National Library of Energy BETA

Sample records for magnetic domain walls

  1. Stochastic Domain-Wall Depinning in Magnetic Nanowires

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

    Stochastic Domain-Wall Depinning in Magnetic Nanowires Stochastic Domain-Wall Depinning in Magnetic Nanowires Print Wednesday, 29 July 2009 00:00 Reliably controlling the motion of magnetic domain walls along magnetic nanowires is a key requirement for current technological development of novel classes of logic and storage devices, but understanding the nature of non-deterministic domain-wall motion remains a scientific challenge. A statistical analysis of high-resolution magnetic soft x-ray

  2. Stochastic Domain-Wall Depinning in Magnetic Nanowires

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

    Stochastic Domain-Wall Depinning in Magnetic Nanowires Print Reliably controlling the motion of magnetic domain walls along magnetic nanowires is a key requirement for current technological development of novel classes of logic and storage devices, but understanding the nature of non-deterministic domain-wall motion remains a scientific challenge. A statistical analysis of high-resolution magnetic soft x-ray microscopy images by a Berkeley Lab-University of Hamburg group has now revealed that

  3. Stochastic Domain-Wall Depinning in Magnetic Nanowires

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

    Stochastic Domain-Wall Depinning in Magnetic Nanowires Print Reliably controlling the motion of magnetic domain walls along magnetic nanowires is a key requirement for current technological development of novel classes of logic and storage devices, but understanding the nature of non-deterministic domain-wall motion remains a scientific challenge. A statistical analysis of high-resolution magnetic soft x-ray microscopy images by a Berkeley Lab-University of Hamburg group has now revealed that

  4. Stochastic Domain-Wall Depinning in Magnetic Nanowires

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

    Stochastic Domain-Wall Depinning in Magnetic Nanowires Print Reliably controlling the motion of magnetic domain walls along magnetic nanowires is a key requirement for current technological development of novel classes of logic and storage devices, but understanding the nature of non-deterministic domain-wall motion remains a scientific challenge. A statistical analysis of high-resolution magnetic soft x-ray microscopy images by a Berkeley Lab-University of Hamburg group has now revealed that

  5. Stochastic Domain-Wall Depinning in Magnetic Nanowires

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

    Stochastic Domain-Wall Depinning in Magnetic Nanowires Print Reliably controlling the motion of magnetic domain walls along magnetic nanowires is a key requirement for current technological development of novel classes of logic and storage devices, but understanding the nature of non-deterministic domain-wall motion remains a scientific challenge. A statistical analysis of high-resolution magnetic soft x-ray microscopy images by a Berkeley Lab-University of Hamburg group has now revealed that

  6. Stochastic Domain-Wall Depinning in Magnetic Nanowires

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

    Stochastic Domain-Wall Depinning in Magnetic Nanowires Print Reliably controlling the motion of magnetic domain walls along magnetic nanowires is a key requirement for current technological development of novel classes of logic and storage devices, but understanding the nature of non-deterministic domain-wall motion remains a scientific challenge. A statistical analysis of high-resolution magnetic soft x-ray microscopy images by a Berkeley Lab-University of Hamburg group has now revealed that

  7. Stochastic Domain-Wall Depinning in Magnetic Nanowires

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

    Stochastic Domain-Wall Depinning in Magnetic Nanowires Print Reliably controlling the motion of magnetic domain walls along magnetic nanowires is a key requirement for current technological development of novel classes of logic and storage devices, but understanding the nature of non-deterministic domain-wall motion remains a scientific challenge. A statistical analysis of high-resolution magnetic soft x-ray microscopy images by a Berkeley Lab-University of Hamburg group has now revealed that

  8. Stochastic Domain-Wall Depinning in Magnetic Nanowires

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

    Stochastic Domain-Wall Depinning in Magnetic Nanowires Print Reliably controlling the motion of magnetic domain walls along magnetic nanowires is a key requirement for current technological development of novel classes of logic and storage devices, but understanding the nature of non-deterministic domain-wall motion remains a scientific challenge. A statistical analysis of high-resolution magnetic soft x-ray microscopy images by a Berkeley Lab-University of Hamburg group has now revealed that

  9. Stochastic Domain-Wall Depinning in Magnetic Nanowires

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

    concept called a racetrack memory, for example, the electron spin provides the driving force that moves a domain wall (boundary between regions of different magnetization) down...

  10. Thermal effects on transverse domain wall dynamics in magnetic nanowires

    SciTech Connect (OSTI)

    Leliaert, J.; Van de Wiele, B.; Vandermeulen, J.; Coene, A.; Dupré, L.; Vansteenkiste, A.; Waeyenberge, B. Van; Laurson, L.; Durin, G.

    2015-05-18

    Magnetic domain walls are proposed as data carriers in future spintronic devices, whose reliability depends on a complete understanding of the domain wall motion. Applications based on an accurate positioning of domain walls are inevitably influenced by thermal fluctuations. In this letter, we present a micromagnetic study of the thermal effects on this motion. As spin-polarized currents are the most used driving mechanism for domain walls, we have included this in our analysis. Our results show that at finite temperatures, the domain wall velocity has a drift and diffusion component, which are in excellent agreement with the theoretical values obtained from a generalized 1D model. The drift and diffusion component are independent of each other in perfect nanowires, and the mean square displacement scales linearly with time and temperature.

  11. Increased magnetic damping of a single domain wall and adjacent magnetic domains detected by spin torque diode in a nanostripe

    SciTech Connect (OSTI)

    Lequeux, Steven; Sampaio, Joao; Bortolotti, Paolo; Cros, Vincent; Grollier, Julie; Matsumoto, Rie; Yakushiji, Kay; Kubota, Hitoshi; Fukushima, Akio; Yuasa, Shinji; Nishimura, Kazumasa; Nagamine, Yoshinori; Tsunekawa, Koji

    2015-11-02

    Spin torque resonance has been used to simultaneously probe the dynamics of a magnetic domain wall and of magnetic domains in a nanostripe magnetic tunnel junction. Due to the large associated resistance variations, we are able to analyze quantitatively the resonant properties of these single nanoscale magnetic objects. In particular, we find that the magnetic damping of both the domains and the domain wall is doubled compared to the damping value of the host magnetic layer. We estimate the contributions to the damping arising from the dipolar couplings between the different layers in the junction and from the intralayer spin pumping effect, and find that they cannot explain the large damping enhancement that we observe. We conclude that the measured increased damping is intrinsic to large amplitudes excitations of spatially localized modes or solitons such as vibrating or propagating domain walls.

  12. Magnetic bead detection using domain wall-based nanosensor

    SciTech Connect (OSTI)

    Corte-León, H.; Krzysteczko, P.; Schumacher, H. W.; Manzin, A.; Cox, D.; Antonov, V.; Kazakova, O.

    2015-05-07

    We investigate the effect of a single magnetic bead (MB) on the domain wall (DW) pinning/depinning fields of a DW trapped at the corner of an L-shaped magnetic nanodevice. DW propagation across the device is investigated using magnetoresistance measurements. DW pinning/depinning fields are characterized in as-prepared devices and after placement of a 1 μm-sized MB (Dynabeads{sup ®} MyOne{sup ™}) at the corner. The effect of the MB on the DW dynamics is seen as an increase in the depinning field for specific orientations of the device with respect to the external magnetic field. The shift of the depinning field, ΔB{sub dep} = 4.5–27.0 mT, is highly stable and reproducible, being significantly above the stochastic deviation which is about 0.5 mT. The shift in the deppinning field is inversely proportional to the device width and larger for small negative angles between the device and the external magnetic field. Thus, we demonstrate that DW-based devices can be successfully used for detection of single micron size MB.

  13. Domain wall motion driven by spin Hall effect—Tuning with in-plane magnetic anisotropy

    SciTech Connect (OSTI)

    Rushforth, A. W.

    2014-04-21

    This letter investigates the effects of in-plane magnetic anisotropy on the current induced motion of magnetic domain walls in systems with dominant perpendicular magnetic anisotropy, where accumulated spins from the spin Hall effect in an adjacent heavy metal layer are responsible for driving the domain wall motion. It is found that that the sign and magnitude of the domain wall velocity in the uniform flow regime can be tuned significantly by the in-plane magnetic anisotropy. These effects are sensitive to the ratio of the adiabatic and non-adiabatic spin transfer torque parameters and are robust in the presence of pinning and thermal fluctuations.

  14. X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires

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

    X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print The quest to increase both computer data-storage density and the speed at which one can read and write the information remains unconsummated. One novel concept is based on the use of a local electric current to push magnetic domain walls along a thin nanowire. A German, Korean, Berkeley Lab team has used the x-ray microscope XM-1 at the ALS to demonstrate that magnetic domain walls in curved permalloy nanowires can be

  15. X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires

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

    X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print The quest to increase both computer data-storage density and the speed at which one can read and write the information remains unconsummated. One novel concept is based on the use of a local electric current to push magnetic domain walls along a thin nanowire. A German, Korean, Berkeley Lab team has used the x-ray microscope XM-1 at the ALS to demonstrate that magnetic domain walls in curved permalloy nanowires can be

  16. X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires

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

    X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print The quest to increase both computer data-storage density and the speed at which one can read and write the information remains unconsummated. One novel concept is based on the use of a local electric current to push magnetic domain walls along a thin nanowire. A German, Korean, Berkeley Lab team has used the x-ray microscope XM-1 at the ALS to demonstrate that magnetic domain walls in curved permalloy nanowires can be

  17. X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires

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

    X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print The quest to increase both computer data-storage density and the speed at which one can read and write the information remains unconsummated. One novel concept is based on the use of a local electric current to push magnetic domain walls along a thin nanowire. A German, Korean, Berkeley Lab team has used the x-ray microscope XM-1 at the ALS to demonstrate that magnetic domain walls in curved permalloy nanowires can be

  18. X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires

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

    X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print Wednesday, 26 September 2007 00:00 The quest to increase both computer data-storage density and the speed at which one can read and write the information remains unconsummated. One novel concept is based on the use of a local electric current to push magnetic domain walls along a thin nanowire. A German, Korean, Berkeley Lab team has used the x-ray

  19. X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires

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

    X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print The quest to increase both computer data-storage density and the speed at which one can read and write the information remains unconsummated. One novel concept is based on the use of a local electric current to push magnetic domain walls along a thin nanowire. A German, Korean, Berkeley Lab team has used the x-ray microscope XM-1 at the ALS to demonstrate that magnetic domain walls in curved permalloy nanowires can be

  20. X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires

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

    X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print The quest to increase both computer data-storage density and the speed at which one can read and write the information remains unconsummated. One novel concept is based on the use of a local electric current to push magnetic domain walls along a thin nanowire. A German, Korean, Berkeley Lab team has used the x-ray microscope XM-1 at the ALS to demonstrate that magnetic domain walls in curved permalloy nanowires can be

  1. X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires

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

    X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print The quest to increase both computer data-storage density and the speed at which one can read and write the information remains unconsummated. One novel concept is based on the use of a local electric current to push magnetic domain walls along a thin nanowire. A German, Korean, Berkeley Lab team has used the x-ray microscope XM-1 at the ALS to demonstrate that magnetic domain walls in curved permalloy nanowires can be

  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. Stochastic Domain-Wall Depinning in Magnetic Nanowires

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

    walls and opens a path to further technological developments in spintronics applications. ... included under the umbrella of "spintronics," a technology based on using the ...

  4. Electric field driven magnetic domain wall motion in ferromagnetic-ferroelectric heterostructures

    SciTech Connect (OSTI)

    Van de Wiele, Ben; Laurson, Lasse; Franke, Kvin J. A.; Dijken, Sebastiaan van

    2014-01-06

    We investigate magnetic domain wall (MDW) dynamics induced by applied electric fields in ferromagnetic-ferroelectric thin-film heterostructures. In contrast to conventional driving mechanisms where MDW motion is induced directly by magnetic fields or electric currents, MDW motion arises here as a result of strong pinning of MDWs onto ferroelectric domain walls (FDWs) via local strain coupling. By performing extensive micromagnetic simulations, we find several dynamical regimes, including instabilities such as spin wave emission and complex transformations of the MDW structure. In all cases, the time-averaged MDW velocity equals that of the FDW, indicating the absence of Walker breakdown.

  5. Stability of a pinned magnetic domain wall as a function of its internal configuration

    SciTech Connect (OSTI)

    Montaigne, F.; Duluard, A.; Briones, J.; Lacour, D.; Hehn, M.; Childress, J. R.

    2015-01-14

    It is shown that there are many stable configurations for a domain wall pinned by a notch along a magnetic stripe. The stability of several of these configurations is investigated numerically as a function of the thickness of the magnetic film. The depinning mechanism depends on the structure of the domain wall and on the thickness of the magnetic film. In the case of a spin-valve structure, it appears that the stray fields emerging from the hard layer at the notch location influence the stability of the micromagnetic configuration. Different depinning mechanisms are thus observed for the same film thickness depending on the magnetization orientation of the propagating domain. This conclusion qualitatively explains experimental magnetoresistance measurements.

  6. Stochastic Domain-Wall Depinning in Magnetic Nanowires

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

    while. Such is the dream for novel magnetic data storage devices included under the umbrella of "spintronics," a technology based on using the electron's quantum-mechanical spin...

  7. Stochastic Domain-Wall Depinning in Magnetic Nanowires

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

    Ferromagnetic wires of nanometer sizes are considered to be key components in future spintronic applications for novel classes of magnetic storage devices. One example is the ...

  8. Stochastic Domain-Wall Depinning in Magnetic Nanowires

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

    Ferromagnetic wires of nanometer sizes are considered to be key components in future spintronic applications for novel classes of magnetic storage devices. One example is the...

  9. 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

  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

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. Magnetic domain wall manipulation in (Ga,Mn)As nanostructures for spintronic applications

    SciTech Connect (OSTI)

    Wosinski, Tadeusz; Andrearczyk, Tomasz; Figielski, Tadeusz; Olender, Karolina; Wrobel, Jerzy

    2014-02-21

    Ring-shaped nanostructures have been designed and fabricated by electron-beam lithography patterning and chemical etching from thin epitaxial layers of the ferromagnetic semiconductor (Ga,Mn)As. The nanostructures, in a form of planar rings with a slit, were supplied with four electrical terminals and subjected to magneto-transport studies under planar weak magnetic field. Magnetoresistive effects caused by manipulation of magnetic domain walls and magnetization reversal in the nanostructures have been investigated and possible applications of the nanostructures as four-terminal spintronic devices are discussed.

  17. Automotion of domain walls for spintronic interconnects

    SciTech Connect (OSTI)

    Nikonov, Dmitri E.; Manipatruni, Sasikanth; Young, Ian A.

    2014-06-07

    We simulate “automotion,” the transport of a magnetic domain wall under the influence of demagnetization and magnetic anisotropy, in nanoscale spintronic interconnects. In contrast to spin transfer driven magnetic domain wall motion, the proposed interconnects operate without longitudinal charge current transfer, with only a transient current pulse at domain wall creation and have favorable scaling down to the 20 nm dimension. Cases of both in-plane and out-of-plane magnetization are considered. Analytical dependence of the velocity of domain walls on the angle of magnetization are compared with full micromagnetic simulations. Deceleration, attenuation and disappearance, and reflection of domain walls are demonstrated through simulation. Dependences of the magnetization angle on the current pulse parameters are studied. The energy and delay analysis suggests that automotion is an attractive option for spintronic logic interconnects.

  18. Axion domain wall baryogenesis

    SciTech Connect (OSTI)

    Daido, Ryuji; Kitajima, Naoya; Takahashi, Fuminobu

    2015-07-28

    We propose a new scenario of baryogenesis, in which annihilation of axion domain walls generates a sizable baryon asymmetry. Successful baryogenesis is possible for a wide range of the axion mass and decay constant, m≃10{sup 8}–10{sup 13} GeV and f≃10{sup 13}–10{sup 16} GeV. Baryonic isocurvature perturbations are significantly suppressed in our model, in contrast to various spontaneous baryogenesis scenarios in the slow-roll regime. In particular, the axion domain wall baryogenesis is consistent with high-scale inflation which generates a large tensor-to-scalar ratio within the reach of future CMB B-mode experiments. We also discuss the gravitational waves produced by the domain wall annihilation and its implications for the future gravitational wave experiments.

  19. In-plane current induced domain wall nucleation and its stochasticity in perpendicular magnetic anisotropy Hall cross structures

    SciTech Connect (OSTI)

    Sethi, P.; Murapaka, C.; Lim, G. J.; Lew, W. S.

    2015-11-09

    Hall cross structures in magnetic nanowires are commonly used for electrical detection of magnetization reversal in which a domain wall (DW) is conventionally nucleated by a local Oersted field. In this letter, we demonstrate DW nucleation in Co/Ni perpendicular magnetic anisotropy nanowire at the magnetic Hall cross junction. The DWs are nucleated by applying an in-plane pulsed current through the nanowire without the need of a local Oersted field. The change in Hall resistance, detected using anomalous Hall effect, is governed by the magnetic volume switched at the Hall junction, which can be tuned by varying the magnitude of the applied current density and pulse width. The nucleated DWs are driven simultaneously under the spin transfer torque effect when the applied current density is above a threshold. The possibility of multiple DW generation and variation in magnetic volume switched makes nucleation process stochastic in nature. The in-plane current induced stochastic nature of DW generation may find applications in random number generation.

  20. Domain wall assisted magnetization switching in (111) oriented L1{sub 0} FePt grown on a soft magnetic metallic glass

    SciTech Connect (OSTI)

    Kaushik, Neelam; Sharma, Parmanand; Yubuta, Kunio; Makino, Akihiro; Inoue, Akihisa

    2010-08-16

    We report on growth and magnetic properties of exchange-coupled (111)-L1{sub 0} FePt hard/CoFeTaB soft magnetic metallic glass bilayered structure processed at lower temperature ({approx}400 deg. C). Single phaselike hysteresis loops with tailorable coercivity (<8.2 kOe) in out of plane direction are obtained. The magnetization switching mechanism is identified as domain wall assisted. In views of excellent nanofabrication abilities of metallic glass thin film and the ability to grow preferred oriented L1{sub 0} FePt, the present bilayered structure is very promising for the fabrication of high density bit--patterned magnetic recording media and other spintronic devices.

  1. X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires

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

    One of these, called racetrack memory, involves no rotating disk at all. Instead, it is based on wires made of a magnetic ... by applying and releasing an external magnetic field (Hext). ...

  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)

    and still work much faster than a hard disk. "Magnetic memory" computers could boot-up instantaneously, access files rapidly, require little power, and withstand power outages. ...

  3. Magnetic soft x-ray microscopy of the domain wall depinning process...

    Office of Scientific and Technical Information (OSTI)

    Citation Details In-Document Search Title: Magnetic soft ... OSTI Identifier: 1172969 Report Number(s): LBNL-5866E DOE Contract Number: DE-AC02-05CH11231 Resource Type: Journal ...

  4. Magnetic domain structure and domain-wall energy in UFe{sub 8}Ni{sub 2}Si{sub 2} and UFe{sub 6}Ni{sub 4}Si{sub 2} intermetallic compounds

    SciTech Connect (OSTI)

    Wyslocki, J.J.; Suski, W.; Wochowski, K.

    1994-03-01

    Magnetic domain structures in the UFe{sub 8}Ni{sub 2}Si{sub 2} and UFe{sub 6}Ni{sub 4}Si{sub 2} compounds were studied using the powder pattern method. The domain structure observed is typical for uniaxial materials. The domain-wall energy density {gamma} was determined from the average surface domain width D{sub s} observed on surfaces perpendicular to the easy axis as equal to 16 erg/cm{sup 2} for UFe{sub 8}Ni{sub 2}Si{sub 2} and 10 erg/cm{sup 2} for UFe{sub 6}Ni{sub 4}Si{sub 2}. Moreover, the critical diameter for single domain particle D{sub c} was calculated for the studied compounds.

  5. Domain wall conduction in multiaxial ferroelectrics

    SciTech Connect (OSTI)

    Eliseev, E. A.; Morozovska, A. N.; Svechnikov, S. V.; Maksymovych, Petro; Kalinin, Sergei V

    2012-01-01

    The conductance of domain wall structures consisting of either stripes or cylindrical domains in multiaxial ferroelectric-semiconductors is analyzed. The effects of the flexoelectric coupling, domain size, wall tilt, and curvature on charge accumulation are analyzed using the Landau-Ginsburg Devonshire theory for polarization vector combined with the Poisson equation for charge distributions. The proximity and size effect of the electron and donor accumulation/depletion by thin stripe domains and cylindrical nanodomains are revealed. In contrast to thick domain stripes and wider cylindrical domains, in which the carrier accumulation (and so the static conductivity) sharply increases at the domain walls only, small nanodomains of radii less than 5-10 correlation lengths appeared conducting across the entire cross-section. Implications of such conductive nanosized channels may be promising for nanoelectronics.

  6. Standing gravitational waves from domain walls

    SciTech Connect (OSTI)

    Gogberashvili, Merab; Myrzakul, Shynaray; Singleton, Douglas

    2009-07-15

    We construct a plane symmetric, standing gravitational wave for a domain wall plus a massless scalar field. The scalar field can be associated with a fluid which has the properties of 'stiff' matter, i.e., matter in which the speed of sound equals the speed of light. Although domain walls are observationally ruled out in the present era, the solution has interesting features which might shed light on the character of exact nonlinear wave solutions to Einstein's equations. Additionally this solution may act as a template for higher dimensional 'brane-world' model standing waves.

  7. Current-driven vortex domain wall motion in wire-tube nanostructures

    SciTech Connect (OSTI)

    Espejo, A. P.; Vidal-Silva, N.; López-López, J. A.; Goerlitz, D.; Nielsch, K.; Escrig, J.

    2015-03-30

    We have investigated the current-driven domain wall motion in nanostructures comprised of a pair of nanotube and nanowire segments. Under certain values of external magnetic fields, it is possible to pin a vortex domain wall in the transition zone between the wire and tube segments. We explored the behavior of this domain wall under the action of an electron flow applied in the opposite direction to the magnetic field. Thus, for a fixed magnetic field, it is possible to release a domain wall pinned simply by increasing the intensity of the current density, or conversely, for a fixed current density, it is possible to release the domain wall simply decreasing the magnetic external field. When the domain wall remains pinned due to the competition between the current density and the magnetic external field, it exhibits a oscillation frequency close to 8 GHz. The amplitude of the oscillations increases with the current density and decreases over time. On the other hand, when the domain wall is released and propagated through the tube segment, this shows the standard separation between a steady and a precessional regime. The ability to pin and release a domain wall by varying the geometric parameters, the current density, or the magnetic field transforms these wire-tube nanostructures in an interesting alternative as an on/off switch nano-transistor.

  8. Temperature dependence of carrier spin polarization determined from current-induced domain wall motion in a Co/Ni nanowire

    SciTech Connect (OSTI)

    Ueda, K.; Koyama, T.; Hiramatsu, R.; Kobayashi, K.; Ono, T.; Chiba, D.; Fukami, S.; Tanigawa, H.; Suzuki, T.; Ohshima, N.; Ishiwata, N.; Nakatani, Y.

    2012-05-14

    We have investigated the temperature dependence of the current-induced magnetic domain wall (DW) motion in a perpendicularly magnetized Co/Ni nanowire at various temperatures and with various applied currents. The carrier spin polarization was estimated from the measured domain wall velocity. We found that it decreased more with increasing temperature from 100 K to 530 K than the saturation magnetization did.

  9. Inflationary power asymmetry from primordial domain walls

    SciTech Connect (OSTI)

    Jazayeri, Sadra; Akrami, Yashar; Firouzjahi, Hassan; Solomon, Adam R.; Wang, Yi E-mail: yashar.akrami@astro.uio.no E-mail: a.r.solomon@damtp.cam.ac.uk

    2014-11-01

    We study the asymmetric primordial fluctuations in a model of inflation in which translational invariance is broken by a domain wall. We calculate the corrections to the power spectrum of curvature perturbations; they are anisotropic and contain dipole, quadrupole, and higher multipoles with non-trivial scale-dependent amplitudes. Inspired by observations of these multipole asymmetries in terms of two-point correlations and variance in real space, we demonstrate that this model can explain the observed anomalous power asymmetry of the cosmic microwave background (CMB) sky, including its characteristic feature that the dipole dominates over higher multipoles. We test the viability of the model and place approximate constraints on its parameters by using observational values of dipole, quadrupole, and octopole amplitudes of the asymmetry measured by a local-variance estimator. We find that a configuration of the model in which the CMB sphere does not intersect the domain wall during inflation provides a good fit to the data. We further derive analytic expressions for the corrections to the CMB temperature covariance matrix, or angular power spectra, which can be used in future statistical analysis of the model in spherical harmonic space.

  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. Experimental observation of the interaction of propagating spin waves with Néel domain walls in a Landau domain structure

    SciTech Connect (OSTI)

    Pirro, P.; Sebastian, T.; Leven, B.; Hillebrands, B.; Koyama, T.; Brächer, T.

    2015-06-08

    The interaction of propagating dipolar spin waves with magnetic domain walls is investigated in square-shaped microstructures patterned from the Heusler compound Co{sub 2}Mn{sub 0.6}Fe{sub 0.4}Si. Using magnetic force microscopy, the reversible preparation of a Landau state with four magnetic domains separated by Néel domain walls is confirmed. A local spin-wave excitation using a microstructured antenna is realized in one of the domains. It is shown by Brillouin light scattering microscopy that the domain structure in the remanence state has a strong influence on the spin-wave excitation and propagation. The domain walls strongly reflect the spin waves and can be used as spin-wave reflectors. A comparison with micromagnetic simulations shows that the strong reflection is due to the long-range dipolar interaction which has important implications for the use of these spin waves for exerting an all-magnonic spin-transfer torque.

  12. Depinning transition of a domain wall in ferromagnetic films

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

    Xi, Bin; Luo, Meng -Bo; Vinokur, Valerii M.; Hu, Xiao

    2015-09-14

    We report first principle numerical study of domain wall (DW) depinning in two-dimensional magnetic film, which is modeled by 2D random-field Ising system with the dipole-dipole interaction. We observe non-conventional activation-type motion of DW and reveal the fractal structure of DW near the depinning transition. We determine scaling functions describing critical dynamics near the transition and obtain universal exponents establishing connection between thermal softening of pinning potential and critical dynamics. In addition, we observe that tuning the strength of the dipole-dipole interaction switches DW dynamics between two different universality classes, corresponding to two distinct dynamic regimes characterized by non-Arrhenius andmore » conventional Arrhenius-type DW motions.« less

  13. Depinning transition of a domain wall in ferromagnetic films

    SciTech Connect (OSTI)

    Xi, Bin; Luo, Meng -Bo; Vinokur, Valerii M.; Hu, Xiao

    2015-09-14

    We report first principle numerical study of domain wall (DW) depinning in two-dimensional magnetic film, which is modeled by 2D random-field Ising system with the dipole-dipole interaction. We observe non-conventional activation-type motion of DW and reveal the fractal structure of DW near the depinning transition. We determine scaling functions describing critical dynamics near the transition and obtain universal exponents establishing connection between thermal softening of pinning potential and critical dynamics. In addition, we observe that tuning the strength of the dipole-dipole interaction switches DW dynamics between two different universality classes, corresponding to two distinct dynamic regimes characterized by non-Arrhenius and conventional Arrhenius-type DW motions.

  14. 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

  15. 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

  16. 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

  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)

    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...

  3. Magnetoelectric domain wall dynamics and its implications for magnetoelectric memory

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

    Belashchenko, K. D.; Tchernyshyov, O.; Kovalev, Alexey A.; Tretiakov, O. A.

    2016-03-30

    Domain wall dynamics in a magnetoelectric antiferromagnet is analyzed, and its implications for magnetoelectric memory applications are discussed. Cr2O3 is used in the estimates of the materials parameters. It is found that the domain wall mobility has a maximum as a function of the electric field due to the gyrotropic coupling induced by it. In Cr2O3, the maximal mobility of 0.1 m/(s Oe) is reached at E≈0.06 V/nm. Fields of this order may be too weak to overcome the intrinsic depinning field, which is estimated for B-doped Cr2O3. These major drawbacks for device implementation can be overcome by applying amore » small in-plane shear strain, which blocks the domain wall precession. Domain wall mobility of about 0.7 m/(s Oe) can then be achieved at E = 0.2 V/nm. Furthermore, a split-gate scheme is proposed for the domain-wall controlled bit element; its extension to multiple-gate linear arrays can offer advantages in memory density, programmability, and logic functionality.« less

  4. Control of domain wall pinning by localised focused Ga {sup +} ion irradiation on Au capped NiFe nanowires

    SciTech Connect (OSTI)

    Burn, D. M. Atkinson, D.

    2014-10-28

    Understanding domain wall pinning and propagation in nanowires are important for future spintronics and nanoparticle manipulation technologies. Here, the effects of microscopic local modification of the magnetic properties, induced by focused-ion-beam intermixing, in NiFe/Au bilayer nanowires on the pinning behavior of domain walls was investigated. The effects of irradiation dose and the length of the irradiated features were investigated experimentally. The results are considered in the context of detailed quasi-static micromagnetic simulations, where the ion-induced modification was represented as a local reduction of the saturation magnetization. Simulations show that domain wall pinning behavior depends on the magnitude of the magnetization change, the length of the modified region, and the domain wall structure. Comparative analysis indicates that reduced saturation magnetisation is not solely responsible for the experimentally observed pinning behavior.

  5. Scaling Behavior of the First Arrival Time of a Random-Walking Magnetic Domain

    SciTech Connect (OSTI)

    Im, M.-Y.; Lee, S.-H.; Kim, D.-H.; Fischer, P.; Shin, S.-C.

    2008-02-04

    We report a universal scaling behavior of the first arrival time of a traveling magnetic domain wall into a finite space-time observation window of a magneto-optical microscope enabling direct visualization of a Barkhausen avalanche in real time. The first arrival time of the traveling magnetic domain wall exhibits a nontrivial fluctuation and its statistical distribution is described by universal power-law scaling with scaling exponents of 1.34 {+-} 0.07 for CoCr and CoCrPt films, despite their quite different domain evolution patterns. Numerical simulation of the first arrival time with an assumption that the magnetic domain wall traveled as a random walker well matches our experimentally observed scaling behavior, providing an experimental support for the random-walking model of traveling magnetic domain walls.

  6. Domain wall and isocurvature perturbation problems in axion models

    SciTech Connect (OSTI)

    Kawasaki, Masahiro; Yoshino, Kazuyoshi; Yanagida, Tsutomu T. E-mail: tsutomu.tyanagida@ipmu.jp

    2013-11-01

    Axion models have two serious cosmological problems, domain wall and isocurvature perturbation problems. In order to solve these problems we investigate the Linde's model in which the field value of the Peccei-Quinn (PQ) scalar is large during inflation. In this model the fluctuations of the PQ field grow after inflation through the parametric resonance and stable axionic strings may be produced, which results in the domain wall problem. We study formation of axionic strings using lattice simulations. It is found that in chaotic inflation the axion model is free from both the domain wall and the isocurvature perturbation problems if the initial misalignment angle ?{sub a} is smaller than O(10{sup ?2}). Furthermore, axions can also account for the dark matter for the breaking scale v ? 10{sup 12?16}GeV and the Hubble parameter during inflation H{sub inf}?<10{sup 11?12}GeV in general inflation models.

  7. Propagating and reflecting of spin wave in permalloy nanostrip with 360 domain wall

    SciTech Connect (OSTI)

    Zhang, Senfu; Mu, Congpu; Zhu, Qiyuan; Zheng, Qi; Liu, Xianyin; Wang, Jianbo; Liu, Qingfang

    2014-01-07

    By micromagnetic simulation, we investigated the interaction between propagating spin wave (or magnonic) and a 360 domain wall in a nanostrip. It is found that propagating spin wave can drive a 360 domain wall motion, and the velocity and direction are closely related to the transmission coefficient of the spin wave of the domain wall. When the spin wave passes through the domain wall completely, the 360 domain wall moves toward the spin wave source. When the spin wave is reflected by the domain wall, the 360 domain wall moves along the spin wave propagation direction. Moreover, when the frequency of the spin wave is coincident with that of the 360 domain wall normal mode, the 360 domain wall velocity will be resonantly enhanced no matter which direction the 360 DW moves along. On the other hand, when the spin wave is reflected from the moving 360 domain wall, we observed the Doppler effect clearly. After passing through a 360 domain wall, the phase of the spin wave is changed, and the phase shift is related to the frequency. Nevertheless, phase shift could be manipulated by the number of 360 domain walls that spin wave passing through.

  8. Shaping nanoscale magnetic domain memory in exchange-coupled ferromagnets

    Office of Scientific and Technical Information (OSTI)

    by field cooling (Journal Article) | SciTech Connect Shaping nanoscale magnetic domain memory in exchange-coupled ferromagnets by field cooling Citation Details In-Document Search Title: Shaping nanoscale magnetic domain memory in exchange-coupled ferromagnets by field cooling The advance of magnetic nanotechnologies relies on detailed understanding of nanoscale magnetic mechanisms in materials. Magnetic domain memory (MDM), that is, the tendency for magnetic domains to repeat the same

  9. Category:Controlled Source Frequency-Domain Magnetics | Open...

    Open Energy Info (EERE)

    Controlled Source Frequency-Domain Magnetics Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Geothermalpower.jpg Looking for the Controlled Source Frequency-Domain...

  10. Investigation of dominant spin wave modes by domain walls collision

    SciTech Connect (OSTI)

    Ramu, M.; Purnama, I.; Goolaup, S.; Chandra Sekhar, M.; Lew, W. S.

    2014-06-28

    Spin wave emission due to field-driven domain wall (DW) collision has been investigated numerically and analytically in permalloy nanowires. The spin wave modes generated are diagonally symmetric with respect to the collision point. The non-propagating mode has the highest amplitude along the middle of the width. The frequency of this mode is strongly correlated to the nanowire geometrical dimensions and is independent of the strength of applied field within the range of 0.1?mT to 1?mT. For nanowire with film thickness below 5?nm, a second spin wave harmonic mode is observed. The decay coefficient of the spin wave power suggests that the DWs in a memory device should be at least 300?nm apart for them to be free of interference from the spin waves.

  11. Intense Magnetized Plasma-Wall Interaction

    SciTech Connect (OSTI)

    Bauer, Bruno S.; Fuelling, Stephan

    2013-11-30

    This research project studied wall-plasma interactions relevant to fusion science. Such interactions are a critical aspect of Magneto-Inertial Fusion (MIF) because flux compression by a pusher material, in particular the metal for the liner approach to MIF, involves strong eddy current heating on the surface of the pusher, and probably interactions and mixing of the pusher with the interior fuel during the time when fusion fuel is being burned. When the pusher material is a metal liner, high-energy-density conditions result in fascinating behavior. For example, "warm dense matter" is produced, for which material properties such as resistivity and opacity are not well known. In this project, the transformation into plasma of metal walls subjected to pulsed megagauss magnetic fields was studied with an experiment driven by the UNR 1 MA Zebra generator. The experiment was numerically simulated with using the MHRDR code. This simple, fundamental high-energy-density physics experiment, in a regime appropriate to MIF, has stimulated an important and fascinating comparison of numerical modeling codes and tables with experiment. In addition, we participated in developing the FRCHX experiment to compress a field-reversed-configuration (FRC) plasma with a liner, in collaboration with researchers from Air Force Research Laboratory and Los Alamos National Lab, and we helped develop diagnostics for the Plasma Liner Experiment (PLX) at LANL. Last, but not least, this project served to train students in high-energy-density physics.

  12. Existence and uniqueness of domain wall solitons in a Maxwell–Chern–Simons model

    SciTech Connect (OSTI)

    Zhang, Ruifeng; College of Mathematics and Information Science, Henan University, Kaifeng 475001 ; Li, Fangfang

    2014-02-15

    We present some sharp existence and uniqueness theorems for the domain wall solutions of the basic governing equations of a self-dual Maxwell–Chern–Simons model.

  13. Cosmic bubble and domain wall instabilities II: fracturing of colliding walls

    SciTech Connect (OSTI)

    Braden, Jonathan; Bond, J. Richard; Mersini-Houghton, Laura

    2015-08-26

    We study collisions between nearly planar domain walls including the effects of small initial nonplanar fluctuations. These perturbations represent the small fluctuations that must exist in a quantum treatment of the problem. In a previous paper, we demonstrated that at the linear level a subset of these fluctuations experience parametric amplification as a result of their coupling to the planar symmetric background. Here we study the full three-dimensional nonlinear dynamics using lattice simulations, including both the early time regime when the fluctuations are well described by linear perturbation theory as well as the subsequent stage of fully nonlinear evolution. We find that the nonplanar fluctuations have a dramatic effect on the overall evolution of the system. Specifically, once these fluctuations begin to interact nonlinearly the split into a planar symmetric part of the field and the nonplanar fluctuations loses its utility. At this point the colliding domain walls dissolve, with the endpoint of this being the creation of a population of oscillons in the collision region. The original (nearly) planar symmetry has been completely destroyed at this point and an accurate study of the system requires the full three-dimensional simulation.

  14. Time-resolved observation of fast domain-walls driven by vertical spin currents in short tracks

    SciTech Connect (OSTI)

    Sampaio, Joao; Lequeux, Steven; Chanthbouala, Andre; Cros, Vincent; Grollier, Julie; Matsumoto, Rie; Yakushiji, Kay; Kubota, Hitoshi; Fukushima, Akio; Yuasa, Shinji; Nishimura, Kazumasa; Nagamine, Yoshinori; Maehara, Hiroki; Tsunekawa, Koji

    2013-12-09

    We present time-resolved measurements of the displacement of magnetic domain-walls (DWs) driven by vertical spin-polarized currents in track-shaped magnetic tunnel junctions. In these structures, we observe very high DW velocities (600 m/s) at current densities below 10{sup 7} A/cm{sup 2}. We show that the efficient spin-transfer torque combined with a short propagation distance allows avoiding the Walker breakdown process and achieving deterministic, reversible, and fast (≈1 ns) DW-mediated switching of magnetic tunnel junction elements, which is of great interest for the implementation of fast DW-based spintronic devices.

  15. Evolution of domain wall networks: The Press-Ryden-Spergel algorithm

    SciTech Connect (OSTI)

    Sousa, L.; Avelino, P. P.

    2010-04-15

    The Press-Ryden-Spergel (PRS) algorithm is a modification to the field theory equations of motion, parametrized by two parameters ({alpha} and {beta}), implemented in numerical simulations of cosmological domain wall networks, in order to ensure a fixed comoving resolution. In this paper we explicitly demonstrate that the PRS algorithm provides the correct domain wall dynamics in (N+1)-dimensional Friedmann-Robertson-Walker universes if {alpha}+{beta}/2=N, fully validating its use in numerical studies of cosmic domain evolution. We further show that this result is valid for generic thin featureless domain walls, independently of the Lagrangian of the model.

  16. Controlled Source Frequency-Domain Magnetics (Montgomery, Et...

    Open Energy Info (EERE)

    (Montgomery, Et Al., 2005) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Controlled Source Frequency-Domain Magnetics (Montgomery, Et Al.,...

  17. Controlled Source Frequency-Domain Magnetics At Salt Wells Area...

    Open Energy Info (EERE)

    At Salt Wells Area (Montgomery, Et Al., 2005) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Controlled Source Frequency-Domain Magnetics At...

  18. Current-driven domain wall motion enhanced by the microwave field

    SciTech Connect (OSTI)

    Wang, Xi-guang; Guo, Guang-hua Nie, Yao-zhuang; Wang, Dao-wei; Li, Zhi-xiong; Tang, Wei; Zeng, Zhong-ming

    2014-07-14

    The magnetic domain wall (DW) motion driven by a spin-polarized current opens a new concept for memory and logic devices. However, the critical current density required to overcome the intrinsic and/or extrinsic pinning of DW remains too large for practical applications. Here, we show, by using micromagnetic simulations and analytical approaches, that the application of a microwave field offers an effective solution to this problem. When a transverse microwave field is applied, the adiabatic spin-transfer torque (STT) alone can sustain a steady-state DW motion without the sign of Walker breakdown, meaning that the intrinsic pinning disappears. The extrinsic pinning can also be effectively reduced. Moreover, the DW velocity is increased greatly for the microwave-assisted DW motion. This provides a new way to manipulate the DW motion at low current densities.

  19. Hidden Rotational Symmetries in Magnetic Domain Patterns

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

    California, San Diego, have recently used coherent soft x-ray scattering with angular Fourier analysis to discover that the disordered domain patterns do, in fact, exhibit...

  20. Magnetic anisotropy and domain structure of the layered manganite...

    Office of Scientific and Technical Information (OSTI)

    1.64Mnsub 2Osub 7 Citation Details In-Document Search Title: Magnetic anisotropy and domain structure of the layered manganite Lasub 1.36Srsub 1.64Mnsub 2Osub ...

  1. Detection of ferromagnetic domain wall pinning and depinning with a semiconductor device

    SciTech Connect (OSTI)

    Malec, Chris E.; Bennett, Brian R.; Johnson, Mark B.

    2015-12-21

    We demonstrate the detection of a ferromagnetic domain wall using a nanoscale Hall cross. A narrow permalloy wire is defined lithographically on top of a Hall cross fabricated from an InAs quantum well. The width of the Hall cross (500 nm–1 μm) is similar to the width of the ferromagnetic wire (200–500 nm), and a geometric pinning site is fabricated in the ferromagnetic wire to trap a domain wall within the area of the Hall cross. The devices provide a signal that is often the same order of magnitude as the offset Hall voltage when a domain wall is located above the Hall cross, and may be useful for memory applications. Different geometries for the Hall cross and ferromagnetic wire are tested, and radiofrequency pulses are sent into the wire to demonstrate current driven domain wall motion. Further changes to the Hall bar geometry with respect to the wire geometry are investigated by numerical computation. A large gain in signal is seen for Hall bars only slightly wider than the ferromagnetic wires as compared to those twice as wide, as well as a larger sensitivity to the exact position of the domain wall with respect to the center of the Hall cross.

  2. Hidden Rotational Symmetries in Magnetic Domain Patterns

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

    and magnetization history. Left: A typical speckle pattern from the CoPd multilayer. Color bar at bottom indicates relative intensity. The rotational symmetry of a scattering...

  3. Highly mobile ferroelastic domain walls in compositionally graded ferroelectric thin films

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

    Damodaran, Anoop; Okatan, M. B.; Kacher, J.; Gammer, C.; Vasudevan, Rama; Pandya, S.; Dedon, L. R.; Mangalam, R. V.; Jesse, Stephen; Balke, Nina; et al

    2016-02-15

    Domains and domain walls are critical in determining the response of ferroelectrics, and the ability to controllably create, annihilate, or move domains is essential to enable a range of next-generation devices. Whereas electric-field control has been demonstrated for ferroelectric 180° domain walls, similar control of ferroelastic domains has not been achieved. Here, using controlled composition and strain gradients, we demonstrate deterministic control of ferroelastic domains that are rendered highly mobile in a controlled and reversible manner. Through a combination of thin-film growth, transmission-electron-microscopy-based nanobeam diffraction and nanoscale band-excitation switching spectroscopy, we show that strain gradients in compositionally graded PbZr1-xTixO3 heterostructuresmore » stabilize needle-like ferroelastic domains that terminate inside the film. These needle-like domains are highly labile in the out-of-plane direction under applied electric fields, producing a locally enhanced piezoresponse. This work demonstrates the efficacy of novel modes of epitaxy in providing new modalities of domain engineering and potential for as-yet-unrealized nanoscale functional devices.« less

  4. 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...

  5. Hidden Rotational Symmetries in Magnetic Domain Patterns

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

    low-temperature control, and high coherent x-ray flux. The sample used was a CoPd multilayer film that shows perpendicular anisotropy, meaning the magnetization points...

  6. Gravitational waves from domain walls in the next-to-minimal supersymmetric standard model

    SciTech Connect (OSTI)

    Kadota, Kenji; Kawasaki, Masahiro; Saikawa, Ken’ichi

    2015-10-16

    The next-to-minimal supersymmetric standard model predicts the formation of domain walls due to the spontaneous breaking of the discrete Z{sub 3}-symmetry at the electroweak phase transition, and they collapse before the epoch of big bang nucleosynthesis if there exists a small bias term in the potential which explicitly breaks the discrete symmetry. Signatures of gravitational waves produced from these unstable domain walls are estimated and their parameter dependence is investigated. It is shown that the amplitude of gravitational waves becomes generically large in the decoupling limit, and that their frequency is low enough to be probed in future pulsar timing observations.

  7. Fast strain wave induced magnetization changes in long cobalt bars: Domain motion versus coherent rotation

    SciTech Connect (OSTI)

    Davis, S.; Adenwalla, S.; Borchers, J. A.; Maranville, B. B.

    2015-02-14

    A high frequency (88 MHz) traveling strain wave on a piezoelectric substrate is shown to change the magnetization direction in 40 μm wide Co bars with an aspect ratio of 10{sup 3}. The rapidly alternating strain wave rotates the magnetization away from the long axis into the short axis direction, via magnetoelastic coupling. Strain-induced magnetization changes have previously been demonstrated in ferroelectric/ferromagnetic heterostructures, with excellent fidelity between the ferromagnet and the ferroelectric domains, but these experiments were limited to essentially dc frequencies. Both magneto-optical Kerr effect and polarized neutron reflectivity confirm that the traveling strain wave does rotate the magnetization away from the long axis direction and both yield quantitatively similar values for the rotated magnetization. An investigation of the behavior of short axis magnetization with increasing strain wave amplitude on a series of samples with variable edge roughness suggests that the magnetization reorientation that is seen proceeds solely via coherent rotation. Polarized neutron reflectivity data provide direct experimental evidence for this model. This is consistent with expectations that domain wall motion cannot track the rapidly varying strain.

  8. A time-domain estimation of wall conduction transfer function coefficients

    SciTech Connect (OSTI)

    Davies, M.G.

    1996-11-01

    The wall and roof transfer function coefficients, b{sub n} and d{sub n}, listed in the 1993 ASHRAE Fundamentals Handbook, have up to now been derived using laplace and Z-transform methods. This paper shows that they can be readily evaluated using straightforward time-domain solutions of the Fourier continuity equation. These include the response of a wall to a ramp increase in temperature and its transient response. The values of d{sub n} can be found from the first few terms in the series of wall decay times in the transient solution. The solutions are combined using a form of Fourier analysis. Appropriate layer transmission matrices enable one to find the wall`s overall characteristics readily. The wall response factors {phi}{sub j} can thus be found. The b{sub n} transfer coefficients are related to the {phi}{sub j} and d{sub n} values. The approach is illustrated using the data for wall group 6. Allowing for conversion from I-P to SI units, the present approach gives results that are almost identical to those listed. It shows, however, that the performance of the coefficients is very specific to the wall from which they were derived. The b{sub n} and d{sub n} values listed in the Handbook permit an estimate to be made of the wall response factors, including the time of peak flow and the first decay time. For heavy walls, however, values beyond d{sub 6} may be needed.

  9. Stochastic Domain-Wall Depinning in Magnetic Nanowires

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

    today's spinning disk, such a dialog could become ancient history. Not only that, the computer could hold more information, retrieve it more quickly, and consume less power all the...

  10. Stochastic Domain-Wall Depinning in Magnetic Nanowires

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

    moving parts, in contrast to today's spinning disk, such a dialog could become ancient history. Not only that, the computer could hold more information, retrieve it more...

  11. LiWall Fusion - The New Concept of Magnetic Fusion

    SciTech Connect (OSTI)

    L.E. Zakharov

    2011-01-12

    Utilization of the outstanding abilities of a liquid lithium layer in pumping hydrogen isotopes leads to a new approach to magnetic fusion, called the LiWall Fusion. It relies on innovative plasma regimes with low edge density and high temperature. The approach combines fueling the plasma by neutral injection beams with the best possible elimination of outside neutral gas sources, which cools down the plasma edge. Prevention of cooling the plasma edge suppresses the dominant, temperature gradient related turbulence in the core. Such an approach is much more suitable for controlled fusion than the present practice, relying on high heating power for compensating essentially unlimited turbulent energy losses.

  12. Quantum Decay of the 'False Vacuum' and Pair Creation of Soliton Domain Walls

    SciTech Connect (OSTI)

    Miller, John H. Jr.

    2011-03-28

    Quantum decay of metastable states ('false vacua') has been proposed as a mechanism for bubble nucleation of new universes and phase transitions in the early universe. Experiments indicate the occurrence of false vacuum decay, within a region bounded by soliton domain walls that nucleate via quantum tunneling, in a highly anisotropic condensed matter system. This phenomenon provides a compelling example of false vacuum decay in the laboratory.

  13. Flat Bogomolnyi-Prasad-Sommerfeld domain walls on two-dimensional Kaehler-Ricci soliton

    SciTech Connect (OSTI)

    Gunara, Bobby Eka; Zen, Freddy Permana

    2009-06-15

    In this paper we address several aspects of flat Bogomolnyi-Prasad-Sommerfeld (BPS) domain walls together with their Lorentz invariant vacua of four-dimensional N=1 supergravity coupled to a chiral multiplet. The scalar field spans a one-parameter family of two-dimensional Kaehler manifolds satisfying a Kaehler-Ricci flow equation. We find that BPS equations and the scalar potential deform with respect to the real parameter related to the Kaehler-Ricci soliton. In addition, the analysis using gradient and renormalization group flows is carried out to ensure the existence of Lorentz invariant vacua related to anti-de Sitter/conformal field theory correspondence.

  14. Axial couplings of heavy hadrons from domain-wall lattice QCD

    SciTech Connect (OSTI)

    W. Detmold, C.J.D. Lin, S. Meinel

    2011-12-01

    We calculate matrix elements of the axial current for static-light mesons and baryons in lattice QCD with dynamical domain wall fermions. We use partially quenched heavy hadron chiral perturbation theory in a finite volume to extract the axial couplings g{sub 1}, g{sub 2}, and g{sub 3} from the data. These axial couplings allow the prediction of strong decay rates and enter chiral extrapolations of most lattice results in the b sector. Our calculations are performed with two lattice spacings and with pion masses down to 227 MeV.

  15. Domain wall pinning on strain relaxation defects (stacking faults) in nanoscale FePd (001)/MgO thin films

    SciTech Connect (OSTI)

    Hsiao, C. H.; Ouyang, Chuenhou E-mail: houyang@mx.nthu.edu.tw; Yao, Y. D.; Lo, S. C.; Chang, H. W. E-mail: houyang@mx.nthu.edu.tw

    2015-10-05

    FePd (001) films, prepared by an electron beam deposition system on MgO(100), exhibit a perpendicular magnetic anisotropy (1.7 × 10{sup 7 }erg/cc) with a high order parameter (0.92). The relation between stacking faults induced by the strain relaxation, which act as strong domain wall pinning sites, and the perpendicular coercivity of (001) oriented L1{sub 0} FePd films prepared at different temperatures have been investigated. Perpendicular coercivity can be apparently enhanced by raising the stacking fault densities, which can be elevated by climbing dissociation of total dislocation. The increased stacking fault densities (1.22 nm{sup −2}) with large perpendicular coercivity (6000 Oe) are obtained for samples prepared at 650 °C. This present work shows through controlling stacking fault density in FePd film, the coercivity can be manipulated, which can be applied in future magnetic devices.

  16. An in-situ study of magnetic domain structures in undercooled Fe-29.5 at. %Pd magnetostrictive alloys by Lorentz microscopy and electron holography

    SciTech Connect (OSTI)

    Sun, Wen; Xu, Xianhui; Liu, Jian E-mail: xiawxing@nimte.ac.cn; Xia, Weixing E-mail: xiawxing@nimte.ac.cn; Yan, Aru

    2015-04-28

    Understanding of correlation between magnetic domain structure and functional properties is of importance for the magnetic field driven phase transition (e.g., martensitic transformation) or microstructure variation (e.g., twin boundary motion) materials. In this work, we report a Fe-29.5 at. %Pd shape memory alloy treated by undercooling processing upon a degree of 320?K below the liquid temperature. The effect of high undercooling on the solidified microstructure and martensitic transformation temperatures was investigated. By in-situ Lorentz transmission electron microscopy and electron holography, magnetic domain structure and the field-induced domain wall motion behavior in as-cast and undercooled samples have been schematically studied. The irregular domain structure can be observed in these alloys. On the application of a field up to 300?Oe, the domain walls for both samples are able to move along the direction of the external magnetic field, but structural transition and rearrangement of variants are not observed in the undercooled alloy. The large magnetostriction of Fe-29.5 at. %Pd undercooled alloy originates from the irregular domain walls motion instead of the rearrangement of martensitic twin variants.

  17. Insights into Substrate Specificity of NlpC/P60 Cell Wall Hydrolases Containing Bacterial SH3 Domains

    SciTech Connect (OSTI)

    Xu, Qingping; Mengin-Lecreulx, Dominique; Liu, Xueqian W.; Patin, Delphine; Farr, Carol L.; Grant, Joanna C.; Chiu, Hsiu-Ju; Jaroszewski, Lukasz; Knuth, Mark W.; Godzik, Adam; Lesley, Scott A.; Elsliger, Marc-André; Deacon, Ashley M.; Wilson, Ian A.

    2015-09-15

    ABSTRACT

    Bacterial SH3 (SH3b) domains are commonly fused with papain-like Nlp/P60 cell wall hydrolase domains. To understand how the modular architecture of SH3b and NlpC/P60 affects the activity of the catalytic domain, three putative NlpC/P60 cell wall hydrolases were biochemically and structurally characterized. These enzymes all have γ-d-Glu-A2pm (A2pm is diaminopimelic acid) cysteine amidase (ordl-endopeptidase) activities but with different substrate specificities. One enzyme is a cell wall lysin that cleaves peptidoglycan (PG), while the other two are cell wall recycling enzymes that only cleave stem peptides with an N-terminall-Ala. Their crystal structures revealed a highly conserved structure consisting of two SH3b domains and a C-terminal NlpC/P60 catalytic domain, despite very low sequence identity. Interestingly, loops from the first SH3b domain dock into the ends of the active site groove of the catalytic domain, remodel the substrate binding site, and modulate substrate specificity. Two amino acid differences at the domain interface alter the substrate binding specificity in favor of stem peptides in recycling enzymes, whereas the SH3b domain may extend the peptidoglycan binding surface in the cell wall lysins. Remarkably, the cell wall lysin can be converted into a recycling enzyme with a single mutation.

    IMPORTANCEPeptidoglycan is a meshlike polymer that envelops the bacterial plasma membrane and bestows structural integrity. Cell wall lysins and recycling enzymes are part of a set of lytic enzymes that target covalent bonds connecting the amino acid and amino sugar building blocks of the PG network. These hydrolases are involved in processes such as cell growth and division, autolysis, invasion, and PG turnover and recycling. To avoid cleavage of unintended substrates, these enzymes have very selective substrate specificities. Our biochemical and structural

  18. Insights into substrate specificity of NlpC/P60 cell wall hydrolases containing bacterial SH3 domains

    SciTech Connect (OSTI)

    Xu, Qingping; Mengin-Lecreulx, Dominique; Liu, Xueqian W.; Patin, Delphine; Farr, Carol L.; Grant, Joanna C.; Chiu, Hsiu -Ju; Jaroszewski, Lukasz; Knuth, Mark W.; Godzik, Adam; Lesley, Scott A.; Elsliger, Marc -André; Deacon, Ashley M.; Wilson, Ian A.

    2015-09-15

    Bacterial SH3 (SH3b) domains are commonly fused with papain-like Nlp/P60 cell wall hydrolase domains. To understand how the modular architecture of SH3b and NlpC/P60 affects the activity of the catalytic domain, three putative NlpC/P60 cell wall hydrolases were biochemically and structurally characterized. In addition, these enzymes all have γ-d-Glu-A2pm (A2pm is diaminopimelic acid) cysteine amidase (ordl-endopeptidase) activities but with different substrate specificities. One enzyme is a cell wall lysin that cleaves peptidoglycan (PG), while the other two are cell wall recycling enzymes that only cleave stem peptides with an N-terminall-Ala. Their crystal structures revealed a highly conserved structure consisting of two SH3b domains and a C-terminal NlpC/P60 catalytic domain, despite very low sequence identity. Interestingly, loops from the first SH3b domain dock into the ends of the active site groove of the catalytic domain, remodel the substrate binding site, and modulate substrate specificity. Two amino acid differences at the domain interface alter the substrate binding specificity in favor of stem peptides in recycling enzymes, whereas the SH3b domain may extend the peptidoglycan binding surface in the cell wall lysins. Remarkably, the cell wall lysin can be converted into a recycling enzyme with a single mutation.

    Peptidoglycan is a meshlike polymer that envelops the bacterial plasma membrane and bestows structural integrity. Cell wall lysins and recycling enzymes are part of a set of lytic enzymes that target covalent bonds connecting the amino acid and amino sugar building blocks of the PG network. These hydrolases are involved in processes such as cell growth and division, autolysis, invasion, and PG turnover and recycling. To avoid cleavage of unintended substrates, these enzymes have very selective substrate specificities. Our biochemical and structural analysis of three modular NlpC/P60

  19. Insights into substrate specificity of NlpC/P60 cell wall hydrolases containing bacterial SH3 domains

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

    Xu, Qingping; Mengin-Lecreulx, Dominique; Liu, Xueqian W.; Patin, Delphine; Farr, Carol L.; Grant, Joanna C.; Chiu, Hsiu -Ju; Jaroszewski, Lukasz; Knuth, Mark W.; Godzik, Adam; et al

    2015-09-15

    Bacterial SH3 (SH3b) domains are commonly fused with papain-like Nlp/P60 cell wall hydrolase domains. To understand how the modular architecture of SH3b and NlpC/P60 affects the activity of the catalytic domain, three putative NlpC/P60 cell wall hydrolases were biochemically and structurally characterized. In addition, these enzymes all have γ-d-Glu-A2pm (A2pm is diaminopimelic acid) cysteine amidase (ordl-endopeptidase) activities but with different substrate specificities. One enzyme is a cell wall lysin that cleaves peptidoglycan (PG), while the other two are cell wall recycling enzymes that only cleave stem peptides with an N-terminall-Ala. Their crystal structures revealed a highly conserved structure consisting ofmore » two SH3b domains and a C-terminal NlpC/P60 catalytic domain, despite very low sequence identity. Interestingly, loops from the first SH3b domain dock into the ends of the active site groove of the catalytic domain, remodel the substrate binding site, and modulate substrate specificity. Two amino acid differences at the domain interface alter the substrate binding specificity in favor of stem peptides in recycling enzymes, whereas the SH3b domain may extend the peptidoglycan binding surface in the cell wall lysins. Remarkably, the cell wall lysin can be converted into a recycling enzyme with a single mutation.Peptidoglycan is a meshlike polymer that envelops the bacterial plasma membrane and bestows structural integrity. Cell wall lysins and recycling enzymes are part of a set of lytic enzymes that target covalent bonds connecting the amino acid and amino sugar building blocks of the PG network. These hydrolases are involved in processes such as cell growth and division, autolysis, invasion, and PG turnover and recycling. To avoid cleavage of unintended substrates, these enzymes have very selective substrate specificities. Our biochemical and structural analysis of three modular NlpC/P60 hydrolases, one lysin, and two recycling enzymes, show

  20. Steady-state domain wall motion driven by adiabatic spin-transfer torque with assistance of microwave field

    SciTech Connect (OSTI)

    Wang, Xi-guang; Guo, Guang-hua Nie, Yao-zhuang; Xia, Qing-lin; Tang, Wei; Wang, D.; Zeng, Zhong-ming

    2013-12-23

    We have studied the current-induced displacement of a 180° Bloch wall by means of micromagnetic simulation and analytical approach. It is found that the adiabatic spin-transfer torque can sustain a steady-state domain wall (DW) motion in the direction opposite to that of the electron flow without Walker Breakdown when a transverse microwave field is applied. This kind of motion is very sensitive to the microwave frequency and can be resonantly enhanced by exciting the domain wall thickness oscillation mode. A one-dimensional analytical model was established to account for the microwave-assisted wall motion. These findings may be helpful for reducing the critical spin-polarized current density and designing DW-based spintronic devices.

  1. Magnetic shielding of walls from the unmagnetized ion beam in a Hall thruster

    SciTech Connect (OSTI)

    Mikellides, Ioannis G.; Katz, Ira; Hofer, Richard R.; Goebel, Dan M.

    2013-01-14

    We demonstrate by numerical simulations and experiments that the unmagnetized ion beam formed in a Hall thruster can be controlled by an applied magnetic field in a manner that reduces by 2-3 orders of magnitude deleterious ion bombardment of the containing walls. The suppression of wall erosion in Hall thrusters to such low levels has remained elusive for decades.

  2. Magnetic shielding of the channel walls in a Hall plasma accelerator

    SciTech Connect (OSTI)

    Mikellides, Ioannis G.; Katz, Ira; Hofer, Richard R.; Goebel, Dan M.; Grys, Kristi de; Mathers, Alex

    2011-03-15

    In a qualification life test of a Hall thruster it was found that the erosion of the acceleration channel practically stopped after {approx}5600 h. Numerical simulations using a two-dimensional axisymmetric plasma solver with a magnetic field-aligned mesh reveal that when the channel receded from its early-in-life to its steady-state configuration the following changes occurred near the wall: (1) reduction of the electric field parallel to the wall that prohibited ions from acquiring significant impact kinetic energy before entering the sheath, (2) reduction of the potential fall in the sheath that further diminished the total energy ions gained before striking the material, and (3) reduction of the ion number density that decreased the flux of ions to the wall. All these changes, found to have been induced by the magnetic field, constituted collectively an effective shielding of the walls from any significant ion bombardment. Thus, we term this process in Hall thrusters 'magnetic shielding'.

  3. 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.

  4. A self-consistent two-fluid model of a magnetized plasma-wall transition

    SciTech Connect (OSTI)

    Gyergyek, T.; Kovačič, J.

    2015-09-15

    A self-consistent one-dimensional two-fluid model of the magnetized plasma-wall transition is presented. The model includes magnetic field, elastic collisions between ions and electrons, and creation/annihilation of charged particles. Two systems of differential equations are derived. The first system describes the whole magnetized plasma-wall transition region, which consists of the pre-sheath, the magnetized pre-sheath (Chodura layer), and the sheath, which is not neutral, but contains a positive space charge. The second system of equations describes only the neutral part of the plasma-wall transition region—this means only the pre-sheath and the Chodura layer, but not also the sheath. Both systems are solved numerically. The first system of equations has two singularities. The first occurs when ion velocity in the direction perpendicularly to the wall drops below the ion thermal velocity. The second occurs when the electron velocity in the direction perpendicularly to the wall exceeds the electron thermal velocity. The second system of differential equations only has one singularity, which has also been derived analytically. For finite electron to ion mass ratio, the integration of the second system always breaks down before the Bohm criterion is fulfilled. Some properties of the first system of equations are examined. It is shown that the increased collision frequency demagnetizes the plasma. On the other hand, if the magnetic field is so strong that the ion Larmor radius and the Debye length are comparable, the electron velocity in the direction perpendicularly to the wall reaches the electron thermal velocity before the ion velocity in the direction perpendicularly to the wall reaches the ion sound velocity. In this case, the integration of the model equations breaks down before the Bohm criterion is fulfilled and the sheath is formed.

  5. Temperature dependent nucleation, propagation, and annihilation of domain walls in all-perpendicular spin-valve nanopillars

    SciTech Connect (OSTI)

    Gopman, D. B. Kent, A. D.; Bedau, D.; Mangin, S.; Fullerton, E. E.; Katine, J. A.

    2014-03-21

    We present a study of the temperature dependence of the switching fields in Co/Ni-based perpendicularly magnetized spin-valves. While magnetization reversal of all-perpendicular Co/Ni spin valves at ambient temperatures is typically marked by a single sharp step change in resistance, low temperature measurements can reveal a series of resistance steps, consistent with non-uniform magnetization configurations. We propose a model that consists of domain nucleation, propagation, and annihilation to explain the temperature dependence of the switching fields. Interestingly, low temperature (<30?K) step changes in resistance that we associate with domain nucleation have a bimodal switching field and resistance step distribution, attributable to two competing nucleation pathways.

  6. Controlled Source Frequency-Domain Magnetics | Open Energy Information

    Open Energy Info (EERE)

    of the ground where magnetic field measurements are recorded. The locations of the field measurement stations are identified using a Global Positioning System (GPS). The measured...

  7. Scaling of the plasma sheath in a magnetic field parallel to the wall

    SciTech Connect (OSTI)

    Krasheninnikova, Natalia S.; Tang Xianzhu; Roytershteyn, Vadim S.

    2010-05-15

    Motivated by the magnetized target fusion [R. E. Siemon et al., Comments Plasma Phys. Controlled Fusion 18, 363 (1999)] experiment, a systematic investigation of the scaling of a one-dimensional plasma sheath with a magnetic field parallel to the wall was carried out using analytical theory and the particle-in-cell code VPIC [K. J. Bowers et al., Phys. Plasmas 15, 055703 (2008)]. Starting with a uniform Maxwellian distribution in three-dimensional velocity space, plasma consisting of collisionless electrons, and ions of the same temperature interacts with a perfectly absorbing wall. A much larger ion Larmor radius causes the wall to be charged positively, creating an electric field that tends to repel the ions and attract the electrons, which is the opposite of the conventional Bohm sheath [D. Bohm, Characteristics of Electrical Discharges in Magnetic Fields (McGraw-Hill, New York, 1949)]. This manifests in the form of gyro-orbit modification by this spatially varying electric field, the degree of which is found to intricately depend on the relation between three parameters: electron and ion thermal Larmor radii and plasma Debye length: rho{sub the}, rho{sub thi}, and lambda{sub D}. Furthermore, the study of the sheath width scaling through the analysis of the full width at half max of electric field, x{sub Eh}, elucidates three distinct types of behavior of x{sub Eh}, corresponding to three different regimes: rho{sub thi}wall potential phi{sub Wall}, as well as the role of the ion mass and charge Z are investigated. The results of this analytical and computational approach can also be useful in studying the plasma sheath in the conventional magnetic confinement devices, in particular at the first wall of tokamaks.

  8. Effects of twin boundary mobility on domain microstructure evolution in magnetic shape memory alloys: Phase field simulation

    SciTech Connect (OSTI)

    Jin, Yongmei M.

    2009-02-09

    Effects of twin boundary mobility on domain microstructure evolution during magnetic field-induced deformation in magnetic shape memory alloys are studied by phase field micromagnetic microelastic modeling. The simulations show that different twin boundary mobilities lead to drastically different domain microstructures and evolution pathways, yielding very different magnetization and strain responses, even with opposite signs. The study also reveals complex domain phenomena in magnetic shape memory alloys.

  9. Nucleon transverse momentum-dependent parton distributions from domain wall fermion calculations at 297 MeV pion mass

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

    Engelhardt, M.; Musch, B.; Bhattacharya, T.; Gupta, R.; Hagler, P.; Negele, J.; Pochinsky, A.; Schafer, A.; Syritsyn, S.; Yoon, B.

    2014-06-23

    Here, lattice QCD calculations of transverse momentum-dependent parton distributions (TMDs) in a nucleon are performed based on a definition of TMDs via hadronic matrix elements of quark bilocal operators containing staple-shaped gauge connections. A parametrization of the matrix elements in terms of invariant amplitudes serves to cast them in the Lorentz frame preferred for the lattice calculation. Using a RBC/UKQCD domain wall fermion ensemble corresponding to a pion mass of 297 MeV, on a lattice with spacing 0.084 fm, selected TMD observables are accessed and compared to previous exploration at heavier pion masses on coarser lattices.

  10. Comprehensive kinetic analysis of the plasma-wall transition layer in a strongly tilted magnetic field

    SciTech Connect (OSTI)

    Tskhakaya, D. D.; Kos, L.

    2014-10-15

    The magnetized plasma-wall transition (MPWT) layer at the presence of the obliquity of the magnetic field to the wall consists of three sub-layers: the Debye sheath (DS), the magnetic pre-sheath (MPS), and the collisional pre-sheath (CPS) with characteristic lengths ?{sub D} (electron Debye length), ?{sub i} (ion gyro-radius), and ? (the smallest relevant collision length), respectively. Tokamak plasmas are usually assumed to have the ordering ?{sub D}??{sub i}??, when the above-mentioned sub-layers can be distinctly distinguished. In the limits of ?{sub Dm}(?{sub D}/?{sub i})?0 and ?{sub mc}(?{sub i}/?)?0 (asymptotic three-scale (A3S) limits), these sub-layers are precisely defined. Using the smallness of the tilting angle of the magnetic field to the wall, the ion distribution functions are found for three sub-regions in the analytic form. The equations and characteristic length-scales governing the transition (intermediate) regions between the neighboring sub-layers (CPS MPS and MPS DS) are derived, allowing to avoid the singularities arising from the ?{sub Dm}?0 and ?{sub mc}?0 approximations. The MPS entrance and the related kinetic form of the BohmChodura condition are successfully defined for the first time. At the DS entrance, the Bohm condition maintains its usual form. The results encourage further study and understanding of physics of the MPWT layers in the modern plasma facilities.

  11. Cosmic bubble and domain wall instabilities I: parametric amplification of linear fluctuations

    SciTech Connect (OSTI)

    Braden, Jonathan; Bond, J. Richard; Mersini-Houghton, Laura

    2015-03-03

    This is the first paper in a series where we study collisions of nucleated bubbles taking into account the effects of small initial (quantum) fluctuations in a fully 3+1-dimensional setting. In this paper, we consider the evolution of linear fluctuations around highly symmetric though inhomogeneous backgrounds. In particular, we demonstrate that a large degree of asymmetry develops over time from tiny initial fluctuations superposed upon planar and SO(2,1) symmetric backgrounds. These fluctuations are inevitable consequences of zero-point vacuum oscillations, so excluding them by enforcing a high degree of spatial symmetry is inconsistent in a quantum treatment. To simplify the analysis we consider the limit of two colliding planar walls, with mode functions for the fluctuations characterized by the wavenumber transverse to the collision direction and a longitudinal shape along the collision direction x, which we solve for. In the linear regime, the fluctuations obey a linear wave equation with a time- and space-dependent mass m{sub eff}(x,t). In situations where the walls collide multiple times, m{sub eff} oscillates in time. We use Floquet theory to study the evolution of the fluctuations and generalize the calculations familiar from the preheating literature to the case with many coupled degrees of freedom. The inhomogeneous case has bands of unstable transverse wavenumbers k{sub ⊥} whose corresponding mode functions grow exponentially. By examining the detailed spatial structure of the mode functions in x, we identify both broad and narrow parametric resonance generalizations of the homogeneous m{sub eff}(t) case of preheating. The unstable k{sub ⊥} modes are longitudinally localized, yet can be described as quasiparticles in the Bogoliubov sense. We define an effective occupation number and show they are created in bursts for the case of well-defined collisions in the background. The transverse-longitudinal coupling accompanying nonlinearity radically

  12. 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.

  13. Interplay between intrinsic and stacking-fault magnetic domains in bi-layered manganites

    SciTech Connect (OSTI)

    Hossain, M.A; Burkhardt, Mark H.; Sarkar, S.; Ohldag, H.; Chuang, Y.-D.; Scholl, A.; Young, A.T.; Doran, A.; Dessau, D.S.; Zheng, H.; Mitchell, J.F.; Durr, H.A.; Stohr, J.

    2012-09-11

    We present a low temperature X-ray photoemission electron microscopy study of the bi-layered manganite compound La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7} (BL-LSMO) to investigate the influence of stacking faults, which are structurally and magnetically different from the bi-layered host. In BL-LSMO small magnetic moment persists to T* = 300K, well above the Curie temperature of 120K (T{sub C}). Our magnetic images show that 3D stacking faults are responsible for the T* transition. Furthermore, close to the T{sub C}, stacking faults are well coupled to the bi-layered host with latter magnetic domains controlling the spin direction of the stacking faults. Contrary to recent reports, we find that stacking faults do not seed magnetic domains in the host via an exchange spring mechanism and the intrinsic T{sub C} of the BL-LSMO is not lower than 120K.

  14. 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.

  15. Neutron and proton electric dipole moments from Nf=2+1 domain-wall fermion lattice QCD

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

    Shintani, Eigo; Blum, Thomas; Izubuchi, Taku; Soni, Amarjit

    2016-05-05

    We present a lattice calculation of the neutron and proton electric dipole moments (EDM’s) with Nf = 2 + 1 flavors of domain-wall fermions. The neutron and proton EDM form factors are extracted from three-point functions at the next-to-leading order in the θ vacuum of QCD. In this computation, we use pion masses 330 and 420 MeV and 2.7 fm3 lattices with Iwasaki gauge action and a 170 MeV pion and 4.6 fm3 lattice with I-DSDR gauge action, all generated by the RBC and UKQCD collaborations. The all-mode-averaging technique enables an efficient, high statistics calculation; however the statistical errors onmore » our results are still relatively large, so we investigate a new direction to reduce them, reweighting with the local topological charge density which appears promising. Furthermore, we discuss the chiral behavior and finite size effects of the EDM’s in the context of baryon chiral perturbation theory.« less

  16. Effect of the magnetic lenses on the electron current due to near wall conductivity in a Hall thruster

    SciTech Connect (OSTI)

    Wu Zhiwen; Liu Xiangyang; Wang Ningfei; Yu Daren

    2010-07-15

    The effect of magnetic lens on the electron current due to near wall conductivity (NWC) in a Hall thruster is studied. A Monte Carlo model is employed to simulate the effect of the large magnetic field incidence angle on the electron current. The simulation results show that the electron current due to NWC decreases in the case of large incidence. The simulation qualitatively agrees with the related experimental result. And the simulation also demonstrates that choosing the curvature angle of the magnetic field is also a key factor to design a Hall thruster with high operation performance.

  17. ANNULUS CLOSURE TECHNOLOGY DEVELOPMENT INSPECTION/SALT DEPOSIT CLEANING MAGNETIC WALL CRAWLER

    SciTech Connect (OSTI)

    Minichan, R; Russell Eibling, R; James Elder, J; Kevin Kane, K; Daniel Krementz, D; Rodney Vandekamp, R; Nicholas Vrettos, N

    2008-06-01

    The Liquid Waste Technology Development organization is investigating technologies to support closure of radioactive waste tanks at the Savannah River Site (SRS). Tank closure includes removal of the wastes that have propagated to the tank annulus. Although amounts and types of residual waste materials in the annuli of SRS tanks vary, simple salt deposits are predominant on tanks with known leak sites. This task focused on developing and demonstrating a technology to inspect and spot clean salt deposits from the outer primary tank wall located in the annulus of an SRS Type I tank. The Robotics, Remote and Specialty Equipment (RRSE) and Materials Science and Technology (MS&T) Sections of the Savannah River National Laboratory (SRNL) collaborated to modify and equip a Force Institute magnetic wall crawler with the tools necessary to demonstrate the inspection and spot cleaning in a mock-up of a Type I tank annulus. A remote control camera arm and cleaning head were developed, fabricated and mounted on the crawler. The crawler was then tested and demonstrated on a salt simulant also developed in this task. The demonstration showed that the camera is capable of being deployed in all specified locations and provided the views needed for the planned inspection. It also showed that the salt simulant readily dissolves with water. The crawler features two different techniques for delivering water to dissolve the salt deposits. Both water spay nozzles were able to dissolve the simulated salt, one is more controllable and the other delivers a larger water volume. The cleaning head also includes a rotary brush to mechanically remove the simulated salt nodules in the event insoluble material is encountered. The rotary brush proved to be effective in removing the salt nodules, although some fine tuning may be required to achieve the best results. This report describes the design process for developing technology to add features to a commercial wall crawler and the results of the

  18. Peculiar long-range supercurrent in superconductor-ferromagnet-superconductor junction containing a noncollinear magnetic domain in the ferromagnetic region

    SciTech Connect (OSTI)

    Meng, Hao; Wu, Xiuqiang; Ren, Yajie

    2015-01-14

    We study the supercurrent in clean superconductor-ferromagnet-superconductor heterostructure containing a noncollinear magnetic domain in the ferromagnetic region. It is demonstrated that the magnetic domain can lead to a spin-flip scattering process, which reverses the spin orientations of the singlet Cooper pair and simultaneously changes the sign of the corresponding electronic momentum. If the ferromagnetic layers on both sides of magnetic domain have the same features, the long-range proximity effect will take place. That is because the singlet Cooper pair will create an exact phase-cancellation effect and gets an additional π phase shift as it passes through the entire ferromagnetic region. Then, the equal spin triplet pair only exists in the magnetic domain region and can not diffuse into the other two ferromagnetic layers. So, the supercurrent mostly arises from the singlet Cooper pairs, and the equal spin triplet pairs are not involved. This result can provide a approach for generating the long-range supercurrent.

  19. Analysis of magnetic probe signals including effect of cylindrical conducting wall for field-reversed configuration experiment

    SciTech Connect (OSTI)

    Ikeyama, Taeko; Hiroi, Masanori; Nemoto, Yuuichi; Nogi, Yasuyuki

    2008-06-15

    A confinement field is disturbed by magnetohydrodynamic (MHD) motions of a field-reversed configuration (FRC) plasma in a cylindrical conductor. The effect of the conductor should be included to obtain a spatial structure of the disturbed field with a good precision. For this purpose, a toroidal current in the plasma and an eddy current on a conducting wall are replaced by magnetic dipole and image magnetic dipole moments, respectively. Typical spatial structures of the disturbed field are calculated by using the dipole moments for such MHD motions as radial shift, internal tilt, external tilt, and n=2 mode deformation. Then, analytic formulas for estimating the shift distance, tilt angle, and deformation rate of the MHD motions from magnetic probe signals are derived. It is estimated from the calculations by using the dipole moments that the analytic formulas include an approximately 40% error. Two kinds of experiment are carried out to investigate the reliability of the calculations. First, a magnetic field produced by a circular current is measured in an aluminum pipe to confirm the replacement of the eddy current with the image magnetic dipole moments. The measured fields coincide well with the calculated values including the image magnetic dipole moments. Second, magnetic probe signals measured from the FRC plasma are substituted into the analytic formulas to obtain shift distance and deformation rate. The experimental results are compared to the MHD motions measured by using a radiation from the plasma. If the error included in the analytic formulas and the difference between the magnetic and optical structures in the plasma are considered, the results of the radiation measurement support well those of the magnetic analysis.

  20. High efficiency of the spin-orbit torques induced domain wall motion in asymmetric interfacial multilayered Tb/Co wires

    SciTech Connect (OSTI)

    Bang, Do; Awano, Hiroyuki

    2015-05-07

    We investigated current-induced DW motion in asymmetric interfacial multilayered Tb/Co wires for various thicknesses of magnetic and Pt-capping layers. It is found that the driving mechanism for the DW motion changes from interfacial to bulk effects at much thick magnetic layer (up to 19.8 nm). In thin wires, linearly depinning field dependence of critical current density and in-plane field dependence of DW velocity suggest that the extrinsic pinning governs field-induced DW motion and injecting current can be regarded as an effective field. It is expected that the high efficiency of spin-orbit torques in thick magnetic multilayers would have important implication for future spintronic devices based on in-plane current induced-DW motion or switching.

  1. Low-energy planar magnetic defects in BaFe2As2: Nanotwins, twins, antiphase, and domain boundaries

    SciTech Connect (OSTI)

    Khan, Suffian N. [Ames Laboratory; Alam, Aftab [Ames Laboratory; Johnson, Duane D. [Ames Laboratory

    2013-11-27

    In BaFe2As2, structural and magnetic planar defects begin to proliferate below the structural phase transition, affecting descriptions of magnetism and superconductivity. We study, using density-functional theory, the stability and magnetic properties of competing antiphase and domain boundaries, twins and isolated nanotwins (twin nuclei), and spin excitations proposed and/or observed. These nanoscale defects have a very low surface energy (22210 m Jm?2), with twins favorable to the mesoscale. Defects exhibit smaller moments confined near their boundariesmaking a uniform-moment picture inappropriate for long-range magnetic order in real samples. Nanotwins explain features in measured pair distribution functions so should be considered when analyzing scattering data. All these defects can be weakly mobile and/or can have fluctuations that lower assessed ordered moments from longer spatial and/or time averaging and should be considered directly.

  2. Low-energy planar magnetic defects in BaFe2As2: Nanotwins, twins, antiphase, and domain boundaries

    SciTech Connect (OSTI)

    Khan, S. N. [Ames Laboratory] [Ames Laboratory; Alam, A. [Ames Laboratory] [Ames Laboratory; Johnson, Duane D. [University of Illinois, Urbana-Champaign] [University of Illinois, Urbana-Champaign

    2013-01-01

    In BaFe2As2, structural and magnetic planar defects begin to proliferate below the structural phase transition, affecting descriptions of magnetism and superconductivity.We study, using density-functional theory, the stability and magnetic properties of competing antiphase and domain boundaries, twins and isolated nanotwins (twin nuclei), and spin excitations proposed and/or observed. These nanoscale defects have a very low surface energy (22 210 m Jm 2), with twins favorable to the mesoscale. Defects exhibit smaller moments confined near their boundaries making a uniform-moment picture inappropriate for long-range magnetic order in real samples. Nanotwins explain features in measured pair distribution functions so should be considered when analyzing scattering data. All these defects can be weakly mobile and/or can have fluctuations that lower

  3. Preparation and characterization of multi-walled carbon nanotubes with nickelphosphorous layers of high magnetic properties

    SciTech Connect (OSTI)

    Zhang, Yi; Qi, Shuhua; Zhang, Fan

    2012-11-15

    Highlights: ? Impurities in crude MWNTs were effectively removed after purification treatment. ? Many Ni nanoparticles were homogenously coated on the purified MWNTs. ? The saturation magnetization (Ms) of the MWNTs with NiP layers is 91.5 emu/g. -- Abstract: The multi-wall carbon nanotubes (MWNTs) with nickelphosphorous (NiP) layers were prepared by electroless plating method. To obtain the MWNTs with NiP layers of high magnetic properties, an effective purification treatment and a pre-treatment procedure were developed. The crude MWNTs, the purified MWNTs and the MWNTs with NiP layers were characterized by scanning electron microscope (SEM)/energy dispersive spectroscopy (EDS), transmission electron microscope (TEM), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). SEM results, TEM images and XRD results indicate that impurities in the crude MWNTs were effectively removed after the purification treatment and a large number of Ni nanoparticles were homogenously coated on the surface of the purified MWNTs. According to the VSM test, the saturation magnetization (Ms) of the MWNTs with NiP layers is 91.5 emu/g which is higher than results of other researchers.

  4. B-meson decay constants from 2+1-flavor lattice QCD with domain-wall light quarks and relativistic heavy quarks

    SciTech Connect (OSTI)

    Christ, Norman H.; Flynn, Jonathan M.; Izubuchi, Taku; Kawanai, Taichi; Lehner, Christoph; Soni, Amarjit; Van de Water, Ruth S.; Witzel, Oliver

    2015-03-10

    We calculate the B-meson decay constants fB, fBs, and their ratio in unquenched lattice QCD using domain-wall light quarks and relativistic b-quarks. We use gauge-field ensembles generated by the RBC and UKQCD collaborations using the domain-wall fermion action and Iwasaki gauge action with three flavors of light dynamical quarks. We analyze data at two lattice spacings of a ≈ 0.11, 0.086 fm with unitary pion masses as light as Mπ ≈ 290 MeV; this enables us to control the extrapolation to the physical light-quark masses and continuum. For the b-quarks we use the anisotropic clover action with the relativistic heavy-quark interpretation, such that discretization errors from the heavy-quark action are of the same size as from the light-quark sector. We renormalize the lattice heavy-light axial-vector current using a mostly nonperturbative method in which we compute the bulk of the matching factor nonperturbatively, with a small correction, that is close to unity, in lattice perturbation theory. We also improve the lattice heavy-light current through O(αsa). We extrapolate our results to the physical light-quark masses and continuum using SU(2) heavy-meson chiral perturbation theory, and provide a complete systematic error budget. We obtain fB0 = 196.2(15.7) MeV, fB+ = 195.4(15.8) MeV, fBs = 235.4(12.2) MeV, fBs/fB0 = 1.193(59), and fBs/fB+ = 1.220(82), where the errors are statistical and total systematic added in quadrature. In addition, these results are in good agreement with other published results and provide an important independent cross check of other three-flavor determinations of B-meson decay constants using staggered light quarks.

  5. Magnetic domain tuning and the emergence of bubble domains in the bilayer manganite La2–2xSr1+2xMn2O7(x=0.32)

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

    Jeong, Juyoung; Yang, Ilkyu; Yang, Jinho; Ayala-Valenzuela, Oscar E.; Wulferding, Dirk; Zhou, J. -S.; Goodenough, John B.; de Lozanne, Alex; Mitchell, J. F.; Leon, Neliza; et al

    2015-08-17

    We report a magnetic force microscopy study of the magnetic domain evolution in the layered manganite La2-2xSr1+2xMn2O7 (with x=0.32). This strongly correlated electron compound is known to exhibit a wide range of magnetic phases, including a recently uncovered biskyrmion phase. We observe a continuous transition from dendritic to stripelike domains, followed by the formation of magnetic bubbles due to a field- and temperature-dependent competition between in-plane and out-of-plane spin alignments. The magnetic bubble phase appears at comparable field and temperature ranges as the biskyrmion phase, suggesting a close relation between both phases. Based on our real-space images we construct amore » temperature-field phase diagram for this composition.« less

  6. Magnetic domain tuning and the emergence of bubble domains in the bilayer manganite La2–2xSr1+2xMn2O7(x=0.32)

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

    Jeong, Juyoung; Yang, Ilkyu; Yang, Jinho; Ayala-Valenzuela, Oscar E.; Wulferding, Dirk; Zhou, J. -S.; Goodenough, John B.; de Lozanne, Alex; Mitchell, J. F.; Leon, Neliza; et al

    2015-08-17

    We report a magnetic force microscopy study of the magnetic domain evolution in the layered manganite La2-2xSr1+2xMn2O7 (with x=0.32). This strongly correlated electron compound is known to exhibit a wide range of magnetic phases, including a recently uncovered biskyrmion phase. We observe a continuous transition from dendritic to stripelike domains, followed by the formation of magnetic bubbles due to a field- and temperature-dependent competition between in-plane and out-of-plane spin alignments. The magnetic bubble phase appears at comparable field and temperature ranges as the biskyrmion phase, suggesting a close relation between both phases. Based on our real-space images we construct amore »temperature-field phase diagram for this composition.« less

  7. Magnetic domain tuning and the emergence of bubble domains in the bilayer manganite La2-2xSr1+2xMn2O7(x=0.32)

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

    Jeong, Juyoung; Yang, Ilkyu; Yang, Jinho; Ayala-Valenzuela, Oscar E.; Wulferding, Dirk; Zhou, J. -S.; Goodenough, John B.; de Lozanne, Alex; Mitchell, J. F.; Leon, Neliza; et al

    2015-08-17

    Here, we report a magnetic force microscopy study of the magnetic domain evolution in the layered manganite La2–2xSr1+2xMn2O7 (with x = 0.32). This strongly correlated electron compound is known to exhibit a wide range of magnetic phases, including a recently uncovered biskyrmion phase. We observe a continuous transition from dendritic to stripelike domains, followed by the formation of magnetic bubbles due to a field- and temperature-dependent competition between in-plane and out-of-plane spin alignments. The magnetic bubble phase appears at comparable field and temperature ranges as the biskyrmion phase, suggesting a close relation between both phases. Based on our real-space imagesmore » we construct a temperature-field phase diagram for this composition.« less

  8. First results from 2+1-Flavor Domain Wall QCD: Mass Spectrum, Topology Change and Chiral Symmetry with $L_s=8$

    SciTech Connect (OSTI)

    D. J. Antonio; T. Blum; K. C. Bowler; P. A. Boyle; N. H. Christ; S. D. Cohen; M. A. Clark; C. Dawson; A. Hart; K. Hashimoto; T. Izubuchi; B. Joó; C. Jung; A. D. Kennedy; R. D. Kenway; S. Li; H. W. Lin; M.F. Lin; R. D. Mawhinney; C.M. Maynard; J. Noaki; S. Ohta; S. Sasaki; A. Soni; R. J. Tweedie; A. Yamaguchi

    2007-06-01

    We present results for the static interquark potential, light meson and baryon masses, and light pseudoscalar meson decay constants obtained from simulations of domain wall QCD with one dynamical flavour approximating the $s$ quark, and two degenerate dynamical flavours with input bare masses ranging from $m_s$ to $m_s/4$ approximating the $u$ and $d$ quarks. We compare these quantities obtained using the Iwasaki and DBW2 improved gauge actions, and actions with larger rectangle coefficients, on $16^3\\times32$ lattices. We seek parameter values at which both the chiral symmetry breaking residual mass due to the finite lattice extent in the fifth dimension and the Monte Carlo time history for topological charge are acceptable for this set of quark masses at lattice spacings above 0.1 fm. We find that the Iwasaki gauge action is best, demonstrating the feasibility of using QCDOC to generate ensembles which are good representations of the QCD path integral on lattices of up to 3 fm in spatial extent with lattice spacings in the range 0.09-0.13 fm. Despite large residual masses and a limited number of sea quark mass values with which to perform chiral extrapolations, our results for light hadronic physics scale and agree with experimental measurements within our statistical uncertainties.

  9. Method and apparatus to produce and maintain a thick, flowing, liquid lithium first wall for toroidal magnetic confinement DT fusion reactors

    DOE Patents [OSTI]

    Woolley, Robert D.

    2002-01-01

    A system for forming a thick flowing liquid metal, in this case lithium, layer on the inside wall of a toroid containing the plasma of a deuterium-tritium fusion reactor. The presence of the liquid metal layer or first wall serves to prevent neutron damage to the walls of the toroid. A poloidal current in the liquid metal layer is oriented so that it flows in the same direction as the current in a series of external magnets used to confine the plasma. This current alignment results in the liquid metal being forced against the wall of the toroid. After the liquid metal exits the toroid it is pumped to a heat extraction and power conversion device prior to being reentering the toroid.

  10. 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.

  11. Domain Dynamics in Piezoresponse Force Microscopy: Quantitative...

    Office of Scientific and Technical Information (OSTI)

    The fine structure of the hysteresis loop is shown to be related to the observed jumps in the domain geometry during domain wall propagation (nanoscale Barkhausen jumps), ...

  12. Domain Dynamics in Piezoresponse Force Spectroscopy: Quantitative...

    Office of Scientific and Technical Information (OSTI)

    The fine structure of the hysteresis loop is shown to be related to the observed jumps in the domain geometry during domain wall propagation (nanoscale Barkhausen jumps), ...

  13. Wall Insulation

    SciTech Connect (OSTI)

    2000-10-01

    This fact sheet provides information on advanced wall framing, including insulating walls, airtight construction, and moisture control.

  14. In-situ observation of domain wall motion in Pb(In{sub 1/2}Nb{sub 1/2})O{sub 3}-Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} crystals

    SciTech Connect (OSTI)

    Lin, Dabin; Cai, Changlong [Laboratory of Thin Film Techniques and Optical Test, Xi'an Technological University, Xi'an 710032 (China); Li, Zhenrong, E-mail: zhrli@mail.xjtu.edu.cn; Li, Fei; Xu, Zhuo [Electronic Materials Research Laboratory, Key Laboratory of Education Ministry and International Center for Dielectric Research, Xi'an Jiaotong University, Xi'an 710049 (China); Zhang, Shujun, E-mail: soz1@psu.edu [Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Cheng, Yaojin [Science and Technology on Low-Light-Level Night Vision Laboratory, Xi'an 710065 (China)

    2014-07-21

    Various domain structures, including wave-like domains, mixed needle-like and laminar domains, typical embedded 90 and 180 domains, have been observed in unpoled rhombohedral, monoclinic, and tetragonal Pb(In{sub 1/2}Nb{sub 1/2})O{sub 3}-Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} (PIN-PMN-PT) crystals by polarizing light microscope; while in poled tetragonal crystals, the parallel 180 domains were reversed and only vertical 90 domain walls were observed. For 0.24PIN-0.42PMN-0.34PT crystals with morphotropic phase boundary composition, the domain wall motion was in-situ observed as a function of applied electric field along crystallographic [100] direction. With increasing the electric field from 0 to 12?kV/cm, the rhombohedral (R) domains were found to change to monoclinic (M) domains and then to tetragonal (T) domains. The electric field-induced phase transition was also confirmed by X-ray diffraction and the temperature-dependent dielectric behavior.

  15. Magnetization Reversal Process of Single Crystal α-Fe Containing a Nonmagnetic Particle

    SciTech Connect (OSTI)

    Li, Yi; Xu, Ben; Hu, Shenyang Y.; Li, Yulan; Li, Qiu-Lin; Liu, Wei

    2015-09-25

    The magnetization reversal process and hysteresis loops in a single crystal α-iron with nonmagnetic particles are simulated in this work based on the Landau-Lifshitz–Gilbert equation. The evolutions of the magnetic domain morphology are studied, and our analyses show that the magnetization reversal process is affected by the interaction between the moving domain wall and the existing nonmagnetic particles. This interaction strongly depends on the size of the particles, and it is found that particles with a particular size contribute the most to magnetic hardening.

  16. Effect of substrate temperature on the magnetic properties of epitaxial sputter-grown Co/Pt

    SciTech Connect (OSTI)

    Mihai, A. P.; Whiteside, A. L.; Canwell, E. J.; Marrows, C. H.; Moore, T. A.; Benitez, M. J.; McGrouther, D.; McVitie, S.; McFadzean, S.

    2013-12-23

    Epitaxial Co/Pt films have been deposited by dc-magnetron sputtering onto heated C-plane sapphire substrates. X-ray diffraction, the residual resistivity, and transmission electron microscopy indicate that the Co/Pt films are highly ordered on the atomic scale. The coercive field and the perpendicular magnetic anisotropy increase as the substrate temperature is increased from 100250?C during deposition of the Co/Pt. Measurement of the domain wall creep velocity as a function of applied magnetic field yields the domain wall pinning energy, which scales with the coercive field. Evidence for an enhanced creep velocity in highly ordered epitaxial Co/Pt is found.

  17. 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

  18. Current induced perpendicular-magnetic-anisotropy racetrack memory with magnetic field assistance

    SciTech Connect (OSTI)

    Zhang, Y.; Klein, J.-O.; Chappert, C.; Ravelosona, D.; Zhao, W. S.

    2014-01-20

    High current density is indispensable to shift domain walls (DWs) in magnetic nanowires, which limits the using of racetrack memory (RM) for low power and high density purposes. In this paper, we present perpendicular-magnetic-anisotropy (PMA) Co/Ni RM with global magnetic field assistance, which lowers the current density for DW motion. By using a compact model of PMA RM and 40 nm design kit, we perform mixed simulation to validate the functionality of this structure and analyze its density potential. Stochastic DW motion behavior has been taken into account and statistical Monte-Carlo simulations are carried out to evaluate its reliability performance.

  19. Modeling the Sedimentation of Red Blood Cells in Flow under Strong External Magnetic Body Force using a Lattice Boltzmann Fictitious Domain Method

    SciTech Connect (OSTI)

    Shi, Xing; Lin, Guang

    2014-11-01

    To model the sedimentation of the red blood cell (RBC) in a square duct and a circular pipe, the recently developed technique derived from the lattice Boltzmann method and the distributed Lagrange multiplier/fictitious domain method (LBM-DLM/FD) is extended to employ the mesoscopic network model for simulations of the sedimentation of the RBC in flow. The flow is simulated by the lattice Boltzmann method with a strong magnetic body force, while the network model is used for modeling RBC deformation. The fluid-RBC interactions are enforced by the Lagrange multiplier. The sedimentation of the RBC in a square duct and a circular pipe is simulated, revealing the capacity of the current method for modeling the sedimentation of RBC in various flows. Numerical results illustrate that that the terminal setting velocity increases with the increment of the exerted body force. The deformation of the RBC has significant effect on the terminal setting velocity due to the change of the frontal area. The larger the exerted force is, the smaller the frontal area and the larger deformation of the RBC are.

  20. Hysteretic magnetoresistance and unconventional anomalous Hall effect in the frustrated magnet TmB4

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

    Sunku, Sai Swaroop; Kong, Tai; Ito, Toshimitsu; Canfield, Paul C.; Shastry, B. Sriram; Sengupta, Pinaki; Panagopoulos, Christos

    2016-05-11

    We study TmB4, a frustrated magnet on the Archimedean Shastry-Sutherland lattice, through magnetization and transport experiments. The lack of anisotropy in resistivity shows that TmB4 is an electronically three-dimensional system. The magnetoresistance (MR) is hysteretic at low temperature even though a corresponding hysteresis in magnetization is absent. The Hall resistivity shows unconventional anomalous Hall effect (AHE) and is linear above saturation despite a large MR. In conclusion, we propose that complex structures at magnetic domain walls may be responsible for the hysteretic MR and may also lead to the AHE.

  1. Fast chirality reversal of the magnetic vortex by electric current

    SciTech Connect (OSTI)

    Lim, W. L. Liu, R. H.; Urazhdin, S.; Tyliszczak, T.; Erokhin, S. G.; Berkov, D.

    2014-12-01

    The possibility of high-density information encoding in magnetic materials by topologically stable inhomogeneous magnetization configurations such as domain walls, skyrmions, and vortices has motivated intense research into mechanisms enabling their control and detection. While the uniform magnetization states can be efficiently controlled by electric current using magnetic multilayer structures, this approach has proven much more difficult to implement for inhomogeneous states. Here, we report direct observation of fast reversal of magnetic vortex by electric current in a simple planar structure based on a bilayer of spin Hall material Pt with a single microscopic ferromagnetic disk contacted by asymmetric electrodes. The reversal is enabled by a combination of the chiral Oersted field and spin current generated by the nonuniform current distribution in Pt. Our results provide a route for the efficient control of inhomogeneous magnetization configurations by electric current.

  2. Critical role of domain crystallinity, domain purity and domain...

    Office of Scientific and Technical Information (OSTI)

    Critical role of domain crystallinity, domain purity and domain interface sharpness for reduced bimolecular recombination in polymer solar cells Citation Details In-Document Search ...

  3. Wall thickness measuring method and apparatus

    DOE Patents [OSTI]

    Salzer, L.J.; Bergren, D.A.

    1987-10-06

    An apparatus for measuring the wall thickness of a nonmagnetic article having a housing supporting a magnet and a contiguous supporting surface. The tubular article and the housing are releasably secured to the supporting surface and a support member of an optical comparator, respectively. To determine the wall thickness of the article at a selected point, a magnetically responsive ball is positioned within the tubular article over said point and retained therein by means of a magnetic field produced by the magnet. Thereafter, an optical comparator is employed to project a magnified image of the ball on a screen and the wall thickness at the selected point is calculated by using a ball surface measurement taken with the comparator in conjunction with a previously determined base line measurement.

  4. Wall thickness measuring method and apparatus

    DOE Patents [OSTI]

    Salzer, Leander J.; Bergren, Donald A.

    1989-01-01

    An apparatus for measuring the wall thickness of a nonmagnetic article having a housing supporting a magnet and a contiguous supporting surface. The tubular article and the housing are releasably secured to the supporting surface and a support member of an optical comparator, respectively. To determine the wall thickness of the article at a selected point, a magnetically responsive ball is positioned within the tubular article over said point and retained therein by means of a magnetic field produced by the magnet. Thereafter, an optical comparator is employed to project a magnified image of the ball on a screen and the wall thickness at the selected point is calculated by using a ball surface measurement taken with the comparator in conjunction with a previously determined base line measurement.

  5. Dielectric and magnetic investigations of GaFeO{sub 3} single crystals

    SciTech Connect (OSTI)

    Srimathy, B. Bhaumik, Indranil Ganesamoorthy, S. Karnal, A. K. Kumar, J.

    2014-04-24

    Structural, dielectric and magnetic properties have been investigated for the polar ferrimagnet, GaFeO{sub 3} single crystals grown by optical floating zone technique. Phase formation was confirmed from X-ray diffraction. Hopping conduction mechanism of Fe{sup 2+} ions and oxygen vacancies contribute to the electric polarization and dielectric constant of the material. Disorderness in the cation site gives rise to the magnetic ordering and the splitting in the zero field cooled (ZFC) and field cooled (FC) magnetization curves reveals the movement of the domain walls.

  6. System and method for manipulating domain pinning and reversal in ferromagnetic materials

    SciTech Connect (OSTI)

    Silevitch, Daniel M.; Rosenbaum, Thomas F.; Aeppli, Gabriel

    2013-10-15

    A method for manipulating domain pinning and reversal in a ferromagnetic material comprises applying an external magnetic field to a uniaxial ferromagnetic material comprising a plurality of magnetic domains, where each domain has an easy axis oriented along a predetermined direction. The external magnetic field is applied transverse to the predetermined direction and at a predetermined temperature. The strength of the magnetic field is varied at the predetermined temperature, thereby isothermally regulating pinning of the domains. A magnetic storage device for controlling domain dynamics includes a magnetic hard disk comprising a uniaxial ferromagnetic material, a magnetic recording head including a first magnet, and a second magnet. The ferromagnetic material includes a plurality of magnetic domains each having an easy axis oriented along a predetermined direction. The second magnet is positioned adjacent to the magnetic hard disk and is configured to apply a magnetic field transverse to the predetermined direction.

  7. High performance magnetic bearing systems using high temperature superconductors

    DOE Patents [OSTI]

    Abboud, R.G.

    1998-05-05

    Disclosed are a magnetic bearing apparatus and a method for providing at least one stabilizing force in a magnetic bearing structure with a superconducting magnetic assembly and a magnetic assembly, by providing a superconducting magnetic member in the superconducting magnetic assembly with a plurality of domains and arranging said superconducting magnetic member such that at least one domain has a domain C-axis vector alignment angularly disposed relative to a reference axis of the magnetic member in the magnetic assembly. 7 figs.

  8. High performance magnetic bearing systems using high temperature superconductors

    DOE Patents [OSTI]

    Abboud, Robert G.

    1998-01-01

    A magnetic bearing apparatus and a method for providing at least one stabilizing force in a magnetic bearing structure with a superconducting magnetic assembly and a magnetic assembly, by providing a superconducting magnetic member in the superconducting magnetic assembly with a plurality of domains and arranging said superconducting magnetic member such that at least one domain has a domain C-axis vector alignment angularly disposed relative to a reference axis of the magnetic member in the magnetic assembly.

  9. 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.

  10. Wall surveyor project report

    SciTech Connect (OSTI)

    Mullenhoff, D.J.; Johnston, B.C.; Azevedo, S.G.

    1996-02-22

    A report is made on the demonstration of a first-generation Wall Surveyor that is capable of surveying the interior and thickness of a stone, brick, or cement wall. LLNL`s Micropower Impulse Radar is used, based on emitting and detecting very low amplitude and short microwave impulses (MIR rangefinder). Six test walls were used. While the demonstrator MIR Wall Surveyor is not fieldable yet, it has successfully scanned the test walls and produced real-time images identifying the walls. It is planned to optimize and package the evaluation wall surveyor into a hand held unit.

  11. Magnetization reversal assisted by half antivortex states in nanostructured circular cobalt disks

    SciTech Connect (OSTI)

    Lara, A.; Aliev, F. G.; Dobrovolskiy, O. V.; Prieto, J. L.; Huth, M.

    2014-11-03

    The half antivortex, a fundamental topological structure which determines magnetization reversal of submicron magnetic devices with domain walls, has been suggested also to play a crucial role in spin torque induced vortex core reversal in circular disks. Here, we report on magnetization reversal in circular disks with nanoholes through consecutive metastable states with half antivortices. In-plane anisotropic magnetoresistance and broadband susceptibility measurements accompanied by micromagnetic simulations reveal that cobalt (Co) disks with two and three linearly arranged nanoholes directed at 45° and 135° with respect to the external magnetic field show reproducible step-like changes in the anisotropic magnetoresistance and magnetic permeability due to transitions between different intermediate states mediated by vortices and half antivortices confined to the dot nanoholes and edges, respectively. Our findings are relevant for the development of multi-hole based spintronic and magnetic memory devices.

  12. Time-domain detection of current controlled magnetization damping in Pt/Ni{sub 81}Fe{sub 19} bilayer and determination of Pt spin Hall angle

    SciTech Connect (OSTI)

    Ganguly, A.; Haldar, A.; Sinha, J.; Barman, A. E-mail: del.atkinson@durham.ac.uk; Rowan-Robinson, R. M.; Jaiswal, S.; Hindmarch, A. T.; Atkinson, D. A. E-mail: del.atkinson@durham.ac.uk

    2014-09-15

    The effect of spin torque from the spin Hall effect in Pt/Ni{sub 81}Fe{sub 19} rectangular bilayer film was investigated using time-resolved magneto-optical Kerr microscopy. Current flow through the stack resulted in a linear variation of effective damping up to ±7%, attributed to spin current injection from the Pt into the Ni{sub 81}Fe{sub 19}. The spin Hall angle of Pt was estimated as 0.11 ± 0.03. The modulation of the damping depended on the angle between the current and the bias magnetic field. These results demonstrate the importance of optical detection of precessional magnetization dynamics for studying spin transfer torque due to spin Hall effect.

  13. 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.

  14. 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.

  15. 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.

  16. Axisymmetric Tandem Mirror Magnetic Fusion Energy Power Plant...

    Office of Scientific and Technical Information (OSTI)

    Magnetic Fusion Energy Power Plant with Thick Liquid-Walls Citation Details In-Document Search Title: Axisymmetric Tandem Mirror Magnetic Fusion Energy Power Plant with Thick ...

  17. Magnetic domain tuning and the emergence of bubble domains in the bilayer manganite La2-2xSr1+2xMn2O7(x=0.32)

    SciTech Connect (OSTI)

    Jeong, Juyoung; Yang, Ilkyu; Yang, Jinho; Ayala-Valenzuela, Oscar E.; Wulferding, Dirk; Zhou, J. -S.; Goodenough, John B.; de Lozanne, Alex; Mitchell, J. F.; Leon, Neliza; Movshovich, Roman; Jeong, Yoon Hee; Yeom, Han Woong; Kim, Jeehoon

    2015-08-17

    Here, we report a magnetic force microscopy study of the magnetic domain evolution in the layered manganite La2–2xSr1+2xMn2O7 (with x = 0.32). This strongly correlated electron compound is known to exhibit a wide range of magnetic phases, including a recently uncovered biskyrmion phase. We observe a continuous transition from dendritic to stripelike domains, followed by the formation of magnetic bubbles due to a field- and temperature-dependent competition between in-plane and out-of-plane spin alignments. The magnetic bubble phase appears at comparable field and temperature ranges as the biskyrmion phase, suggesting a close relation between both phases. Based on our real-space images we construct a temperature-field phase diagram for this composition.

  18. Resistive and ferritic-wall plasma dynamos in a sphere

    SciTech Connect (OSTI)

    Khalzov, I. V.; Brown, B. P.; Kaplan, E. J.; Katz, N.; Paz-Soldan, C.; Rahbarnia, K.; Forest, C. B. [University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706 (United States); Center for Magnetic Self Organization in Laboratory and Astrophysical Plasmas (United States); Spence, E. J. [Center for Magnetic Self Organization in Laboratory and Astrophysical Plasmas (United States); Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 (United States)

    2012-10-15

    We numerically study the effects of varying electric conductivity and magnetic permeability of the bounding wall on a kinematic dynamo in a sphere for parameters relevant to Madison plasma dynamo experiment. The dynamo is excited by a laminar, axisymmetric flow of von Karman type. The flow is obtained as a solution to the Navier-Stokes equation for an isothermal fluid with a velocity profile specified at the sphere's boundary. The properties of the wall are taken into account as thin-wall boundary conditions imposed on the magnetic field. It is found that an increase in the permeability of the wall reduces the critical magnetic Reynolds number Rm{sub cr}. An increase in the conductivity of the wall leaves Rm{sub cr} unaffected but reduces the dynamo growth rate.

  19. The effect of boron doping on crystal structure, magnetic properties and magnetocaloric effect of DyCo2

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

    Wang, C. L.; Liu, J.; Mudryk, Y.; Gschneidner, Jr., K. A.; Long, Y.; Pecharsky, V. K.

    2015-12-19

    The magnetic properties and magnetic entropy changes of DyCo2Bx (x=0, 0.05, 0.1, and 0.2) alloys were investigated. The Curie temperature (TC) increases with increasing B concentration. The frequency dependence of ac magnetic susceptibility of DyCo2 caused by the narrow domain wall pinning effect is depressed by B doping, but the coercivity and the magnetic viscosity are prominently increased in the B doped alloys. The magnetic transition nature of DyCo2Bx changes from the first-order to the second-order with increasing x, which leads to the decrease of the maximum magnetic entropy change. Furthermore, the relative cooling power (RCP) of DyCo2 and themore » B doped alloys remains nearly constant.« less

  20. The effect of boron doping on crystal structure, magnetic properties and magnetocaloric effect of DyCo2

    SciTech Connect (OSTI)

    Wang, C. L.; Liu, J.; Mudryk, Y.; Gschneidner, Jr., K. A.; Long, Y.; Pecharsky, V. K.

    2015-12-19

    The magnetic properties and magnetic entropy changes of DyCo2Bx (x=0, 0.05, 0.1, and 0.2) alloys were investigated. The Curie temperature (TC) increases with increasing B concentration. The frequency dependence of ac magnetic susceptibility of DyCo2 caused by the narrow domain wall pinning effect is depressed by B doping, but the coercivity and the magnetic viscosity are prominently increased in the B doped alloys. The magnetic transition nature of DyCo2Bx changes from the first-order to the second-order with increasing x, which leads to the decrease of the maximum magnetic entropy change. Furthermore, the relative cooling power (RCP) of DyCo2 and the B doped alloys remains nearly constant.

  1. The effect of boron doping on crystal structure, magnetic properties and magnetocaloric effect of DyCo2

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

    Wang, C. L.; Liu, J.; Mudryk, Y.; Gschneidner, Jr., K. A.; Long, Y.; Pecharsky, V. K.

    2015-12-19

    In this study, the magnetic properties and magnetic entropy changes of DyCo2Bx (x=0, 0.05, 0.1, and 0.2) alloys were investigated. The Curie temperature (TC) increases with increasing B concentration. The frequency dependence of ac magnetic susceptibility of DyCo2 caused by the narrow domain wall pinning effect is depressed by B doping, but the coercivity and the magnetic viscosity are prominently increased in the B doped alloys. The magnetic transition nature of DyCo2Bx changes from the first-order to the second-order with increasing x, which leads to the decrease of the maximum magnetic entropy change. However, the relative cooling power (RCP) ofmore » DyCo2 and the B doped alloys remains nearly constant.« less

  2. Imaging of magnetic DW injection processed in patterened Ni80Fe20 structures

    SciTech Connect (OSTI)

    Bryan, M. T.; Basu, S.; Fry, P. W.; Schrefl, T.; Gibbs, M.R.J.; Allwood, D. A.; Im, M.-Y.; Fischer, P.

    2009-03-23

    Magnetization reversal in patterned ferromagnetic nanowires usually occurs via domain wall (DW) nucleation and propagation from one end (or both ends) of the wire which can be significantly reduced by a large, magnetically soft pad on one of the wire ends. These 'nucleation pads' reverse at lower fields than an isolated nanowire and introduce a DW to the wire from the wire end attached to the pad. Once a critical 'injection' field is reached, the DW sweeps through the wire, reversing its magnetization. Nucleation pads are frequently used as part of nanowire devices and experimental structures. Magnetic-field-driven shift register memory can include an injection pad to write data while those attached to nanowire spiral turn sensors act as both a source and sink of domain walls. Both of these devices use two-dimensional wire circuits and therefore require the use of orthogonal in-plane magnetic fields to drive domain walls through wires of different orientations. These bi-axial fields can significantly alter the fields at which DW injection occurs and control the number of different injection modes. We have used magnetic transmission soft X-ray microscopy (M-TXM) [6] providing 25nm spatial resolution to image the evolution of magnetization configurations in patterned 24nm thick Ni{sub 80}Fe{sub 20} rectangular nucleation pads and attached wires during DW injection. The structures consisted of 2 {micro}m x 3 {micro}m nucleation pads with wires of width 200 nm, 300 nm or 500 nm attached Comparing the magnetic configuration of the injection pads with micromagnetic models, we find that the relative orientation of closure domains in the remanent magnetization configuration of injection pads determines the reversal pathway that follows, although this is further affected by applied transverse fields. Micromagnetic simulations were performed using a hybrid finite element/boundary element code. The magnetic elements were designed with 20 nm thickness and discretized into a

  3. Fluidized wall for protecting fusion chamber walls

    DOE Patents [OSTI]

    Maniscalco, James A.; Meier, Wayne R.

    1982-01-01

    Apparatus for protecting the inner wall of a fusion chamber from microexplosion debris, x-rays, neutrons, etc. produced by deuterium-tritium (DT) targets imploded within the fusion chamber. The apparatus utilizes a fluidized wall similar to a waterfall comprising liquid lithium or solid pellets of lithium-ceramic, the waterfall forming a blanket to prevent damage of the structural materials of the chamber.

  4. Soft X-ray techniques to study mesoscale magnetism

    SciTech Connect (OSTI)

    Kortright, Jeffrey B.

    2003-06-26

    Heterogeneity in magnetization (M) is ubiquitous in modern systems. Even in nominally homogeneous materials, domains or pinning centers typically mediate magnetization reversal. Fundamental lengths determining M structure include the domain wall width and the exchange stiffness length, typically in the 4-400 nm range. Chemical heterogeneity (phase separation, polycrystalline microstructure, lithographic or other patterning, etc.) with length scales from nanometers to microns is often introduced to influence magnetic properties. With 1-2 nm wavelengths {lambda}, soft x-rays in principle can resolve structure down to {lambda}/2, and are well suited to study these mesoscopic length scales [1, 2]. This article highlights recent advances in resonant soft x-ray methods to resolve lateral magnetic structure [3], and discusses some of their relative merits and limitations. Only techniques detecting x-ray photons (rather than photo-electrons) are considered [4], since they are compatible with strong applied fields to probe relatively deeply into samples. The magneto-optical (MO) effects discovered by Faraday and Kerr were observed in the x-ray range over a century later, first at ''hard'' wavelengths in diffraction experiments probing interatomic magnetic structure [5]. In the soft x-ray range, magnetic linear [6] and circular [7] dichroism spectroscopies first developed that average over lateral magnetic structure. These large resonant MO effects enable different approaches to study magnetic structure or heterogeneity that can be categorized as microscopy or scattering [1]. Direct images of magnetic structure result from photo-emission electron microscopes [4, 8] and zone-plate microscopes [9, 10]. Scattering techniques extended into the soft x-ray include familiar specular reflection that laterally averages over structure but can provide depth-resolved information, and diffuse scattering and diffraction that provide direct information about lateral magnetic structure

  5. Dynamic domain walls in a Maxwell-dilaton background (Journal...

    Office of Scientific and Technical Information (OSTI)

    72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CONFIGURATION; COUPLING; ELECTROMAGNETIC FIELDS; ENERGY DENSITY; EXPANSION; GRAVITATION; MANY-DIMENSIONAL CALCULATIONS; MATHEMATICAL ...

  6. Iran Thomas Auditorium, 8600 Charged Domain Walls in Ferroelectrics

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

    Ceramics Laboratory, Swiss Federal Institute of Technology (EPFL) Lausanne 1015, Switzerland CNMS D D I I S S C C O O V V E E R R Y Y SEMINAR SERIES Abstract: A ferroelectric...

  7. Tokamak reactor first wall

    DOE Patents [OSTI]

    Creedon, R.L.; Levine, H.E.; Wong, C.; Battaglia, J.

    1984-11-20

    This invention relates to an improved first wall construction for a tokamak fusion reactor vessel, or other vessels subjected to similar pressure and thermal stresses.

  8. 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.

  9. Jamming Behavior of Domains in a Spiral Antiferromagnetic System

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

    Jamming Behavior of Domains in a Spiral Antiferromagnetic System Jamming Behavior of Domains in a Spiral Antiferromagnetic System Print Tuesday, 04 June 2013 13:34 This schematic of x-ray scattering is from a spiral antiferromagnet with a spin structure that gives rise to domains with jamming behavior. Using resonant magnetic x-ray photon correlation spectroscopy, this research shows that the domains of a spiral antiferromagnet enter a jammed state at the onset of long-range order. Researchers

  10. Optical coherence domain reflectometry guidewire

    DOE Patents [OSTI]

    Colston, Billy W.; Everett, Matthew; Da Silva, Luiz B.; Matthews, Dennis

    2001-01-01

    A guidewire with optical sensing capabilities is based on a multiplexed optical coherence domain reflectometer (OCDR), which allows it to sense location, thickness, and structure of the arterial walls or other intra-cavity regions as it travels through the body during minimally invasive medical procedures. This information will be used both to direct the guidewire through the body by detecting vascular junctions and to evaluate the nearby tissue. The guidewire contains multiple optical fibers which couple light from the proximal to distal end. Light from the fibers at the distal end of the guidewire is directed onto interior cavity walls via small diameter optics such as gradient index lenses and mirrored corner cubes. Both forward viewing and side viewing fibers can be included. The light reflected or scattered from the cavity walls is then collected by the fibers, which are multiplexed at the proximal end to the sample arm of an optical low coherence reflectometer. The guidewire can also be used in nonmedical applications.

  11. Spatially resolved ultrafast magnetic dynamics initiated at a complex oxide heterointerface

    SciTech Connect (OSTI)

    Forst, M.; Wilkins, S. B.; Caviglia, A. D.; Scherwitz, R.; Mankowsky, R.; Zubko, P.; Khanna, V.; Bromberger, H.; Chuang, Y. -D.; Lee, W. S.; Schlotter, W. F.; Turner, J. J.; Dakovski, G. L.; Minitti, M. P.; Robinson, J.; Clark, S. R.; Jaksch, D.; Triscone, J. -M.; Hill, J. P.; Dhesi, S. S.; Cavalleri, A.

    2015-07-06

    Static strain in complex oxide heterostructures1,2 has been extensively used to engineer electronic and magnetic properties at equilibrium3. In the same spirit, deformations of the crystal lattice with light may be used to achieve functional control across heterointerfaces dynamically4. Here, by exciting large-amplitude infrared-active vibrations in a LaAlO3 substrate we induce magnetic order melting in a NdNiO3 film across a heterointerface. Femtosecond resonant soft X-ray diffraction is used to determine the spatiotemporal evolution of the magnetic disordering. We observe a magnetic melt front that propagates from the substrate interface into the film, at a speed that suggests electronically driven motion. Lastly, light control and ultrafast phase front propagation at heterointerfaces may lead to new opportunities in optomagnetism, for example by driving domain wall motion to transport information across suitably designed devices.

  12. Spatially resolved ultrafast magnetic dynamics initiated at a complex oxide heterointerface

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

    Forst, M.; Wilkins, S. B.; Caviglia, A. D.; Scherwitz, R.; Mankowsky, R.; Zubko, P.; Khanna, V.; Bromberger, H.; Chuang, Y. -D.; Lee, W. S.; et al

    2015-07-06

    Static strain in complex oxide heterostructures1,2 has been extensively used to engineer electronic and magnetic properties at equilibrium3. In the same spirit, deformations of the crystal lattice with light may be used to achieve functional control across heterointerfaces dynamically4. Here, by exciting large-amplitude infrared-active vibrations in a LaAlO3 substrate we induce magnetic order melting in a NdNiO3 film across a heterointerface. Femtosecond resonant soft X-ray diffraction is used to determine the spatiotemporal evolution of the magnetic disordering. We observe a magnetic melt front that propagates from the substrate interface into the film, at a speed that suggests electronically driven motion.more » Lastly, light control and ultrafast phase front propagation at heterointerfaces may lead to new opportunities in optomagnetism, for example by driving domain wall motion to transport information across suitably designed devices.« less

  13. Hidden Rotational Symmetries in Magnetic Domain Patterns

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

    a patterned structure on a longer mesoscopic length scale. One way for this pattern to emerge from building blocks that are nominally random and disordered is through hidden...

  14. Hidden Rotational Symmetries in Magnetic Domain Patterns

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

    One of the most powerful tools in the mathematics of science, from the physics of elementary particles to macroscopic matter, is symmetry, no doubt reflecting the...

  15. Magnetic spectroscopy and microscopy of functional materials

    SciTech Connect (OSTI)

    Jenkins, C.A.

    2011-01-28

    Heusler intermetallics Mn{sub 2}Y Ga and X{sub 2}MnGa (X; Y =Fe, Co, Ni) undergo tetragonal magnetostructural transitions that can result in half metallicity, magnetic shape memory, or the magnetocaloric effect. Understanding the magnetism and magnetic behavior in functional materials is often the most direct route to being able to optimize current materials for todays applications and to design novel ones for tomorrow. Synchrotron soft x-ray magnetic spectromicroscopy techniques are well suited to explore the the competing effects from the magnetization and the lattice parameters in these materials as they provide detailed element-, valence-, and site-specifc information on the coupling of crystallographic ordering and electronic structure as well as external parameters like temperature and pressure on the bonding and exchange. Fundamental work preparing the model systems of spintronic, multiferroic, and energy-related compositions is presented for context. The methodology of synchrotron spectroscopy is presented and applied to not only magnetic characterization but also of developing a systematic screening method for future examples of materials exhibiting any of the above effects. The chapter progression is as follows: an introduction to the concepts and materials under consideration (Chapter 1); an overview of sample preparation techniques and results, and the kinds of characterization methods employed (Chapter 2); spectro- and microscopic explorations of X{sub 2}MnGa/Ge (Chapter 3); spectroscopic investigations of the composition series Mn{sub 2}Y Ga to the logical Mn{sub 3}Ga endpoint (Chapter 4); and a summary and overview of upcoming work (Chapter 5). Appendices include the results of a Think Tank for the Graduate School of Excellence MAINZ (Appendix A) and details of an imaging project now in progress on magnetic reversal and domain wall observation in the classical Heusler material Co{sub 2}FeSi (Appendix B).

  16. Lifshitz metal–insulator transition induced by the all-in/all-out magnetic order in the pyrochlore oxide Cd{sub 2}Os{sub 2}O{sub 7}

    SciTech Connect (OSTI)

    Hiroi, Z. Hirose, T.; Nagashima, I.; Okamoto, Y.; Yamaura, J.

    2015-04-01

    We investigate the metal–insulator transition (MIT) of the osmium pyrochlore oxide Cd{sub 2}Os{sub 2}O{sub 7} through transport and magnetization measurements. The MIT and a magnetic transition to the all-in/all-out (AIAO) order occur simultaneously at 227 K. We propose a mechanism based on a Lifshitz transition induced by the AIAO magnetic order probably via strong spin–orbit couplings in the specific semimetallic band structure. It is suggested, moreover, that two observed puzzles, a finite conductivity near T = 0 and an emergence of weak ferromagnetic moments, are not bulk properties but originate at magnetic domain walls between two kinds of AIAO domains.

  17. Thermal treatment wall

    DOE Patents [OSTI]

    Aines, Roger D.; Newmark, Robin L.; Knauss, Kevin G.

    2000-01-01

    A thermal treatment wall emplaced to perform in-situ destruction of contaminants in groundwater. Thermal destruction of specific contaminants occurs by hydrous pyrolysis/oxidation at temperatures achievable by existing thermal remediation techniques (electrical heating or steam injection) in the presence of oxygen or soil mineral oxidants, such as MnO.sub.2. The thermal treatment wall can be installed in a variety of configurations depending on the specific objectives, and can be used for groundwater cleanup, wherein in-situ destruction of contaminants is carried out rather than extracting contaminated fluids to the surface, where they are to be cleaned. In addition, the thermal treatment wall can be used for both plume interdiction and near-wellhead in-situ groundwater treatment. Thus, this technique can be utilized for a variety of groundwater contamination problems.

  18. Polarization reversal and domain kinetics in magnesium doped stoichiometric lithium tantalate

    SciTech Connect (OSTI)

    Shur, V. Ya., E-mail: vladimir.shur@urfu.ru; Akhmatkhanov, A. R.; Baturin, I. S. [Institute of Natural Sciences, Ural Federal University, 620000 Ekaterinburg (Russian Federation); Labfer Ltd., 620014 Ekaterinburg (Russian Federation); Chuvakova, M. A. [Institute of Natural Sciences, Ural Federal University, 620000 Ekaterinburg (Russian Federation)

    2014-10-13

    The polarization reversal process has been studied in 1?mol.?% MgO doped stoichiometric lithium tantalate (LT) single crystal. The revealed stages of domain structure evolution represent (1) continuous nucleation and growth of isolated hexagonal domains with walls oriented along Y directions and (2) continuous motion of the plane domain walls stimulated by merging with isolated domains. The activation field dependence of the switching time has been revealed. The coercive field for quasi-static switching is about 150?V/mm. The bulk screening process has been analyzed. The main parameters of the switching process have been compared with other representatives of LT family.

  19. Moisture Research - Optimizing Wall Assemblies

    SciTech Connect (OSTI)

    Arena, Lois; Mantha, Pallavi

    2013-05-01

    In this project, the Consortium for Advanced Residential Buildings (CARB) team evaluated several different configurations of wall assemblies to determine the accuracy of moisture modeling and make recommendations to ensure durable, efficient assemblies. WUFI and THERM were used to model the hygrothermal and heat transfer characteristics of these walls. Wall assemblies evaluated included code minimum walls using spray foam insulation and fiberglass batts, high R-value walls at least 12 in. thick (R-40 and R-60 assemblies), and brick walls with interior insulation.

  20. Disorder-Induced Microscopic Magnetic Memory

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

    Disorder-Induced Microscopic Magnetic Memory Disorder-Induced Microscopic Magnetic Memory Print Wednesday, 26 October 2005 00:00 The magnetic-recording industry deliberately introduces carefully controlled disorder into its materials to obtain the desired magnetic properties. But as the density of magnetic disks climbs, the size of the magnetic domains responsible for storage must decrease, posing new challenges. Beautiful theories based on random microscopic disorder have been developed over

  1. High-R Walls for Remodeling: Wall Cavity Moisture Monitoring

    SciTech Connect (OSTI)

    Wiehagen, J.; Kochkin, V.

    2012-12-01

    The focus of the study is on the performance of wall systems, and in particular, the moisture characteristics inside the wall cavity and in the wood sheathing. Furthermore, while this research will initially address new home construction, the goal is to address potential moisture issues in wall cavities of existing homes when insulation and air sealing improvements are made.

  2. High-R Walls for Remodeling. Wall Cavity Moisture Monitoring

    SciTech Connect (OSTI)

    Wiehagen, J.; Kochkin, V.

    2012-12-01

    The focus of the study is on the performance of wall systems, and in particular, the moisture characteristics inside the wall cavity and in the wood sheathing. Furthermore, while this research will initially address new home construction, the goal is to address potential moisture issues in wall cavities of existing homes when insulation and air sealing improvements are made.

  3. Axisymmetric Tandem Mirror Magnetic Fusion Energy Power Plant...

    Office of Scientific and Technical Information (OSTI)

    A fusion power plant is described that utilizes a new version of the tandem mirror device including spinning liquid walls. The magnetic configuration is evaluated with an ...

  4. Deuterium Uptake in Magnetic Fusion Devices with Lithium Conditioned...

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

    Fusion Devices with Lithium Conditioned Carbon Walls American Fusion News Category: U.S. Universities Link: Deuterium Uptake in Magnetic Fusion Devices with Lithium ...

  5. The Dielectric Wall Accelerator

    SciTech Connect (OSTI)

    Caporaso, George J.; Chen, Yu-Jiuan; Sampayan, Stephen E.

    2009-01-01

    The Dielectric Wall Accelerator (DWA), a class of induction accelerators, employs a novel insulating beam tube to impress a longitudinal electric field on a bunch of charged particles. The surface flashover characteristics of this tube may permit the attainment of accelerating gradients on the order of 100 MV/m for accelerating pulses on the order of a nanosecond in duration. A virtual traveling wave of excitation along the tube is produced at any desired speed by controlling the timing of pulse generating modules that supply a tangential electric field to the tube wall. Because of the ability to control the speed of this virtual wave, the accelerator is capable of handling any charge to mass ratio particle; hence it can be used for electrons, protons and any ion. The accelerator architectures, key technologies and development challenges will be described.

  6. Bumper wall for plasma device

    DOE Patents [OSTI]

    Coultas, Thomas A.

    1977-01-01

    Operation of a plasma device such as a reactor for controlled thermonuclear fusion is facilitated by an improved bumper wall enclosing the plasma to smooth the flow of energy from the plasma as the energy impinges upon the bumper wall. The bumper wall is flexible to withstand unequal and severe thermal shocks and it is readily replaced at less expense than the cost of replacing structural material in the first wall and blanket that surround it.

  7. NREL: Energy Analysis - Anna Wall

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

    Anna Wall Photo of Anna Wall Anna Wall is a member of the Technology Systems and Sustainability Analysis Group in the Strategic Energy Analysis Center. Energy Technologies Analyst On staff since April 2014 Phone number: 303-384-6887 E-mail: anna.wall@nrel.gov Areas of expertise Geochemistry (aqueous and hard rock), with applications to geothermal resource characterization and mineral carbon sequestration Ratings methodologies and energy resource reporting standards Sustainable equity finance:

  8. Internal stress distribution for generating closure domains in laser-irradiated Fe3%Si(110) steels

    SciTech Connect (OSTI)

    Iwata, Keiji; Imafuku, Muneyuki; Orihara, Hideto; Sakai, Yusuke; Ohya, Shin-Ichi; Suzuki, Tamaki; Shobu, Takahisa; Akita, Koichi; Ishiyama, Kazushi

    2015-05-07

    Internal stress distribution for generating closure domains occurring in laser-irradiated Fe3%Si(110) steels was investigated using high-energy X-ray analysis and domain theory based on the variational principle. The measured triaxial stresses inside the specimen were compressive and the stress in the rolling direction became more dominant than stresses in the other directions. The calculations based on the variational principle of magnetic energy for closure domains showed that the measured triaxial stresses made the closure domains more stable than the basic domain without closure domains. The experimental and calculation results reveal that the laser-introduced internal stresses result in the occurrence of the closure domains.

  9. MAYmw Wall0

    Office of Legacy Management (LM)

    ,...-. ~_I : Cd.0 / ., j: ' ! -;:---- /,5l2 MAYmw Wall0 50 l/89 NE-23 NE-23 List of California Sites Hattie Carwell. SAN/NSQA Division Attached for your information is the list of California sites we identified in our search of Manhattdn Engineer District records for the Formerly Utilized Sites Remedial Action Program (FUSRAP). None of the facilities listed qualified for FUSRAP,'Vhe;:only'site in California that was included in FUSRAP was Gilman Hall on the University of California-Berkeley

  10. Engineering the fusion reactor first wall

    SciTech Connect (OSTI)

    Wurden, Glen; Scott, Willms

    2008-01-01

    Recently the National Academy of Engineering published a set of Grand Challenges in Engineering in which the second item listed was entitled 'Provide energy from fusion'. Clearly a key component of this challenge is the science and technology associated with creating and maintaining burning plasmas. This is being vigorously addressed with both magnetic and inertial approaches with various experiments such as ITER and NIF. Considerably less attention is being given to another key component of this challenge, namely engineering the first wall that will contain the burning plasma. This is a daunting problem requiring technologies and materials that can not only survive, but also perform multiple essential functions in this extreme environment. These functions are (1) shield the remainder of the device from radiation. (2) convert of neutron energy to useful heat and (3) breed and extract tritium to maintain the reactor fuel supply. The first wall must not contaminate the plasma with impurities. It must be infused with cooling to maintain acceptable temperatures on plasma facing and structural components. It must not degrade. It must avoid excessive build-up of tritium on surfaces, and, if surface deposits do form, must be receptive to cleaning techniques. All these functions and constraints must be met while being subjected to nuclear and thermal radiation, particle bombardment, high magnetic fields, thermal cycling and occasional impingement of plasma on the surface. And, operating in a nuclear environment, the first wall must be fully maintainable by remotely-operated manipulators. Elements of the first wall challenge have been studied since the 1970' s both in the US and internationally. Considerable foundational work has been performed on plasma facing materials and breeding blanket/shield modules. Work has included neutronics, materials fabrication and joining, fluid flow, tritium breeding, tritium recovery and containment, energy conversion, materials damage and

  11. Detrimental effect of interfacial Dzyaloshinskii-Moriya interaction on perpendicular spin-transfer-torque magnetic random access memory

    SciTech Connect (OSTI)

    Jang, Peong-Hwa; Lee, Seo-Won E-mail: kj-lee@korea.ac.kr; Song, Kyungmi; Lee, Seung-Jae; Lee, Kyung-Jin E-mail: kj-lee@korea.ac.kr

    2015-11-16

    Interfacial Dzyaloshinskii-Moriya interaction in ferromagnet/heavy metal bilayers is recently of considerable interest as it offers an efficient control of domain walls and the stabilization of magnetic skyrmions. However, its effect on the performance of perpendicular spin transfer torque memory has not been explored yet. We show based on numerical studies that the interfacial Dzyaloshinskii-Moriya interaction decreases the thermal energy barrier while increases the switching current. As high thermal energy barrier as well as low switching current is required for the commercialization of spin torque memory, our results suggest that the interfacial Dzyaloshinskii-Moriya interaction should be minimized for spin torque memory applications.

  12. Micromagnetic analysis of dynamical bubble-like solitons based on the time domain evolution of the topological density

    SciTech Connect (OSTI)

    Puliafito, Vito Azzerboni, Bruno; Finocchio, Giovanni; Torres, Luis; Ozatay, Ozhan

    2014-05-07

    Dynamical bubble-like solitons have been recently investigated in nanocontact-based spin-torque oscillators with a perpendicular free layer. Those magnetic configurations can be excited also in different geometries as long as they consist of perpendicular materials. Thus, in this paper, a systematic study of the influence of both external field and high current on that kind of dynamics is performed for a spin-valve point-contact geometry where both free and fixed layers present strong perpendicular anisotropy. The usage of the topological density tool highlights the excitation of complex bubble/antibubble configurations. In particular, at high currents, a deformation of the soliton and its simultaneous shift from the contact area are observed and can be ascribable to the Oersted field. Results provide further detailed information on the excitation of solitons in perpendicular materials for application in spintronics, magnonics, and domain wall logic.

  13. Influence of microstructural changes due to tempering at 923 K and 1,023 K on magnetic Barkhausen noise behavior in normalized 2.25Cr-1Mo ferritic steel

    SciTech Connect (OSTI)

    Raj, B.; Moorthy, V.; Vaidyanathan, S.

    1997-01-01

    Magnetic Barkhausen noise analysis has been used to characterize the microstructural changes in normalized and tempered 2.25 Cr-1Mo steel. It is observed that tempering at 923 K shows a single peak behavior up to 20 h and tempering at 1,023 K shows a two peak behavior. This has been explained on the basis of the two stage process of irreversible domain wall movement during magnetization, associated with two major obstacles to domain wall movement: namely lath/grain boundaries and secondary phase precipitates. At lower fields, existing reverse domain walls at lath/grain boundaries overcome the resistance offered by the grain boundaries and move to a distance before they are pined by the precipitates. Then, at higher field, they overcome these precipitates. These two processes occur over a range of critical field strengths with some mean values. If these two mean values are close to each other, then a single peak in the rms voltage of the magnetic Barkhausen noise, with the associated changes in its shape, is observed. On the other hand, if the mean values of the critical fields for these two barriers are widely separated, then a two peak behavior is the clear possibility. The effect of the microstructural changes due to tempering for different durations at 923 K and 1,023 K in 2.25 Cr-1Mo ferritic steel on magnetic Barkhausen noise is explained based on these two stage processes. The influence of high dislocation density in bainitic structure, dissociation of bainite, and precipitation of different carbides such as Fe{sub 3}C, Mo{sub 2}C, Cr{sub 7}Ce{sub 3}, M{sub 23}C{sub 6}, etc., on magnetic Barkhausen noise behavior has been analyzed in this study.

  14. Antiferromagnetism and domain effects in UPdSn

    SciTech Connect (OSTI)

    Nakotte, H. [Manual Lujan Jr. Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Manual Lujan Jr. Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); [Department of Physics, New Mexico State University, Las Cruces, New Mexico 88003 (United States); Robinson, R.A.; Purwanto, A. [Manuel Lujan Jr. Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Manuel Lujan Jr. Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Tun, Z. [Chalk River Laboratories, Atomic Energy of Canada Limited, Chalk River, Ontario, K0J 1J0 (CANADA)] [Chalk River Laboratories, Atomic Energy of Canada Limited, Chalk River, Ontario, K0J 1J0 (CANADA); Prokes, K.; Brueck, E.; de Boer, F.R. [Van der Waals-Zeeman Institute, University of Amsterdam, 1018 XE Amsterdam (The Netherlands)] [Van der Waals-Zeeman Institute, University of Amsterdam, 1018 XE Amsterdam (The Netherlands)

    1998-10-01

    Neutron-diffraction experiments have been performed on a single crystal of the hexagonal noncollinear antiferromagnetic compound UPdSn as a function of temperature and magnetic field. The use of a special horizontal-field magnet (with very wide horizontal access to the neutron beams) has allowed the study of the principal magnetic Bragg reflections in all three antiferromagnetic domain pairs throughout the magnetic phase diagram for B{lt}3thinspT and T{gt}6thinspK. The data confirm a picture in which one domain pair (1) grows at the expense of the other two domain pairs (2 and 3), for fields along the [100] axis for domain 1. On the other hand, if the field is applied along the perpendicular axis, [010] for domain 1, the other two domains are preferred. These results are consistent with the picture given in a previous vertical-field study of only one magnetic reflection from one domain, in which the 3-T field-induced transition is viewed as a spin-flop transition. There is, however, a small amount of irreversible moment rotation (from {theta}=43{degree} to 48{degree}, where {theta} is the moment canting angle within the hexagonal basal plane), on passing through the spin-flop transition. This seems to be connected with whether the sample is single or multidomain. In addition, the field independence of the N{acute e}el temperature (T{sub N}=37thinspK) has been measured up to 3 T, and data on the domain kinetics are presented. {copyright} {ital 1998} {ital The American Physical Society}

  15. Disorder-Induced Microscopic Magnetic Memory

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

    Disorder-Induced Microscopic Magnetic Memory Print The magnetic-recording industry deliberately introduces carefully controlled disorder into its materials to obtain the desired magnetic properties. But as the density of magnetic disks climbs, the size of the magnetic domains responsible for storage must decrease, posing new challenges. Beautiful theories based on random microscopic disorder have been developed over the past ten years. To directly compare these theories with precise experiments,

  16. Disorder-Induced Microscopic Magnetic Memory

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

    Disorder-Induced Microscopic Magnetic Memory Print The magnetic-recording industry deliberately introduces carefully controlled disorder into its materials to obtain the desired magnetic properties. But as the density of magnetic disks climbs, the size of the magnetic domains responsible for storage must decrease, posing new challenges. Beautiful theories based on random microscopic disorder have been developed over the past ten years. To directly compare these theories with precise experiments,

  17. Disorder-Induced Microscopic Magnetic Memory

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

    Disorder-Induced Microscopic Magnetic Memory Print The magnetic-recording industry deliberately introduces carefully controlled disorder into its materials to obtain the desired magnetic properties. But as the density of magnetic disks climbs, the size of the magnetic domains responsible for storage must decrease, posing new challenges. Beautiful theories based on random microscopic disorder have been developed over the past ten years. To directly compare these theories with precise experiments,

  18. Disorder-Induced Microscopic Magnetic Memory

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

    Disorder-Induced Microscopic Magnetic Memory Print The magnetic-recording industry deliberately introduces carefully controlled disorder into its materials to obtain the desired magnetic properties. But as the density of magnetic disks climbs, the size of the magnetic domains responsible for storage must decrease, posing new challenges. Beautiful theories based on random microscopic disorder have been developed over the past ten years. To directly compare these theories with precise experiments,

  19. Todd Vander Wall | Bioenergy | NREL

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

    Vander Wall Research Scientist Todd.Vander.Wall@nrel.gov | 303-384-7783 Research Interests Todd Vander Wall comes to the National Renewable Energy Laboratory (NREL) from the environmental and chemical engineering industry, where he focused on environmental chemistry. He originally designed and implemented methanogenesis systems for the growth and collection of biogenic methane from municipal solid waste. Following that, he performed in-situ investigations on thermogenic methane from subsurface

  20. Oven wall panel construction

    DOE Patents [OSTI]

    Ellison, Kenneth; Whike, Alan S.

    1980-04-22

    An oven roof or wall is formed from modular panels, each of which comprises an inner fabric and an outer fabric. Each such fabric is formed with an angle iron framework and somewhat resilient tie-bars or welded at their ends to flanges of the angle irons to maintain the inner and outer frameworks in spaced disposition while minimizing heat transfer by conduction and permitting some degree of relative movement on expansion and contraction of the module components. Suitable thermal insulation is provided within the module. Panels or skins are secured to the fabric frameworks and each such skin is secured to a framework and projects laterally so as slidingly to overlie the adjacent frame member of an adjacent panel in turn to permit relative movement during expansion and contraction.

  1. disrupting the plant cell wall

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

    disrupting the plant cell wall - Sandia Energy Energy Search Icon Sandia Home Locations ... Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power ...

  2. Catheter guided by optical coherence domain reflectometry

    DOE Patents [OSTI]

    Everett, Matthew; Colston, Billy W.; Da Silva, Luiz B.; Matthews, Dennis

    2002-01-01

    A guidance and viewing system based on multiplexed optical coherence domain reflectometry is incorporated into a catheter, endoscope, or other medical device to measure the location, thickness, and structure of the arterial walls or other intra-cavity regions at discrete points on the medical device during minimally invasive medical procedures. The information will be used both to guide the device through the body and to evaluate the tissue through which the device is being passed. Multiple optical fibers are situated along the circumference of the device. Light from the distal end of each fiber is directed onto the interior cavity walls via small diameter optics (such as gradient index lenses and mirrored corner cubes). Both forward viewing and side viewing fibers can be included. The light reflected or scattered from the cavity walls is then collected by the fibers and multiplexed at the proximal end to the sample arm of an optical low coherence reflectometer. The system may also be implemented in a nonmedical inspection device.

  3. Moisture Research - Optimizing Wall Assemblies

    SciTech Connect (OSTI)

    Arena, L.; Mantha, P.

    2013-05-01

    The Consortium for Advanced Residential Buildings (CARB) evaluated several different configurations of wall assemblies to determine the accuracy of moisture modeling and make recommendations to ensure durable, efficient assemblies. WUFI and THERM were used to model the hygrothermal and heat transfer characteristics of these walls.

  4. Cellulose binding domain proteins

    DOE Patents [OSTI]

    Shoseyov, O.; Shpiegl, I.; Goldstein, M.; Doi, R.

    1998-11-17

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques. 16 figs.

  5. Cellulose binding domain proteins

    DOE Patents [OSTI]

    Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc; Doi, Roy

    1998-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  6. Dynamics of spintronic materials: Exploration in the time and frequency domain

    SciTech Connect (OSTI)

    Zabel, Hartmut

    2014-12-14

    X-ray and neutron reflectivity are mature experimental techniques for the exploration of film thicknesses and interface roughnesses on the nanoscale. Combining with photon and neutron polarization, these methods can be carried forward to the analysis of magnetic thin films and magnetic domain structures. New opportunities open up when these methods are used either in the time or in the frequency domain. Then dynamical processes can be studied such as domain oscillations, domain propagation, precession of spins, and damping effects. Two methods are discussed which have been developed recently: polarized neutron reflectivity from magnetic films in an alternating magnetic field and time resolved resonant magnetic x-ray reflectivity of the free precessional dynamics in films and multilayers.

  7. Investigation of coercivity mechanism in hot deformed Nd-Fe-B permanent magnets by small-angle neutron scattering

    SciTech Connect (OSTI)

    Yano, M., E-mail: masao-yano-aa@mail.toyota.co.jp; Manabe, A.; Shoji, T.; Kato, A. [Advanced Material Engineering Division, Toyota Motor Corporation, Susono 410-1193 (Japan); Ono, K. [High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801 (Japan); Harada, M. [Toyota Central R and D Labs, Inc., Aichi 480-1192 (Japan); Kohlbrecher, J. [Laboratory for Neutron Scattering, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland)

    2014-05-07

    The magnetic reversal behaviors of single domain sized Nd-Fe-B permanent magnets, with and without isolation between the Nd{sub 2}Fe{sub 14}B grains, was clarified using small-angle neutron scattering (SANS). The SANS patterns obtained arose from changes in the magnetic domains and were analyzed using the TeubnerStray model, a phenomenological correlation length model, to quantify the periodicity and morphology of the magnetic domains. The results indicated that the magnetic reversal evolved with the magnetic domains that had similar sized grains. The grain isolation enabled us to realize the reversals of single domains.

  8. Wall Insulation; BTS Technology Fact Sheet

    SciTech Connect (OSTI)

    Southface Energy Institute; Tromly, K.

    2000-11-07

    Properly sealed, moisture-protected, and insulated walls help increase comfort, reduce noise, and save on energy costs. This fact sheet addresses these topics plus advanced framing techniques, insulation types, wall sheathings, and steps for effective wall construction and insulation.

  9. Security_Walls_VPP_Award

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

    Recognized for Outstanding Safety CARLSBAD, N.M., May 10, 2013 - The U.S. Department of Energy (DOE) has awarded Security Walls, LLC, the Waste Isolation Pilot Plant's (WIPP)...

  10. 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.

  11. MHD Electrode and wall constructions

    DOE Patents [OSTI]

    Way, Stewart; Lempert, Joseph

    1984-01-01

    Electrode and wall constructions for the walls of a channel transmitting the hot plasma in a magnetohydrodynamic generator. The electrodes and walls are made of a plurality of similar modules which are spaced from one another along the channel. The electrodes can be metallic or ceramic, and each module includes one or more electrodes which are exposed to the plasma and a metallic cooling bar which is spaced from the plasma and which has passages through which a cooling fluid flows to remove heat transmitted from the electrode to the cooling bar. Each electrode module is spaced from and electrically insulated from each adjacent module while interconnected by the cooling fluid which serially flows among selected modules. A wall module includes an electrically insulating ceramic body exposed to the plasma and affixed, preferably by mechanical clips or by brazing, to a metallic cooling bar spaced from the plasma and having cooling fluid passages. Each wall module is, similar to the electrode modules, electrically insulated from the adjacent modules and serially interconnected to other modules by the cooling fluid.

  12. Simulation of magnetic hysteresis loops and magnetic Barkhausen noise of α-iron containing nonmagnetic particles

    SciTech Connect (OSTI)

    Li, Yi; Xu, Ben; Hu, Shenyang Y.; Li, Yulan; Li, Qiulin; Liu, Wei

    2015-09-25

    Hysteresis loops and Magnetic Barkhausen Noise in a single crystal α-iron containing a nonmagnetic particle were simulated based on the Laudau-Lifshitz-Gilbert equation. The analyses of domain morphologies and hysteresis loops show that reversal magnetization process is control by nucleation of reversed domains at nonmagnetic particle when the particle size reaches a particle value. In such a situation, the value of nucleation field is determined by the size of nonmagnetic particles, and moreover, coercive field and Magnetic Barkhausen Noise signal are strongly affected by the nucleation field of reversed domains.

  13. Turbine airfoil with outer wall thickness indicators

    DOE Patents [OSTI]

    Marra, John J; James, Allister W; Merrill, Gary B

    2013-08-06

    A turbine airfoil usable in a turbine engine and including a depth indicator for determining outer wall blade thickness. The airfoil may include an outer wall having a plurality of grooves in the outer surface of the outer wall. The grooves may have a depth that represents a desired outer surface and wall thickness of the outer wall. The material forming an outer surface of the outer wall may be removed to be flush with an innermost point in each groove, thereby reducing the wall thickness and increasing efficiency. The plurality of grooves may be positioned in a radially outer region of the airfoil proximate to the tip.

  14. Shear wall ultimate drift limits

    SciTech Connect (OSTI)

    Duffey, T.A.; Goldman, A.; Farrar, C.R.

    1994-04-01

    Drift limits for reinforced-concrete shear walls are investigated by reviewing the open literature for appropriate experimental data. Drift values at ultimate are determined for walls with aspect ratios ranging up to a maximum of 3.53 and undergoing different types of lateral loading (cyclic static, monotonic static, and dynamic). Based on the geometry of actual nuclear power plant structures exclusive of containments and concerns regarding their response during seismic (i.e.,cyclic) loading, data are obtained from pertinent references for which the wall aspect ratio is less than or equal to approximately 1, and for which testing is cyclic in nature (typically displacement controlled). In particular, lateral deflections at ultimate load, and at points in the softening region beyond ultimate for which the load has dropped to 90, 80, 70, 60, and 50 percent of its ultimate value, are obtained and converted to drift information. The statistical nature of the data is also investigated. These data are shown to be lognormally distributed, and an analysis of variance is performed. The use of statistics to estimate Probability of Failure for a shear wall structure is illustrated.

  15. 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

  16. Apparatus and method for continuous separation of magnetic particles from non-magnetic fluids

    DOE Patents [OSTI]

    Oder, Robin R.; Jamison, Russell E.

    2010-02-09

    A magnetic separator vessel (1) for separating magnetic particles from non-magnetic fluid includes a separation chamber having an interior and exterior wall, a top and bottom portion; a magnet (3) having first and second poles (2) positioned adjacent to the exterior wall, wherein the first pole is substantially diametrically opposed to the second pole; a inlet port (5) is directed into the top portion of the separation chamber, wherein the inlet port (5) is positioned adjacent to one of the first and second poles (2), wherein the inlet port (5) is adapted to transfer a mixture into the separation chamber; an underflow port (6) in communication with the bottom portion, wherein the underflow port (6) is adapted to receive the magnetic particles; and an overflow port (9) in communication with the separation chamber, wherein the overflow port (9) is adapted to receive the non-magnetic fluid.

  17. Ternary superlattice boosting interface-stabilized magnetic chirality

    SciTech Connect (OSTI)

    Chen, Gong; Schmid, Andreas K.; N'Diaye, Alpha T.; Wu, Yizheng

    2015-02-09

    In cobalt-nickel multilayers grown on iridium surfaces, magnetic homo-chirality can be stabilized by Dzyaloshinskii-Moriya interactions (DMI) at the interface with the substrate. When thickness of the multilayers is increased beyond threshold values, then non-chiral bulk properties exceed interface contributions and this type of chirality vanishes. Here, we use spin-polarized low energy electron microscopy to measure these thickness thresholds, and we determine estimates of the strength of the DMI from the measurements. Even though the same 5d heavy metal is used as a substrate, a remarkably large variation is found between the two 3d magnets: our results indicate that the strength of the DMI at Co/Ir interfaces is three times larger than at Ni/Ir interfaces. We show how this finding provides ways to extend interfacial-DMI stabilization of domain wall chirality to 3d/5d/3d ternary multilayers such as [Ni/Ir/Co]{sub n}. Such strategies may extend chirality-control to larger film thickness and a wider range of substrates, which may be useful for designing new spintronics devices.

  18. Magnetic shielding of a laboratory Hall thruster. II. Experiments

    SciTech Connect (OSTI)

    Hofer, Richard R. Goebel, Dan M.; Mikellides, Ioannis G.; Katz, Ira

    2014-01-28

    The physics of magnetic shielding in Hall thrusters were validated through laboratory experiments demonstrating essentially erosionless, high-performance operation. The magnetic field near the walls of a laboratory Hall thruster was modified to effectively eliminate wall erosion while maintaining the magnetic field topology away from the walls necessary to retain efficient operation. Plasma measurements at the walls validate our understanding of magnetic shielding as derived from the theory. The plasma potential was maintained very near the anode potential, the electron temperature was reduced by a factor of two to three, and the ion current density was reduced by at least a factor of two. Measurements of the carbon backsputter rate, wall geometry, and direct measurement of plasma properties at the wall indicate that the wall erosion rate was reduced by a factor of 1000 relative to the unshielded thruster. These changes effectively eliminate wall erosion as a life limitation in Hall thrusters, enabling a new class of deep-space missions that could not previously be attempted.

  19. Fractional diffusion on bounded domains

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

    Defterli, Ozlem; D'Elia, Marta; Du, Qiang; Gunzburger, Max Donald; Lehoucq, Richard B.; Meerschaert, Mark M.

    2015-03-13

    We found that the mathematically correct specification of a fractional differential equation on a bounded domain requires specification of appropriate boundary conditions, or their fractional analogue. In this paper we discuss the application of nonlocal diffusion theory to specify well-posed fractional diffusion equations on bounded domains.

  20. 2013 Wall Street Perspective on SMRs | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Wall Street Perspective on SMRs 2013 Wall Street Perspective on SMRs Summary of results of a 2013 survey on Wall Street attitudes toward small modular reactors. 2013 Wall Street Perspective on SMRs (597.12 KB) More Documents & Publications 2014 Wall Street Perspectives on SMRs - Report 2014 Wall Street Perspective on SMRs 2015 Wall Street Perspectives on SMRs Update

  1. Tube wall thickness measurement apparatus

    DOE Patents [OSTI]

    Lagasse, Paul R.

    1987-01-01

    An apparatus for measuring the thickness of a tube's wall for the tube's entire length and circumference by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

  2. Tube wall thickness measurement apparatus

    DOE Patents [OSTI]

    Lagasse, P.R.

    1985-06-21

    An apparatus for measuring the thickness of a tube's wall for the tube's entire length and radius by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

  3. Wall System Innovations: Familiar Materials, Better Performance |

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Department of Energy Wall System Innovations: Familiar Materials, Better Performance Wall System Innovations: Familiar Materials, Better Performance This presentation was delivered at the U.S. Department of Energy Building America Technical Update meeting on April 29-30, 2013, in Denver, Colorado. wall_system_innovations_kochkin.pdf (1.48 MB) More Documents & Publications Building America New Homes Case Study: Advanced Extended Plate and Beam Wall System in a Cold-Climate House Building

  4. Promising Technology: Cool Paints for Exterior Walls

    Broader source: Energy.gov [DOE]

    Cool Paints increase the solar reflectance of exterior walls. By reflecting more sunlight, the wall surface maintains a cooler temperature. This decrease in temperature leads to less heat transfer through the walls into the building. During the cooling season, the addition of cool paints can decrease the cooling load of the building.

  5. Magnetic anisotropy and domain patterning of amorphous films...

    Office of Scientific and Technical Information (OSTI)

    Language: English Subject: 36 MATERIALS SCIENCE; ANISOTROPY; BORON ALLOYS; COBALT ALLOYS; FERROMAGNETIC MATERIALS; HELIUM IONS; ION BEAMS; IRON ALLOYS; IRRADIATION; KERR EFFECT; ...

  6. Radial force on the vacuum chamber wall during thermal quench in tokamaks

    SciTech Connect (OSTI)

    Pustovitov, V. D.

    2015-12-15

    The radial force balance during a thermal quench in tokamaks is analyzed. As a rule, the duration τ{sub tp} of such events is much shorter than the resistive time τ{sub w} of the vacuum chamber wall. Therefore, the perturbations of the magnetic field B produced by the evolving plasma cannot penetrate the wall, which makes different the magnetic pressures on its inner and outer sides. The goal of this work is the analytical estimation of the resulting integral radial force on the wall. The plasma is considered axially symmetric; for the description of radial forces on the wall, the results of V.D. Shafranov’s classical work [J. Nucl. Energy C 5, 251 (1963)] are used. Developed for tokamaks, the standard equilibrium theory considers three interacting systems: plasma, poloidal field coils, and toroidal field coils. Here, the wall is additionally incorporated with currents driven by ∂B/∂t≠0 accompanying the fast loss of the plasma thermal energy. It is shown that they essentially affect the force redistribution, thereby leading to large loads on the wall. The estimates prove that these loads have to be accounted for in the disruptive scenarios in large tokamaks.

  7. Response of a partial wall to an external perturbation of rotating plasma

    SciTech Connect (OSTI)

    Atanasiu, C. V.; Zakharov, L. E.

    2013-09-15

    In this paper, we present the response of a 3D thin multiply connected wall to an external kink mode perturbation in axisymmetric tokamak configurations. To calculate the contribution of the plasma perturbed magnetic field in the vacuum region, we have made use of the concept of surface currents [following C. V. Atanasiu, A. H. Boozer, L. E. Zakharov, and A. A. Subbotin, Phys. Plasmas 6, 2781 (1999)]. The wall response is expressed in terms of a stream function of the wall surface currents, which are obtained by solving a diffusion type equation, taking into account the contribution of the wall currents themselves iteratively. The use of stream function makes the approach applicable for both well-studied earlier Resistive Wall Modes and for Wall Touching Kink Modes, which were discovered recently as a key phenomenon in disruptions [L. E. Zakharov, S. A. Galkin, and S. N. Gerasimov, Phys. Plasmas 19, 055703 (2012)]. New analytical expressions, suitable for numerical calculations of toroidal harmonics of the vacuum magnetic fields from the surface currents on axisymmetric shells, are derived.

  8. POROUS WALL, HOLLOW GLASS MICROSPHERES

    SciTech Connect (OSTI)

    Sexton, W.

    2012-06-30

    Hollow Glass Microspheres (HGM) is not a new technology. All one has to do is go to the internet and Google{trademark} HGM. Anyone can buy HGM and they have a wide variety of uses. HGM are usually between 1 to 100 microns in diameter, although their size can range from 100 nanometers to 5 millimeters in diameter. HGM are used as lightweight filler in composite materials such as syntactic foam and lightweight concrete. In 1968 a patent was issued to W. Beck of the 3M{trademark} Company for 'Glass Bubbles Prepared by Reheating Solid Glass Particles'. In 1983 P. Howell was issued a patent for 'Glass Bubbles of Increased Collapse Strength' and in 1988 H. Marshall was issued a patent for 'Glass Microbubbles'. Now Google{trademark}, Porous Wall, Hollow Glass Microspheres (PW-HGMs), the key words here are Porous Wall. Almost every article has its beginning with the research done at the Savannah River National Laboratory (SRNL). The Savannah River Site (SRS) where SRNL is located has a long and successful history of working with hydrogen and its isotopes for national security, energy, waste management and environmental remediation applications. This includes more than 30 years of experience developing, processing, and implementing special ceramics, including glasses for a variety of Department of Energy (DOE) missions. In the case of glasses, SRS and SRNL have been involved in both the science and engineering of vitreous or glass based systems. As a part of this glass experience and expertise, SRNL has developed a number of niches in the glass arena, one of which is the development of porous glass systems for a variety of applications. These porous glass systems include sol gel glasses, which include both xerogels and aerogels, as well as phase separated glass compositions, that can be subsequently treated to produce another unique type of porosity within the glass forms. The porous glasses can increase the surface area compared to 'normal glasses of a 1 to 2 order of

  9. Mechanism of bubble detachment from vibrating walls

    SciTech Connect (OSTI)

    Kim, Dongjun; Park, Jun Kwon Kang, Kwan Hyoung; Kang, In Seok

    2013-11-15

    We discovered a previously unobserved mechanism by which air bubbles detach from vibrating walls in glasses containing water. Chaotic oscillation and subsequent water jets appeared when a wall vibrated at greater than a critical level. Wave forms were developed at water-air interface of the bubble by the wall vibration, and water jets were formed when sufficiently grown wave-curvatures were collapsing. Droplets were pinched off from the tip of jets and fell to the surface of the glass. When the solid-air interface at the bubble-wall attachment point was completely covered with water, the bubble detached from the wall. The water jets were mainly generated by subharmonic waves and were generated most vigorously when the wall vibrated at the volume resonant frequency of the bubble. Bubbles of specific size can be removed by adjusting the frequency of the wall's vibration.

  10. SRNL POROUS WALL GLASS MICROSPHERES

    SciTech Connect (OSTI)

    Wicks, G; Leung Heung, L; Ray Schumacher, R

    2008-04-15

    The Savannah River National Laboratory (SRNL) has developed a new medium for storage of hydrogen and other gases. This involves fabrication of thin, Porous Walled, Hollow Glass Microspheres (PW-HGMs), with diameters generally in the range of 1 to several hundred microns. What is unique about the glass microballons is that porosity has been induced and controlled within the thin, one micron thick walls, on the scale of 10 to several thousand Angstroms. This porosity results in interesting properties including the ability to use these channels to fill the microballons with special absorbents and other materials, thus providing a contained environment even for reactive species. Gases can now enter the microspheres and be retained on the absorbents, resulting in solid-state and contained storage of even reactive species. Also, the porosity can be altered and controlled in various ways, and even used to filter mixed gas streams within a system. SRNL is involved in about a half dozen different programs involving these PW-HGMs and an overview of some of these activities and results emerging are presented.

  11. Domain walls in a Born-Infeld-dilaton background (Journal Article...

    Office of Scientific and Technical Information (OSTI)

    Subject: 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; BORN-INFELD THEORY; ELECTRODYNAMICS; ELECTROMAGNETIC FIELDS; EXPANSION; INFLATIONARY UNIVERSE; MATHEMATICAL SOLUTIONS; ...

  12. Domain walls as dark energy (Journal Article) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Report Number(s): LBNL--50255 R&D Project: PTHOPS; TRN: US0502453 DOE Contract Number: AC03-76SF00098 Resource Type: Journal Article Resource Relation: Journal Name: Physical ...

  13. f{sub K}/f{sub {pi}} in full QCD with domain wall valence quarks...

    Office of Scientific and Technical Information (OSTI)

    -0.024sup +0.011 where the first error is statistical and the second error is an estimate of the systematic due to chiral extrapolation and fitting procedures. ...

  14. 2014 Wall Street Perspective on SMRs | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    4 Wall Street Perspective on SMRs 2014 Wall Street Perspective on SMRs Summary briefing on the results of a 2014 survey of Wall Street attitudes toward SMRs. 2014 New Generation Financial Survey (423.08 KB) More Documents & Publications 2014 Wall Street Perspectives on SMRs - Report 2015 Wall Street Perspectives on SMRs Update 2013 Wall Street Perspective on SMRs

  15. 2015 Wall Street Perspectives on SMRs Update | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    5 Wall Street Perspectives on SMRs Update 2015 Wall Street Perspectives on SMRs Update Summary briefing on the results of a September 2015 survey of Wall Street attitudes toward SMRs. 2015 Financial Survey: Nuclear Energy (415.36 KB) More Documents & Publications 2014 Wall Street Perspective on SMRs 2014 Wall Street Perspectives on SMRs - Report 2013 Wall Street Perspective on SMRs

  16. Seismic behavior of geogrid reinforced slag wall

    SciTech Connect (OSTI)

    Edincliler, Ayse; Baykal, Gokhan; Saygili, Altug

    2008-07-08

    Flexible retaining structures are known with their high performance under earthquake loads. In geogrid reinforced walls the performance of the fill material and the interface of the fill and geogrid controls the performance. Geosynthetic reinforced walls in seismic regions must be safe against not only static forces but also seismic forces. The objective of this study is to determine the behavior of a geogrid reinforced slag wall during earthquake by using shaking table experiments. This study is composed of three stages. In the first stage the physical properties of the material to be used were determined. In the second part, a case history involving the use of slag from steel industry in the construction of geogrid reinforced wall is presented. In the third stage, the results of shaking table tests conducted using model geogrid wall with slag are given. From the results, it is seen that slag can be used as fill material for geogrid reinforced walls subjected to earthquake loads.

  17. Magnetic-compression/magnetized-target fusion (MAGO/MTF): A marriage of inertial and magnetic confinement

    SciTech Connect (OSTI)

    Lindemuth, I.R.; Ekdahl, C.A.; Kirkpatrick, R.C.

    1996-12-31

    Intermediate between magnetic confinement (MFE) and inertial confinement (ICF) in time and density scales is an area of research now known in the US as magnetized target fusion (MTF) and in Russian as MAGO (MAGnitnoye Obzhatiye--magnetic compression). MAGO/MTF uses a magnetic field and preheated, wall-confined plasma fusion fuel within an implodable fusion target. The magnetic field suppresses thermal conduction losses in the fuel during the target implosion and hydrodynamic compression heating process. In contrast to direct, hydrodynamic compression of initially ambient-temperature fuel (i.e., ICF), MAGO/MTF involves two steps: (a) formation of a warm (e.g., 100 eV or higher), magnetized (e.g., 100 kG) plasma within a fusion target prior to implosion; (b) subsequent quasi-adiabatic compression by an imploding pusher, of which a magnetically driven imploding liner is one example. In this paper, the authors present ongoing activities and potential future activities in this relatively unexplored area of controlled thermonuclear fusion.

  18. Textural break foundation wall construction modules

    DOE Patents [OSTI]

    Phillips, Steven J.

    1990-01-01

    Below-grade, textural-break foundation wall structures are provided for inhibiting diffusion and advection of liquids and gases into and out from a surrounding hydrogeologic environment. The foundation wall structure includes a foundation wall having an interior and exterior surface and a porous medium disposed around a portion of the exterior surface. The structure further includes a modular barrier disposed around a portion of the porous medium. The modular barrier is substantially removable from the hydrogeologic environment.

  19. Panelized wall system with foam core insulation

    SciTech Connect (OSTI)

    Kosny, Jan; Gaskin, Sally

    2009-10-20

    A wall system includes a plurality of wall members, the wall members having a first metal panel, a second metal panel, and an insulating core between the first panel and the second panel. At least one of the first panel and the second panel include ridge portions. The insulating core can be a foam, such as a polyurethane foam. The foam can include at least one opacifier to improve the k-factor of the foam.

  20. First wall for polarized fusion reactors

    DOE Patents [OSTI]

    Greenside, Henry S.; Budny, Robert V.; Post, Jr., Douglass E.

    1988-01-01

    Depolarization mechanisms arising from the recycling of the polarized fuel at the limiter and the first-wall of a fusion reactor are greater than those mechanisms in the plasma. Rapid depolarization of the plasma is prevented by providing a first-wall or first-wall coating formed of a low-Z, non-metallic material having a depolarization rate greater than 1 sec.sup.-1.

  1. Beetle Kill Wall at NREL

    ScienceCinema (OSTI)

    None

    2013-05-29

    When it comes to designing an interior decorative feature for one of the most energy efficient office buildings in the world, very few would consider bringing in a beetle to do the job. But thats what happened at the U.S. Department of Energy's (DOE) Research Support Facility (RSF) located on the National Renewable Energy Laboratory (NREL) campus.In June, the RSF will become home to more than 800 workers from DOE and NREL and building visitors will be greeted with a soaring, two-story high wall entirely covered with wood harvested from the bark beetle infestation that has killed millions of pine trees in the Western U.S. But, the use of beetle kill wood is just one example of the resources being leveraged to make the RSF a model for sustainability and one more step toward NRELs goal to be a net zero energy campus.

  2. Virtual gap dielectric wall accelerator

    DOE Patents [OSTI]

    Caporaso, George James; Chen, Yu-Jiuan; Nelson, Scott; Sullivan, Jim; Hawkins, Steven A

    2013-11-05

    A virtual, moving accelerating gap is formed along an insulating tube in a dielectric wall accelerator (DWA) by locally controlling the conductivity of the tube. Localized voltage concentration is thus achieved by sequential activation of a variable resistive tube or stalk down the axis of an inductive voltage adder, producing a "virtual" traveling wave along the tube. The tube conductivity can be controlled at a desired location, which can be moved at a desired rate, by light illumination, or by photoconductive switches, or by other means. As a result, an impressed voltage along the tube appears predominantly over a local region, the virtual gap. By making the length of the tube large in comparison to the virtual gap length, the effective gain of the accelerator can be made very large.

  3. Magnetic study of M-type doped barium hexaferrite nanocrystalline particles

    SciTech Connect (OSTI)

    Alsmadi, A. M.; Bsoul, I.; Mahmood, S. H.; Alnawashi, G.; Prokeš, K.; Siemensmeyer, K.; Klemke, B.; Nakotte, H.

    2013-12-28

    Co-Ti and Ru-Ti substituted barium ferrite nanocrystalline particles BaFe{sub 12−2x}Co{sub x}Ti{sub x}O{sub 19} with (0≤x≤1) and BaFe{sub 12−2x}Ru{sub x}Ti{sub x}O{sub 19} with (0≤x≤0.6) were prepared by ball milling method, and their magnetic properties and their temperature dependencies were studied. The zero-field-cooled (ZFC) and field-cooled (FC) processes were recorded at low magnetic fields and the ZFC curves displayed a broad peak at a temperature T{sub M}. In all samples under investigation, a clear irreversibility between the ZFC and FC curves was observed below room temperature, and this irreversibility disappeared above room temperature. These results were discussed within the framework of random particle assembly model and associated with the magnetic domain wall motion. The resistivity data showed some kind of a transition from insulator to perfect insulator around T{sub M}. At 2 K, the saturation magnetization slightly decreased and the coercivity dropped dramatically with increasing the Co-Ti concentration x. With Ru-Ti substitution, the saturation magnetization showed small variations, while the coercivity decreased monotonically, recording a reduction of about 73% at x = 0.6. These results were discussed in light of the single ion anisotropy model and the cationic distributions based on previously reported neutron diffraction data for the CoTi substituted system, and the results of our Mössbauer spectroscopy data for the RuTi substituted system.

  4. CXD 4606, 9831 Wall Construction Project (4606)

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

    9831 Wall Construction Project (4606) Y-12 Site Office Oak Ridge, Anderson County, Tennessee The proposed action is to upgrade of the existing contamination area associated with an...

  5. Fillability of Thin-Wall Steel Castings

    SciTech Connect (OSTI)

    Robert C. Voigt; Joseph Bertoletti; Andrew Kaley; Sandi Ricotta; Travis Sunday

    2002-07-30

    The use of steel components is being challenged by lighter nonferrous or cast iron components. The development of techniques for enhancing and ensuring the filability of thin-wall mold cavities is most critical for thinner wall cast steel production. The purpose of this research was to develop thin-wall casting techniques that can be used to reliably produce thin-wall castings from traditional gravity poured sand casting processes. The focus of the research was to enhance the filling behavior to prevent misrunds. Experiments were conducted to investigate the influence of various foundry variables on the filling of thin section steel castings. These variables include casting design, heat transfer, gating design, and metal fluidity. Wall thickness and pouring temperature have the greatest effect on casting fill. As wall thickness increases the volume to surface area of the casting increases, which increases the solidification time, allowing the metal to flow further in thicker sect ions. Pouring time is another significant variable affecting casting fill. Increases or decreases of 20% in the pouring time were found to have a significant effect on the filling of thin-wall production castings. Gating variables, including venting, pouring head height, and mold tilting also significantly affected thin-wall casting fill. Filters offer less turbulent, steadier flow, which is appropriate for thicker castings, but they do not enhance thin-wall casting fill.

  6. First wall for polarized fusion reactors

    DOE Patents [OSTI]

    Greenside, H.S.; Budny, R.V.; Post, D.E. Jr.

    1985-01-29

    A first-wall or first-wall coating for use in a fusion reactor having polarized fuel may be formed of a low-Z non-metallic material having slow spin relaxation, i.e., a depolarization rate greater than 1 sec/sup -1/. Materials having these properties include hydrogenated and deuterated amorphous semiconductors. A method for preventing the rapid depolarization of a polarized plasma in a fusion device may comprise the step of providing a first-wall or first-wall coating formed of a low-Z, non-metallic material having a depolarization rate greater than 1 sec/sup -1/.

  7. Living Walls | OpenEI Community

    Open Energy Info (EERE)

    systems and the new field of biomimicry. Biomimicry is the science of imitating nature to solve human design problems. The Living Wall concept takes the principles behind...

  8. Water Wall Turbine | Open Energy Information

    Open Energy Info (EERE)

    Jump to: navigation, search Name: Water Wall Turbine Region: Canada Sector: Marine and Hydrokinetic Website: www.wwturbine.com This company is listed in the Marine and Hydrokinetic...

  9. new chemistry to break down cell walls

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

    new chemistry to break down cell walls - Sandia Energy Energy Search Icon Sandia Home ... Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power ...

  10. Wall, Pennsylvania: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Wall, Pennsylvania: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 40.3936801, -79.7861577 Show Map Loading map... "minzoom":false,"mappingser...