0.9}RE{sub 0.1})(Fe{sub 0.97}Co{sub 0.03})O{sub 3} (RE = Nd and Gd) thin films

    SciTech Connect (OSTI)

    Xue, Xu Tan, Guoqiang Liu, Wenlong; Ren, Huijun

    2014-04-01

    Highlights: • Nd–Co and Gd–Co codoped BiFeO{sub 3} thin films are synthesized by chemical solution deposition method. • Enhanced magnetic property is observed in BGFC thin film at room temperature. • The onset electric field of FN tunneling of the films is associated with band gaps. • Both ferromagnetism and diamagnetism coexist in the BNFC film. - Abstract: Rhombohedral (Bi{sub 0.9}RE{sub 0.1})(Fe{sub 0.97}Co{sub 0.03})O{sub 3} (RE = Nd and Gd) thin films were deposited on FTO substrates by using a chemical solution deposition method. Raman scattering spectra reveal that the BiFeO{sub 3} lattices are able to incorporate Nd/Gd and Co ions with no effect on the basic rhombohedral structure. The chemical shift of Bi 4f, Fe 2p and O 1s core levels of the films is investigated by the X-ray photoelectron spectroscopy (XPS) analysis. The presence of defects in the films has been estimated through XPS study, which has a great effect on the dielectric dispersion and ferroelectric polarization. The intrinsic density of free electrons associated with band gap is the dominating factor which controls the FN tunneling conductance mechanism of the films. Both ferromagnetism and diamagnetism coexist in the BNFC film, while only ferromagnetism is observed in the BGFC film.

  4. Effect of chemical order on the magnetic and electronic properties of epitaxial off-stoichiometry F e x S i 1 - x thin films

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Karel, J.; Juraszek, J.; Minar, J.; Bordel, C.; Stone, K. H.; Zhang, Y. N.; Hu, J.; Wu, R. Q.; Ebert, H.; Kortright, J. B.; et al

    2015-04-06

    Off-stoichiometry, epitaxial FexSi1-x thin films (0.5more »and D0₃ and the strong enhancement for the A2 structure. The calculated electronic density of states shows many similarities in both structure and spin polarization between the D0₃ and B2 structures, while the A2 structure exhibits disorder broadening and a reduced spin polarization.« less

  5. Optimization of L1{sub 0} FePt/Fe{sub 45}Co{sub 55} thin films for rare earth free permanent magnet applications

    SciTech Connect (OSTI)

    Giannopoulos, G. Psycharis, V.; Niarchos, D.; Reichel, L.; Markou, A.; Panagiotopoulos, I.; Damm, C.; Fähler, S.; Khan, Imran; Hong, Jisang

    2015-06-14

    The magnetic properties of magnetron sputtered bilayers consisting of Fe{sub 45}Co{sub 55} ultrathin layers on top of L1{sub 0} FePt films epitaxially grown on MgO substrates are studied in view of their possible application as rare earth free permanent magnets. It is found that FePt layers induce a tetragonal distortion to the Fe-Co layers which leads to increased anisotropy. This allows to take advantage of the Fe-Co high magnetic moment with less significant loss of the coercivity compared to a typical hard/soft exchange spring system. A maximum energy product approaching 50 MGOe is obtained for a FePt(7 ML)/FeCo/(5 ML) sample. The results are in accordance with first-principles computational methods, which predict that even higher energy products are possible for micromagnetically optimized microstructures.

  6. Hidden Rotational Symmetries in Magnetic Domain Patterns

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    A magnetic thin film with perpendicular anisotropy, such as that used in computer hard drives, for example, commonly exhibits labyrinthine domain patterns. These patterns are...

  7. Ferromagnetic properties of fcc Gd thin films

    SciTech Connect (OSTI)

    Bertelli, T. P. Passamani, E. C.; Larica, C.; Nascimento, V. P.; Takeuchi, A. Y.

    2015-05-28

    Magnetic properties of sputtered Gd thin films grown on Si (100) substrates kept at two different temperatures were investigated using X-ray diffraction, ac magnetic susceptibility, and dc magnetization measurements. The obtained Gd thin films have a mixture of hcp and fcc structures, but with their fractions depending on the substrate temperature T{sub S} and film thickness x. Gd fcc samples were obtained when T{sub S} = 763 K and x = 10 nm, while the hcp structure was stabilized for lower T{sub S} (300 K) and thicker film (20 nm). The fcc structure is formed on the Ta buffer layer, while the hcp phase grows on the fcc Gd layer as a consequence of the lattice relaxation process. Spin reorientation phenomenon, commonly found in bulk Gd species, was also observed in the hcp Gd thin film. This phenomenon is assumed to cause the magnetization anomalous increase observed below 50 K in stressed Gd films. Magnetic properties of fcc Gd thin films are: Curie temperature above 300 K, saturation magnetization value of about 175 emu/cm{sup 3}, and coercive field of about 100 Oe at 300 K; features that allow us to classify Gd thin films, with fcc structure, as a soft ferromagnetic material.

  8. Transport and magnetization current in a thin layer of Bi{sub 1.8}Pb{sub 0.4}Sr{sub 2.0}Ca{sub 2.2}Cu{sub 3.0}O{sub y} adjacent to silver sheathing in BSCCO-2223 tapes

    SciTech Connect (OSTI)

    Lelovic, M.; Krishnaraj, P.; Deis, T.

    1995-07-01

    The thin superconducting region next to the silver sheath appears to be the region of high critical current density in BSCCO-2223 tapes. Transport current measurements on Bi{sub 1.8}Pb{sub 0.4}Sr{sub 2.0}Ca{sub 2.2}Cu{sub 3.0}O{sub y} tape at 77 K in a low magnetic field applied parallel to the tape thickness indicate an exponential field dependence [J / J{sub c} {proportional_to} exp (- B / B{sub 0})] for transport currents. Magnetic hysteresis was measured in a 10-{mu}m-thick layer of superconductor near the silver sheath as a function of temperature, intensity, and orientation of applied field with respect to the tape. The characteristic field for full penetration depth, B*, for a superconducting slab was found to have a power law dependence on temperature. Magnetization currents as a function of temperature and applied field oriented parallel to the tape thickness, J{sub c,m}(B,T), were determined from the magnetization loop width with a Bean- model expression adapted for an orthorhombic sample. The critical-state model, adjusted for scaling and magnetic relaxation, correlates well with the magnetization current of the thin layer at 77 K.

  9. The effect of strain induced by Ag underlayer on saturation magnetization of partially ordered Fe16N2 thin films

    SciTech Connect (OSTI)

    Yang, Meiyin; Allard, Lawrence F.; Ji, Nian; Zhang, Xiaowei; Yu, Guang-Hua; Wang, Jian -Ping

    2013-12-12

    Small angle neutron scattering (SANS) and scanning transmission electron microscopy (STEM) were used to study film formation by magnesium alloys AZ31B (Mg-3Al-1Zn base) and ZE10A (Elektron®717, E717: Mg-1Zn + Nd, Zr) in H2O and D2O with and without 1 or 5 wt.% NaCl. No SANS scattering changes were observed after 24 h D2O or H2O exposures compared with as received (unreacted) alloy, consistent with relatively dense MgO-base film formation. However, exposure to 5 wt.% NaCl resulted in accelerated corrosion, with resultant SANS scattering changes detected. The SANS data indicated both particle and rough surface (internal and external) scattering, but with no preferential size features. The films formed in 5 wt.% NaCl consisted of a thin, inner MgO-base layer, and a nano-porous and filamentous Mg(OH)2 outer region tens of microns thick. Chlorine was detected extending to the inner MgO-base film region, with segregation of select alloying elements also observed in the inner MgO, but not the outer Mg(OH)2. Modeling of the SANS data suggested that the outer Mg(OH)2 films had very high surface areas, consistent with loss of film protectiveness. Here, implications for the NaCl corrosion mechanism, and the potential utility of SANS for Mg corrosion, are discussed.

  10. Hidden Rotational Symmetries in Magnetic Domain Patterns

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Hidden Rotational Symmetries in Magnetic Domain Patterns Hidden Rotational Symmetries in Magnetic Domain Patterns Print Wednesday, 27 June 2012 00:00 Magnetic thin films have complicated domain patterns that may or may not repeat with each cycle through a hysteresis loop. A magnetic thin film with perpendicular anisotropy, such as that used in computer hard drives, for example, commonly exhibits labyrinthine domain patterns. These patterns are disordered over a macroscopic length scale, and

  11. X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in...

  12. Enhanced electrical and magnetic properties in La{sub 0.7}Sr{sub 0.3}MnO{sub 3} thin films deposited on CaTiO{sub 3}-buffered silicon substrates

    SciTech Connect (OSTI)

    Adamo, C.; Méchin, L.; Guillet, B.; Wu, S.; Routoure, J.-M.; Heeg, T.; Katz, M.; Pan, X. Q.; Mercone, S.; Schubert, J.; Zander, W.; Misra, R.; Schiffer, P.; and others

    2015-06-01

    We investigate the suitability of an epitaxial CaTiO{sub 3} buffer layer deposited onto (100) Si by reactive molecular-beam epitaxy (MBE) for the epitaxial integration of the colossal magnetoresistive material La{sub 0.7}Sr{sub 0.3}MnO{sub 3} with silicon. The magnetic and electrical properties of La{sub 0.7}Sr{sub 0.3}MnO{sub 3} films deposited by MBE on CaTiO{sub 3}-buffered silicon (CaTiO{sub 3}/Si) are compared with those deposited on SrTiO{sub 3}-buffered silicon (SrTiO{sub 3}/Si). In addition to possessing a higher Curie temperature and a higher metal-to-insulator transition temperature, the electrical resistivity and 1/f noise level at 300 K are reduced by a factor of two in the heterostructure with the CaTiO{sub 3} buffer layer. These results are relevant to device applications of La{sub 0.7}Sr{sub 0.3}MnO{sub 3} thin films on silicon substrates.

  13. Steering magnet design for a limited space

    SciTech Connect (OSTI)

    Okamura,M.; Fite, J.; Lodestro, V.; Raparia, D.; Ritter, J.

    2009-05-04

    We compare two extreme designs of steering magnets. The first one is a very thin steering magnet design which occupies only 6 mm in length and can be additionally installed as needed. The other is realized by applying extra coil windings to a quadrupole magnet and does not consume any length. The properties and the features of these steering magnets are discussed.

  14. Dynamic high pressure process for fabricating superconducting and permanent magnetic materials

    DOE Patents [OSTI]

    Nellis, William J.; Geballe, Theodore H.; Maple, M. Brian

    1988-01-01

    Shock wave formation of thin layers of materials with improved superconducting and permanent magnetic properties and improved microstructures.

  15. Evolution of twisted magnetic fields

    SciTech Connect (OSTI)

    Zweibel, E.G.; Boozer, A.H.

    1985-02-01

    The magnetic field of the solar corona evolves quasistatically in response to slowly changing photospheric boundary conditions. The magnetic topology is preserved by the low resistivity of the solar atmosphere. We show that a magnetic flux coordinate system simplifies the problem of calculating field evolution with invariant topology. As an example, we calculate the equilibrium of a thin magnetic flux tube with small twist per unit length.

  16. Thin-Film Fiber Optic Sensors for Power Control and Fault Detection. Final Report

    SciTech Connect (OSTI)

    Duncan, Paul Grems

    2003-09-30

    Described is the development of an optical current measurement device, an active power conditioning system, and sol gel type thin films for the detection of magnetic fields.

  17. Hidden Rotational Symmetries in Magnetic Domain Patterns

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Hidden Rotational Symmetries in Magnetic Domain Patterns Print Magnetic thin films have complicated domain patterns that may or may not repeat with each cycle through a hysteresis loop. A magnetic thin film with perpendicular anisotropy, such as that used in computer hard drives, for example, commonly exhibits labyrinthine domain patterns. These patterns are disordered over a macroscopic length scale, and intuitively we do not expect to observe any symmetry in such systems. Scientists at the

  18. Hidden Rotational Symmetries in Magnetic Domain Patterns

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Hidden Rotational Symmetries in Magnetic Domain Patterns Print Magnetic thin films have complicated domain patterns that may or may not repeat with each cycle through a hysteresis loop. A magnetic thin film with perpendicular anisotropy, such as that used in computer hard drives, for example, commonly exhibits labyrinthine domain patterns. These patterns are disordered over a macroscopic length scale, and intuitively we do not expect to observe any symmetry in such systems. Scientists at the

  19. Hidden Rotational Symmetries in Magnetic Domain Patterns

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Hidden Rotational Symmetries in Magnetic Domain Patterns Print Magnetic thin films have complicated domain patterns that may or may not repeat with each cycle through a hysteresis loop. A magnetic thin film with perpendicular anisotropy, such as that used in computer hard drives, for example, commonly exhibits labyrinthine domain patterns. These patterns are disordered over a macroscopic length scale, and intuitively we do not expect to observe any symmetry in such systems. Scientists at the

  20. Hidden Rotational Symmetries in Magnetic Domain Patterns

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Hidden Rotational Symmetries in Magnetic Domain Patterns Print Magnetic thin films have complicated domain patterns that may or may not repeat with each cycle through a hysteresis loop. A magnetic thin film with perpendicular anisotropy, such as that used in computer hard drives, for example, commonly exhibits labyrinthine domain patterns. These patterns are disordered over a macroscopic length scale, and intuitively we do not expect to observe any symmetry in such systems. Scientists at the

  1. Hidden Rotational Symmetries in Magnetic Domain Patterns

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Hidden Rotational Symmetries in Magnetic Domain Patterns Print Magnetic thin films have complicated domain patterns that may or may not repeat with each cycle through a hysteresis loop. A magnetic thin film with perpendicular anisotropy, such as that used in computer hard drives, for example, commonly exhibits labyrinthine domain patterns. These patterns are disordered over a macroscopic length scale, and intuitively we do not expect to observe any symmetry in such systems. Scientists at the

  2. Hidden Rotational Symmetries in Magnetic Domain Patterns

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Hidden Rotational Symmetries in Magnetic Domain Patterns Print Magnetic thin films have complicated domain patterns that may or may not repeat with each cycle through a hysteresis loop. A magnetic thin film with perpendicular anisotropy, such as that used in computer hard drives, for example, commonly exhibits labyrinthine domain patterns. These patterns are disordered over a macroscopic length scale, and intuitively we do not expect to observe any symmetry in such systems. Scientists at the

  3. Hidden Rotational Symmetries in Magnetic Domain Patterns

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Hidden Rotational Symmetries in Magnetic Domain Patterns Print Magnetic thin films have complicated domain patterns that may or may not repeat with each cycle through a hysteresis loop. A magnetic thin film with perpendicular anisotropy, such as that used in computer hard drives, for example, commonly exhibits labyrinthine domain patterns. These patterns are disordered over a macroscopic length scale, and intuitively we do not expect to observe any symmetry in such systems. Scientists at the

  4. Hidden Rotational Symmetries in Magnetic Domain Patterns

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Hidden Rotational Symmetries in Magnetic Domain Patterns Print Magnetic thin films have complicated domain patterns that may or may not repeat with each cycle through a hysteresis loop. A magnetic thin film with perpendicular anisotropy, such as that used in computer hard drives, for example, commonly exhibits labyrinthine domain patterns. These patterns are disordered over a macroscopic length scale, and intuitively we do not expect to observe any symmetry in such systems. Scientists at the

  5. Ultrafast optical control of magnetization dynamics in polycrystalline...

    Office of Scientific and Technical Information (OSTI)

    bismuth doped iron garnet thin films Citation Details In-Document Search Title: Ultrafast optical control of magnetization dynamics in polycrystalline bismuth doped iron ...

  6. Cell culture arrays using micron-sized ferromagnetic ring-shaped thin films

    SciTech Connect (OSTI)

    Huang, Chen-Yu; Wei, Zung-Hang; Lai, Mei-Feng; Ger, Tzong-Rong

    2015-05-07

    Cell patterning has become an important technology for tissue engineering. In this research, domain walls are formed at the two ends of a ferromagnetic ring thin film after applying a strong external magnetic field, which can effectively attract magnetically labeled cells and control the position for biological cell. Magnetophoresis experiment was conducted to quantify the magnetic nanoparticle inside the cells. A ring-shaped magnetic thin films array was fabricated through photolithography. It is observed that magnetically labeled cells can be successfully attracted to the two ends of the ring-shaped magnetic thin film structure and more cells were attracted and further attached to the structures. The cells are co-cultured with the structure and kept proliferating; therefore, such ring thin film can be an important candidate for in-vitro biomedical chips or tissue engineering.

  7. Hidden Rotational Symmetries in Magnetic Domain Patterns

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    patterns that may or may not repeat with each cycle through a hysteresis loop. A magnetic thin film with perpendicular anisotropy, such as that used in computer hard drives, for...

  8. Chemical stability of highly (0001) textured Sm(CoCu){sub 5} thin films with a thin Ta capping layer

    SciTech Connect (OSTI)

    Zhao Haibao; Wang Hao; Liu Xiaoqi; Wang Jianping; Zhang Tao

    2011-04-01

    With the highest magnetocrystalline anisotropy constant (Ku) among practical magnetic materials, SmCo{sub 5} could be a very attractive candidate for future high areal density magnetic recording. However, its corrosion resistance is always a concern in recording media applications. In this paper, the chemical stability and microstructures of highly (0001) textured Sm(CoCu){sub 5} thin films with and without a 3 nm Ta capping layer were reported. For Sm(CoCu){sub 5} thin films without a capping layer, the coercivity decreases significantly (from 8kOe to 1kOe) within one month. Sm(CoCu){sub 5} thin films capped with a thin Ta layer (3 nm) behave differently. Even exposed to a laboratory environment (25 deg. C) over 3 years, the Ta-capped Sm(CoCu){sub 5} thin films are stable in terms of structural and magnetic properties, i.e., there were no changes in X-ray diffraction peaks and vibrating sample magnetometer hysteresis loops. Microstructure of Ta-capped Sm(CoCu){sub 5} thin films showed that Sm(CoCu){sub 5} formed a domelike particle assembly structure on a smooth Ru underlayer and were well covered by partially oxidized Ta capping layer, as shown by TEM cross-section micrographs. Accelerated corrosion treatment (130 deg. C, 95% relative humidity, 6 h) was performed on Ta-capped Sm(CoCu){sub 5} thin films. X-ray photoelectron spectroscopy (XPS) results showed that no Co was detected on the sample surface before the corrosion treatment, but strong XPS signals of CoOx and Co(OH)x were observed after treatment. Therefore, none of our Sm(CoCu){sub 5} thin films can pass the accelerated corrosion test. Hcp-phased CoPt-alloys are proposed as better capping materials for Sm(CoCu){sub 5} thin films in future high-density magnetic recording applications.

  9. Horizontal electromagnetic casting of thin metal sheets

    DOE Patents [OSTI]

    Hull, John R.; Lari, Robert J.; Praeg, Walter F.; Turner, Larry R.

    1987-01-01

    Thin metal sheets are cast by magnetically suspending molten metal deposited within a ferromagnetic yoke and between AC conducting coils and linearly displacing the magnetically levitated liquid metal while it is being cooled to form a solid metal sheet. Magnetic flux increases as the molten metal sheet moves downward and decreases as the molten metal sheet moves upward to stabilize the sheet and maintain it in equilibrium as it is linearly displaced and solidified by cooling gases. A conducting shield is electrically coupled to the molten metal sheet by means of either metal sheet engaging rollers or brushes on the solidified metal, and by means of an electrode in the vessel containing the molten metal thereby providing a return path for the eddy currents induced in the metal sheet by the AC coil generated magnetic flux. Variation in the geometry of the conducting shield allows the magnetic flux between the metal sheet and the conducting shield to be varied and the thickness in surface quality of the metal sheet to be controlled. Side guards provide lateral containment for the molten metal sheet and stabilize and shape the magnetic field while a leader sheet having electromagnetic characteristics similar to those of the metal sheet is used to start the casting process and precedes the molten metal sheet through the magnet and forms a continuous sheet therewith. The magnet may be either U-shaped with a single racetrack coil or may be rectangular with a pair of facing bedstead coils.

  10. Horizontal electromagnetic casting of thin metal sheets

    DOE Patents [OSTI]

    Hull, John R.; Lari, Robert J.; Praeg, Walter F.; Turner, Larry R.

    1988-01-01

    Thin metal sheets are cast by magnetically suspending molten metal deposited within a ferromagnetic yoke and between AC conducting coils and linearly displacing the magnetically levitated liquid metal while it is being cooled to form a solid metal sheet. Magnetic flux increases as the molten metal sheet moves downward and decreases as the molten metal sheet moves upward to stabilize the sheet and maintain it in equilibrium as it is linearly displaced and solidified by cooling gases. A conducting shield is electrically coupled to the molten metal sheet by means of either metal sheet engaging rollers or brushes on the solidified metal, and by means of an electrode in the vessel containing the molten metal thereby providing a return path for the eddy currents induced in the metal sheet by the AC coil generated magnetic flux. Variation in the geometry of the conducting shield allows the magnetic flux between the metal sheet and the conducting shield to be varied and the thickness in surface quality of the metal sheet to be controlled. Side guards provide lateral containment for the molten metal sheet and stabilize and shape the magnetic field while a leader sheet having electromagnetic characteristics similar to those of the metal sheet is used to start the casting process and precedes the molten metal sheet through the magnet and forms a continuous sheet therewith. The magnet may be either U-shaped with a single racetrack coil or may be rectangular with a pair of facing bedstead coils.

  11. Thin sheet casting with electromagnetic pressurization

    DOE Patents [OSTI]

    Walk, Steven R.; Slepian, R. Michael; Nathenson, Richard D.; Williams, Robert S.

    1991-01-01

    An apparatus, method and system for the casting of thin strips or strips of metal upon a moving chill block that includes an electromagnet located so that molten metal poured from a reservoir onto the chill block passes into the magnetic field produced by the electromagnet. The electromagnet produces a force on the molten metal on said chill block in the direction toward said chill block in order to enhance thermal contact between the molten metal and the chill block.

  12. Porous thin films

    DOE Patents [OSTI]

    Xu, Ting

    2015-11-17

    Compositions of porous thin films and methods of making are provided. The methods involve self-assembly of a cyclic peptide in the presence of a block copolymer.

  13. Atomic layer deposition of superparamagnetic and ferrimagnetic magnetite thin films

    SciTech Connect (OSTI)

    Zhang, Yijun; Liu, Ming E-mail: wren@mail.xjtu.edu.cn Ren, Wei E-mail: wren@mail.xjtu.edu.cn; Zhang, Yuepeng; Chen, Xing; Ye, Zuo-Guang E-mail: wren@mail.xjtu.edu.cn

    2015-05-07

    One of the key challenges in realizing superparamagnetism in magnetic thin films lies in finding a low-energy growth way to create sufficiently small grains and magnetic domains which allow the magnetization to randomly and rapidly reverse. In this work, well-defined superparamagnetic and ferrimagnetic Fe{sub 3}O{sub 4} thin films are successfully prepared using atomic layer deposition technique by finely controlling the growth condition and post-annealing process. As-grown Fe{sub 3}O{sub 4} thin films exhibit a conformal surface and poly-crystalline nature with an average grain size of 7 nm, resulting in a superparamagnetic behavior with a blocking temperature of 210 K. After post-annealing in H{sub 2}/Ar at 400 °C, the as-grown α−Fe{sub 2}O{sub 3} sample is reduced to Fe{sub 3}O{sub 4} phase, exhibiting a ferrimagnetic ordering and distinct magnetic shape anisotropy. Atomic layer deposition of magnetite thin films with well-controlled morphology and magnetic properties provides great opportunities for integrating with other order parameters to realize magnetic nano-devices with potential applications in spintronics, electronics, and bio-applications.

  14. Cosmic magnetism

    SciTech Connect (OSTI)

    Seymour, P.

    1986-01-01

    This book deals with the cosmic magnetism in a non-mathematical way. It uses Faraday's very powerful and highly pictorial concept of lines of magnetic force and their associated physical properties to explain the structure and behavior of magnetic fields in extraterrestrial objects. Contents include: forces of nature; magnetic field of earth; solar and interplanetary magnetic fields; magnetic fields in the solar system; stars and pulsars; and magnetic fields of the milky way and other galaxies.

  15. Electrochemical thinning of silicon

    DOE Patents [OSTI]

    Medernach, John W.

    1994-01-01

    Porous semiconducting material, e.g. silicon, is formed by electrochemical treatment of a specimen in hydrofluoric acid, using the specimen as anode. Before the treatment, the specimen can be masked. The porous material is then etched with a caustic solution or is oxidized, depending of the kind of structure desired, e.g. a thinned specimen, a specimen, a patterned thinned specimen, a specimen with insulated electrical conduits, and so on. Thinned silicon specimen can be subjected to tests, such as measurement of interstitial oxygen by Fourier transform infra-red spectroscopy (FTIR).

  16. Electrochemical thinning of silicon

    DOE Patents [OSTI]

    Medernach, J.W.

    1994-01-11

    Porous semiconducting material, e.g. silicon, is formed by electrochemical treatment of a specimen in hydrofluoric acid, using the specimen as anode. Before the treatment, the specimen can be masked. The porous material is then etched with a caustic solution or is oxidized, depending of the kind of structure desired, e.g. a thinned specimen, a specimen, a patterned thinned specimen, a specimen with insulated electrical conduits, and so on. Thinned silicon specimen can be subjected to tests, such as measurement of interstitial oxygen by Fourier transform infra-red spectroscopy (FTIR). 14 figures.

  17. Thin film hydrogen sensor

    DOE Patents [OSTI]

    Cheng, Y.T.; Poli, A.A.; Meltser, M.A.

    1999-03-23

    A thin film hydrogen sensor includes a substantially flat ceramic substrate with first and second planar sides and a first substrate end opposite a second substrate end; a thin film temperature responsive resistor on the first planar side of the substrate proximate to the first substrate end; a thin film hydrogen responsive metal resistor on the first planar side of the substrate proximate to the fist substrate end and proximate to the temperature responsive resistor; and a heater on the second planar side of the substrate proximate to the first end. 5 figs.

  18. Thin film hydrogen sensor

    DOE Patents [OSTI]

    Cheng, Yang-Tse; Poli, Andrea A.; Meltser, Mark Alexander

    1999-01-01

    A thin film hydrogen sensor, includes: a substantially flat ceramic substrate with first and second planar sides and a first substrate end opposite a second substrate end; a thin film temperature responsive resistor on the first planar side of the substrate proximate to the first substrate end; a thin film hydrogen responsive metal resistor on the first planar side of the substrate proximate to the fist substrate end and proximate to the temperature responsive resistor; and a heater on the second planar side of the substrate proximate to the first end.

  19. Thin film tritium dosimetry

    DOE Patents [OSTI]

    Moran, Paul R.

    1976-01-01

    The present invention provides a method for tritium dosimetry. A dosimeter comprising a thin film of a material having relatively sensitive RITAC-RITAP dosimetry properties is exposed to radiation from tritium, and after the dosimeter has been removed from the source of the radiation, the low energy electron dose deposited in the thin film is determined by radiation-induced, thermally-activated polarization dosimetry techniques.

  20. Multifunctional thin film surface

    DOE Patents [OSTI]

    Brozik, Susan M.; Harper, Jason C.; Polsky, Ronen; Wheeler, David R.; Arango, Dulce C.; Dirk, Shawn M.

    2015-10-13

    A thin film with multiple binding functionality can be prepared on an electrode surface via consecutive electroreduction of two or more aryl-onium salts with different functional groups. This versatile and simple method for forming multifunctional surfaces provides an effective means for immobilization of diverse molecules at close proximities. The multifunctional thin film has applications in bioelectronics, molecular electronics, clinical diagnostics, and chemical and biological sensing.

  1. Household magnets

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Household magnets Chances are very good that you have experimented with magnets. People have been fascinated with magnetism for thousands of years. As familiar to us as they may be, magnets still have some surprises for us. Here is a small collection of some of our favorite magnet experiments. What happens when we break a magnet in half? Radio Shack sells cheap ceramic magnets in several shapes. Get a ring shaped magnet and break it with pliers or a tap with a hammer. Try to put it back

  2. Active superconducting devices formed of thin films

    DOE Patents [OSTI]

    Martens, Jon S.; Beyer, James B.; Nordman, James E.; Hohenwarter, Gert K. G.

    1991-05-28

    Active superconducting devices are formed of thin films of superconductor which include a main conduction channel which has an active weak link region. The weak link region is composed of an array of links of thin film superconductor spaced from one another by voids and selected in size and thickness such that magnetic flux can propagate across the weak link region when it is superconducting. Magnetic flux applied to the weak link region will propagate across the array of links causing localized loss of superconductivity in the links and changing the effective resistance across the links. The magnetic flux can be applied from a control line formed of a superconducting film deposited coplanar with the main conduction channel and weak link region on a substrate. The devices can be formed of any type to superconductor but are particularly well suited to the high temperature superconductors since the devices can be entirely formed from coplanar films with no overlying regions. The devices can be utilized for a variety of electrical components, including switching circuits, amplifiers, oscillators and modulators, and are well suited to microwave frequency applications.

  3. Multiferroic oxide thin films and heterostructures

    SciTech Connect (OSTI)

    Lu, Chengliang E-mail: Tao.Wu@kaust.edu.sa; Hu, Weijin; Wu, Tom E-mail: Tao.Wu@kaust.edu.sa; Tian, Yufeng

    2015-06-15

    Multiferroic materials promise a tantalizing perspective of novel applications in next-generation electronic, memory, and energy harvesting technologies, and at the same time they also represent a grand scientific challenge on understanding complex solid state systems with strong correlations between multiple degrees of freedom. In this review, we highlight the opportunities and obstacles in growing multiferroic thin films with chemical and structural integrity and integrating them in functional devices. Besides the magnetoelectric effect, multiferroics exhibit excellent resistant switching and photovoltaic properties, and there are plenty opportunities for them to integrate with other ferromagnetic and superconducting materials. The challenges include, but not limited, defect-related leakage in thin films, weak magnetism, and poor control on interface coupling. Although our focuses are Bi-based perovskites and rare earth manganites, the insights are also applicable to other multiferroic materials. We will also review some examples of multiferroic applications in spintronics, memory, and photovoltaic devices.

  4. Magnetic Propulsion of Intense Lithium Streams in a Tokamak Magnetic Field

    SciTech Connect (OSTI)

    Leonid E. Zakharov

    2002-03-13

    The paper gives the theory of magnetic propulsion of liquid lithium streams and their stability in tokamaks. In the approximation of a thin flowing layer the MHD equations are reduced to one integro-differential equation which takes into account the propulsion effect, viscosity and the drag force due to magnetic pumping and other interactions with the magnetic field. A criterion is obtained for the stabilization of the ''sausage'' instability of the streams by centrifugal force.

  5. Thin-film optical initiator

    DOE Patents [OSTI]

    Erickson, Kenneth L.

    2001-01-01

    A thin-film optical initiator having an inert, transparent substrate, a reactive thin film, which can be either an explosive or a pyrotechnic, and a reflective thin film. The resultant thin-film optical initiator system also comprises a fiber-optic cable connected to a low-energy laser source, an output charge, and an initiator housing. The reactive thin film, which may contain very thin embedded layers or be a co-deposit of a light-absorbing material such as carbon, absorbs the incident laser light, is volumetrically heated, and explodes against the output charge, imparting about 5 to 20 times more energy than in the incident laser pulse.

  6. Thin film photovoltaic device

    DOE Patents [OSTI]

    Catalano, Anthony W.; Bhushan, Manjul

    1982-01-01

    A thin film photovoltaic solar cell which utilizes a zinc phosphide semiconductor is of the homojunction type comprising an n-type conductivity region forming an electrical junction with a p-type region, both regions consisting essentially of the same semiconductor material. The n-type region is formed by treating zinc phosphide with an extrinsic dopant such as magnesium. The semiconductor is formed on a multilayer substrate which acts as an opaque contact. Various transparent contacts may be used, including a thin metal film of the same chemical composition as the n-type dopant or conductive oxides or metal grids.

  7. Thin film photovoltaic device

    DOE Patents [OSTI]

    Catalano, A.W.; Bhushan, M.

    1982-08-03

    A thin film photovoltaic solar cell which utilizes a zinc phosphide semiconductor is of the homojunction type comprising an n-type conductivity region forming an electrical junction with a p-type region, both regions consisting essentially of the same semiconductor material. The n-type region is formed by treating zinc phosphide with an extrinsic dopant such as magnesium. The semiconductor is formed on a multilayer substrate which acts as an opaque contact. Various transparent contacts may be used, including a thin metal film of the same chemical composition as the n-type dopant or conductive oxides or metal grids. 5 figs.

  8. Impact of interstitial oxygen on the electronic and magnetic...

    Office of Scientific and Technical Information (OSTI)

    interstitial oxygen on the electronic and magnetic structure in superconducting Fe 1 + y Te O x thin films Citation Details In-Document Search Title: Impact of interstitial oxygen...

  9. Characterization of Thin Films by XAFS: Application to Spintronics Materials

    SciTech Connect (OSTI)

    Heald, Steve M.; Kaspar, Tiffany C.; Droubay, Timothy C.; Chambers, Scott A.

    2009-10-25

    X-ray absorption fine structure (XAFS) has proven very valuable in characterizing thin films. This is illustrated with some examples from the area of diluted magnetic semiconductor (DMS) materials for spintronics applications. A promising route to DMS materials is doping of oxides such as TiO2 and ZnO with magnetic atoms such as Co. These can be grown as epitaxial thin films on various substrates. XAFS is especially valuable for characterizing the dopant atoms. The near edge region is sensitive to the symmetry of the bonding and valence of the dopants, and the extended XAFS can determine the details of the lattice site. XAFS is also valuable for detecting metallic nanoparticles. These can be difficult to detect by other methods, and can give a spurious magnetic signal. The power of XAFS is illustrated by examples from studies on Co doped ZnO films.

  10. Equiatomic CoPt thin films with extremely high coercivity

    SciTech Connect (OSTI)

    Varghese, Binni; Piramanayagam, S. N. Yang, Yi; Kai Wong, Seng; Khume Tan, Hang; Kiat Lee, Wee; Okamoto, Iwao

    2014-05-07

    In this paper, magnetic and structural properties of near-equiatomic CoPt thin films, which exhibited a high coercivity in the film-normal directionsuitable for perpendicular magnetic recording media applicationsare reported. The films exhibited a larger coercivity of about 6.5 kOe at 8?nm. The coercivity showed a monotonous decrease as the film thickness was increased. The transmission electron microscopy images indicated that the as fabricated CoPt film generally consists of a stack of magnetically hard hexagonal-close-packed phase, followed by stacking faults and face-centred-cubic phase. The thickness dependent magnetic properties are explained on the basis of exchange-coupled composite media. Epitaxial growth on Ru layers is a possible factor leading to the unusual observation of magnetically hard hcp-phase at high concentrations of Pt.

  11. Thin film photovoltaic cell

    DOE Patents [OSTI]

    Meakin, John D.; Bragagnolo, Julio

    1982-01-01

    A thin film photovoltaic cell having a transparent electrical contact and an opaque electrical contact with a pair of semiconductors therebetween includes utilizing one of the electrical contacts as a substrate and wherein the inner surface thereof is modified by microroughening while being macro-planar.

  12. Epitaxial thin films

    DOE Patents [OSTI]

    Hunt, Andrew Tye; Deshpande, Girish; Lin, Wen-Yi; Jan, Tzyy-Jiuan

    2006-04-25

    Epitatial thin films for use as buffer layers for high temperature superconductors, electrolytes in solid oxide fuel cells (SOFC), gas separation membranes or dielectric material in electronic devices, are disclosed. By using CCVD, CACVD or any other suitable deposition process, epitaxial films having pore-free, ideal grain boundaries, and dense structure can be formed. Several different types of materials are disclosed for use as buffer layers in high temperature superconductors. In addition, the use of epitaxial thin films for electrolytes and electrode formation in SOFCs results in densification for pore-free and ideal gain boundary/interface microstructure. Gas separation membranes for the production of oxygen and hydrogen are also disclosed. These semipermeable membranes are formed by high-quality, dense, gas-tight, pinhole free sub-micro scale layers of mixed-conducting oxides on porous ceramic substrates. Epitaxial thin films as dielectric material in capacitors are also taught herein. Capacitors are utilized according to their capacitance values which are dependent on their physical structure and dielectric permittivity. The epitaxial thin films of the current invention form low-loss dielectric layers with extremely high permittivity. This high permittivity allows for the formation of capacitors that can have their capacitance adjusted by applying a DC bias between their electrodes.

  13. Thin Wall Iron Castings

    SciTech Connect (OSTI)

    J.F. Cuttino; D.M. Stefanescu; T.S. Piwonka

    2001-10-31

    Results of an investigation made to develop methods of making iron castings having wall thicknesses as small as 2.5 mm in green sand molds are presented. It was found that thin wall ductile and compacted graphite iron castings can be made and have properties consistent with heavier castings. Green sand molding variables that affect casting dimensions were also identified.

  14. Magnetically insulated transmission line oscillator

    DOE Patents [OSTI]

    Bacon, Larry D.; Ballard, William P.; Clark, M. Collins; Marder, Barry M.

    1988-01-01

    A magnetically insulated transmission line oscillator employs self-generated magnetic fields to generate microwave energy. An anode of the oscillator includes slow-wave structures which are formed of a plurality of thin conductive vanes defining cavities therebetween, and a gap is formed between the anode and a cathode of the oscillator. In response to a pulsed voltage applied to the anode and cathode, self-generated magnetic fields arfe produced in a cross-field orientation with respect to the orientation of the electric field between the anode and the cathode. The cross-field magnetic fields insulate the flow of electrons in the gap and confine the flow of electrons within the gap.

  15. Magnetically insulated transmission line oscillator

    DOE Patents [OSTI]

    Bacon, L.D.; Ballard, W.P.; Clark, M.C.; Marder, B.M.

    1987-05-19

    A magnetically insulated transmission line oscillator employs self-generated magnetic fields to generate microwave energy. An anode of the oscillator includes slow-wave structures which are formed of a plurality of thin conductive vanes defining cavities therebetween, and a gap is formed between the anode and a cathode of the oscillator. In response to a pulsed voltage applied to the anode and cathode, self-generated magnetic fields are produced in a cross-field orientation with respect to the orientation of the electric field between the anode and the cathode. The cross-field magnetic fields insulate the flow of electrons in the gap and confine the flow of electrons within the gap. 11 figs.

  16. Final Technical Progress Report NANOSTRUCTURED MAGNETIC MATERIALS

    SciTech Connect (OSTI)

    Charles M. Falco

    2012-09-13

    This report describes progress made during the final phase of our DOE-funded program on Nanostructured Magnetic Materials. This period was quite productive, resulting in the submission of three papers and presentation of three talks at international conferences and three seminars at research institutions. Our DOE-funded research efforts were directed toward studies of magnetism at surfaces and interfaces in high-quality, well-characterized materials prepared by Molecular Beam Epitaxy (MBE) and sputtering. We have an exceptionally well-equipped laboratory for these studies, with: Thin film preparation equipment; Characterization equipment; Equipment to study magnetic properties of surfaces and ultra-thin magnetic films and interfaces in multi-layers and superlattices.

  17. Thin film composite electrolyte

    DOE Patents [OSTI]

    Schucker, Robert C. (The Woodlands, TX)

    2007-08-14

    The invention is a thin film composite solid (and a means for making such) suitable for use as an electrolyte, having a first layer of a dense, non-porous conductive material; a second layer of a porous ionic conductive material; and a third layer of a dense non-porous conductive material, wherein the second layer has a Coefficient of thermal expansion within 5% of the coefficient of thermal expansion of the first and third layers.

  18. Thin film hydrogen sensor

    DOE Patents [OSTI]

    Lauf, Robert J.; Hoffheins, Barbara S.; Fleming, Pamela H.

    1994-01-01

    A hydrogen sensor element comprises an essentially inert, electrically-insulating substrate having a thin-film metallization deposited thereon which forms at least two resistors on the substrate. The metallization comprises a layer of Pd or a Pd alloy for sensing hydrogen and an underlying intermediate metal layer for providing enhanced adhesion of the metallization to the substrate. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors, and at least one of the resistors is left uncovered. The difference in electrical resistances of the covered resistor and the uncovered resistor is related to hydrogen concentration in a gas to which the sensor element is exposed.

  19. Method for thinning specimen

    DOE Patents [OSTI]

    Follstaedt, David M.; Moran, Michael P.

    2005-03-15

    A method for thinning (such as in grinding and polishing) a material surface using an instrument means for moving an article with a discontinuous surface with an abrasive material dispersed between the material surface and the discontinuous surface where the discontinuous surface of the moving article provides an efficient means for maintaining contact of the abrasive with the material surface. When used to dimple specimens for microscopy analysis, a wheel with a surface that has been modified to produce a uniform or random discontinuous surface significantly improves the speed of the dimpling process without loss of quality of finish.

  20. NMR of thin layers using a meanderline surface coil

    DOE Patents [OSTI]

    Cowgill, Donald F.

    2001-01-01

    A miniature meanderline sensor coil which extends the capabilities of nuclear magnetic resonance (NMR) to provide analysis of thin planar samples and surface layer geometries. The sensor coil allows standard NMR techniques to be used to examine thin planar (or curved) layers, extending NMRs utility to many problems of modern interest. This technique can be used to examine contact layers, non-destructively depth profile into films, or image multiple layers in a 3-dimensional sense. It lends itself to high resolution NMR techniques of magic angle spinning and thus can be used to examine the bonding and electronic structure in layered materials or to observe the chemistry associated with aging coatings. Coupling this sensor coil technology with an arrangement of small magnets will produce a penetrator probe for remote in-situ chemical analysis of groundwater or contaminant sediments. Alternatively, the sensor coil can be further miniaturized to provide sub-micron depth resolution within thin films or to orthoscopically examine living tissue. This thin-layer NMR technique using a stationary meanderline coil in a series-resonant circuit has been demonstrated and it has been determined that the flat meanderline geometry has about he same detection sensitivity as a solenoidal coil, but is specifically tailored to examine planar material layers, while avoiding signals from the bulk.

  1. Magnetic shielding

    DOE Patents [OSTI]

    Kerns, John A.; Stone, Roger R.; Fabyan, Joseph

    1987-01-01

    A magnetically-conductive filler material bridges the gap between a multi-part magnetic shield structure which substantially encloses a predetermined volume so as to minimize the ingress or egress of magnetic fields with respect to that volume. The filler material includes a heavy concentration of single-magnetic-domain-sized particles of a magnetically conductive material (e.g. soft iron, carbon steel or the like) dispersed throughout a carrier material which is generally a non-magnetic material that is at least sometimes in a plastic or liquid state. The maximum cross-sectional particle dimension is substantially less than the nominal dimension of the gap to be filled. An epoxy base material (i.e. without any hardening additive) low volatility vacuum greases or the like may be used for the carrier material. The structure is preferably exposed to the expected ambient magnetic field while the carrier is in a plastic or liquid state so as to facilitate alignment of the single-magnetic-domain-sized particles with the expected magnetic field lines.

  2. Magnetic shielding

    DOE Patents [OSTI]

    Kerns, J.A.; Stone, R.R.; Fabyan, J.

    1987-10-06

    A magnetically-conductive filler material bridges the gap between a multi-part magnetic shield structure which substantially encloses a predetermined volume so as to minimize the ingress or egress of magnetic fields with respect to that volume. The filler material includes a heavy concentration of single-magnetic-domain-sized particles of a magnetically conductive material (e.g. soft iron, carbon steel or the like) dispersed throughout a carrier material which is generally a non-magnetic material that is at least sometimes in a plastic or liquid state. The maximum cross-sectional particle dimension is substantially less than the nominal dimension of the gap to be filled. An epoxy base material (i.e. without any hardening additive) low volatility vacuum greases or the like may be used for the carrier material. The structure is preferably exposed to the expected ambient magnetic field while the carrier is in a plastic or liquid state so as to facilitate alignment of the single-magnetic-domain-sized particles with the expected magnetic field lines. 3 figs.

  3. Magnetic coupling at rare earth ferromagnet/transition metal ferromagnet

    Office of Scientific and Technical Information (OSTI)

    interfaces: A comprehensive study of Gd/Ni (Journal Article) | SciTech Connect Magnetic coupling at rare earth ferromagnet/transition metal ferromagnet interfaces: A comprehensive study of Gd/Ni Citation Details In-Document Search Title: Magnetic coupling at rare earth ferromagnet/transition metal ferromagnet interfaces: A comprehensive study of Gd/Ni Thin film magnetic heterostructures with competing interfacial coupling and Zeeman energy provide a fertile ground to study phase transition

  4. Scientists use world's fastest supercomputer to explore magnetic

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    reconnection Supercomputer to explore magnetic reconnection Scientists use world's fastest supercomputer to explore magnetic reconnection The focus is to understand the three-dimensional evolution of thin electrical current layers where magnetic reconnection initially develops. October 30, 2009 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience,

  5. Superconducting magnet development in Japan

    SciTech Connect (OSTI)

    Yasukochi, K.

    1983-05-01

    The present state of R and D works on the superconducting magnet and its applications in Japan are presented. On electrical rotating machines, 30 MVA superconducting synchronous rotary condenser (Mitsubishi and Fuji) and 50 MVA generator are under construction. Two ways of ship propulsion by superconducting magnets are developing. A superconducting magnetically levitated and linear motor propelled train ''MAGLEV'' was developed by the Japan National Railways (JNR). The superconducting magnet development for fusion is the most active field in Japan. The Cluster Test program has been demonstrated on a 10 T Nb/sub 3/Sn coil and the first coil of Large Coil Task in IEA collaboration has been constructed and the domestic test was completed in JAERI. These works are for the development of toroidal coils of the next generation tokamak machine. R and D works on superconducting ohmic heating coil are in progress in JAERI and ETL. The latter group has constructed 3.8 MJ pulsed coil. A high ramp rate of changing field in pulsed magnet, 200 T/s, has been tested successfully. High Energy Physics Laboratory (KEK) are conducting active works. The superconducting ..mu.. meson channel and ..pi.. meson channel have been constructed and are operating successfully. KEK has also a project of big accelerator named ''TRISTAN'', which is similar to ISABELLE project of BNL. Superconducting synchrotron magnets are developed for this project. The development of superconducting three thin wall solenoid has been started. One of them, CDF, is progressing under USA-Japan collaboration.

  6. Magnetic filtration process, magnetic filtering material, and...

    Office of Scientific and Technical Information (OSTI)

    The present invention provides magnetically responsive activated carbon, and a method of forming magnetically responsive activated carbon. The method of forming magnetically ...

  7. Magnetic shielding

    DOE Patents [OSTI]

    Kerns, J.A.; Stone, R.R.; Fabyan, J.

    1985-02-12

    A magnetically-conductive filler material bridges the gap between a multi-part magnetic shield structure which substantially encloses a predetermined volume so as to minimize the ingress or egress of magnetic fields with respect to that volume. The filler material includes a heavy concentration of single-magnetic-domain-sized particles of a magnetically conductive material (e.g. soft iron, carbon steel or the like) dispersed throughout a carrier material which is generally a non-magnetic material that is at least sometimes in a plastic or liquid state. The maximum cross-sectional particle dimension is substantially less than the nominal dimension of the gap to be filled. An epoxy base material (i.e. without any hardening additive) low volatility vacuum greases or the like may be used for the carrier material. The structure is preferably exposed to the expected ambient field while the carrier is in a plastic or liquid state so as to facilitate alignment of the single-magnetic-domain-sized particles with the expected magnetic field lines.

  8. Thin film ion conducting coating

    DOE Patents [OSTI]

    Goldner, Ronald B.; Haas, Terry; Wong, Kwok-Keung; Seward, George

    1989-01-01

    Durable thin film ion conducting coatings are formed on a transparent glass substrate by the controlled deposition of the mixed oxides of lithium:tantalum or lithium:niobium. The coatings provide durable ion transport sources for thin film solid state storage batteries and electrochromic energy conservation devices.

  9. Magnetic nanotubes

    DOE Patents [OSTI]

    Matsui, Hiroshi; Matsunaga, Tadashi

    2010-11-16

    A magnetic nanotube includes bacterial magnetic nanocrystals contacted onto a nanotube which absorbs the nanocrystals. The nanocrystals are contacted on at least one surface of the nanotube. A method of fabricating a magnetic nanotube includes synthesizing the bacterial magnetic nanocrystals, which have an outer layer of proteins. A nanotube provided is capable of absorbing the nanocrystals and contacting the nanotube with the nanocrystals. The nanotube is preferably a peptide bolaamphiphile. A nanotube solution and a nanocrystal solution including a buffer and a concentration of nanocrystals are mixed. The concentration of nanocrystals is optimized, resulting in a nanocrystal to nanotube ratio for which bacterial magnetic nanocrystals are immobilized on at least one surface of the nanotubes. The ratio controls whether the nanocrystals bind only to the interior or to the exterior surfaces of the nanotubes. Uses include cell manipulation and separation, biological assay, enzyme recovery, and biosensors.

  10. Ferromagnetic thin films

    DOE Patents [OSTI]

    Krishnan, K.M.

    1994-12-20

    A ferromagnetic [delta]-Mn[sub 1[minus]x]Ga[sub x] thin film having perpendicular anisotropy is described which comprises: (a) a GaAs substrate, (b) a layer of undoped GaAs overlying said substrate and bonded thereto having a thickness ranging from about 50 to about 100 nanometers, (c) a layer of [delta]-Mn[sub 1[minus]x]Ga[sub x] overlying said layer of undoped GaAs and bonded thereto having a thickness ranging from about 20 to about 30 nanometers, and (d) a layer of GaAs overlying said layer of [delta]-Mn[sub 1[minus]x]Ga[sub x] and bonded thereto having a thickness ranging from about 2 to about 5 nanometers, wherein x is 0.4[+-]0.05. 7 figures.

  11. Thin film hydrogen sensor

    DOE Patents [OSTI]

    Lauf, R.J.; Hoffheins, B.S.; Fleming, P.H.

    1994-11-22

    A hydrogen sensor element comprises an essentially inert, electrically-insulating substrate having a thin-film metallization deposited thereon which forms at least two resistors on the substrate. The metallization comprises a layer of Pd or a Pd alloy for sensing hydrogen and an underlying intermediate metal layer for providing enhanced adhesion of the metallization to the substrate. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors, and at least one of the resistors is left uncovered. The difference in electrical resistances of the covered resistor and the uncovered resistor is related to hydrogen concentration in a gas to which the sensor element is exposed. 6 figs.

  12. Josephson magnetic rotary valve

    SciTech Connect (OSTI)

    Soloviev, I. I.; Klenov, N. V.; Bakurskiy, S. V.; Bol'ginov, V. V.; Ryazanov, V. V.; Kupriyanov, M. Yu.; Golubov, A. A.

    2014-12-15

    We propose a control element for a Josephson spin valve. It is a complex Josephson device containing ferromagnetic (F) layer in the weak-link area consisting of two regions, representing 0 and π Josephson junctions, respectively. The valve's state is defined by mutual orientations of the F-layer magnetization vector and boundary line between 0 and π sections of the device. We consider possible implementation of the control element by introduction of a thin normal metal layer in a part of the device area. By means of theoretical simulations, we study properties of the valve's structure as well as its operation, revealing such advantages as simplicity of control, high characteristic frequency, and good legibility of the basic states.

  13. ThinSilicon | Open Energy Information

    Open Energy Info (EERE)

    ThinSilicon Place: California Product: US-based developer of thin-film PV module manufacturing technology. References: ThinSilicon1 This article is a stub. You can help OpenEI...

  14. Experimental correlation between nonlinear optical and magnetotransport properties observed in Au-Co thin films

    SciTech Connect (OSTI)

    Yang, Kaida; Kryutyanskiy, Victor; Kolmychek, Irina; Murzina, Tatiana V.; Lukaszew, R. Alejandra

    2016-01-01

    Magnetic materials where at least one dimension is in the nanometer scale typically exhibit different magnetic, magnetotransport, and magnetooptical properties compared to bulk materials. Composite magnetic thin films where the matrix composition, magnetic cluster size, and overall composite film thickness can be experimentally tailored via adequate processing or growth parameters offer a viable nanoscale platform to investigate possible correlations between nonlinear magnetooptical and magnetotransport properties, since both types of properties are sensitive to the local magnetization landscape. As a result, it has been shown that the local magnetization contrast affects the nonlinear magnetooptical properties as well as the magnetotransport properties in magnetic-metal/nonmagnetic metal multilayers; thus, nanocomposite films showcase another path to investigate possible correlations between these distinct properties which may prove useful for sensing applications.

  15. Experimental correlation between nonlinear optical and magnetotransport properties observed in Au-Co thin films

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yang, Kaida; Kryutyanskiy, Victor; Kolmychek, Irina; Murzina, Tatiana V.; Lukaszew, R. Alejandra

    2016-01-01

    Magnetic materials where at least one dimension is in the nanometer scale typically exhibit different magnetic, magnetotransport, and magnetooptical properties compared to bulk materials. Composite magnetic thin films where the matrix composition, magnetic cluster size, and overall composite film thickness can be experimentally tailored via adequate processing or growth parameters offer a viable nanoscale platform to investigate possible correlations between nonlinear magnetooptical and magnetotransport properties, since both types of properties are sensitive to the local magnetization landscape. As a result, it has been shown that the local magnetization contrast affects the nonlinear magnetooptical properties as well as the magnetotransport propertiesmore » in magnetic-metal/nonmagnetic metal multilayers; thus, nanocomposite films showcase another path to investigate possible correlations between these distinct properties which may prove useful for sensing applications.« less

  16. Titanium nitride thin films for minimizing multipactoring

    DOE Patents [OSTI]

    Welch, Kimo M.

    1979-01-01

    Applying a thin film coating to the surface of a workpiece, in particular, applying a coating of titanium nitride to a klystron window by means of a crossed-field diode sputtering array. The array is comprised of a cohesive group of numerous small hollow electrically conducting cylinders and is mounted so that the open ends of the cylinders on one side of the group are adjacent a titanium cathode plate. The workpiece is mounted so as to face the open ends of the other side of the group. A magnetic field is applied to the array so as to be coaxial with the cylinders and a potential is applied across the cylinders and the cathode plate, the cylinders as an anode being positive with respect to the cathode plate. The cylinders, the cathode plate and the workpiece are situated in an atmosphere of nitrogen which becomes ionized such as by field emission because of the electric field between the cylinders and cathode plate, thereby establishing an anode-cathode discharge that results in sputtering of the titanium plate. The sputtered titanium coats the workpiece and chemically combines with the nitrogen to form a titanium nitride coating on the workpiece. Gas pressure, gas mixtures, cathode material composition, voltages applied to the cathode and anode, the magnetic field, cathode, anode and workpiece spacing, and the aspect ratio (ratio of length to inner diameter) of the anode cylinders, all may be controlled to provide consistent optimum thin film coatings of various compositions and thicknesses. Another facet of the disclosure is the coating of microwave components per se with titanium nitride to reduce multipactoring under operating conditions of the components.

  17. Improved superconducting magnet wire

    DOE Patents [OSTI]

    Schuller, I.K.; Ketterson, J.B.

    1983-08-16

    This invention is directed to a superconducting tape or wire composed of alternating layers of copper and a niobium-containing superconductor such as niobium of NbTi, Nb/sub 3/Sn or Nb/sub 3/Ge. In general, each layer of the niobium-containing superconductor has a thickness in the range of about 0.05 to 1.5 times its coherence length (which for Nb/sub 3/Si is 41 A) with each copper layer having a thickness in the range of about 170 to 600 A. With the use of very thin layers of the niobium composition having a thickness within the desired range, the critical field (H/sub c/) may be increased by factors of 2 to 4. Also, the thin layers of the superconductor permit the resulting tape or wire to exhibit suitable ductility for winding on a magnet core. These compositions are also characterized by relatively high values of critical temperature and therefore will exhibit a combination of useful properties as superconductors.

  18. Retrieving spin textures on curved magnetic thin films with full...

    Office of Scientific and Technical Information (OSTI)

    Additional Journal Information: Journal Volume: 6; Journal ID: ISSN 2041-1723 Publisher: Nature Publishing Group Research Org: Lawrence Berkeley National Laboratory (LBNL), ...

  19. Innovative Thin Films LLC | Open Energy Information

    Open Energy Info (EERE)

    Thin Films LLC Place: Toledo, Ohio Zip: 43607 Product: Provider of altnernative energy thin film deposition technology. Coordinates: 46.440613, -122.847838 Show Map Loading...

  20. Enabling Thin Silicon Solar Cell Technology

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Enabling Thin Silicon Solar Cell Technology Enabling Thin Silicon Solar Cell Technology Print Friday, 21 June 2013 10:49 Generic silicon solar cells showing +45, -45, and ...

  1. Thin Film Solar Technologies | Open Energy Information

    Open Energy Info (EERE)

    help OpenEI by expanding it. Thin Film Solar Technologies is a company located in South Africa . References "Thin Film Solar Technologies" Retrieved from "http:...

  2. Electromagnetic augmentation for casting of thin metal sheets

    DOE Patents [OSTI]

    Hull, J.R.

    1987-10-28

    Thin metal sheets are cast by magnetically levitating molten metal deposited in a model within a ferromagnetic yoke and between AC conducting coils and linearly displacing the magnetically levitated liquid metal while it is being cooled by the water-cooled walls of the mold to form a solid metal sheet. A conducting shield is electrically coupled to the molten metal sheet to provide a return path for eddy currents induced in the metal sheet by the current in the AC conducting coils. In another embodiment, a DC conducting coil is coupled to the metal sheet for providing a direct current therein which interacts with the magnetic field to levitate the moving metal sheet. Levitation of the metal sheet in both molten and solid forms reduces its contact pressure with the mold walls while maintaining sufficient engagement therebetween to permit efficient conductive cooling by the mold through which a coolant fluid may be circulated. 8 figs.

  3. Magnetic monopoles

    SciTech Connect (OSTI)

    Fryberger, D.

    1984-12-01

    In this talk on magnetic monopoles, first the author briefly reviews some historical background; then, the author describes what several different types of monopoles might look like; and finally the author discusses the experimental situation. 81 references.

  4. Mineral Magnetism

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    March 8, 2016 Small piles of rare earth elements In the United States, rare-earth elements used in strong magnets, such as neodymium and samarium, are scarce due to limits on ...

  5. CRYOGENIC MAGNETS

    DOE Patents [OSTI]

    Post, R.F.; Taylor, C.E.

    1963-05-21

    A cryogenic magnet coil is described for generating magnetic fields of the order of 100,000 gauss with a minimum expenditure of energy lost in resistive heating of the coil inductors and energy lost irreversibly in running the coil refrigeration plant. The cryogenic coil comprises a coil conductor for generating a magnetic field upon energization with electrical current, and refrigeration means disposed in heat conductive relation to the coil conductor for cooling to a low temperature. A substantial reduction in the power requirements for generating these magnetic fields is attained by scaling the field generating coil to large size and particular dimensions for a particular conductor, and operating the coil at a particular optimum temperature commensurate with minimum overall power requirements. (AEC)

  6. Thin seam mining machine

    SciTech Connect (OSTI)

    Nelson, R.L.

    1984-05-22

    A low profile thin seam miner includes a main frame mounting a lower transverse axis rotary cutter and a parallel axis conveyor rearwardly of the lower cutter. The main frame also mounts a forward transverse axis rotary cutter somewhat above the lower cutter, the forward upper cutter being supported on a longitudinal boom pivoted to the main frame and being vertically swingable under influence of a single cylinder. The main frame and all of its parts is incrementally advanced into the seam by the alternating action of two horizontal longitudinal parallel axis cylinders connected between the main frame and a pair of floor-engaging plates. Two vertical axis jacks are connected between the two floor-engaging plates and two cooperating overhead roof plates, connected with the floor-engaging plates by separate toggle linkages. Two more generally upright cylinders connected between the floor plates and the rear of the main frame can tilt the main frame on a transverse pivot axis to vary the depth of cut of the lower rear cutter responsive to the control of a sensing tooth on such cutter. The single cylinder connected with the boom of the forward upper cutter can swing the boom on its transverse pivot axis to vary the depth of cut of the forward upper cutter, responsive to the control of a sensing tooth on such cutter.

  7. Soft x-ray ptychography studies of nanoscale magnetic and structural...

    Office of Scientific and Technical Information (OSTI)

    Soft x-ray ptychography studies of nanoscale magnetic and structural correlations in thin SmCo5 films Citation Details In-Document Search This content will become publicly ...

  8. Axisymmetric plasma equilibrium in gravitational and magnetic fields

    SciTech Connect (OSTI)

    Krasheninnikov, S. I.; Catto, P. J.

    2015-12-15

    Plasma equilibria in gravitational and open-ended magnetic fields are considered for the case of topologically disconnected regions of the magnetic flux surfaces where plasma occupies just one of these regions. Special dependences of the plasma temperature and density on the magnetic flux are used which allow the solution of the Grad–Shafranov equation in a separable form permitting analytic treatment. It is found that plasma pressure tends to play the dominant role in the setting the shape of magnetic field equilibrium, while a strong gravitational force localizes the plasma density to a thin disc centered at the equatorial plane.

  9. Method for the detection of a magnetic field utilizing a magnetic vortex

    DOE Patents [OSTI]

    Novosad, Valentyn; Buchanan, Kristen

    2010-04-13

    The determination of the strength of an in-plane magnetic field utilizing one or more magnetically-soft, ferromagnetic member, having a shape, size and material whereas a single magnetic vortex is formed at remanence in each ferromagnetic member. The preferred shape is a thin circle, or dot. Multiple ferromagnetic members can also be stacked on-top of each other and separated by a non-magnetic spacer. The resulting sensor is hysteresis free. The sensor's sensitivity, and magnetic saturation characteristics may be easily tuned by simply altering the material, size, shape, or a combination thereof to match the desired sensitivity and saturation characteristics. The sensor is self-resetting at remanence and therefore does not require any pinning techniques.

  10. Cool Magnetic Molecules

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Underlying the magnetocaloric effect is the idea that magnetism is the result of the ... with the magnetic field, the magnetic entropy (disorder) of the system decreases; if ...

  11. Cool Magnetic Molecules

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... Underlying the magnetocaloric effect is the idea that magnetism is the result of the ... with the magnetic field, the magnetic entropy (disorder) of the system decreases; if ...

  12. X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic

  13. X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic

  14. X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic

  15. X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic

  16. X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Wednesday, 25 November 2009 00:00 Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core

  17. X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic

  18. X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic

  19. X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic

  20. Oxygen-induced immediate onset of the antiferromagnetic stacking in thin Cr films on Fe(001)

    SciTech Connect (OSTI)

    Berti, Giulia Brambilla, Alberto; Calloni, Alberto; Bussetti, Gianlorenzo; Finazzi, Marco; Duò, Lamberto; Ciccacci, Franco

    2015-04-20

    We investigated the magnetic coupling of ultra-thin Cr films grown at 600 K on a Fe(001)-p(1 × 1)O substrate by means of spin-polarized photoemission spectroscopy. Our findings show that the expected antiferromagnetic stacking of the magnetization in Cr(001) layers occurs right from the first atomic layer at the Cr/Fe interface. This is at variance with all previous observations in similar systems, prepared in oxygen-free conditions, which always reported on a delayed onset of the magnetic oscillations due to the occurrence of significant chemical alloying at the interface, which is substantially absent in our preparation.

  1. Magnetoelectric coupling of multiferroic chromium doped barium titanate thin film probed by magneto-impedance spectroscopy

    SciTech Connect (OSTI)

    Shah, Jyoti Kotnala, Ravinder K. E-mail: rkkotnala@gmail.com

    2014-04-07

    Thin film of BaTiO{sub 3} doped with 0.1 at. % Cr (Cr:BTO) has been prepared by pulsed laser deposition technique. Film was deposited on Pt/SrTiO{sub 3} substrate at 500 °C in 50 mTorr Oxygen gas pressure using KrF (298 nm) laser. Polycrystalline growth of single phase Cr:BTO thin film has been confirmed by grazing angle X-ray diffraction. Cr:BTO film exhibited remnant polarization 6.4 μC/cm{sup 2} and 0.79 MV/cm coercivity. Magnetization measurement of Cr:BTO film showed magnetic moment 12 emu/cc. Formation of weakly magnetic domains has been captured by magnetic force microscopy. Theoretical impedance equation fitted to experimental data in Cole-Cole plot for thin film in presence of transverse magnetic field resolved the increase in grain capacitance from 4.58 × 10{sup −12} to 5.4 × 10{sup −11} F. Film exhibited high value 137 mV/cm-Oe magneto-electric (ME) coupling coefficient at room temperature. The high value of ME coupling obtained can reduce the typical processing steps involved in multilayer deposition to obtain multiferrocity in thin film. Barium titanate being best ferroelectric material has been tailored to be multiferroic by non ferromagnetic element, Cr, doping in thin film form opens an avenue for more stable and reliable spintronic material for low power magnetoelectric random excess memory applications.

  2. FINAL REPORT: FG02-01ER-45906 - A novel class of artificially modulated magnetic multilayers based on magnetic shape memory alloys

    SciTech Connect (OSTI)

    Chopra, H. D.

    2005-06-20

    The temperature dependent micromagnetic behavior, structural phase transitions, magnetic transition, and the dynamics of phase transitions have been investigated using magnetic shape memory alloys. Results provide a novel concept of ?polymagnets?. In thin film form the number of martensite variants is greatly reduced. A new technique to study dynamics of magnetic phase transitions has been developed applicable to bulk, thin films or multilayers. Transition pathways in magnetic shape memory alloys are as follows: Structural transitions followed by magnetic transition on cooling, and magnetic transition followed by structural transition on heating. The anisotropy of exchange spring mulilayers is greatly sensitive to substrate constraints, and shows a marked rotational hysteresis at lower temperatures. Results also show that a large reduction in coercivity of multilayers is a direct result of broadening of domain wall width by interlayer magnetostatic interactions.

  3. High-temperature superconducting thin-film-based electronic devices

    SciTech Connect (OSTI)

    Wu, X.D; Finokoglu, A.; Hawley, M.; Jia, Q.; Mitchell, T.; Mueller, F.; Reagor, D.; Tesmer, J.

    1996-09-01

    This the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project involved optimization of processing of Y123 and Tl-2212 thin films deposited on novel substrates for advanced electronic devices. The Y123 films are the basis for development of Josephson Junctions to be utilized in magnetic sensors. Microwave cavities based on the Tl-2212 films are the basis for subsequent applications as communication antennas and transmitters in satellites.

  4. Vapor deposition of thin films

    SciTech Connect (OSTI)

    Smith, D.C.; Pattillo, S.G.; Laia, J.R. Jr.; Sattelberger, A.P.

    1990-10-05

    A highly pure thin metal film having a nanocrystalline structure and a process of preparing such highly pure thin metal films of, e.g., rhodium, iridium, molybdenum, tungsten, rhenium, platinum, or palladium by plasma assisted chemical vapor deposition of, e.g., rhodium(allyl){sub 3}, iridium(allyl){sub 3}, molybdenum(allyl){sub 4}, tungsten(allyl){sub 4}, rhenium (allyl){sub 4}, platinum(allyl){sub 2}, or palladium(allyl){sub 2} are disclosed. Additionally, a general process of reducing the carbon content of a metallic film prepared from one or more organometallic precursor compounds by plasma assisted chemical vapor deposition is disclosed.

  5. Vapor deposition of thin films

    DOE Patents [OSTI]

    Smith, David C. (Los Alamos, NM); Pattillo, Stevan G. (Los Alamos, NM); Laia, Jr., Joseph R. (Los Alamos, NM); Sattelberger, Alfred P. (Los Alamos, NM)

    1992-01-01

    A highly pure thin metal film having a nanocrystalline structure and a process of preparing such highly pure thin metal films of, e.g., rhodium, iridium, molybdenum, tungsten, rhenium, platinum, or palladium by plasma assisted chemical vapor deposition of, e.g., rhodium(allyl).sub.3, iridium(allyl).sub.3, molybdenum(allyl).sub.4, tungsten(allyl).sub.4, rhenium(allyl).sub.4, platinum(allyl).sub.2, or palladium(allyl).sub.2 are disclosed. Additionally, a general process of reducing the carbon content of a metallic film prepared from one or more organometallic precursor compounds by plasma assisted chemical vapor deposition is disclosed.

  6. High-resolution dichroic imaging of magnetic flux distributions in superconductors with scanning x-ray microscopy

    SciTech Connect (OSTI)

    Ruoß, S. Stahl, C.; Weigand, M.; Schütz, G.; Albrecht, J.

    2015-01-12

    The penetration of magnetic flux into high-temperature superconductors has been observed using a high-resolution technique based on x-ray magnetic circular dichroism. Superconductors coated with thin soft-magnetic layers are observed in a scanning x-ray microscope under the influence of external magnetic fields. Resulting electric currents in the superconductor create an inhomogeneous magnetic field distribution above the superconductor and lead to a local reorientation of the ferromagnetic layer. Measuring the local magnetization of the ferromagnet by x-ray absorption microscopy with circular-polarized radiation allows the analysis of the magnetic flux distribution in the superconductor with a spatial resolution on the nanoscale.

  7. Magnetic Reconnection

    SciTech Connect (OSTI)

    Masaaki Yamada, Russell Kulsrud and Hantao Ji

    2009-09-17

    We review the fundamental physics of magnetic reconnection in laboratory and space plasmas, by discussing results from theory, numerical simulations, observations from space satellites, and the recent results from laboratory plasma experiments. After a brief review of the well-known early work, we discuss representative recent experimental and theoretical work and attempt to interpret the essence of significant modern findings. In the area of local reconnection physics, many significant findings have been made with regard to two- uid physics and are related to the cause of fast reconnection. Profiles of the neutral sheet, Hall currents, and the effects of guide field, collisions, and micro-turbulence are discussed to understand the fundamental processes in a local reconnection layer both in space and laboratory plasmas. While the understanding of the global reconnection dynamics is less developed, notable findings have been made on this issue through detailed documentation of magnetic self-organization phenomena in fusion plasmas. Application of magnetic reconnection physics to astrophysical plasmas is also brie y discussed.

  8. Magneto-optical characterizations of FeTe???Se??? thin films with critical current density over 1 MA/cm

    SciTech Connect (OSTI)

    Sun, Yue; Li, Qiang; Tsuchiya, Yuji; Pyon, Sunseng; Tamegai, Tsuyoshi; Zhang, Cheng; Ozaki, Toshinori

    2015-01-01

    We performed magneto-optical (MO) measurements on FeTe???Se??? thin films grown on LaAlO? (LAO) and Yttria-stabilized zirconia (YSZ) single-crystalline substrates. These thin films show superconducting transition temperature Tc ~19 K, 4 K higher than the bulk sample. Typical roof-top patterns can be observed in the MO images of thin films grown on LAO and YSZ, from which a large and homogeneous critical current density Jc ~ 3 - 4 x 10? A/cm at 5 K was obtained. Magnetic flux penetration measurement reveals that the current is almost isotropically distributed in the two thin films. Compared with bulk crystals, FeTe???Se??? thin film demonstrates not only higher Tc, but also much larger Jc, which is attractive for applications.

  9. Thin film polymeric gel electrolytes

    DOE Patents [OSTI]

    Derzon, Dora K.; Arnold, Jr., Charles; Delnick, Frank M.

    1996-01-01

    Novel hybrid thin film electrolyte, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities .apprxeq.10.sup.-3 .OMEGA..sup.-1 cm.sup.-1 are useful as electrolytes for rechargeable lithium batteries.

  10. Thin film polymeric gel electrolytes

    DOE Patents [OSTI]

    Derzon, D.K.; Arnold, C. Jr.; Delnick, F.M.

    1996-12-31

    Novel hybrid thin film electrolytes, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities {approx_equal}10{sup {minus}3}{Omega}{sup {minus}1} cm{sup {minus}1} are useful as electrolytes for rechargeable lithium batteries. 1 fig.

  11. Stability of charged thin shells

    SciTech Connect (OSTI)

    Eiroa, Ernesto F.; Simeone, Claudio

    2011-05-15

    In this article we study the mechanical stability of spherically symmetric thin shells with charge, in Einstein-Maxwell and Einstein-Born-Infeld theories. We analyze linearized perturbations preserving the symmetry, for shells around vacuum and shells surrounding noncharged black holes.

  12. Semiconductor-nanocrystal/conjugated polymer thin films

    DOE Patents [OSTI]

    Alivisatos, A. Paul; Dittmer, Janke J.; Huynh, Wendy U.; Milliron, Delia

    2010-08-17

    The invention described herein provides for thin films and methods of making comprising inorganic semiconductor-nanocrystals dispersed in semiconducting-polymers in high loading amounts. The invention also describes photovoltaic devices incorporating the thin films.

  13. Solar Thin Power | Open Energy Information

    Open Energy Info (EERE)

    Power Jump to: navigation, search Name: Solar Thin Power Place: New York Sector: Solar Product: Solar Thin Power was formed to seek out solar projects in North America, Asia and...

  14. Semiconductor-nanocrystal/conjugated polymer thin films

    DOE Patents [OSTI]

    Alivisatos, A. Paul; Dittmer, Janke J.; Huynh, Wendy U.; Milliron, Delia

    2014-06-17

    The invention described herein provides for thin films and methods of making comprising inorganic semiconductor-nanocrystals dispersed in semiconducting-polymers in high loading amounts. The invention also describes photovoltaic devices incorporating the thin films.

  15. Low work function, stable thin films

    DOE Patents [OSTI]

    Dinh, Long N.; McLean, II, William; Balooch, Mehdi; Fehring, Jr., Edward J.; Schildbach, Marcus A.

    2000-01-01

    Generation of low work function, stable compound thin films by laser ablation. Compound thin films with low work function can be synthesized by simultaneously laser ablating silicon, for example, and thermal evaporating an alkali metal into an oxygen environment. For example, the compound thin film may be composed of Si/Cs/O. The work functions of the thin films can be varied by changing the silicon/alkali metal/oxygen ratio. Low work functions of the compound thin films deposited on silicon substrates were confirmed by ultraviolet photoelectron spectroscopy (UPS). The compound thin films are stable up to 500.degree. C. as measured by x-ray photoelectron spectroscopy (XPS). Tests have established that for certain chemical compositions and annealing temperatures of the compound thin films, negative electron affinity (NEA) was detected. The low work function, stable compound thin films can be utilized in solar cells, field emission flat panel displays, electron guns, and cold cathode electron guns.

  16. Thin film-coated polymer webs

    DOE Patents [OSTI]

    Wenz, Robert P.; Weber, Michael F.; Arudi, Ravindra L.

    1992-02-04

    The present invention relates to thin film-coated polymer webs, and more particularly to thin film electronic devices supported upon a polymer web, wherein the polymer web is treated with a purifying amount of electron beam radiation.

  17. Beta (β) tungsten thin films: Structure, electron transport, and giant spin Hall effect

    SciTech Connect (OSTI)

    Hao, Qiang; Chen, Wenzhe; Xiao, Gang

    2015-05-04

    We use a simple magnetron sputtering process to fabricate beta (β) tungsten thin films, which are capable of generating giant spin Hall effect. As-deposited thin films are always in the metastable β-W phase from 3.0 to 26.7 nm. The β-W phase remains intact below a critical thickness of 22.1 nm even after magnetic thermal annealing at 280 °C, which is required to induce perpendicular magnetic anisotropy (PMA) in a layered structure of β-W/Co{sub 40}Fe{sub 40}B{sub 20}/MgO. Intensive annealing transforms the thicker films (>22.1 nm) into the stable α-W phase. We analyze the structure and grain size of both β- and α-W thin films. Electron transport in terms of resistivity and normal Hall effect is studied over a broad temperature range of 10 K to at least 300 K on all samples. Very low switching current densities are achieved in β-W/Co{sub 40}Fe{sub 40}B{sub 20}/MgO with PMA. These basic properties reveal useful behaviors in β-W thin films, making them technologically promising for spintronic magnetic random access memories and spin-logic devices.

  18. Progress in thin film solar photovoltaic technologies

    SciTech Connect (OSTI)

    Ullal, H.S.; Zweibel, K.; Mitchell, R.L. )

    1991-01-01

    This paper focuses on the rapid recent advances made by thin film solar cell technologies, namely, amorphous silicon, copper indium diselenide, and cadmium telluride. It also indicates the several advantages of thin films. Various consumer products and power applications using thin film solar cells are also discussed. The increasing interest among the utilities for PV system applications is also elucidated.

  19. Electromagnetic augmentation for casting of thin metal sheets

    DOE Patents [OSTI]

    Hull, John R.

    1989-01-01

    Thin metal sheets are cast by magnetically levitating molten metal deposited in a mold within a ferromagnetic yoke and between AC conducting coils and linearly displacing the magnetically levitated liquid metal while it is being cooled by the water-cooled walls of the mold to form a solid metal sheet. A conducting shield is electrically coupled to the molten metal sheet to provide a return path for eddy currents induced in the metal sheet by the current in the AC conducting coils. In another embodiment, a DC conducting coil is coupled to the metal sheet for providing a direct current therein which interacts with the magnetic field to levitate the moving metal sheet. Levitation of the metal sheet in both molten and solid forms reduces its contact pressure with the mold walls while maintaining sufficient engagement therebetween to permit efficient conductive cooling by the mold through which a coolant fluid may be circulated. The magnetic fields associated with the currents in the aforementioned coils levitate the molten metal sheet while the mold provides for its lateral and vertical confinement. A leader sheet having electromagnetic characteristics similar to those of the molten metal sheet is used to start the casing process and precedes the molten metal sheet through the yoke/coil arrangement and mold and forms a continuous sheet therewith. The yoke/coil arrangement may be either U-shaped with a single racetrack coil or may be rectangular with a pair of spaced, facing bedstead coils.

  20. Superconducting magnet

    DOE Patents [OSTI]

    Satti, John A. (Naperville, IL)

    1980-01-01

    A superconducting magnet designed to produce magnetic flux densities of the order of 4 to 5 Webers per square meter is constructed by first forming a cable of a plurality of matrixed superconductor wires with each wire of the plurality insulated from each other one. The cable is shaped into a rectangular cross-section and is wound with tape in an open spiral to create cooling channels. Coils are wound in a calculated pattern in saddle shapes to produce desired fields, such as dipoles, quadrupoles, and the like. Wedges are inserted between adjacent cables as needed to maintain substantially radial placement of the long dimensions of cross sections of the cables. After winding, individual strands in each of the cables are brought out to terminals and are interconnected to place all of the strands in series and to maximize the propagation of a quench by alternating conduction from an inner layer to an outer layer and from top half to bottom half as often as possible. Individual layers are separated from others by spiraled aluminum spacers to facilitate cooling. The wound coil is wrapped with an epoxy tape that is cured by heat and then machined to an interference fit with an outer aluminum pipe which is then affixed securely to the assembled coil by heating it to make a shrink fit. In an alternate embodiment, one wire of the cable is made of copper or the like to be heated externally to propagate a quench.

  1. Magnetic vortex crystal formation in the antidot complement of square artificial spin ice

    SciTech Connect (OSTI)

    Araujo, C. I. L. de Silva, R. C.; Ribeiro, I. R. B.; Nascimento, F. S.; Felix, J. F.; Ferreira, S. O.; Moura-Melo, W. A.; Pereira, A. R.; Ml, L. A. S.

    2014-03-03

    We have studied ferromagnetic nickel thin films patterned with square lattices of elongated antidots that are negative analogues of square artificial spin ice. Micromagnetic simulations and direct current magnetic moment measurements reveal in-plane anisotropy of the magnetic hysteresis loops, and the formation of a dense array of magnetic vortices with random polarization and chirality. These multiply-connected antidot arrays could be superior to lattices of disconnected nanodisks for investigations of vortex switching by applied electric current.

  2. Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Vortices Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Print Wednesday, 27 August 2008 00:00 Soft magnetic, micron-sized thin-film structures with magnetic vortices are intriguing systems that may one day be used in ultrafast computer memories. In such systems, the otherwise in-plane magnetization turns perpendicular to the plane at the center of the vortex, forming the vortex core.

  3. FEM calculation of eddy current losses and forces in thin conducting sheets of test facilities for fusion reactor components

    SciTech Connect (OSTI)

    Biro, O.; Preis, K.; Richter, K.R. ); Heller, R.; Komarek, P.; Maurer, W. )

    1992-03-01

    The eddy current carrying conducting parts in fusion reactor models are frequently relatively thin sheets. To avoid the associated numerical problems, the surface current density is represented in this paper by a scalar quantity and, as a novelty, the magnetic field is described overall by a magnetic vector potential to treat multiply connected conductors easily. The method is applied to several problems involving fusion reactor components.

  4. Permanent magnet assembly

    DOE Patents [OSTI]

    Chell, Jeremy; Zimm, Carl B.

    2006-12-12

    A permanent magnet assembly is disclosed that is adapted to provide a magnetic field across an arc-shaped gap. Such a permanent magnet assembly can be used, for example, to provide a time-varying magnetic field to an annular region for use in a magnetic refrigerator.

  5. Magnetic reconnection in a weakly ionized plasma

    SciTech Connect (OSTI)

    Leake, James E.; Lukin, Vyacheslav S.; Linton, Mark G.

    2013-06-15

    Magnetic reconnection in partially ionized plasmas is a ubiquitous phenomenon spanning the range from laboratory to intergalactic scales, yet it remains poorly understood and relatively little studied. Here, we present results from a self-consistent multi-fluid simulation of magnetic reconnection in a weakly ionized reacting plasma with a particular focus on the parameter regime of the solar chromosphere. The numerical model includes collisional transport, interaction and reactions between the species, and optically thin radiative losses. This model improves upon our previous work in Leake et al.[“Multi-fluid simulations of chromospheric magnetic reconnection in a weakly ionized reacting plasma,” Astrophys. J. 760, 109 (2012)] by considering realistic chromospheric transport coefficients, and by solving a generalized Ohm's law that accounts for finite ion-inertia and electron-neutral drag. We find that during the two dimensional reconnection of a Harris current sheet with an initial width larger than the neutral-ion collisional coupling scale, the current sheet thins until its width becomes less than this coupling scale, and the neutral and ion fluids decouple upstream from the reconnection site. During this process of decoupling, we observe reconnection faster than the single-fluid Sweet-Parker prediction, with recombination and plasma outflow both playing a role in determining the reconnection rate. As the current sheet thins further and elongates, it becomes unstable to the secondary tearing instability, and plasmoids are seen. The reconnection rate, outflows, and plasmoids observed in this simulation provide evidence that magnetic reconnection in the chromosphere could be responsible for jet-like transient phenomena such as spicules and chromospheric jets.

  6. Try This: Household Magnets

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Now which is stronger, gravity or magnetism? What is going on? How do flexible refrigerator magnets work? Get two of these magnets, they are often the size of a business card....

  7. Magnetization of neutron matter

    SciTech Connect (OSTI)

    Bigdeli, M.

    2011-09-21

    In this paper, we compute magnetization of neutron matter at strong magnetic field using the lowest order constrained variational (LOCV) technique.

  8. Metallic transport and large anomalous Hall effect at room temperature in ferrimagnetic Mn{sub 4}N epitaxial thin film

    SciTech Connect (OSTI)

    Shen, Xi; Shigematsu, Kei; Chikamatsu, Akira Fukumura, Tomoteru; Hirose, Yasushi; Hasegawa, Tetsuya

    2014-08-18

    We report the electrical transport properties of ferrimagnetic Mn{sub 4}N (001) epitaxial thin films grown by pulsed laser deposition on MgO (001) substrates. The Mn{sub 4}N thin films were tetragonally distorted with a ratio of out-of-plane to in-plane lattice constants of 0.987 and showed perpendicular magnetic anisotropy with an effective magnetic anisotropy constant of 0.16 MJ/m{sup 3}, which is comparable with that of a recently reported molecular-beam-epitaxy-grown film. The thin films exhibited metallic transport with a room temperature resistivity of 125 μΩ cm in addition to a large anomalous Hall effect with a Hall angle tangent of 0.023.

  9. Near-field radiative heat transfer between metamaterials coated with silicon carbide thin films

    SciTech Connect (OSTI)

    Basu, Soumyadipta Yang, Yue; Wang, Liping

    2015-01-19

    In this letter, we study the near-field radiative heat transfer between two metamaterial substrates coated with silicon carbide (SiC) thin films. It is known that metamaterials can enhance the near-field heat transfer over ordinary materials due to excitation of magnetic plasmons associated with s polarization, while strong surface phonon polariton exists for SiC. By careful tuning of the optical properties of metamaterial, it is possible to excite electrical and magnetic resonances for the metamaterial and surface phonon polaritons for SiC at different spectral regions, resulting in the enhanced heat transfer. The effect of the SiC film thickness at different vacuum gaps is investigated. Results obtained from this study will be beneficial for application of thin film coatings for energy harvesting.

  10. Generation of localized strain in a thin film piezoelectric to control individual magnetoelectric heterostructures

    SciTech Connect (OSTI)

    Cui, Jizhai; Liang, Cheng-Yen; Sepulveda, Abdon; Carman, Gregory P.; Lynch, Christopher S.; Paisley, Elizabeth A.; Ihlefeld, Jon F.

    2015-08-31

    Experimental results demonstrate the ability of a surface electrode pattern to produce sufficient in-plane strain in a PbZr{sub 0.52}Ti{sub 0.48}O{sub 3} (PZT) thin film clamped by a Si substrate to control magnetism in a 1000 nm diameter Ni ring. The electrode pattern and the Ni ring/PZT thin film heterostructure were designed using a finite element based micromagnetics code. The magnetoelectric heterostructures were fabricated on the PZT film using e-beam lithography and characterized using magnetic force microscopy. Application of voltage to the electrodes moved one of the “onion” state domain walls. This method enables the development of complex architectures incorporating strain-mediated multiferroic devices.

  11. Interface Coupling Transition in a Thin EpitaxialAntiferromagnetic Film Interacting with a Ferromagnetic Substrate

    SciTech Connect (OSTI)

    Finazzi, M.; Brambilla, A.; Biagioni, P.; Graf, J.; Gweon, G.-H.; Scholl, A.; Lanzara, A.; Duo, L.

    2006-09-07

    We report experimental evidence for a transition in theinterface coupling between an antiferromagnetic film and a ferromagneticsubstrate. The transition is observed in a thin epitaxial NiO film grownon top of Fe(001) as the film thickness is increased. Photoemissionelectron microscopy excited with linearly polarized x rays shows that theNiO film is antiferromagnetic at room temperature with in-plane uniaxialmagnetic anisotropy. The anisotropy axis is perpendicular to the Fesubstrate magnetization when the NiO thickness is less than about 15A,but rapidly becomes parallel to the Fe magnetization for a NiO coveragehigher than 25 A.

  12. Thin film solar energy collector

    DOE Patents [OSTI]

    Aykan, Kamran; Farrauto, Robert J.; Jefferson, Clinton F.; Lanam, Richard D.

    1983-11-22

    A multi-layer solar energy collector of improved stability comprising: (1) a substrate of quartz, silicate glass, stainless steel or aluminum-containing ferritic alloy; (2) a solar absorptive layer comprising silver, copper oxide, rhodium/rhodium oxide and 0-15% by weight of platinum; (3) an interlayer comprising silver or silver/platinum; and (4) an optional external anti-reflective coating, plus a method for preparing a thermally stable multi-layered solar collector, in which the absorptive layer is undercoated with a thin film of silver or silver/platinum to obtain an improved conductor-dielectric tandem.

  13. Thin film buried anode battery

    DOE Patents [OSTI]

    Lee, Se-Hee; Tracy, C. Edwin; Liu, Ping

    2009-12-15

    A reverse configuration, lithium thin film battery (300) having a buried lithium anode layer (305) and process for making the same. The present invention is formed from a precursor composite structure (200) made by depositing electrolyte layer (204) onto substrate (201), followed by sequential depositions of cathode layer (203) and current collector (202) on the electrolyte layer. The precursor is subjected to an activation step, wherein a buried lithium anode layer (305) is formed via electroplating a lithium anode layer at the interface of substrate (201) and electrolyte film (204). The electroplating is accomplished by applying a current between anode current collector (201) and cathode current collector (202).

  14. MAGNETIC DENSITOMETER

    DOE Patents [OSTI]

    McCann, J.A.; Jones, R.H.

    1961-08-15

    A magnetic densitometer for locating defects and metallic inclusions in materials is described. The apparatus consists of two primary coils connected in series opposition and adapted te be placed in inductive relation to the material under test, a source of constant frequency alternating current coupled across the primary coil combination, a pick-up coil disposed in symmetrical inductive relationship with said primary coils, a phase-shifter coupled to the output of the energizing source. The output of the phase-shifter is coupled in series with the pick-up coil. An amplifier is provided selective to the third harmonic of the energizing source frequency. The series combination of the pick-up coil and the phase-shifter output are connected across the input of the amplifier, and an amplitude comparitor is coupled to the output of the amplifier and the energizing source for comparing the instantaneous amplitude of the amplifier output and the instantaneous output of the energizing source and producing an output proportional to the difference in amplitude. A recorder is coupled to the output of the amplitude comparison means to give an indication of the amplitude difference, thereby providing a permanent presentation of the character of the changes in characteristics exhibited by the material under test. (AEC)

  15. Progress in thin film solar photovoltaic technologies

    SciTech Connect (OSTI)

    Ullal, H.S.; Zweibel, K.

    1989-12-01

    This paper focuses on the rapid recent advances made by thin film solar cell technologies, namely, amorphous silicon, copper indium diselenide, and cadmium telluride. It also indicates the several advantages of thin films. Various consumer products and power applications using thin film solar cells are also discussed. The increasing interest among the utilities for PV system applications is also elucidated. 29 refs., 8 figs., 3 tabs.

  16. Method of producing amorphous thin films

    DOE Patents [OSTI]

    Brusasco, Raymond M.

    1992-01-01

    Disclosed is a method of producing thin films by sintering which comprises: a. coating a substrate with a thin film of an inorganic glass forming parulate material possessing the capability of being sintered, and b. irridiating said thin film of said particulate material with a laser beam of sufficient power to cause sintering of said material below the temperature of liquidus thereof. Also disclosed is the article produced by the method claimed.

  17. Sputtered Thin Film Photovoltaics - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Solar Photovoltaic Solar Photovoltaic Find More Like This Return to Search Sputtered Thin Film Photovoltaics Naval Research Laboratory Contact NRL About This Technology ...

  18. Superhydrophobic Thin Film Coatings - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Solar Thermal Solar Thermal Solar Photovoltaic Solar Photovoltaic Industrial Technologies ... Find More Like This Return to Search Superhydrophobic Thin Film Coatings Oak Ridge ...

  19. Suppression of the thermal hysteresis in magnetocaloric MnAs thin film by highly charged ion bombardment

    SciTech Connect (OSTI)

    Trassinelli, M. Marangolo, M.; Eddrief, M.; Etgens, V. H.; Gafton, V.; Hidki, S.; Lacaze, E.; Lamour, E.; Prigent, C.; Rozet, J.-P.; Steydli, S.; Zheng, Y.; Vernhet, D.

    2014-02-24

    We present the investigation on the modifications of structural and magnetic properties of MnAs thin film epitaxially grown on GaAs induced by slow highly charged ions bombardment under well-controlled conditions. The ion-induced defects facilitate the nucleation of one phase with respect to the other in the first-order magneto-structural MnAs transition, with a consequent suppression of thermal hysteresis without any significant perturbation on the other structural and magnetic properties. In particular, the irradiated film keeps the giant magnetocaloric effect at room temperature opening new perspective on magnetic refrigeration technology for everyday use.

  20. Magnetic multilayer structure

    DOE Patents [OSTI]

    Herget, Philipp; O'Sullivan, Eugene J.; Romankiw, Lubomyr T.; Wang, Naigang; Webb, Bucknell C.

    2016-07-05

    A mechanism is provided for an integrated laminated magnetic device. A substrate and a multilayer stack structure form the device. The multilayer stack structure includes alternating magnetic layers and diode structures formed on the substrate. Each magnetic layer in the multilayer stack structure is separated from another magnetic layer in the multilayer stack structure by a diode structure.

  1. Magnetic Membrane System

    DOE Patents [OSTI]

    McElfresh, Michael W.; ; Lucas, Matthew S.

    2004-12-30

    The present invention provides a membrane with magnetic particles. In one embodiment the membrane is created by mixing particles in a non-magnetic base. The membrane may act as an actuator, a sensor, a pump, a valve, or other device. A magnet is operatively connected to the membrane. The magnet acts on and changes the shape of the membrane.

  2. Recycling Magnets | Jefferson Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Recycling Magnets Recycling Magnets July 15, 2013 The cost of a nuclear or particle physics experiment can be enormous, several hundred million dollars for the Large Hadron Collider Experiments, ATLAS and CMS at CERN, several tens of millions of dollars for an experiment like our GlueX experiment in Hall D, being built as part of our upgrade project. Among the expensive components of many experiments is a large magnet or sometimes more than one magnet. Sometimes the magnets have interesting

  3. Magnetic Damping For Maglev

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhu, S.; Cai, Y.; Rote, D. M.; Chen, S. S.

    1998-01-01

    Magnetic damping is one of the important parameters that control the response and stability of maglev systems. An experimental study to measure magnetic damping directly is presented. A plate attached to a permanent magnet levitated on a rotating drum was tested to investigate the effect of various parameters, such as conductivity, gap, excitation frequency, and oscillation amplitude, on magnetic damping. The experimental technique is capable of measuring all of the magnetic damping coefficients, some of which cannot be measured indirectly.

  4. Tag gas capsule with magnetic piercing device

    DOE Patents [OSTI]

    Nelson, Ira V.

    1976-06-22

    An apparatus for introducing a tag (i.e., identifying) gas into a tubular nuclear fuel element. A sealed capsule containing the tag gas is placed in the plenum in the fuel tube between the fuel and the end cap. A ferromagnetic punch having a penetrating point is slidably mounted in the plenum. By external electro-magnets, the punch may be caused to penetrate a thin rupturable end wall of the capsule and release the tag gas into the fuel element. Preferably the punch is slidably mounted within the capsule, which is in turn loaded as a sealed unit into the fuel element.

  5. Tailoring the coercivity in ferromagnetic ZnO thin films by 3d and 4f elements codoping

    SciTech Connect (OSTI)

    Lee, J. J.; Xing, G. Z. Yi, J. B.; Li, S.; Chen, T.; Ionescu, M.

    2014-01-06

    Cluster free, Co (3d) and Eu (4f) doped ZnO thin films were prepared using ion implantation technique accompanied by post annealing treatments. Compared with the mono-doped ZnO thin films, the samples codoped with Co and Eu exhibit a stronger magnetization with a giant coercivity of 1200 Oe at ambient temperature. This was further verified through x-ray magnetic circular dichroism analysis, revealing the exchange interaction between the Co 3d electrons and the localized carriers induced by Eu{sup 3+} ions codoping. The insight gained with modulating coercivity in magnetic oxides opens up an avenue for applications requiring non-volatility in spintronic devices.

  6. Thin films of mixed metal compounds

    SciTech Connect (OSTI)

    Mickelsen, Reid A.; Chen, Wen S.

    1985-01-01

    A compositionally uniform thin film of a mixed metal compound is formed by simultaneously evaporating a first metal compound and a second metal compound from independent sources. The mean free path between the vapor particles is reduced by a gas and the mixed vapors are deposited uniformly. The invention finds particular utility in forming thin film heterojunction solar cells.

  7. Nanocomposite Magnets: Transformational Nanostructured Permanent Magnets

    SciTech Connect (OSTI)

    2010-10-01

    Broad Funding Opportunity Announcement Project: GE is using nanomaterials technology to develop advanced magnets that contain fewer rare earth materials than their predecessors. Nanomaterials technology involves manipulating matter at the atomic or molecular scale, which can represent a stumbling block for magnets because it is difficult to create a finely grained magnet at that scale. GE is developing bulk magnets with finely tuned structures using iron-based mixtures that contain 80% less rare earth materials than traditional magnets, which will reduce their overall cost. These magnets will enable further commercialization of HEVs, EVs, and wind turbine generators while enhancing U.S. competitiveness in industries that heavily utilize these alternatives to rare earth minerals.

  8. Origin of superstructures in (double) perovskite thin films

    SciTech Connect (OSTI)

    Shabadi, V. Major, M.; Komissinskiy, P.; Vafaee, M.; Radetinac, A.; Baghaie Yazdi, M.; Donner, W.; Alff, L.

    2014-09-21

    We have investigated the origin of superstructure peaks as observed by X-ray diffraction of multiferroic Bi(Fe{sub 0.5}Cr{sub 0.5})O{sub 3} thin films grown by pulsed laser deposition on single crystal SrTiO{sub 3} substrates. The photon energy dependence of the contrast between the atomic scattering factors of Fe and Cr is used to rule out a chemically ordered double perovskite Bi{sub 2}FeCrO{sub 6} (BFCO). Structural calculations suggest that the experimentally observed superstructure occurs due to unequal cation displacements along the pseudo-cubic [111] direction that mimic the unit cell of the chemically ordered compound. This result helps to clarify discrepancies in the correlations of structural and magnetic order reported for Bi{sub 2}FeCrO{sub 6}. The observation of a superstructure in itself is not a sufficient proof of chemical order in double perovskites.

  9. Room-temperature magnetoelectric multiferroic thin films and applications thereof

    DOE Patents [OSTI]

    Katiyar, Ram S; Kuman, Ashok; Scott, James F.

    2014-08-12

    The invention provides a novel class of room-temperature, single-phase, magnetoelectric multiferroic (PbFe.sub.0.67W.sub.0.33O.sub.3).sub.x (PbZr.sub.0.53Ti.sub.0.47O.sub.3).sub.1-x (0.2.ltoreq.x.ltoreq.0.8) (PFW.sub.x-PZT.sub.1-x) thin films that exhibit high dielectric constants, high polarization, weak saturation magnetization, broad dielectric temperature peak, high-frequency dispersion, low dielectric loss and low leakage current. These properties render them to be suitable candidates for room-temperature multiferroic devices. Methods of preparation are also provided.

  10. Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Vortices Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Print Soft magnetic, micron-sized thin-film structures with magnetic vortices are intriguing systems that may one day be used in ultrafast computer memories. In such systems, the otherwise in-plane magnetization turns perpendicular to the plane at the center of the vortex, forming the vortex core. Because such a core has two possible polarizations (up or down) and can be switched between these two states