Nucleon-nucleon bremsstrahlung: Anomalous magnetic moment effects
Timmermans, R.G.E.; Penninga, T.D.; Gibson, B.F.; Liou, M.K.
2006-03-15
Background: Two soft-photon amplitudes, the two-u-two-t special (TuTts) amplitude and the Low amplitude, are known to produce quantitatively similar np{gamma} cross sections, but they predict quite different pp{gamma} cross sections for those kinematic conditions in which the nucleon scattering angles are small (less than 25 deg.). Purpose: These two amplitudes have been applied to systematically investigate three different nucleon-nucleon bremsstrahlung (NN{gamma}) processes: pp{gamma},np{gamma}, and nn{gamma}. The nn{gamma} process is explored for the first time. The primary focus of this work is to investigate the contribution of the proton and the neutron anomalous magnetic moments to all three NN{gamma} processes for projectile energies above 150 MeV and for laboratory scattering angles ({theta}{sub 1} and {theta}{sub 2}) lying between 8 deg. and 40 deg.. Method: A special soft-photon expansion in which the TuTts amplitude is expanded in terms of the Low amplitude plus additional amplitudes is utilized to explore the relationship between the TuTts and Low amplitudes and the reasons why they agree and disagree. We also used the TuTts amplitude to calculate the NN{gamma} cross section with and without the anomalous magnetic moment contributions to explore the importance of that element of the electromagnetic current. Results: The TuTts amplitude describes well the available pp{gamma} cross-section data. The anomalous magnetic moment contribution is (i) significant in the pp{gamma} process when each scattering angle is less than 25 deg. but insignificant when each scattering angle is 40 deg. or greater and (ii) insignificant in the np{gamma} process for all scattering angles. The nn{gamma} cross sections for the TuTts and Low amplitudes differ substantially for the kinematics investigated. Conclusions: In general, the Low amplitude agrees well with the TuTts amplitude when anomalous magnetic moment effects are not significant, but the two amplitudes can yield
The measurement of the anomalous magnetic moment of the muon at Fermilab
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Logashenko, I.
2015-06-17
The anomalous magnetic moment of the muon is one of the most precisely measured quantities in experimental particle physics. Its latest measurement at Brookhaven National Laboratory deviates from the Standard Model expectation by approximately 3.5 standard deviations. The goal of the new experiment, E989, now under construction at Fermilab, is a fourfold improvement in precision. Furthermore, we discuss the details of the future measurement and its current status.
The Hadronic Contribution to the Anomalous Magnetic Moment of the Muon |
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Argonne Leadership Computing Facility Hadronic Contribution to the Anomalous Magnetic Moment of the Muon PI Name: Paul Mackenzie PI Email: mackenzie@fnal.gov Institution: Fermilab Allocation Program: ESP Year: 2015 Research Domain: Physics Tier 2 Code Development Project Numerical Methods/Algorithms Two codes are involved in this project: MILC and the Columbia Physics System (CPS). The application operates on a four-dimensional hypercubic lattice (grid) with quark data as- associated with
Leptophilic dark matter and the anomalous magnetic moment of the muon
Agrawal, Prateek; Chacko, Zackaria; Verhaaren, Christopher B.
2014-08-26
We consider renormalizable theories such that the scattering of dark matter off leptons arises at tree level, but scattering off nuclei only arises at loop. In this framework, the various dark matter candidates can be classified by their spins and by the forms of their interactions with leptons. In this study, we determine the corrections to the anomalous magnetic moment of the muon that arise from its interactions with dark matter. We then consider the implications of these results for a set of simplified models of leptophilic dark matter. When a dark matter candidate reduces the existing tension between the standard model prediction of the anomalous magnetic moment and the experimental measurement, the region of parameter space favored to completely remove the discrepancy is highlighted. Conversely, when agreement is worsened, we place limits on the parameters of the corresponding simplified model. These bounds and favored regions are compared against the experimental constraints on the simplified model from direct detection and from collider searches. Although these constraints are severe, we find there do exist limited regions of parameter space in these simple theories that can explain the observed anomaly in the muon magnetic moment while remaining consistent with all experimental bounds.
Leptophilic dark matter and the anomalous magnetic moment of the muon
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Agrawal, Prateek; Chacko, Zackaria; Verhaaren, Christopher B.
2014-08-26
We consider renormalizable theories such that the scattering of dark matter off leptons arises at tree level, but scattering off nuclei only arises at loop. In this framework, the various dark matter candidates can be classified by their spins and by the forms of their interactions with leptons. In this study, we determine the corrections to the anomalous magnetic moment of the muon that arise from its interactions with dark matter. We then consider the implications of these results for a set of simplified models of leptophilic dark matter. When a dark matter candidate reduces the existing tension between themore » standard model prediction of the anomalous magnetic moment and the experimental measurement, the region of parameter space favored to completely remove the discrepancy is highlighted. Conversely, when agreement is worsened, we place limits on the parameters of the corresponding simplified model. These bounds and favored regions are compared against the experimental constraints on the simplified model from direct detection and from collider searches. Although these constraints are severe, we find there do exist limited regions of parameter space in these simple theories that can explain the observed anomaly in the muon magnetic moment while remaining consistent with all experimental bounds.« less
Electron Anomalous Magnetic Moment in Basis Light-Front Quantization Approach
Zhao, Xingbo; Honkanen, Heli; Maris, Pieter; Vary, James P.; Brodsky, Stanley J.; /SLAC
2012-02-17
We apply the Basis Light-Front Quantization (BLFQ) approach to the Hamiltonian field theory of Quantum Electrodynamics (QED) in free space. We solve for the mass eigenstates corresponding to an electron interacting with a single photon in light-front gauge. Based on the resulting non-perturbative ground state light-front amplitude we evaluate the electron anomalous magnetic moment. The numerical results from extrapolating to the infinite basis limit reproduce the perturbative Schwinger result with relative deviation less than 1.2%. We report significant improvements over previous works including the development of analytic methods for evaluating the vertex matrix elements of QED.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Blum, Thomas; Chowdhury, Saumitra; Hayakawa, Masashi; Izubuchi, Taku
2015-01-07
The form factor that yields the light-by-light scattering contribution to the muon anomalous magnetic moment is computed in lattice QCD+QED and QED. A non-perturbative treatment of QED is used and is checked against perturbation theory. The hadronic contribution is calculated for unphysical quark and muon masses, and only the diagram with a single quark loop is computed. Statistically significant signals are obtained. Initial results appear promising, and the prospect for a complete calculation with physical masses and controlled errors is discussed.
Lattice calculation of hadronic light-by-light contribution to the muon anomalous magnetic moment
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Blum, Thomas; Christ, Norman; Hayakawa, Masashi; Izubuchi, Taku; Jin, Luchang; Lehner, Christoph
2016-01-12
The quark-connected part of the hadronic light-by-light scattering contribution to the muon’s anomalous magnetic moment is computed using lattice QCD with chiral fermions. Here we report several significant algorithmic improvements and demonstrate their effectiveness through specific calculations which show a reduction in statistical errors by more than an order of magnitude. The most realistic of these calculations is performed with a near-physical 171 MeV pion mass on a (4.6 fm)3 spatial volume using the 323×64 Iwasaki+DSDR gauge ensemble of the RBC/UKQCD Collaboration.
Photon equation of motion with application to the electron's anomalous magnetic moment
Ritchie, A B
2007-12-06
The photon equation of motion previously applied to the Lamb shift is here applied to the anomalous magnetic moment of the electron. Exact agreement is obtained with the QED result of Schwinger. The photon theory treats the radiative correction to the photon in the presence of the electron rather than its inverse as in standard QED. The result is found to be first-order in the photon-electron interaction rather than second-order as in standard QED, introducing an ease of calculation hitherto unavailable.
Four-flavour leading-order hadronic contribution to the muon anomalous magnetic moment
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Burger, Florian; Feng, Xu; Hotzel, Grit; Jansen, Karl; Petschlies, Marcus; Renner, Dru B.
2014-02-24
We present a four-flavour lattice calculation of the leading-order hadronic vacuum polarisation contribution to the anomalous magnetic moment of the muon, aμhvp, arising from quark-connected Feynman graphs. It is based on ensembles featuring Nf=2+1+1 dynamical twisted mass fermions generated by the European Twisted Mass Collaboration (ETMC). Several light quark masses are used in order to yield a controlled extrapolation to the physical pion mass. We employ three lattice spacings to examine lattice artefacts and several different volumes to check for finite-size effects. Including the complete first two generations of quarks allows for a direct comparison with phenomenological determinations of amore » μhvp. The final result involving an estimate of the systematic uncertainty aμhvp=6.74 (21)(18) 10-8 shows a good overall agreement with these computations.« less
Four-flavour leading-order hadronic contribution to the muon anomalous magnetic moment
Burger, Florian; Feng, Xu; Hotzel, Grit; Jansen, Karl; Petschlies, Marcus; Renner, Dru B.
2014-02-24
We present a four-flavour lattice calculation of the leading-order hadronic vacuum polarisation contribution to the anomalous magnetic moment of the muon, a?^{hvp}, arising from quark-connected Feynman graphs. It is based on ensembles featuring N_{f}=2+1+1 dynamical twisted mass fermions generated by the European Twisted Mass Collaboration (ETMC). Several light quark masses are used in order to yield a controlled extrapolation to the physical pion mass. We employ three lattice spacings to examine lattice artefacts and several different volumes to check for finite-size effects. Including the complete first two generations of quarks allows for a direct comparison with phenomenological determinations of a ?^{hvp}. The final result involving an estimate of the systematic uncertainty a_{?}^{hvp}=6.74 (21)(18) 10^{-8} shows a good overall agreement with these computations.
Yukawa coupling and anomalous magnetic moment of the muon: An update for the LHC era
Crivellin, Andreas; Girrbach, Jennifer; Nierste, Ulrich
2011-03-01
We study the interplay between a soft muon Yukawa coupling generated radiatively with the trilinear A-terms of the minimal supersymmetric standard model (MSSM) and the anomalous magnetic moment of the muon. In the absence of a tree-level muon Yukawa coupling the lightest smuon mass is predicted to be in the range between 600 GeV and 2200 GeV at 2{sigma}, if the bino mass M{sub 1} is below 1 TeV. Therefore, a detection of a smuon (in conjunction with a sub-TeV bino) at the LHC would directly imply a nonzero muon Yukawa coupling in the MSSM superpotential. Inclusion of slepton flavor mixing could in principle lower the mass of one smuonlike slepton below 600 GeV. However, the experimental bounds on radiative lepton decays instead strengthen the lower mass bound, with larger effects for smaller M{sub 1}, We also extend the analysis to the electron case and find that a light selectron close to the current experimental search limit may prove the MSSM electron Yukawa coupling to be nonzero.
Anomalous magnetic moment contributions to NN bremsstrahlung in the soft-photon approximation
Gibson, B.F.; Penninga, T.D.; Timmermans, R.G.E.; Liou, M.K.
2005-05-06
The soft photon approximation (SPA), which is relativistic and based upon a fundamental theorem for photon emission, is applied to explore two separate nucleon-nucleon bremsstrahlung (NN{gamma}) processes: pp{gamma} and np{gamma}. They are examined together in an effort to understand the mechanism which governs photon emission from these basic two-nucleon systems. In this investigation we focus upon the effect of the anomalous magnetic moments of the proton ({kappa}p) and the neutron ({kappa}n). In our SPA calculation we use the standard Low amplitude M{sub {mu}}{sup Low} as derived by Nyman plus the more recently developed amplitude M{sub {mu}}{sup TuTts}, referred to as the two-u-two-t special (TuTts) amplitude. The amplitude M{sub {mu}}{sup TuTts} is identical to the amplitude M{sub {mu}}{sup Low} through order K0 in the soft-photon expansion. However, M{sub {mu}}{sup TuTts} includes an additional term M{sub {mu}}{sup (3)}(K{sup 1}; {kappa}) (plus higher order terms). The term M{sub {mu}}{sup (3)}(K{sup 1}; {kappa}) is of order K1 in the soft-photon expansion and it is a function of {kappa}p and {kappa}n. Using the amplitudes M{sub {mu}}{sup TuTts} and M{sub {mu}}{sup Low}, we have calculated pp{gamma} and np{gamma} cross sections as a function of photon angle {psi}{gamma} with and without contributions from {kappa}p and {kappa}n. Comparison with available pp{gamma} data has been made; in particular, the contribution from M{sub {mu}}{sup (3)}(K{sup 1}; {kappa}) has been investigated. Results will be presented and discussed which relate to the following: (i) The anomalous magnetic moment effect is significant in pp{gamma}; however, it is small in np{gamma}. That is, the two amplitudes M{sub {mu}}{sup TuTts} and M{sub {mu}}{sup Low} yield very similar np{gamma} cross sections, but they predict very different pp{gamma} cross sections. (ii) M{sub {mu}}{sup TuTts} appears to provide a better SPA than M{sub {mu}}{sup Low} in the case of pp{gamma}. Because {kappa
Ledwig, Tim; Silva, Antonio
2010-09-01
We investigate the form factors of the chiral-odd nucleon matrix element of the tensor current. In particular, we aim at the anomalous tensor magnetic form factors of the nucleon within the framework of the SU(3) and SU(2) chiral quark-soliton model. We consider 1/N{sub c} rotational corrections and linear effects of SU(3) symmetry breaking with the symmetry-conserving quantization employed. We first obtain the results of the anomalous tensor magnetic moments for the up and down quarks: {kappa}{sub T}{sup u}=3.56 and {kappa}{sub T}{sup d}=1.83, respectively. The strange anomalous tensor magnetic moment is yielded to be {kappa}{sub T}{sup s}=0.2{approx}-0.2, that is compatible with zero. We also calculate the corresponding form factors {kappa}{sub T}{sup q}(Q{sup 2}) up to a momentum transfer Q{sup 2{<=}}1 GeV{sup 2} at a renormalization scale of 0.36 GeV{sup 2}.
tan{beta}-enhanced supersymmetric corrections to the anomalous magnetic moment of the muon
Marchetti, Schedar; Mertens, Susanne; Nierste, Ulrich; Stoeckinger, Dominik
2009-01-01
We report on a two-loop supersymmetric contribution to the magnetic moment (g-2){sub {mu}} of the muon which is enhanced by two powers of tan{beta}. This contribution arises from a shift in the relation between the muon mass and Yukawa coupling and can increase the supersymmetric contribution to (g-2){sub {mu}} sizably. As a result, if the currently observed 3{sigma} deviation between the experimental and SM theory value of (g-2){sub {mu}} is analyzed within the minimal supersymmetric standard model (MSSM), the derived constraints on the parameter space are modified significantly: If (g-2){sub {mu}} is used to determine tan{beta} as a function of the other MSSM parameters, our corrections decrease tan{beta} by roughly 10% for tan{beta}=50.
Porter, Frank C.
2015-04-29
The BABAR collaboration has an extensive program of studying hadronic cross sections in low-energy e^{+}e^{-} collisions, accessible via initial-state radiation. Our measurements allow significant improvements in the precision of the predicted value of the muon anomalous magnetic moment. These improvements are necessary for illuminating the current 3.6 sigma difference between the predicted and the experimental values. We have published results on a number of processes with two to six hadrons in the final state. We report here the results of recent studies with final states that constitute the main contribution to the hadronic cross section in the energy region between 1 and 3 GeV, as e^{+}e^{-} → K^{+}K^{-}, π^{+}π^{-}, and e^{+}e^{-} → 4 hadrons
Bonanos, Peter
1983-01-01
A toroidal magnet for confining a high magnetic field for use in fusion reactor research and nuclear particle detection. The magnet includes a series of conductor elements arranged about and fixed at its small major radius portion to the outer surface of a central cylindrical support each conductor element having a geometry such as to maintain the conductor elements in pure tension when a high current flows therein, and a support assembly which redistributes all or part of the tension which would otherwise arise in the small major radius portion of each coil element to the large major radius portion thereof.
Hyperon polarization and magnetic moments
Lach, J.
1993-12-01
Inclusively produced hyperons with significant polarization were first observed at Fermilab about seventeen years ago. This and subsequent experiments showed that {Lambda}{degree} were produced polarized while {bar {Lambda}}{degree} had no polarization in the same kinematical region. This set the stage for many experiments which showed that most hyperons are produced polarized. Recent Fermilab experiments have showed that this phenomena is even more complex and theoretical understanding is still lacking. Nevertheless polarized hyperon beams have been an extremely useful experimental tool in measuring hyperon magnetic moments. Recently, magnetic moment precession of channeled particles in bent crystals has been observed. This opens the possibility of measuring the magnetic moments of charmed baryons.
Determination of the Neutron Magnetic Moment
DOE R&D Accomplishments [OSTI]
Greene, G. L.; Ramsey, N. F.; Mampe, W.; Pendlebury, J. M.; Smith, K.; Dress, W. B.; Miller, P. D.; Perrin, P.
1981-06-01
The neutron magnetic moment has been measured with an improvement of a factor of 100 over the previous best measurement. Using a magnetic resonance spectrometer of the separated oscillatory field type capable of determining a resonance signal for both neutrons and protons (in flowing H{sub 2}O), we find ..mu..{sub n}/..mu..{sub p} = 0.68497935(17) (0.25 ppM). The neutron magnetic moment can also be expressed without loss of accuracy in a variety of other units.
Constraining the neutrino magnetic dipole moment from white dwarf pulsations
Crsico, A.H.; Althaus, L.G.; Garca-Berro, E. E-mail: althaus@fcaglp.unlp.edu.ar E-mail: kepler@if.ufrgs.br
2014-08-01
Pulsating white dwarf stars can be used as astrophysical laboratories to constrain the properties of weakly interacting particles. Comparing the cooling rates of these stars with the expected values from theoretical models allows us to search for additional sources of cooling due to the emission of axions, neutralinos, or neutrinos with magnetic dipole moment. In this work, we derive an upper bound to the neutrino magnetic dipole moment (?{sub ?}) using an estimate of the rate of period change of the pulsating DB white dwarf star PG 1351+489. We employ state-of-the-art evolutionary and pulsational codes which allow us to perform a detailed asteroseismological period fit based on fully DB white dwarf evolutionary sequences. Plasmon neutrino emission is the dominant cooling mechanism for this class of hot pulsating white dwarfs, and so it is the main contributor to the rate of change of period with time (Pidot) for the DBV class. Thus, the inclusion of an anomalous neutrino emission through a non-vanishing magnetic dipole moment in these sequences notably influences the evolutionary timescales, and also the expected pulsational properties of the DBV stars. By comparing the theoretical Pidot value with the rate of change of period with time of PG 1351+489, we assess the possible existence of additional cooling by neutrinos with magnetic dipole moment. Our models suggest the existence of some additional cooling in this pulsating DB white dwarf, consistent with a non-zero magnetic dipole moment with an upper limit of ?{sub ?}?<10{sup -11}?{sub B}. This bound is somewhat less restrictive than, but still compatible with, other limits inferred from the white dwarf luminosity function or from the color-magnitude diagram of the Globular cluster M5. Further improvements of the measurement of the rate of period change of the dominant pulsation mode of PG 1351+489 will be necessary to confirm our bound.
Noncommutative magnetic moment of charged particles
Adorno, T. C.; Gitman, D. M.; Shabad, A. E.; Vassilevich, D. V.
2011-10-15
It has been argued that in noncommutative field theories, the sizes of physical objects cannot be taken smaller than an ''elementary length'' related to noncommutativity parameters. By gauge covariantly extending field equations of noncommutative U(1){sub *} theory to cover the presence of external sources, we find electric and magnetic fields produced by an extended static charge. We find that such a charge, apart from being an ordinary electric monopole, is also a magnetic dipole. By writing off the existing experimental clearance in the value of the lepton magnetic moments for the present effect, we get the bound on noncommutativity at the level of 10{sup 4} TeV.
The investigation of anomalous magnetization in the Raft River...
investigation of anomalous magnetization in the Raft River valley, Idaho Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Proceedings: The...
Moment enhancement in dilute magnetic semiconductors: MnxSi1...
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Moment enhancement in dilute magnetic semiconductors: MnxSi1-x with x 0.1% Citation Details In-Document Search Title: Moment enhancement in dilute magnetic semiconductors: ...
Electric quadrupole and magnetic octupole moments of the Delta
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Ramalho, G.; Pena, M. T.; Gross, Franz L.
2009-07-01
Using a covariant spectator constituent quark model we predict an electric quadrupole moment -0.042 efm2 and a magnetic octupole moment -0.0035 efm3 for the Delta+ excited state of the nucleon.
Electric quadrupole and magnetic octupole moments of the Δ
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Ramalho, G.; Peña, M. T.; Gross, Franz
2009-07-01
Using a covariant spectator constituent quark model we predict an electric quadrupole moment -0.042 efm2 and a magnetic octupole moment -0.0035 efm3 for the Delta+ excited state of the nucleon.
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impurity ion heating from Alfvénic cascade in the reversed field pinch Varun Tangri, P. W. Terry, and Gennady Fiksel Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas and Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706, USA ͑Received 15 January 2008; accepted 19 September 2008; published online 3 November 2008͒ Anomalous ion and impurity heating in reversed field pinch plasmas is addressed. Previous work ͓N.
Magnetic moments of light nuclei from lattice quantum chromodynamics
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Beane, S. R.; Chang, E.; Cohen, S.; Detmold, W.; Lin, H. W.; Orginos, K.; Parreño, A.; Savage, M. J.; Tiburzi, B. C.
2014-12-16
We present the results of lattice QCD calculations of the magnetic moments of the lightest nuclei, the deuteron, the triton and 3He, along with those of the neutron and proton. These calculations, performed at quark masses corresponding to mπ ~ 800 MeV, reveal that the structure of these nuclei at unphysically heavy quark masses closely resembles that at the physical quark masses. We find that the magnetic moment of 3He differs only slightly from that of a free neutron, as is the case in nature, indicating that the shell-model configuration of two spin-paired protons and a valence neutron captures itsmore » dominant structure. Similarly a shell-model-like moment is found for the triton, μ3H ~ μp. The deuteron magnetic moment is found to be equal to the nucleon isoscalar moment within the uncertainties of the calculations.« less
Magnetic moments of light nuclei from lattice quantum chromodynamics
Beane, S.? R.; Chang, E.; Cohen, S.; Detmold, W.; Lin, H.? W.; Orginos, K.; Parreo, A.; Savage, M.? J.; Tiburzi, B.? C.
2014-12-16
We present the results of lattice QCD calculations of the magnetic moments of the lightest nuclei, the deuteron, the triton and ^{3}He, along with those of the neutron and proton. These calculations, performed at quark masses corresponding to m_{?} ~ 800 MeV, reveal that the structure of these nuclei at unphysically heavy quark masses closely resembles that at the physical quark masses. We find that the magnetic moment of ^{3}He differs only slightly from that of a free neutron, as is the case in nature, indicating that the shell-model configuration of two spin-paired protons and a valence neutron captures its dominant structure. Similarly a shell-model-like moment is found for the triton, ?_{3H} ~ ?_{p}. The deuteron magnetic moment is found to be equal to the nucleon isoscalar moment within the uncertainties of the calculations.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zhuravlev, I. A.; Antropov, V. P.; Belashchenko, K. D.
2015-11-16
The origins of the anomalous temperature dependence of magnetocrystalline anisotropy in (Fe1–xCox)2B alloys are elucidated using first-principles calculations within the disordered local moment model. Excellent agreement with experimental data is obtained. The anomalies are associated with the changes in band occupations due to Stoner-like band shifts and with the selective suppression of spin-orbit “hot spots” by thermal spin fluctuations. Under certain conditions, the anisotropy can increase, rather than decrease, with decreasing magnetization. These peculiar electronic mechanisms are in stark contrast to the assumptions of the existing models.
Magnetic Moment Enhancement for Mn7 Cluster on Graphene
Liu, Xiaojie; Wang, Cai-Zhuang; Lin, Hai-Qing; Ho, Kai-Ming
2014-08-21
Mn7 cluster on graphene with different structural motifs and magnetic orders are investigated systematically by first-principles calculations. The calculations show that Mn7 on graphene prefers a two-layer motif and exhibits a ferrimagnetic coupling. The magnetic moment of the Mn7 cluster increases from 5.0 ?B at its free-standing state to about 6.0 ?B upon adsorption on graphene. Mn7 cluster also induces about 0.3 ?B of magnetic moment in the graphene layer, leading to an overall enhancement of 1.3 ?B magnetic moment for Mn7 on graphene. Detail electron transfer and bonding analysis have been carried out to investigate the origin of the magnetic enhancement.
Direct Measurement of the Neutral Weak Dipole Moments of the...
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Visit OSTI to utilize additional information resources in energy science and technology. A ... We present direct measurements of the neutral weak anomalous magnetic dipole moment, asub ...
Magnetic moments of light nuclei from lattice quantum chromodynamics
Beane, S. R.; Chang, E.; Cohen, S.; Detmold, W.; Lin, H. W.; Orginos, K.; Parreño, A.; Savage, M. J.; Tiburzi, B. C.
2014-12-16
We present the results of lattice QCD calculations of the magnetic moments of the lightest nuclei, the deuteron, the triton and ^{3}He, along with those of the neutron and proton. These calculations, performed at quark masses corresponding to m_{π} ~ 800 MeV, reveal that the structure of these nuclei at unphysically heavy quark masses closely resembles that at the physical quark masses. We find that the magnetic moment of ^{3}He differs only slightly from that of a free neutron, as is the case in nature, indicating that the shell-model configuration of two spin-paired protons and a valence neutron captures its dominant structure. Similarly a shell-model-like moment is found for the triton, μ_{3H} ~ μ_{p}. The deuteron magnetic moment is found to be equal to the nucleon isoscalar moment within the uncertainties of the calculations.
Anomalous magnetic behavior at the graphene/Co interface
Mandal, Sumit; Saha, Shyamal K., E-mail: cnssks@iacs.res.in [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)
2014-07-14
An intensive theoretical study on the interaction between graphene and transition metal atom has been carried out; however, its experimental verification is still lacking. To explore the theoretical prediction of antiferromagnetic coupling due to charge transfer between graphene and cobalt, epitaxial layer of cobalt is grown on graphene surface. Predicted antiferromagnetic interaction with Neel temperature (T{sub N}???32?K) which anomalously shifts to higher temperature (34?K) and becomes more prominent under application of magnetic field of 1 T is reported. Lowering of magnetoresistance as a consequence of this antiferromagnetic coupling at the interface is also observed.
Mogi, M. Yoshimi, R.; Yasuda, K.; Kozuka, Y.; Tsukazaki, A.; Takahashi, K. S.; Kawasaki, M.; Tokura, Y.
2015-11-02
Quantum anomalous Hall effect (QAHE), which generates dissipation-less edge current without external magnetic field, is observed in magnetic-ion doped topological insulators (TIs) such as Cr- and V-doped (Bi,Sb){sub 2}Te{sub 3}. The QAHE emerges when the Fermi level is inside the magnetically induced gap around the original Dirac point of the TI surface state. Although the size of gap is reported to be about 50 meV, the observable temperature of QAHE has been limited below 300 mK. We attempt magnetic-Cr modulation doping into topological insulator (Bi,Sb){sub 2}Te{sub 3} films to increase the observable temperature of QAHE. By introducing the rich-Cr-doped thin (1 nm) layers at the vicinity of both the surfaces based on non-Cr-doped (Bi,Sb){sub 2}Te{sub 3} films, we have succeeded in observing the QAHE up to 2 K. The improvement in the observable temperature achieved by this modulation-doping appears to be originating from the suppression of the disorder in the surface state interacting with the rich magnetic moments. Such a superlattice designing of the stabilized QAHE may pave a way to dissipation-less electronics based on the higher-temperature and zero magnetic-field quantum conduction.
Magnetism of j = 1/2 moments on the fcc lattice in double perovskite...
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Magnetism of j 12 moments on the fcc lattice in double perovskite Mott insulators Citation Details In-Document Search Title: Magnetism of j 12 moments on the fcc lattice in...
LIMIT ON THE MUON NEUTRINO MAGNETIC MOMENT AND A MEASUREMENT
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LIMIT ON THE MUON NEUTRINO MAGNETIC MOMENT AND A MEASUREMENT OF THE CCPIP TO CCQE CROSS SECTION RATIO A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Physics And Astronomy by Serge Ouedraogo B.S. in Physics, University of Arkansas at Little Rock, 2001 M.S., Louisiana State University, 2004 December 2008 In loving memory
Precise quantization of anomalous Hall effect near zero magnetic field
Bestwick, A. J.; Fox, E. J.; Kou, Xufeng; Pan, Lei; Wang, Kang L.; Goldhaber-Gordon, D.
2015-05-04
In this study, we report a nearly ideal quantum anomalous Hall effect in a three-dimensional topological insulator thin film with ferromagnetic doping. Near zero applied magnetic field we measure exact quantization in the Hall resistance to within a part per 10,000 and a longitudinal resistivity under 1 Ω per square, with chiral edge transport explicitly confirmed by nonlocal measurements. Deviations from this behavior are found to be caused by thermally activated carriers, as indicated by an Arrhenius law temperature dependence. Using the deviations as a thermometer, we demonstrate an unexpected magnetocaloric effect and use it to reach near-perfect quantization by cooling the sample below the dilution refrigerator base temperature in a process approximating adiabatic demagnetization refrigeration.
Taniguchi, T.; Mizusaki, S.; Okada, N.; Nagata, Y.; Mori, K.; Wuernisha, T.; Kamiyama, T.; Hiraoka, N.; Itou, M.; Sakurai, Y.; Ozawa, T. C.; Noro, Y.; Samata, H.
2007-01-01
Neutron powder diffraction and magnetic Compton scattering measurements were conducted for ferromagnetic CaRu{sub 0.85}Fe{sub 0.15}O{sub 3} at temperatures between 10 and 300 K. Anomalous volume expansion was observed in the neutron diffraction measurement below the Curie temperature (85 K), and Invar-like behavior was observed below 40 K. However, no structural phase transition was observed down to 10 K. The strong correlation between the volume expansion, {delta}V, and the square magnetization, M{sup 2}, suggests that the anomalous volume expansion is due to the magnetovolume effect that is caused by the occurrence of ferromagnetism. The magnetic Compton scattering experiments revealed the existence of a magnetic moment on Ru and the antiferromagnetic configuration of Fe and Ru moments. The formation of a ferrimagnetic order through the induction of the magnetic moment on the Ru ion is a possible reason for the anomalous volume expansion observed for CaRu{sub 0.85}Fe{sub 0.15}O{sub 3}.
Kollu, Pratap E-mail: anirmalagrace@vit.ac.in; Prathapani, Sateesh; Varaprasadarao, Eswara K.; Mallick, Sudhanshu; Bahadur, D. E-mail: anirmalagrace@vit.ac.in; Santosh, Chella; Grace, Andrews Nirmala E-mail: anirmalagrace@vit.ac.in
2014-08-04
Magnetic Reduced Graphene Oxide-Nickel/NiFe{sub 2}O{sub 4} (RGO-Ni/NF) nanocomposite has been synthesized by one pot solvothermal method. Respective phase formations and their purities in the composite are confirmed by High Resolution Transmission Electron Microscope and X Ray Diffraction, respectively. For the RGO-Ni/NF composite material finite-size effects lead to the anomalous magnetic behavior, which is corroborated in temperature and field dependent magnetization curves. Here, we are reporting the behavior of higher magnetization values for Zero Field Cooled condition to that of Field Cooled for the RGO-Ni/NF nanocomposite. Also, the observed negative and positive moments in Hysteresis loops at relatively smaller applied fields (100?Oe and 200?Oe) are explained on the basis of surface spin disorder.
Synthesis and anomalous magnetic properties of hexagonal CoO nanoparticles
He, Xuemin; Shi, Huigang
2011-10-15
Highlights: {yields} The as-synthesized CoO nanoparticles are of pyramid configuration with hcp structure. {yields} The hexagonal CoO particles do not exhibit antiferromagnetic transition around 300 K. {yields} The CoO particles have relative large saturation magnetization and coercivity at 5 K. {yields} The shift of hysteresis loops is consistent with the result of multisublattice model. {yields} The particles contain intrinsic antiferromagnetic structure and uncompensated spins. -- Abstract: CoO nanoparticles in the 38-93 nm range have been prepared by thermal decomposition. The particles were characterized to be pyramid shape with a hexagonal close-packed structure. Their anomalous magnetic behavior includes: (i) vanishing of antiferromagnetic transition around 300 K; (ii) creation of hysteresis below a blocking temperature of 6-11 K; (iii) presence of relatively large moments and coercivities accompany with specific loop shifts at 5 K; and (iv) appearance of an additional small peak located in low field in the electron spin resonance spectrum. Further, the present results provide evidence for the existence of uncompensated surface spins. The coercivity and exchange bias decrease with increasing particle size, indicating a distinct size effect. These observations can be explained by the multisublattice model, in which the reduced coordination of surface spins causes a fundamental change in the magnetic order throughout the total CoO particle.
Daugas, J. M.; Gaudefroy, L.; Meot, V.; Morel, P.; Rosse, B.; Hass, M.; Kumar, V.; Angelique, J. C.; Simpson, G. S.; Balabanski, D. L.; Fiori, E.; Georgiev, G.; Lozeva, R.; Force, C.; Grevy, S.; Stodel, Ch.; Thomas, J. C.; Kameda, D.; Matea, I.; Singh, B. S. Nara
2008-11-11
The gyromagnetic factor of the isomeric state of {sup 43}S has been measured using the Time Dependent Perturbed Angular Distribution (TDPAD) technique. The isomer was produced and spin aligned via the fragmentation of a 60 AMeV {sup 48}Ca beam at the GANIL facility. The deduced magnetic moment confirms the 7/2{sup -} spin/parity of the isomeric state and shows, for the first time, the intruder nature of the ground state. Comparison of the experimental values with Shell Model and mean-field based calculations were performed revealing a pronounced ground state deformation and a quasi-spherical isomeric state. A new isomeric state has been observed in the {sup 42}P.
Magnetic dipole moments of {sup 57,58,59}Cu
Cocolios, T. E.; Andreyev, A. N.; Bastin, B.; Bree, N.; Buescher, J.; Elseviers, J.; Gentens, J.; Huyse, M.; Kudryavtsev, Yu.; Pauwels, D.; Bergh, P. Van den; Van Duppen, P.; Sonoda, T.
2010-01-15
In-gas-cell laser spectroscopy of the isotopes {sup 57,58,59,63,65}Cu has been performed at the LISOL facility using the 244.164-nm optical transition from the atomic ground state of copper. A detailed discussion on the hyperfine structure of {sup 63}Cu is presented. The magnetic dipole moments of the isotopes {sup 57,58,59,65}Cu are extracted based on that of {sup 63}Cu. The new value mu=+0.479(13)mu{sub N} is proposed for {sup 58}Cu, consistent with that of a pip{sub 3/2} x nup{sub 3/2} ground-state configuration. Spin assignments for the radioactive isotopes {sup 57,58,59}Cu are confirmed. The isotope shifts between the different isotopes are also given and discussed.
On the possibility of observing variations of the positron magnetic moment in crystals
Tikhomirov, V.V.
1994-12-01
An analysis of the interaction of e{sup {+-}} with a crossed field revealed that the anomalous magnetic moment {mu}{prime} must differ considerably from its Schwinger value for a field strength E, H {approx} H{sub 0} = m{sup 2}c{sup 3}/e{h_bar} = 4.41{times}10{sup 13}G in the intrinsic reference frame. Such a crossed-field strength can be attained in the intrinsic reference frame of e{sup {+-}} that move along the crystallographic axes. This is due to the fact that the field strength E along the axes is {approx} Z{times}10{sup 10}V/cm (Z is the atomic number of the crystal material), while the field strength E{prime}{approx_equal}H{prime}{approx_equal}{gamma}E in the intrinsic system of e{sup {+-}} that have an energy En {approx} 50 GeV is larger than E by a factor of {gamma} = En/m {approx} 10{sup 5}. The effect of spin rotation in bent crystals can be used to observe the variation of {mu}{prime} in a high-intensity crystal field.
Probing the magnetic moment of FePt micromagnets prepared by focused ion beam milling
Overweg, H. C.; Haan, A. M. J. den; Eerkens, H. J.; Bossoni, L.; Oosterkamp, T. H.; Alkemade, P. F. A.; La Rooij, A. L.; Spreeuw, R. J. C.
2015-08-17
We investigate the degradation of the magnetic moment of a 300 nm thick FePt film induced by Focused Ion Beam (FIB) milling. A 1 μm × 8 μm rod is milled out of a film by a FIB process and is attached to a cantilever by electron beam induced deposition. Its magnetic moment is determined by frequency-shift cantilever magnetometry. We find that the magnetic moment of the rod is μ = 1.1 ± 0.1 × 10{sup −12} Am{sup 2}, which implies that 70% of the magnetic moment is preserved during the FIB milling process. This result has important implications for atom trapping and magnetic resonance force microscopy, which are addressed in this paper.
Anomalous Hall effect in magnetic disordered alloys: Effects of spin orbital coupling
Ma, L.; Gao, W. B.; Zhou, S. M.; Shi, Z.; He, P.; Miao, J.; Jiang, Y.
2013-12-28
For disordered ternary Fe{sub 0.5}(Pd{sub 1−x}Pt{sub x}){sub 0.5} alloy films, the anomalous Hall effect obeys the conventional scaling law ρ{sub AH}=aρ{sub xx}+bρ{sub xx}{sup 2} with the longitudinal resistivity ρ{sub xx} and anomalous Hall resistivity ρ{sub AH}. Contributed by the intrinsic term and the extrinsic side-jump one, the scattering-independent anomalous Hall conductivity b increases with increasing Pt/Pd concentration. In contrast, the skew scattering parameter a is mainly influenced by the residual resistivity. The present results will facilitate the theoretical studies of the anomalous Hall effect in magnetic disordered alloys.
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.
Kapitza problem for the magnetic moments of synthetic antiferromagnetic systems
Dzhezherya, Yu. I.; Demishev, K. O.; Korenivskii, V. N.
2012-08-15
The dynamics of magnetization in synthetic antiferromagnetic systems with the magnetic dipole coupling in a rapidly oscillating field has been examined. It has been revealed that the system can behave similar to the Kapitza pendulum. It has been shown that an alternating magnetic field can be efficiently used to control the magnetic state of a cell of a synthetic antiferromagnet. Analytical relations have been obtained between the parameters of such an antiferromagnet and an external magnetic field at which certain quasistationary states are implemented.
Magnetic Moment Enhancement for Mn7 Cluster on Graphene (Journal...
Office of Scientific and Technical Information (OSTI)
Detail electron transfer and bonding analysis have been carried out to investigate the origin of the magnetic enhancement. Authors: Liu, Xiaojie 1 ; Wang, Cai-Zhuang 1 ; Lin,...
Magnetic-Compton-scattering study of spin moments in UFe{sub 2}
Lawson, P.K.; Cooper, M.J.; Dixon, M.A.; Timms, D.N.; Zukowski, E.; Itoh, F.; Sakurai, H.
1997-08-01
Spin moments were derived from the magnetic-Compton profile of UFe{sub 2}, which was measured using 59.38-keV circularly polarized synchrotron radiation from the Accumulation Ring Source at KEK, Japan. Although the net moment on the uranium site is no more than a tenth of a Bohr magneton, the individual spin and orbital moments, which are coupled antiparallel, are much larger and it is the spin moment that can be determined in magnetic-Compton scattering. The data have been analyzed in terms of the U 5f, Fe 3d and delocalized spin moments. The observed uranium-5f spin moment is less than half (i.e., {lt}0.25{mu}{sub B}) and the diffuse spin moment more than double (i.e., {gt}0.20{mu}{sub B}) those predicted from theory. These values compare favorably with those deduced from neutron measurements of the total magnetization. {copyright} {ital 1997} {ital The American Physical Society}
Quantum aspects of a moving magnetic quadrupole moment interacting with an electric field
Fonseca, I. C.; Bakke, K.
2015-06-15
The quantum dynamics of a moving particle with a magnetic quadrupole moment that interacts with electric and magnetic fields is introduced. By dealing with the interaction between an electric field and the magnetic quadrupole moment, it is shown that an analogue of the Coulomb potential can be generated and bound state solutions can be obtained. Besides, the influence of the Coulomb-type potential on the harmonic oscillator is investigated, where bound state solutions to both repulsive and attractive Coulomb-type potentials are achieved and the arising of a quantum effect characterized by the dependence of the harmonic oscillator frequency on the quantum numbers of the system is discussed.
First observation of magnetic moment precession of channeled particles in bent crystals
Chen, D.; Albuquerque, I.F.; Baublis, V.V.; Bondar, N.F.; Carrigan, R.A. Jr.; Cooper, P.S.; Lisheng, D.; Denisov, A.S.; Dobrovolsky, A.V.; Dubbs, T.; Endler, A.M.F.; Escobar, C.O.; Foucher, M.; Golovtsov, V.L.; Goritchev, P.A.; Gottschalk, H.; Gouffon, P.; Grachev, V.T.; Khanzadeev, A.V.; Kubantsev, M.A.; Kuropatkin, N.P.; Lach, J.; Lang Pengfei; Lebedenko, V.N.; Li Chengze; Li Yunshan; Mahon, J.R.P.; McCliment, E.; Morelos, A.; Newsom, C.; Pommot Maia, M.C.; Samsonov, V.M.; Schegelsky, V.A.; Shi Huanzhang; Smith, V.J.; Sun, C.R.; Tang Fukun; Terentyev, N.K.; Timm, S.; Tkatch, I.I.; Uvarov, L.N.; Vorobyov, A.A.; Yan Jie; Zhao Wenheng; Zheng Shuchen; Zhong Yuanyuan Institute of High Energy Physics, Beijing H. H. Wills Physics Laboratory, University of Bristol Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 Fermi National Accelerator Laboratory, Batavia, Illinois 60510
1992-12-07
Spin precession of channeled particles in bent crystals has been observed for the first time. Polarized [Sigma][sup +] were channeled using bent Si crystals. These crystals provided an effective magnetic field of 45 T which resulted in a measured spin precession of 60[plus minus]17[degree]. This agrees with the prediction of 62[plus minus]2[degree] using the world average of [Sigma][sup +] magnetic moment measurements. This new technique gives a [Sigma][sup +] magnetic moment of (2.40[plus minus]0.46[plus minus]0.40)[mu][sub [ital N
Phase formation, thermal stability and magnetic moment of cobalt nitride thin films
Gupta, Rachana; Pandey, Nidhi; Tayal, Akhil; Gupta, Mukul E-mail: dr.mukul.gupta@gmail.com
2015-09-15
Cobalt nitride (Co-N) thin films prepared using a reactive magnetron sputtering process are studied in this work. During the thin film deposition process, the relative nitrogen gas flow (R{sub N{sub 2}}) was varied. As R{sub N{sub 2}} increases, Co(N), Co{sub 4}N, Co{sub 3}N and CoN phases are formed. An incremental increase in R{sub N{sub 2}}, after emergence of Co{sub 4}N phase at R{sub N{sub 2}} = 10%, results in a linear increase of the lattice constant (a) of Co{sub 4}N. For R{sub N{sub 2}} = 30%, a maximizes and becomes comparable to its theoretical value. An expansion in a of Co{sub 4}N, results in an enhancement of the magnetic moment, to the extent that it becomes even larger than pure Co. Such larger than pure metal magnetic moment for tetra-metal nitrides (M{sub 4}N) have been theoretically predicted. Incorporation of N atoms in M{sub 4}N configuration results in an expansion of a (relative to pure metal) and enhances the itinerary of conduction band electrons leading to larger than pure metal magnetic moment for M{sub 4}N compounds. Though a higher (than pure Fe) magnetic moment for Fe{sub 4}N thin films has been evidenced experimentally, higher (than pure Co) magnetic moment is evidenced in this work.
The measurement of the magnetic moment of sigma plus using channeling in bent crystals
Chen, D.
1992-01-01
The measurement of baryon magnetic moments has played an important role in determining the inner structures of baryons and constraining the quark models. The magnetic moments of the spin one-half baryons have been measured with good accuracy. The measurement of the magnetic moment of charm and beauty baryons is a challenge to experimental physics because their life-times are a factor of 1000 shorter than conventional hyperons. A new technique for measuring the magnetic moment of short-lived positively charged particles by using channeling in bent crystals has been tested in Fermilab Proton Center by using a polarized hyperon beam, specifically a [Sigma][sup +] beam. Two 4.5 cm long silicon crystals were bent by 1.6 mrad. There are eight implanted detectors on the surface of each crystal. These detectors are designed to measure the energy loss of those particles which pass through the crystal, and therefore allow selection of channeling particles. The bent crystal can provide to a relativistic channeling particle a very strong effective magnetic field. Under such a field, the author observed spin precession of the channeled [Sigma][sup +] by an angle of the order of one radian. By measuring this precession angle, the value was found for the magnetic moment of the [Sigma][sup +], 2.40 [+-] 0.46 [+-] 0.40 [mu][sub N], the uncertainties being statistical and systematical, respectively. This value is consistent with the world average value of 2.42 [+-] 0.05 [mu][sub N]. This new technique may be applied to measure the magnetic moments of short-lived positively charged particle such as [Lambda][sup +][sub c] in the future.
Prediction of magnetic moment collapse in ZrFe{sub 2} under hydrostatic pressure
Zhang, Wenxu; Zhang, Wanli
2015-04-28
Electronic structure and magnetic properties of ZrFe{sub 2} in the cubic Laves phase are investigated by calculations based on density functional theory. The magnetic moment decreases with the increase of the hydrostatic pressure in an unusual way: Two-step magnetic collapse is predicted. The first one is a continuous change from 1.53??{sub B}/Fe to 0.63??{sub B}/Fe at about 3.6?GPa, and the other is from 0.25??{sub B}/Fe to the nonmagnetic state at about 15?GPa in a first order manner under the local spin density approximation of the exchange correlation potential. A metastable state with intermediate spin moment about 0.15??{sub B}/Fe may exist before that. We understand this process by the changes of density of states during it. The magnetic moment decreases under the pressure in the vicinity of the experimental lattice constant with dlnm/dp=?0.038 GPa{sup ?1}. The spontaneous volume magnetostriction is 3.6%, which is huge enough to find potential applications in magnetostriction actuators and sensors. We suggest that the Invar effect of this compound may be understood when considering the magnetic moment variation according to the magnetostrictive model of Invar.
Magnetic moments of vector, axial, and tensor mesons in lattice QCD
Lee, Frank X.; Moerschbacher, Scott; Wilcox, Walter
2008-11-01
We present a calculation of magnetic moments for selected spin-1 mesons using the techniques of lattice QCD. This is carried out by introducing a progressively small static magnetic field on the lattice and measuring the linear response of a hadron's mass shift. The calculations are done on 24{sup 4} quenched lattices using standard Wilson actions, with {beta}=6.0 and pion mass down to 500 MeV. The results are compared to those from the form factor method.
Electromagnetic Currents and Magnetic Moments in $\\chi$EFT
Saori Pastore, Luca Girlanda, Rocco Schiavilla, Michele Viviani, Robert Wiringa
2009-09-01
A two-nucleon potential and consistent electromagnetic currents are derived in chiral effective field theory ($\\chi$EFT) at, respectively, $Q^{\\, 2}$ (or N$^2$LO) and $e\\, Q$ (or N$^3$LO), where $Q$ generically denotes the low-momentum scale and $e$ is the electric charge. Dimensional regularization is used to renormalize the pion-loop corrections. A simple expression is derived for the magnetic dipole ($M1$) operator associated with pion loops, consisting of two terms, one of which is determined, uniquely, by the isospin-dependent part of the two-pion-exchange potential. This decomposition is also carried out for the $M1$ operator arising from contact currents, in which the unique term is determined by the contact potential. Finally, the low-energy constants (LEC's) entering the N$^2$LO potential are fixed by fits to the $np$ S- and P-wave phase shifts up to 100 MeV lab energies. Three additional LEC's are needed to completely specify the $M1$ operator at N$^3$L
Local-moment magnetism in superconducting FeTe0.35Se0.65 as seen...
Office of Scientific and Technical Information (OSTI)
Local-moment magnetism in superconducting FeTe0.35Se0.65 as seen via inelastic neutron scattering Prev Next Title: Local-moment magnetism in superconducting FeTe0.35Se0.65 as ...
Magnetic structure of Yb2Pt2Pb: Ising moments on the Shastry-Sutherland lattice
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Miiller, W.; Zaliznyak, I.; Wu, L. S.; Kim, M. S.; Orvis, T.; Simonson, J. W.; Gamza, M.; McNally, D. M.; Nelson, C. S.; Ehlers, G.; et al
2016-03-22
Neutron diffraction measurements were carried out on single crystals and powders of Yb2Pt2Pb, where Yb moments form two interpenetrating planar sublattices of orthogonal dimers, a geometry known as Shastry-Sutherland lattice, and are stacked along the c axis in a ladder geometry. Yb2Pt2Pb orders antiferromagnetically at TN=2.07K, and the magnetic structure determined from these measurements features the interleaving of two orthogonal sublattices into a 5×5×1 magnetic supercell that is based on stripes with moments perpendicular to the dimer bonds, which are along (110) and (–110). Magnetic fields applied along (110) or (–110) suppress the antiferromagnetic peaks from an individual sublattice, butmore » leave the orthogonal sublattice unaffected, evidence for the Ising character of the Yb moments in Yb2Pt2Pb that is supported by point charge calculations. Furthermore, specific heat, magnetic susceptibility, and electrical resistivity measurements concur with neutron elastic scattering results that the longitudinal critical fluctuations are gapped with ΔE≃0.07meV.« less
Magnetism of j = 1/2 moments on the fcc lattice in double perovskite Mott insulators
Aczel, Adam A [ORNL; Cook, Ashley [University of Toronto, Canada; Matern, Stephanie [University of Cologne, Germany; Hickey, Ciaran [University of Toronto, Canada; Paramekanti, Arun [University of Toronto, Canada
2015-01-01
Motivated by experiments on La2ZnIrO6 and La2MgIrO6, we study the magnetism of spin-orbit coupled jeff = 1/2 iridium moments on the three-dimensional geometrically-frustrated face-centered cubic lattice. The symmetry-allowed nearest-neighbor interaction includes Heisenberg, Kitaev, and symmetric off-diagonal exchange. Using Luttinger-Tisza and Monte Carlo simulations, we find a rich variety of orders, including collinear A-type antiferromagnetism, collinear stripe order with moments along the {111}-direction, and incommensurate non-coplanar spirals, and determine their magnetic ordering transition temperatures. We argue that thermodynamic data on these iridates underscore the presence of a dominant Kitaev exchange, and suggest a possible resolution to the puzzle of why La2ZnIrO6, but not La2MgIrO6, exhibits 'weak' ferromagnetism.
Itinerancy enhanced quantum fluctuation of magnetic moments in iron-based superconductors
Tam, Yu -T.; Ku, W.; Yao, D. -X.
2015-09-10
We investigate the influence of itinerant carriers on dynamics and fluctuation of local moments in Fe-based superconductors, via linear spin-wave analysis of a spin-fermion model containing both itinerant and local degrees of freedom. Surprisingly against the common lore, instead of enhancing the (π,0) order, itinerant carriers with well nested Fermi surfaces is found to induce significant amount of spatial and temporal quantum fluctuation that leads to the observed small ordered moment. Interestingly, the underlying mechanism is shown to be intra-pocket nesting-associated long-range coupling, rather than the previously believed ferromagnetic double-exchange effect. This challenges the validity of ferromagnetically compensated first-neighbor coupling reported from short-range fitting to the experimental dispersion, which turns out to result instead from the ferro-orbital order that is also found instrumental in stabilizing the magnetic order.
Itinerancy enhanced quantum fluctuation of magnetic moments in iron-based superconductors
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Tam, Yu -T.; Ku, W.; Yao, D. -X.
2015-09-10
We investigate the influence of itinerant carriers on dynamics and fluctuation of local moments in Fe-based superconductors, via linear spin-wave analysis of a spin-fermion model containing both itinerant and local degrees of freedom. Surprisingly against the common lore, instead of enhancing the (π,0) order, itinerant carriers with well nested Fermi surfaces is found to induce significant amount of spatial and temporal quantum fluctuation that leads to the observed small ordered moment. Interestingly, the underlying mechanism is shown to be intra-pocket nesting-associated long-range coupling, rather than the previously believed ferromagnetic double-exchange effect. This challenges the validity of ferromagnetically compensated first-neighbor couplingmore » reported from short-range fitting to the experimental dispersion, which turns out to result instead from the ferro-orbital order that is also found instrumental in stabilizing the magnetic order.« less
Atomic moments in Mn{sub 2}CoAl thin films analyzed by X-ray magnetic circular dichroism
Jamer, M. E.; Assaf, B. A.; Heiman, D.; Sterbinsky, G. E.; Arena, D. A.
2014-12-07
Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The magnetic properties of Mn{sub 2}CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the atomic-specific magnetic moments of Mn and Co atoms measured through X-ray magnetic circular dichroism as a function of annealing and the consequent structural ordering. The results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value.
Atomic moments in Mn2CoAl thin films analyzed by X-ray magnetic circular dichroism
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Jamer, M. E.; Assaf, B. A.; Sterbinsky, G. E.; Arena, D. A.; Heiman, D.
2014-12-05
Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The magnetic properties of Mn2CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the atomic-specific magnetic moments of Mn and Co atoms measured through X-ray magnetic circular dichroism as a function of annealing and the consequent structural ordering. Results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value.
Multiferroicity and spiral magnetism in FeVO{sub 4} with quenched Fe orbital moments
Daoud-Aladine, A.; Chapon, L. C.; Kundys, B.; Martin, C.; Simon, C.; Radaelli, P. G.; Brown, P. J.
2009-12-01
FeVO{sub 4} has been studied by heat capacity, magnetic susceptibility, electric polarization and single-crystal neutron-diffraction experiments. The triclinic crystal structure is made of S-shaped clusters of six Fe{sup 3+} ions, linked by VO{sub 4}{sup 3-} groups. Two long-range magnetic ordering transitions occur at T{sub N1}=22 K and T{sub N2}=15 K. Both magnetic structures are incommensurate and below T{sub N2}, FeVO{sub 4} becomes weakly ferroelectric coincidentally with the loss of the collinearity of the magnetic structure in a very similar fashion than in the classical TbMnO{sub 3} multiferroic material. However we argue that the symmetry considerations and the mechanisms invoked to explain these properties in TbMnO{sub 3} do not straightforwardly apply to FeVO{sub 4}. First, the magnetic structures, even the collinear structure, are all acentric so that ferroelectricity in FeVO{sub 4} is not correlated with the fact magnetic ordering is breaking inversion symmetry. Regarding the mechanism, FeVO{sub 4} has quenched orbital moments that questions the exact role of the spin-orbit interactions.
Using baryon octet magnetic moments and masses to fix the pion cloud contribution
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Franz L. Gross; Ramalho, Gilberto T. F.; Tsushima, Kazuo
2010-05-12
In this study, using SU(3) symmetry to constrain themore » $$\\pi BB'$$ couplings, assuming SU(3) breaking comes only from one-loop pion cloud contributions, and using the the covariant spectator theory to describe the photon coupling to the quark core, we show how the experimental masses and magnetic moments of the baryon octet can be used to set a model independent constraint on the strength of the pion cloud contributions to the octet, and hence the nucleon, form factors at $Q^2=0$.« less
Wang, Liang Germaschewski, K.; Hakim, Ammar H.; Bhattacharjee, A.
2015-01-15
We introduce an extensible multi-fluid moment model in the context of collisionless magnetic reconnection. This model evolves full Maxwell equations and simultaneously moments of the Vlasov-Maxwell equation for each species in the plasma. Effects like electron inertia and pressure gradient are self-consistently embedded in the resulting multi-fluid moment equations, without the need to explicitly solving a generalized Ohm's law. Two limits of the multi-fluid moment model are discussed, namely, the five-moment limit that evolves a scalar pressures for each species and the ten-moment limit that evolves the full anisotropic, non-gyrotropic pressure tensor for each species. We first demonstrate analytically and numerically that the five-moment model reduces to the widely used Hall magnetohydrodynamics (Hall MHD) model under the assumptions of vanishing electron inertia, infinite speed of light, and quasi-neutrality. Then, we compare ten-moment and fully kinetic particle-in-cell (PIC) simulations of a large scale Harris sheet reconnection problem, where the ten-moment equations are closed with a local linear collisionless approximation for the heat flux. The ten-moment simulation gives reasonable agreement with the PIC results regarding the structures and magnitudes of the electron flows, the polarities and magnitudes of elements of the electron pressure tensor, and the decomposition of the generalized Ohm's law. Possible ways to improve the simple local closure towards a nonlocal fully three-dimensional closure are also discussed.
Magnetic order in the induced magnetic moment system Pr_{3}In
Fanelli, V. R.; Christianson, Andrew D; Jaime, M.; Thompson, J. D.; Lawrence, J. M.; Suzuki, H. S.
2008-01-01
Pr3In is a single ground state compound which exhibits antiferromagnetic order below 11.4 K due to the exchange induced admixture of crystalline electric field levels. Additional information regarding the complex magnetic behavior of this compound can be gained through application of magnetic fields. We report specific heat and magnetocaloric effect measurements to 15 T and magnetization measurements to 44 T on single crystal samples of Pr3In. A new magnetic phase is revealed above 1.9 T and below 11.4 K.
Covariant Spectator Theory of np scattering: Deuteron magnetic moment and form factors
Gross, Franz L.
2014-06-01
The deuteron magnetic moment is calculated using two model wave functions obtained from 2007 high precision fits to $np$ scattering data. Included in the calculation are a new class of isoscalar $np$ interaction currents which are automatically generated by the nuclear force model used in these fits. After normalizing the wave functions, nearly identical predictions are obtained: model WJC-1, with larger relativistic P-state components, gives 0.863(2), while model WJC-2 with very small $P$-state components gives 0.864(2) These are about 1\\% larger than the measured value of the moment, 0.857 n.m., giving a new prediction for the size of the $\\rho\\pi\\gamma$ exchange, and other purely transverse interaction currents that are largely unconstrained by the nuclear dynamics. The physical significance of these results is discussed, and general formulae for the deuteron form factors, expressed in terms of deuteron wave functions and a new class of interaction current wave functions, are given.
The spin and orbital contributions to the total magnetic moments of free Fe, Co, and Ni clusters
Meyer, Jennifer; Tombers, Matthias; Wüllen, Christoph van; Niedner-Schatteburg, Gereon; Peredkov, Sergey; Eberhardt, Wolfgang; Neeb, Matthias; Palutke, Steffen; Martins, Michael; Wurth, Wilfried
2015-09-14
We present size dependent spin and orbital magnetic moments of cobalt (Co{sub n}{sup +}, 8 ≤ n ≤ 22), iron (Fe{sub n}{sup +}, 7 ≤ n ≤ 17), and nickel cluster (Ni{sub n}{sup +}, 7 ≤ n ≤ 17) cations as obtained by X-ray magnetic circular dichroism (XMCD) spectroscopy of isolated clusters in the gas phase. The spin and orbital magnetic moments range between the corresponding atomic and bulk values in all three cases. We compare our findings to previous XMCD data, Stern-Gerlach data, and computational results. We discuss the application of scaling laws to the size dependent evolution of the spin and orbital magnetic moments per atom in the clusters. We find a spin scaling law “per cluster diameter,” ∼n{sup −1/3}, that interpolates between known atomic and bulk values. In remarkable contrast, the orbital moments do likewise only if the atomic asymptote is exempt. A concept of “primary” and “secondary” (induced) orbital moments is invoked for interpretation.
Using magnetic moments to study the nuclear structure of I{>=} 2 states
Torres, D. A.
2013-05-06
The experimental study of magnetic moments for nuclear states near the ground state, I{>=} 2, provides a powerful tool to test nuclear structure models. Traditionally, the use of Coulomb excitation reactions have been utilized to study low spin states, mostly I= 2. The use of alternative reaction channels, such as {alpha} transfer, for the production of radioactive species that, otherwise, will be only produced in future radioactive beam facilities has proved to be an alternative to measure not only excited states with I > 2, but to populate and study long-live radioactive nuclei. This contribution will present the experimental tools and challenges for the use of the transient field technique for the measurement of g factors in nuclear states with I{>=} 2, using Coulomb excitation and {alpha}-transfer reactions. Recent examples of experimental results near the N= 50 shell closure, and the experimental challenges for future implementations with radioactive beams, will be discussed.
Weak hybridization and isolated localized magnetic moments in the compounds CeT2Cd20 (T = Ni, Pd)
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
White, B. D.; Yazici, D.; Ho, P. -C.; Kanchanavatee, N.; Pouse, N.; Fang, Y.; Breindel, A. J.; Friedman, A. J.; Maple, M. B.
2015-07-20
Here, we report the physical properties of single crystals of the compounds CeT2Cd20 (T = Ni, Pd) that were grown in a molten Cd flux. Large separations of ~6.7- 6.8 Å between Ce ions favor the localized magnetic moments that are observed in measurements of the magnetization. The strength of the Ruderman-Kittel-Kasuya- Yosida magnetic exchange interaction between the localized moments is severely limited by the large Ce-Ce separations and by weak hybridization between localized Ce 4f and itinerant electron states. Measurements of electrical resistivity performed down to 0.138 K were unable to observe evidence for the emergence of magnetic order;more » however, magnetically-ordered ground states with very low transition temperatures are still expected in these compounds despite the isolated nature of the localized magnetic moments. Such a fragile magnetic order could be highly susceptible to tuning via applied pressure, but evidence for the emergence of magnetic order has not been observed so far in our measurements up to 2.5 GPa.« less
Flambaum, V.V.; Tedesco, A.F.
2006-05-15
We calculate the dependence of the nuclear magnetic moments on the quark masses, including the spin-spin interaction effects, and obtain limits on the variation of the fine structure constant {alpha} and (m{sub q}/{lambda}{sub QCD}) using recent atomic clock experiments examining hyperfine transitions in H, Rb, Cs, Yb{sup +}, and Hg{sup +} and the optical transition in H, Hg{sup +}, and Yb{sup +}.
Magnetic dipole moments of {sup 58}Cu and {sup 59}Cu by in-source laser spectroscopy
Stone, N. J.; Koester, U.; Stone, J. Rikovska; Fedorov, D. V.; Fedoseyev, V. N.; Flanagan, K. T.; Hass, M.; Lakshmi, S.
2008-06-15
Online measurements of the magnetic dipole moments and isotope shifts of {sup 58}Cu and {sup 59}Cu by the in-source laser spectroscopy method are reported. The results for the magnetic moments are {mu} ({sup 58}Cu) =+0.52(8) {mu}{sub N},{mu}({sup 59}Cu) =+1.84(3) {mu}{sub N} and for the isotope shifts {delta}{nu}{sup 59,65}=1.72(22) GHz and {delta}{nu}{sup 58,65}=1.99(30) GHz in the transition from the 3d{sup 10}4s {sup 2}S{sub 1/2} ground state to the 3d{sup 10}4p {sup 2}P{sub 1/2} state in Cu I. The magnetic moment of {sup 58}Cu is discussed in the context of the strength of the subshell closure at {sup 56}Ni, additivity rules and large-scale shell model calculations.
Duong, Le Quy; Das, Tanmoy; Feng, Y. P.; Lin, Hsin
2015-05-07
We study the evolution of quantum anomalous Hall (QAH) effect for a Z{sub 2} topological insulator (TI) thin films in a proximity induced magnetic phase by a realistic layered k·p model with interlayer coupling. We examine three different magnetic configurations in which ferromagnetic (FM) layer(s) is added either from one side (FM-TI), from both sides (FM-TI-FM), or homogeneously distributed (magnetically doped) in a TI slab. We map out the thickness-dependent topological phase diagram under various experimental conditions. The critical magnetic exchange energy for the emergence of QAH effect in the latter two cases decreases monotonically with increasing number of quintuple layers (QLs), while it becomes surprisingly independent of the film thickness in the former case. The gap size of the emergent QAH insulator depends on the non-magnetic “parent” gap of the TI thin film and is tuned by the FM exchange energy, opening a versatile possibility to achieve room-temperature QAH insulator in various topological nanomaterials. Finally, we find that the emergent spin-texture in the QAH effect is very unconventional, non-“hedgehog” type; and it exhibits a chiral out-of-plane spin-flip texture within the same valence band which is reminiscent of dynamical “skyrmion” pattern, except our results are in the momentum space.
Saari, M. M. Sakai, K.; Kiwa, T.; Tsukada, K.; Sasayama, T.; Yoshida, T.
2015-05-07
We developed a highly sensitive AC/DC magnetometer using a high-temperature superconductor superconducting quantum interference device for the evaluation of magnetic nanoparticles in solutions. Using the developed system, we investigated the distribution of magnetic moments of iron oxide multi-core particles of 100 nm at various iron concentrations that are lower than 96 μg/ml by analyzing the measured magnetization curves. Singular value decomposition and non-regularized non-negative least-squares methods were used during the reconstruction of the distribution. Similar distributions were obtained for all concentrations, and the iron concentration could be determined from the measured magnetization curves. The measured harmonics upon the excitation of AC and DC magnetic fields curves agreed well with the harmonics simulated based on the reconstructed magnetization curves, implying that the magnetization curves of magnetic nanoparticles were successfully obtained as we will show in the article. We compared the magnetization curves between multi-core particles of 100 nm and 130 nm, composed of 12-nm iron oxide nanoparticles. A distinctive magnetic property between the 100 nm and 130 nm particles in low-concentration solutions was successfully characterized. The distribution characteristic of magnetic moments suggests that the net magnetic moment in a multi-core particle is affected by the size of the magnetic cores and their degree of aggregation. Exploration of magnetic properties with high sensitivity can be expected using the developed system.
Atomic moments in Mn_{2}CoAl thin films analyzed by X-ray magnetic circular dichroism
Jamer, M.; Sterbinsky, G.; Assaf, B.; Arena, D.; Heiman, D.
2014-12-05
Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The magnetic properties of Mn_{2}CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the atomic-specific magnetic moments of Mn and Co atoms measured through X-ray magnetic circular dichroism as a function of annealing and the consequent structural ordering. The results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value. (auth)
Atomic moments in Mn_{2}CoAl thin films analyzed by X-ray magnetic circular dichroism
Jamer, M. E.; Assaf, B. A.; Sterbinsky, G. E.; Arena, D. A.; Heiman, D.
2014-12-05
Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The magnetic properties of Mn_{2}CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the atomic-specific magnetic moments of Mn and Co atoms measured through X-ray magnetic circular dichroism as a function of annealing and the consequent structural ordering. Results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Oveshnikov, L. N.; Kulbachinskii, V. A.; Davydov, A. B.; Aronzon, B. A.; Rozhansky, I. V.; Averkiev, N. S.; Kugel, K. I.; Tripathi, V.
2015-11-24
In this study, the anomalous Hall effect (AHE) arises from the interplay of spin-orbit interactions and ferromagnetic order and is a potentially useful probe of electron spin polarization, especially in nanoscale systems where direct measurement is not feasible. While AHE is rather well-understood in metallic ferromagnets, much less is known about the relevance of different physical mechanisms governing AHE in insulators. As ferromagnetic insulators, but not metals, lend themselves to gatecontrol of electron spin polarization, understanding AHE in the insulating state is valuable from the point of view of spintronic applications. Among the mechanisms proposed in the literature for AHEmore » in insulators, the one related to a geometric (Berry) phase effect has been elusive in past studies. The recent discovery of quantized AHE in magnetically doped topological insulators - essentially a Berry phase effect - provides strong additional motivation to undertake more careful search for geometric phase effects in AHE in the magnetic semiconductors. Here we report our experiments on the temperature and magnetic field dependences of AHE in insulating, strongly-disordered two-dimensional Mn delta-doped semiconductor heterostructures in the hopping regime. In particular, it is shown that at sufficiently low temperatures, the mechanism of AHE related to the Berry phase is favoured.« less
Oveshnikov, L. N.; Kulbachinskii, V. A.; Davydov, A. B.; Aronzon, B. A.; Rozhansky, I. V.; Averkiev, N. S.; Kugel, K. I.; Tripathi, V.
2015-11-24
In this study, the anomalous Hall effect (AHE) arises from the interplay of spin-orbit interactions and ferromagnetic order and is a potentially useful probe of electron spin polarization, especially in nanoscale systems where direct measurement is not feasible. While AHE is rather well-understood in metallic ferromagnets, much less is known about the relevance of different physical mechanisms governing AHE in insulators. As ferromagnetic insulators, but not metals, lend themselves to gatecontrol of electron spin polarization, understanding AHE in the insulating state is valuable from the point of view of spintronic applications. Among the mechanisms proposed in the literature for AHE in insulators, the one related to a geometric (Berry) phase effect has been elusive in past studies. The recent discovery of quantized AHE in magnetically doped topological insulators - essentially a Berry phase effect - provides strong additional motivation to undertake more careful search for geometric phase effects in AHE in the magnetic semiconductors. Here we report our experiments on the temperature and magnetic field dependences of AHE in insulating, strongly-disordered two-dimensional Mn delta-doped semiconductor heterostructures in the hopping regime. In particular, it is shown that at sufficiently low temperatures, the mechanism of AHE related to the Berry phase is favoured.
Magnetic Dipole Moment of {sup 57,59}Cu Measured by In-Gas-Cell Laser Spectroscopy
Cocolios, T. E.; Andreyev, A. N.; Bastin, B.; Bree, N.; Buescher, J.; Elseviers, J.; Gentens, J.; Huyse, M.; Kudryavtsev, Yu.; Pauwels, D.; Van den Bergh, P.; Van Duppen, P.; Sonoda, T.
2009-09-04
For the first time, in-gas-cell laser spectroscopy study of the {sup 57,59,63,65}Cu isotopes has been performed using the 244.164 nm optical transition from the atomic ground state of copper. The nuclear magnetic dipole moments for {sup 57,59,65}Cu relative to that of {sup 63}Cu have been extracted. The new value for {sup 57}Cu of mu({sup 57}Cu)=+2.582(7)mu{sub N} is in strong disagreement with the previous literature value but in good agreement with recent theoretical and systematic predictions.
Thersleff, Thomas; Rusz, Jan; Rubino, Stefano; Hjörvarsson, Björgvin; Ito, Yasuo; J. Zaluzec, Nestor; Leifer, Klaus
2015-08-17
Understanding the ramifications of reduced crystalline symmetry on magnetic behavior is a critical step in improving our understanding of nanoscale and interfacial magnetism. However, investigations of such effects are often controversial largely due to the challenges inherent in directly correlating nanoscale stoichiometry and structure to magnetic behavior. Here, we describe how to use Transmission Electron Microscope (TEM) to obtain Electron Magnetic Circular Dichroism (EMCD) signals as a function of scattering angle to locally probe the magnetic behavior of thin oxide layers grown on an Fe (1 1 0) surface. Experiments and simulations both reveal a strong dependence of the magnetic orbital to spin ratio on its scattering vector in reciprocal space. We exploit this variation to extract the magnetic properties of the oxide cladding layer, showing that it locally may exhibit an enhanced orbital to spin moment ratio. This finding is supported here by both spatially and angularly resolved EMCD measurements, opening up the way for compelling investigations into how magnetic properties are affected by nanoscale features.
Efficiency enhancement of anomalous-Doppler electron cyclotron masers with tapered magnetic field
Xie, Chao-Ran; Hou, Zhi-Ling; Kong, Ling-Bao E-mail: pkliu@pku.edu.cn; Liu, Pu-Kun E-mail: pkliu@pku.edu.cn; Du, Chao-Hai; Jin, Hai-Bo
2014-02-15
The efficiency of slow-wave electron cyclotron masers (ECM) is usually low, thus limiting the practical applications. Here, a method of tapered magnetic field is introduced for the efficiency enhancement of the slow-wave ECM. The numerical calculations show that the tapered magnetic-field method can enhance the efficiency of slow-wave ECM significantly. The effect of beam electron velocity spread on the efficiency has also been studied. Although the velocity spread reduces the efficiency, a great enhancement of efficiency can still be obtained by the tapered magnetic field method.
Lim, J.; Fabbris, G.; Haskel, D.; Schilling, J. S.
2015-05-26
In previous studies the pressure dependence of the magnetic ordering temperature T_{o} of Dy was found to exhibit a sharp increase above its volume collapse pressure of 73 GPa, appearing to reach temperatures well above ambient at 157 GPa. In a search for a second such lanthanide, electrical resistivity measurements were carried out on neighboring Tb to 141 GPa over the temperature range 3.8 - 295 K. Below Tb’s volume collapse pressure of 53 GPa, the pressure dependence T_{o}(P) mirrors that of both Dy and Gd. However, at higher pressures T_{o}(P) for Tb becomes highly anomalous. This result, together with the very strong suppression of superconductivity by dilute Tb ions in Y, suggests that extreme pressure transports Tb into an unconventional magnetic state with an anomalously high magnetic ordering temperature.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Lim, J.; Fabbris, G.; Haskel, D.; Schilling, J. S.
2015-05-26
In previous studies the pressure dependence of the magnetic ordering temperature To of Dy was found to exhibit a sharp increase above its volume collapse pressure of 73 GPa, appearing to reach temperatures well above ambient at 157 GPa. In a search for a second such lanthanide, electrical resistivity measurements were carried out on neighboring Tb to 141 GPa over the temperature range 3.8 - 295 K. Below Tb’s volume collapse pressure of 53 GPa, the pressure dependence To(P) mirrors that of both Dy and Gd. However, at higher pressures To(P) for Tb becomes highly anomalous. This result, together withmore » the very strong suppression of superconductivity by dilute Tb ions in Y, suggests that extreme pressure transports Tb into an unconventional magnetic state with an anomalously high magnetic ordering temperature.« less
Lim, J.; Fabbris, G.; Haskel, D.; Schilling, J. S.
2015-05-26
In previous studies the pressure dependence of the magnetic ordering temperature T_{o} of Dy was found to exhibit a sharp increase above its volume collapse pressure of 73 GPa, appearing to reach temperatures well above ambient at 157 GPa. In a search for a second such lanthanide, electrical resistivity measurements were carried out on neighboring Tb to 141 GPa over the temperature range 3.8 - 295 K. Below Tbs volume collapse pressure of 53 GPa, the pressure dependence T_{o}(P) mirrors that of both Dy and Gd. However, at higher pressures T_{o}(P) for Tb becomes highly anomalous. This result, together with the very strong suppression of superconductivity by dilute Tb ions in Y, suggests that extreme pressure transports Tb into an unconventional magnetic state with an anomalously high magnetic ordering temperature.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Thersleff, Thomas; Rusz, Jan; Rubino, Stefano; Hjörvarsson, Björgvin; Ito, Yasuo; J. Zaluzec, Nestor; Leifer, Klaus
2015-08-17
Understanding the ramifications of reduced crystalline symmetry on magnetic behavior is a critical step in improving our understanding of nanoscale and interfacial magnetism. However, investigations of such effects are often controversial largely due to the challenges inherent in directly correlating nanoscale stoichiometry and structure to magnetic behavior. Here, we describe how to use Transmission Electron Microscope (TEM) to obtain Electron Magnetic Circular Dichroism (EMCD) signals as a function of scattering angle to locally probe the magnetic behavior of thin oxide layers grown on an Fe (1 1 0) surface. Experiments and simulations both reveal a strong dependence of the magneticmore » orbital to spin ratio on its scattering vector in reciprocal space. We exploit this variation to extract the magnetic properties of the oxide cladding layer, showing that it locally may exhibit an enhanced orbital to spin moment ratio. This finding is supported here by both spatially and angularly resolved EMCD measurements, opening up the way for compelling investigations into how magnetic properties are affected by nanoscale features.« less
Direct evidence of anomalous interfacial magnetization in metamagnetic Pd doped FeRh thin films
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Bennett, S. P.; Ambaye, H.; Lee, H.; LeClair, P.; Mankey, G. J.; Lauter, V.
2015-03-16
Palladium doped iron rhodium is a magnetic material of significant interest for it’s close to room temperature magnetostructural phase transition from antiferromagnetic (AF) to ferromagnetic (FM) ordering. Here we report on the peculiarities of the magnetization distribution in thin films of FeRh(Pd) probed by Polarized Neutron Reflectometry. Remarkably, we’ve found thin interfacial regions with strong magnetization that have unique thermomagnetic properties as compared to the rest of the system. These regions exist at the top and bottom interfaces of the films while the central regions behave similarly to the bulk with a clear AF-FM order transition. Further we explore themore » impact of an additional Pt interlayer introduced in the middle of the FeRh(Pd) film and reveal that it serves to replicate the strong interfacial magnetization found at the top and bottom interfaces. In conclusion, these results are of great value both in understanding the fundamental physics of such an order transition, and in considering FeRh(Pd) for magnetic media and spintronics applications.« less
Ram, Abhay K.; Dasgupta, Brahmananda; Krishnamurthy, V.; Mitra, Dhrubaditya
2014-07-15
The cosmic magnetic fields in regions of low plasma pressure and large currents, such as in interstellar space and gaseous nebulae, are force-free in the sense that the Lorentz force vanishes. The three-dimensional Arnold-Beltrami-Childress (ABC) field is an example of a force-free, helical magnetic field. In fluid dynamics, ABC flows are steady state solutions of the Euler equation. The ABC magnetic field lines exhibit a complex and varied structure that is a mix of regular and chaotic trajectories in phase space. The characteristic features of field line trajectories are illustrated through the phase space distribution of finite-distance and asymptotic-distance Lyapunov exponents. In regions of chaotic trajectories, an ensemble-averaged variance of the distance between field lines reveals anomalous diffusion—in fact, superdiffusion—of the field lines. The motion of charged particles in the force-free ABC magnetic fields is different from the flow of passive scalars in ABC flows. The particles do not necessarily follow the field lines and display a variety of dynamical behavior depending on their energy, and their initial pitch-angle. There is an overlap, in space, of the regions in which the field lines and the particle orbits are chaotic. The time evolution of an ensemble of particles, in such regions, can be divided into three categories. For short times, the motion of the particles is essentially ballistic; the ensemble-averaged, mean square displacement is approximately proportional to t{sup 2}, where t is the time of evolution. The intermediate time region is defined by a decay of the velocity autocorrelation function—this being a measure of the time after which the collective dynamics is independent of the initial conditions. For longer times, the particles undergo superdiffusion—the mean square displacement is proportional to t{sup α}, where α > 1, and is weakly dependent on the energy of the particles. These super-diffusive characteristics
White, B. D.; Yazici, D.; Ho, P. -C.; Kanchanavatee, N.; Pouse, N.; Fang, Y.; Breindel, A. J.; Friedman, A. J.; Maple, M. B.
2015-07-20
Here, we report the physical properties of single crystals of the compounds CeT_{2}Cd_{20} (T = Ni, Pd) that were grown in a molten Cd flux. Large separations of ~6.7- 6.8 Å between Ce ions favor the localized magnetic moments that are observed in measurements of the magnetization. The strength of the Ruderman-Kittel-Kasuya- Yosida magnetic exchange interaction between the localized moments is severely limited by the large Ce-Ce separations and by weak hybridization between localized Ce 4f and itinerant electron states. Measurements of electrical resistivity performed down to 0.138 K were unable to observe evidence for the emergence of magnetic order; however, magnetically-ordered ground states with very low transition temperatures are still expected in these compounds despite the isolated nature of the localized magnetic moments. Such a fragile magnetic order could be highly susceptible to tuning via applied pressure, but evidence for the emergence of magnetic order has not been observed so far in our measurements up to 2.5 GPa.
Anomalous Dynamical Line Shapes in a Quantum Magnet at Finite Temperature
Tennant D. A.; James A.; Lake, B.; Essler, F.H.L.; Notbohm, S.; Mikeska, H.-J.; Fielden, J.; Kogerler,, P.; Canfield, P.C.; Telling, M.T.F.
2012-01-04
The effect of thermal fluctuations on the dynamics of a gapped quantum magnet is studied using inelastic neutron scattering on copper nitrate, a model material for the spin-1/2, one-dimensional (1D) bond alternating Heisenberg chain. A large, highly deuterated, single-crystal sample of copper nitrate is produced using a solution growth method and measurements are made using the high-resolution backscattering spectrometer OSIRIS at the ISIS Facility. Theoretical calculations and numerical analysis are combined to interpret the physical origin of the thermal effects observed in the magnetic spectra. The primary observations are (1) a thermally induced central peak due to intraband scattering, which is similar to Villain scattering familiar from soliton systems in 1D, and (2) the one-magnon quasiparticle pole is seen to develop with temperature into an asymmetric continuum of scattering. We relate this asymmetric line broadening to a thermal strongly correlated state caused by hard-core constraints and quasiparticle interactions. These findings are a counter example to recent assertions of the universality of line broadening in 1D systems and are applicable to a broad range of quantum systems.
Anomalous magnetic structure and spin dynamics in magnetoelectric LiFePO_{4}
Toft-Petersen, Rasmus; Reehuis, Manfred; Jensen, Thomas B. S.; Andersen, Niels H.; Li, Jiying; Le, Manh Duc; Laver, Mark; Niedermayer, Christof; Klemke, Bastian; Lefmann, Kim; Vaknin, David
2015-07-06
We report significant details of the magnetic structure and spin dynamics of LiFePO_{4} obtained by single-crystal neutron scattering. Our results confirm a previously reported collinear rotation of the spins away from the principal b axis, and they determine that the rotation is toward the a axis. In addition, we find a significant spin-canting component along c. Furthermore, the possible causes of these components are discussed, and their significance for the magnetoelectric effect is analyzed. Inelastic neutron scattering along the three principal directions reveals a highly anisotropic hard plane consistent with earlier susceptibility measurements. While using a spin Hamiltonian, we show that the spin dimensionality is intermediate between XY- and Ising-like, with an easy b axis and a hard c axis. As a result, it is shown that both next-nearest neighbor exchange couplings in the bc plane are in competition with the strongest nearest neighbor coupling.
Anomalous magnetic structure and spin dynamics in magnetoelectric LiFePO4
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Toft-Petersen, Rasmus; Reehuis, Manfred; Jensen, Thomas B. S.; Andersen, Niels H.; Li, Jiying; Le, Manh Duc; Laver, Mark; Niedermayer, Christof; Klemke, Bastian; Lefmann, Kim; et al
2015-07-06
We report significant details of the magnetic structure and spin dynamics of LiFePO4 obtained by single-crystal neutron scattering. Our results confirm a previously reported collinear rotation of the spins away from the principal b axis, and they determine that the rotation is toward the a axis. In addition, we find a significant spin-canting component along c. Furthermore, the possible causes of these components are discussed, and their significance for the magnetoelectric effect is analyzed. Inelastic neutron scattering along the three principal directions reveals a highly anisotropic hard plane consistent with earlier susceptibility measurements. While using a spin Hamiltonian, we showmore » that the spin dimensionality is intermediate between XY- and Ising-like, with an easy b axis and a hard c axis. As a result, it is shown that both next-nearest neighbor exchange couplings in the bc plane are in competition with the strongest nearest neighbor coupling.« less
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Vilmercati, Paolo; Fedorov, Alexei; Bondino, Federica; Offi, Francesco; Panaccione, Giancarlo; Lacovig, Paolo; Simonelli, Laura; McGuire, Michael A.; Sefat, Athena S. M.; Mandrus, David; et al
2012-06-15
A direct and element-specific measurement of the local Fe spin moment has been provided by analyzing the Fe 3s core level photoemission spectra in the parent and optimally doped CeFeAsO₁₋xFx (x = 0, 0.11) and Sr(Fe₁₋xCox)2As2 (x = 0, 0.10) pnictides. The rapid time scales of the photoemission process allowed the detection of large local spin moments fluctuating on a 10⁻¹⁵ s time scale in the paramagnetic, antiferromagnetic, and superconducting phases, indicative of the occurrence of ubiquitous strong Hund's magnetic correlations. The magnitude of the spin moment is found to vary significantly among different families, 1.3μB in CeFeAsO and 2.1μBmore » in SrFe₂As₂. Surprisingly, the spin moment is found to decrease considerably in the optimally doped samples, 0.9μB in CeFeAsO₀.₈₉F₀.₁₁ and 1.3μB in Sr(Fe₀.₉Co₀.₁)₂As₂. The strong variation of the spin moment against doping and material type indicates that the spin moments and the motion of itinerant electrons are influenced reciprocally in a self-consistent fashion, reflecting the strong competition between the antiferromagnetic superexchange interaction among the spin moments and the kinetic energy gain of the itinerant electrons in the presence of a strong Hund's coupling. By describing the evolution of the magnetic correlations concomitant with the appearance of superconductivity, these results constitute a fundamental step toward attaining a correct description of the microscopic mechanisms shaping the electronic properties in the pnictides, including magnetism and high-temperature superconductivity.« less
Weyssow, B.
2004-03-15
A complete description of a system in equilibrium is provided by the Grand Canonical Distribution. But, systems are generally not in statistical equilibrium. We shall consider the case of an ideal gaz of charged particles. The linear theory of transport determines the 3 x 1 matrix of dissipative fluxes [circumflex]J{sub r} namely, the electric current and the electronic and ionic heat fluxes, in terms of a 3 x 1 matrix of thermodynamic forces [circumflex]X defined by the electric field and the gradient of the densities and temperatures. The components of the 3 x 3 matrix of tensors [circumflex]L{sub rs} of the linear flux-force relations [circumflex]J{sub r} [summation]{sub s=1}{sup 9}[circumflex]L{sub rs}[circumflex]X define the set of transport coefficients. They are evaluated for an ion-electron magnetized plasma in the framework of the statistical mechanics of charged particles starting from the Landau kinetic equation.
Electromagnetic currents and magnetic moments in chiral effective field theory ({chi}EFT)
Pastore, S.; Girlanda, L.; Schiavilla, R.; Viviani, M.; Wiringa, R. B.
2009-09-15
A two-nucleon potential and consistent electromagnetic currents are derived in chiral effective field theory ({chi}EFT) at, respectively, Q{sup 2} (or N{sup 2}LO) and eQ (or N{sup 3}LO), where Q generically denotes the low-momentum scale and e is the electric charge. Dimensional regularization is used to renormalize the pion-loop corrections. A simple expression is derived for the magnetic dipole (M1) operator associated with pion loops, consisting of two terms, one of which is determined, uniquely, by the isospin-dependent part of the two-pion-exchange potential. This decomposition is also carried out for the M1 operator arising from contact currents, in which the unique term is determined by the contact potential. Finally, the low-energy constants entering the N{sup 2}LO potential are fixed by fits to the np S- and P-wave phase shifts up to 100 MeV laboratory energies.
Evarts, Eric R.; Rippard, William H.; Pufall, Matthew R.; Heindl, Ranko
2014-05-26
In a small fraction of magnetic-tunnel-junction-based magnetic random-access memory devices with in-plane free layers, the write-error rates (WERs) are higher than expected on the basis of the macrospin or quasi-uniform magnetization reversal models. In devices with increased WERs, the product of effective resistance and area, tunneling magnetoresistance, and coercivity do not deviate from typical device properties. However, the field-swept, spin-torque, ferromagnetic resonance (FS-ST-FMR) spectra with an applied DC bias current deviate significantly for such devices. With a DC bias of 300 mV (producing 9.9 × 10{sup 6} A/cm{sup 2}) or greater, these anomalous devices show an increase in the fraction of the power present in FS-ST-FMR modes corresponding to higher-order excitations of the free-layer magnetization. As much as 70% of the power is contained in higher-order modes compared to ≈20% in typical devices. Additionally, a shift in the uniform-mode resonant field that is correlated with the magnitude of the WER anomaly is detected at DC biases greater than 300 mV. These differences in the anomalous devices indicate a change in the micromagnetic resonant mode structure at high applied bias.
Berryman, J. S.; Crawford, H. L.; Mantica, P. F.; Stoker, J. B.; Minamisono, K.; Grinyer, G. F.; Rogers, W. F.; Brown, B. A.; Towner, I. S.
2009-06-15
The nuclear magnetic moment of the ground state of {sup 55}Ni (I{sup {pi}}=3/2{sup -}, T{sub 1/2}=204 ms) has been deduced to be |{mu}({sup 55}Ni)|=(0.976{+-}0.026) {mu}{sub N} using the {beta}-ray detecting nuclear magnetic resonance technique. Results of a shell model calculation in the full fp shell model space with the GXPF1 interaction reproduce the experimental value. Together with the known magnetic moment of the mirror partner {sup 55}Co, the isoscalar spin expectation value was extracted as <{sigma}{sigma}{sub z}>=0.91{+-}0.07. The <{sigma}{sigma}{sub z}> shows a trend similar to that established in the sd shell. The present theoretical interpretations of both {mu}({sup 55}Ni) and <{sigma}{sigma}{sub z}> for the T=1/2, A=55 mirror partners support the softness of the {sup 56}Ni core.
Anomalous-viscosity current drive
Stix, T.H.; Ono, M.
1986-04-25
The present invention relates to a method and apparatus for maintaining a steady-state current for magnetically confining the plasma in a toroidal magnetic confinement device using anomalous viscosity current drive. A second aspect of this invention relates to an apparatus and method for the start-up of a magnetically confined toroidal plasma.
Ruiz-Zepeda, F.; Ma, C.; Bahena Uribe, D.; Cantu-Valle, J.; Wang, H.; Xu, Xing; Yacaman, M. J.; Ponce, A.; Chen, C.; Lorenz, B.; Jacobson, A. J.; Chu, P. C. W.
2014-01-14
A giant magnetoresistance effect (?46% at 20?K under 7?T) and anomalous magnetic properties were found in a highly epitaxial double perovskite LaBaCo{sub 2}O{sub 5.5+?} (LBCO) thin film on (001) MgO. Aberration-corrected Electron Microscopy and related analytical techniques were employed to understand the nature of these unusual physical properties. The as-grown film is epitaxial with the c-axis of the LBCO structure lying in the film plane and with an interface relationship given by (100){sub LBCO} || (001){sub MgO} and [001]{sub LBCO} || [100]{sub MgO} or [010]{sub MgO}. Orderly oxygen vacancies were observed by line profile electron energy loss spectroscopy and by atomic resolution imaging. Especially, oxygen vacancy and nanodomain structures were found to have a crucial effect on the electronic transport and magnetic properties.
Ito, K.; Lee, G. H.; Harada, K.; Suzuno, M.; Suemasu, T.; Takeda, Y.; Saitoh, Y.; Ye, M.; Kimura, A.; Akinaga, H.
2011-03-07
10-nm-thick {gamma}{sup '}-Fe{sub 4}N films were grown epitaxially on LaAlO{sub 3}(001) and MgO(001) substrates by molecular beam epitaxy using solid Fe and a radio-frequency NH{sub 3} plasma. The lattice mismatch of these substrates to {gamma}{sup '}-Fe{sub 4}N is 0% and 11%, respectively. Spin and orbital magnetic moments of these {gamma}{sup '}-Fe{sub 4}N epitaxial films were deduced by x-ray magnetic circular dichroism measurements at 300 K. The total magnetic moments are almost the same for the two substrates, that is, 2.44{+-}0.06 {mu}{sub B} and 2.47{+-}0.06 {mu}{sub B}, respectively. These values are very close to those predicted theoretically, and distinctively larger than that for {alpha}-Fe.
Hyodo, Kazushige Sakuma, Akimasa; Kota, Yohei
2014-05-07
We studied quantitative relationship between the intrinsic anomalous Hall conductivity (σ{sub xy}) and the uniaxial magnetic anisotropy constant (K{sub u}) of bct-Fe{sub 50}Co{sub 50} using first-principles calculation because these quantities originate from spin-orbit interaction. We found that the obtained σ{sub xy} and K{sub u} with changing the axial ratio c/a (1≤c/a≤√(2)) exhibit similar behavior mainly arising from the common band mixing of the minority-spin d{sub xy} and d{sub x{sup 2}−y{sup 2}} states near the Fermi level which is sensitive to c/a.
Fickian dispersion is anomalous
Cushman, John H.; O’Malley, Dan
2015-06-22
The thesis put forward here is that the occurrence of Fickian dispersion in geophysical settings is a rare event and consequently should be labeled as anomalous. What people classically call anomalous is really the norm. In a Lagrangian setting, a process with mean square displacement which is proportional to time is generally labeled as Fickian dispersion. With a number of counter examples we show why this definition is fraught with difficulty. In a related discussion, we show an infinite second moment does not necessarily imply the process is super dispersive. By employing a rigorous mathematical definition of Fickian dispersion we illustrate why it is so hard to find a Fickian process. We go on to employ a number of renormalization group approaches to classify non-Fickian dispersive behavior. Scaling laws for the probability density function for a dispersive process, the distribution for the first passage times, the mean first passage time, and the finite-size Lyapunov exponent are presented for fixed points of both deterministic and stochastic renormalization group operators. The fixed points of the renormalization group operators are p-self-similar processes. A generalized renormalization group operator is introduced whose fixed points form a set of generalized self-similar processes. Finally, power-law clocks are introduced to examine multi-scaling behavior. Several examples of these ideas are presented and discussed.
Fickian dispersion is anomalous
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Cushman, John H.; O’Malley, Dan
2015-06-22
The thesis put forward here is that the occurrence of Fickian dispersion in geophysical settings is a rare event and consequently should be labeled as anomalous. What people classically call anomalous is really the norm. In a Lagrangian setting, a process with mean square displacement which is proportional to time is generally labeled as Fickian dispersion. With a number of counter examples we show why this definition is fraught with difficulty. In a related discussion, we show an infinite second moment does not necessarily imply the process is super dispersive. By employing a rigorous mathematical definition of Fickian dispersion wemore » illustrate why it is so hard to find a Fickian process. We go on to employ a number of renormalization group approaches to classify non-Fickian dispersive behavior. Scaling laws for the probability density function for a dispersive process, the distribution for the first passage times, the mean first passage time, and the finite-size Lyapunov exponent are presented for fixed points of both deterministic and stochastic renormalization group operators. The fixed points of the renormalization group operators are p-self-similar processes. A generalized renormalization group operator is introduced whose fixed points form a set of generalized self-similar processes. Finally, power-law clocks are introduced to examine multi-scaling behavior. Several examples of these ideas are presented and discussed.« less
Gabrielse, Gerald [Harvard University, Cambridge, Massachusetts, United States
2009-09-01
Remarkably, the famous UW measurement of the electron magnetic moment has stood since 1987. With QED theory, this measurement has determined the accepted value of the fine structure constant. This colloquium is about a new Harvard measurement of these fundamental constants. The new measurement has an uncertainty that is about six times smaller, and it shifts the values by 1.7 standard deviations. One electron suspended in a Penning trap is used for the new measurement, like in the old measurement. What is different is that the lowest quantum levels of the spin and cyclotron motion are resolved, and the cyclotron as well as spin frequencies are determined using quantum jump spectroscopy. In addition, a 0.1 mK Penning trap that is also a cylindrical microwave cavity is used to control the radiation field, to suppress spontaneous emission by more than a factor of 100, to control cavity shifts, and to eliminate the blackbody photons that otherwise stimulate excitations from the cyclotron ground state. Finally, great signal-to-noise for one-quantum transitions is obtained using electronic feedback to realize the first one-particle self-excited oscillator. The new methods may also allow a million times improved measurement of the 500 times small antiproton magnetic moment.
Anomalous - viscosity current drive
Stix, Thomas H.; Ono, Masayuki
1988-01-01
An apparatus and method for maintaining a steady-state current in a toroidal magnetically confined plasma. An electric current is generated in an edge region at or near the outermost good magnetic surface of the toroidal plasma. The edge current is generated in a direction parallel to the flow of current in the main plasma and such that its current density is greater than the average density of the main plasma current. The current flow in the edge region is maintained in a direction parallel to the main current for a period of one or two of its characteristic decay times. Current from the edge region will penetrate radially into the plasma and augment the main plasma current through the mechanism of anomalous viscosity. In another aspect of the invention, current flow driven between a cathode and an anode is used to establish a start-up plasma current. The plasma-current channel is magnetically detached from the electrodes, leaving a plasma magnetically insulated from contact with any material obstructions including the cathode and anode.
The charmonium dissociation in an ''anomalous wind''
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Sadofyev, Andrey V.; Yin, Yi
2016-01-11
We study the charmonium dissociation in a strongly coupled chiral plasma in the presence of magnetic field and axial charge imbalance. This type of plasma carries "anomalous flow" induced by the chiral anomaly and exhibits novel transport phenomena such as chiral magnetic effect. We found that the "anomalous flow" would modify the charmonium color screening length by using the gauge/gravity correspondence. We derive an analytical expression quantifying the "anomalous flow" experienced by a charmonium for a large class of chiral plasma with a gravity dual. We elaborate on the similarity and it qualitative difference between anomalous effects on the charmoniummore » color screening length which are model-dependent and those on the heavy quark drag force which are fixed by the second law of thermodynamics. As a result, we speculate on the possible charmonium dissociation induced by the chiral anomaly in heavy ion collisions.« less
Huang, Zhaocong; Chen, Qian; Zhai, Ya E-mail: jlwang@seu.edu.cn; Wang, Jinlan E-mail: jlwang@seu.edu.cn; Xu, Yongbing; Wang, Baoping
2015-05-04
The magnetic and transport properties of half metallic Fe{sub 3}O{sub 4}, which are sensitive to the stoichiometry, are the key issue for applications in spintronics. An anomalous enlargement of the saturation magnetic moment is found in a relatively thick sample of epitaxial Fe{sub 3}O{sub 4} film by post-growth oxidation method. The investigation of the thickness dependence of magnetic moment suggests that the enhanced magnetism moment may come from the existence of oxygen vacancies. First-principles calculations reveal that with oxygen vacancies in Fe{sub 3}O{sub 4} crystal the spin of Fe ions in the tetrahedron site near the vacancy is much easier to switch parallel to the Fe ions in the octahedron site by temperature disturbance, supported by the temperature dependence of magnetic moment of Fe{sub 3}O{sub 4} films in experiment.
Deconfinement to quark matter in neutron stars - The influence of strong magnetic fields
Dexheimer, V.; Negreiros, R.; Schramm, S.; Hempel, M.
2013-03-25
We use an extended version of the hadronic SU(3) non-linear realization of the sigma model that also includes quarks to study hybrid stars. Within this approach, the degrees of freedom change naturally as the temperature/density increases. Different prescriptions of charge neutrality, local and global, are tested and the influence of strong magnetic fields and the anomalous magnetic moment on the particle population is discussed.
Xue, L. C.; Lang, L. L.; Li, Z. Z.; Qi, W. H.; Tang, G. D. Wu, L. Q.; Xu, J.
2015-09-15
Powder samples of the spinel ferrites M{sub x}Ni{sub 0.7−x}Fe{sub 2.3}O{sub 4} (M = Cr, Co and 0.0 ≤ x ≤ 0.3) and Cr{sub x}Ni{sub 0.7}Fe{sub 2.3−x}O{sub 4} (0.0 ≤ x ≤ 0.3) were synthesized using the chemical co-precipitation method. The XRD spectra confirmed that the samples had a single-phase cubic spinel structure. Magnetic measurements showed that the magnetic moments (μ{sub exp}) per formula both at 10 K and 300 K increased with Co substitution, while the values of μ{sub exp} decreased with Cr substitution. Applying the assumption that the magnetic moments of Cr{sup 2+} and Cr{sup 3+} lie antiparallel to those of the divalent and trivalent Fe, Co, and Ni cations in the same sublattice of spinel ferrites, these interesting behaviors could be easily interpreted. The cation distributions of the three series of samples were estimated successfully by fitting the dependences of μ{sub exp}, measured at 10 K, on the doping level x, using a quantum-mechanical potential barrier model earlier proposed by our group. The results obtained for the Cr cation distributions at the (A) and [B] sites are very close to those obtained elsewhere using neutron diffraction.
Eliazar, Iddo; Klafter, Joseph
2011-09-15
Brownian motion is widely considered the quintessential model of diffusion processes-the most elemental random transport processes in Science and Engineering. Yet so, examples of diffusion processes displaying highly non-Brownian statistics-commonly termed 'Anomalous Diffusion' processes-are omnipresent both in the natural sciences and in engineered systems. The scientific interest in Anomalous Diffusion and its applications is growing exponentially in the recent years. In this Paper we review the key statistics of Anomalous Diffusion processes: sub-diffusion and super-diffusion, long-range dependence and the Joseph effect, Levy statistics and the Noah effect, and 1/f noise. We further present a theoretical model-generalizing the Einstein-Smoluchowski diffusion model-which provides a unified explanation for the prevalence of Anomalous Diffusion statistics. Our model shows that what is commonly perceived as 'anomalous' is in effect ubiquitous. - Highlights: > The article provides an overview of Anomalous Diffusion (AD) statistics. > The Einstein-Smoluchowski diffusion model is extended and generalized. > The generalized model universally generates AD statistics. > A unified 'universal macroscopic explanation' for AD statistics is established. > AD statistics are shown to be fundamentally connected to robustness.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Sarkar, Sumanta; Jana, Rajkumar; Siva, Ramesh; Banerjee, Swastika; Pati, Swapan K.; Balasubramanian, Mahalingam; Peter, Sebastian C.
2015-10-27
Here, a new compound, Eu3Ir2In15 has been synthesized using indium as an active metal flux. The compound crystallizes in tetragonal P4/mbm space group with lattice parameters, a = 14.8580(4) Å, b = 14.8580(4) Å, c = 4.3901(2) Å. It was further characterized by SEM-EDX studies. The temperature dependent magnetic susceptibility suggests that Eu in this compound is exclusively in divalent state. The effective magnetic moment (μeff) of this compound is 7.35 μB/Eu ion with paramagnetic Curie temperature (θp) of -28 K suggesting antiferromagnetic interaction. The mixed valent nature of Eu observed in magnetic measurements was confirmed by XANES measurements. Themore » compound undergoes demagnetization at a low magnetic field (10 Oe), which is quite unusual for Eu based intermetallic compounds. Temperature dependent resistivity studies reveal that the compound is metallic in nature. A comparative study was made between Eu3Ir2In15 and hypothetical vacancy variant Eu5Ir4In10 which also crystallizes in the same crystal structure However our computational studies along with control experiments suggest that the latter is thermodynamically less feasible compared to the former and hence we proposed that it is highly unlikely that a RE5T4X10 would exist with X as a group 13 elements.« less
Lapas, Luciano C.; Ferreira, Rogelma M. S.; Rubí, J. Miguel; Oliveira, Fernando A.
2015-03-14
We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton’s law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.
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Library and Files as part of its archive documenting the early years of the agency . . . Sam Moment worked for the Bonneville Power Administration from 1940 to 1954. He specialized...
Lesseux, G. G. Urbano, R. R.; Iwamoto, W.; Garca-Flores, A. F.; Rettori, C.
2014-05-07
The Electron Spin Resonance (ESR) of diluted Er{sup 3+} magnetic ions in Au nanoparticles (NPs) is reported. The NPs were synthesized by reducing chloro triphenyl-phosphine gold(I) and erbium(III) trifluoroacetate. The Er{sup 3+} g-value along with the observed hyperfine splitting indicate that the Er{sup 3+} impurities are in a local cubic symmetry. Furthermore, the Er{sup 3+} ESR spectra show that the exchange interaction between the 4f and the conduction electrons (ce) is absent or negligible in Au{sub 1x}Er{sub x} NPs, in contrast to the ESR results in bulk Au{sub 1x}Er{sub x}. Therefore, the nature of this interaction needs to be reexamined at the nano scale range.
Zhao, R. B.; Zhao, D. W.; Li, G. K.; Ma, L. E-mail: houdenglu@mail.hebtu.edu.cn; Zhen, C. M.; Hou, D. L. E-mail: houdenglu@mail.hebtu.edu.cn; Wang, W. H.; Liu, E. K.; Chen, J. L.; Wu, G. H.
2014-12-08
The magnetic configuration of Mn{sub 2}NiAl ribbon has been investigated. In contrast to Ni{sub 2}MnAl, the compound Mn{sub 2}NiAl with considerable disorder does exhibit ferromagnetism and, due to exchange interaction competition, both ferromagnetic and antiferromagnetic moment orientations can coexist between nearest neighbor Mn atoms. This is unexpected in Heusler alloys. Regarding the mechanism of the martensitic transformation in Mn{sub 50}Ni{sub 50−x}Al{sub x}, it is found that increasing the Al content results in an unusual change in the lattice constant, a decrease of the transformation entropy change, and enhancement of the calculated electron localization. These results indicate that the p-d covalent hybridization between Mn (or Ni) and Al atoms gradually increases at the expense of the d-d hybridization between Ni and Mn atoms. This leads to an increased stability of the austenite phase and a decrease of the martensitic transformation temperature. For 11 ≤ x ≤ 14, Mn{sub 50}Ni{sub 50−x}Al{sub x} ferromagnetic shape memory alloys are obtained.
Ferragut, Erik M.; Laska, Jason A.; Bridges, Robert A.
2016-06-07
A system is described for receiving a stream of events and scoring the events based on anomalousness and maliciousness (or other classification). The system can include a plurality of anomaly detectors that together implement an algorithm to identify low-probability events and detect atypical traffic patterns. The anomaly detector provides for comparability of disparate sources of data (e.g., network flow data and firewall logs.) Additionally, the anomaly detector allows for regulatability, meaning that the algorithm can be user configurable to adjust a number of false alerts. The anomaly detector can be used for a variety of probability density functions, including normal Gaussian distributions, irregular distributions, as well as functions associated with continuous or discrete variables.
Pinpointing the Magnetic Moments of Nuclear Matter
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Energy Pinpointing Clean Energy Financing Programs Just Got Easier Pinpointing Clean Energy Financing Programs Just Got Easier June 2, 2016 - 11:00am Addthis Pinpointing Clean Energy Financing Programs Just Got Easier John J. MacWilliams John J. MacWilliams Associate Deputy Secretary Get the Guide Find the latest edition of "Federal Financing Programs for Clean Energy" here. Not long ago, we let our "fingers do the walking" when searching for categories of businesses in
Pinpointing the Magnetic Moments of Nuclear Matter
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... these nuclei at unphysically large quark masses are remarkably ... Project Title: Hadron-Hadron Interactions with Lattice QCD NERSC Resources Used: Edison DOE Program ...
Anomalous Hall effect in YIG|Pt bilayers
Meyer, Sibylle Schlitz, Richard; Geprägs, Stephan; Opel, Matthias; Huebl, Hans; Goennenwein, Sebastian T. B.; Gross, Rudolf
2015-03-30
We measure the ordinary and the anomalous Hall effect in a set of yttrium iron garnet|platinum (YIG|Pt) bilayers via magnetization orientation dependent magnetoresistance experiments. Our data show that the presence of the ferrimagnetic insulator YIG leads to an anomalous Hall effect like voltage in Pt, which is sensitive to both Pt thickness and temperature. Interpretation of the experimental findings in terms of the spin Hall anomalous Hall effect indicates that the imaginary part of the spin mixing conductance G{sub i} plays a crucial role in YIG|Pt bilayers. In particular, our data suggest a sign change in G{sub i} between 10 K and 300 K. Additionally, we report a higher order Hall effect contribution, which appears in thin Pt films on YIG at low temperatures.
No-Drag Frame for Anomalous Chiral Fluid
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Stephanov, Mikhail A.; Yee, Ho-Ung
2016-03-24
For an anomalous fluid carrying dissipationless chiral magnetic and/or vortical currents we show that there is a frame in which a stationary obstacle experiences no drag, but energy and charge currents do not vanish, resembling superfluidity. Unlike ordinary superfluid flow, the anomalous chiral currents can transport entropy in this frame. Moreover, we show that the second law of thermodynamics completely determines the amounts of these anomalous nondissipative currents in the “no-drag frame” as polynomials in temperature and chemical potential with known anomaly coefficients. These general results are illustrated and confirmed by a calculation in the chiral kinetic theory and inmore » the quark-gluon plasma at high temperature.« less
Constraints on anomalous top quark couplings at the LHC
Rizzo, T.G.
1996-09-01
Measurements of distributions associated with the pair production of top quarks at the LHC can be used to constrain (or observe) the anomalous chromomagnetic dipole moment(k) of the top. For example, using either the tt(bar) invariant mass or the Pt distribution of top we find that sensitivities to ; k; of order 0.05 are obtainable with 100 /fb of integrated luminosity. This is similar in magnitude to what can be obtained at a 500 GeV NLC with an integrated luminosity of 50 /fb through an examination of the e(+)e(-) right arrow tt(bar)g process.
Impurity-induced moments in underdoped cuprates
Khaliullin, G.; Kilian, R.; Krivenko, S.; Fulde, P.
1997-11-01
We examine the effect of a nonmagnetic impurity in a two-dimensional spin liquid in the spin-gap phase, employing a drone-fermion representation of spin-1/2 operators. The properties of the local moment induced in the vicinity of the impurity are investigated and an expression for the nuclear-magnetic-resonance Knight shift is derived, which we compare with experimental results. Introducing a second impurity into the spin liquid an antiferromagnetic interaction between the moments is found when the two impurities are located on different sublattices. The presence of many impurities leads to a screening of this interaction as is shown by means of a coherent-potential approximation. Further, the Kondo screening of an impurity-induced local spin by charge carriers is discussed. {copyright} {ital 1997} {ital The American Physical Society}
Direct Imaging of Asymmetric Magnetization Reversal
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material like iron is itself a tiny magnet represented by a magnetic moment. If the atomic moments are pointing in random directions, they cancel each other out. So, to bring...
Ultrahigh sensitivity of anomalous Hall effect sensor based on Cr-doped
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Bi2Te3 topological insulator thin films (Journal Article) | SciTech Connect Ultrahigh sensitivity of anomalous Hall effect sensor based on Cr-doped Bi2Te3 topological insulator thin films Citation Details In-Document Search This content will become publicly available on July 1, 2017 Title: Ultrahigh sensitivity of anomalous Hall effect sensor based on Cr-doped Bi2Te3 topological insulator thin films Anomalous Hall effect (AHE) was recently discovered in magnetic element-doped topological
Quantum anomalous Hall effect in topological insulator memory
Jalil, Mansoor B. A.; Tan, S. G.; Siu, Z. B.
2015-05-07
We theoretically investigate the quantum anomalous Hall effect (QAHE) in a magnetically coupled three-dimensional-topological insulator (3D-TI) system. We apply the generalized spin-orbit coupling Hamiltonian to obtain the Hall conductivity σ{sup xy} of the system. The underlying topology of the QAHE phenomenon is then analyzed to show the quantization of σ{sup xy} and its relation to the Berry phase of the system. Finally, we analyze the feasibility of utilizing σ{sup xy} as a memory read-out in a 3D-TI based memory at finite temperatures, with comparison to known magnetically doped 3D-TIs.
44th Annual Anomalous Absorption Conference
Beg, Farhat
2014-03-03
Conference Grant Report July 14, 2015 Submitted to the U. S. Department of Energy Attn: Dr. Sean Finnegan By the University of California, San Diego 9500 Gilman Drive La Jolla, California 92093 On behalf of the 44th Annual Anomalous Absorption Conference 8-13 June 2014, in Estes Park, Colorado Support Requested: $10,100 Amount expended: $3,216.14 Performance Period: 1 March 20 14 to 28 February 20 15 Principal Investigator Dr. Farhat Beg Center for Energy Research University of California, San Diego 9500 Gilman Drive La Jolla, California 92093-0417 858-822-1266 (telephone) 858-534-4543 (fax) fbeg@ucsd.edu Administrative Point of Contact: Brandi Pate, 858-534-0851, blpate®ucsd.edu I. Background The forty-fourth Anomalous Absorption Conference was held in Estes Park, Colorado from June 5-8, 2014 (aac2014.ucsd.edu). The first Anomalous Absorption Conference was held in 1971 to assemble experts in the poorly understood area of laser-plasma absorption. The goal of that conference was to address the anomalously large laser absorption seen in plasma experiments with respect to the laser absorption predicted by linear plasma theory. Great progress in this research area has been made in the decades since that first meeting, due in part to the scientific interactions that have occurred annually at this conference. Specifically, this includes the development of nonlinear laser-plasma theory and the simulation of laser interactions with plasmas. Each summer since that first meeting, this week-long conference has been held at unique locations in North America as a scientific forum for intense scientific exchanges relevant to the interaction of laser radiation with plasmas. Responsibility for organizing the conference has traditional rotated each year between the major Inertial Confinement Fusion (ICF) laboratories and universities including LANL, LLNL, LLE, UCLA UC Davis and NRL. As the conference has matured over the past four decades, its technical footprint has expanded
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.
Scattering universality classes of side jump in the anomalous...
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Scattering universality classes of side jump in the anomalous Hall effect Citation Details In-Document Search Title: Scattering universality classes of side jump in the anomalous ...
Anomalous spin precession and spin Hall effect in semiconductor...
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SciTech Connect Search Results Journal Article: Anomalous spin precession and spin Hall effect in semiconductor quantum wells Citation Details In-Document Search Title: Anomalous ...
Microscopic theory of quantum anomalous Hall effect in graphene...
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Microscopic theory of quantum anomalous Hall effect in graphene Citation Details In-Document Search Title: Microscopic theory of quantum anomalous Hall effect in graphene Authors: ...
Anomalous Behavior of the Homogeneous Ice Nucleation Rate in...
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Published Article: Anomalous Behavior of the Homogeneous Ice Nucleation Rate in "No-Man's Land" Prev Next Title: Anomalous Behavior of the Homogeneous Ice Nucleation Rate in ...
Sarkar, Sumanta; Jana, Rajkumar; Siva, Ramesh; Banerjee, Swastika; Pati, Swapan K.; Balasubramanian, Mahalingam; Peter, Sebastian C.
2015-10-27
Here, a new compound, Eu_{3}Ir_{2}In_{15} has been synthesized using indium as an active metal flux. The compound crystallizes in tetragonal P4/mbm space group with lattice parameters, a = 14.8580(4) Å, b = 14.8580(4) Å, c = 4.3901(2) Å. It was further characterized by SEM-EDX studies. The temperature dependent magnetic susceptibility suggests that Eu in this compound is exclusively in divalent state. The effective magnetic moment (μ_{eff}) of this compound is 7.35 μ_{B}/Eu ion with paramagnetic Curie temperature (θ_{p}) of -28 K suggesting antiferromagnetic interaction. The mixed valent nature of Eu observed in magnetic measurements was confirmed by XANES measurements. The compound undergoes demagnetization at a low magnetic field (10 Oe), which is quite unusual for Eu based intermetallic compounds. Temperature dependent resistivity studies reveal that the compound is metallic in nature. A comparative study was made between Eu_{3}Ir_{2}In_{15} and hypothetical vacancy variant Eu_{5}Ir_{4}In_{10} which also crystallizes in the same crystal structure However our computational studies along with control experiments suggest that the latter is thermodynamically less feasible compared to the former and hence we proposed that it is highly unlikely that a RE_{5}T_{4}X_{10} would exist with X as a group 13 elements.
Nuclear Quadrupole Moments and Nuclear Shell Structure
DOE R&D Accomplishments [OSTI]
Townes, C. H.; Foley, H. M.; Low, W.
1950-06-23
Describes a simple model, based on nuclear shell considerations, which leads to the proper behavior of known nuclear quadrupole moments, although predictions of the magnitudes of some quadrupole moments are seriously in error.
Magnetic polarizability of the nucleon
Ragusa, S.
1996-01-01
We derive an expression for the magnetic polarizability of the nucleon, as related to sums of products of its electromagnetic transition moments involving the electric and magnetic dipoles and mean-square radii, as well as the electric quadrupole moment. Two sum rules emerge from the calculation. {copyright} {ital 1995 The American Physical Society.}
Reduced Lorenz models for anomalous transport and profile resilience
Rypdal, K.; Garcia, O. E.
2007-02-15
The physical basis for the Lorenz equations for convective cells in stratified fluids, and for magnetized plasmas imbedded in curved magnetic fields, are reexamined with emphasis on anomalous transport. It is shown that the Galerkin truncation leading to the Lorenz equations for the closed boundary problem is incompatible with finite fluxes through the system in the limit of vanishing diffusion. An alternative formulation leading to the Lorenz equations is proposed, invoking open boundaries and the notion of convective streamers and their back-reaction on the profile gradient, giving rise to resilience of the profile. Particular emphasis is put on the diffusionless limit, where these equations reduce to a simple dynamical system depending only on one single forcing parameter. This model is studied numerically, stressing experimentally observable signatures, and some of the perils of dimension-reducing approximations are discussed.
Structural, magnetic, and transport properties of Fe-doped CoTiSb epitaxial thin films
Sun, N. Y.; Zhang, Y. Q.; Che, W. R.; Shan, R.; Qin, J.
2015-11-07
Epitaxial intrinsic and Fe-doped CoTiSb thin films with C1{sub b} structure were grown on MgO(100) substrates by magnetron sputtering. The semiconducting-like behavior in both intrinsic and Fe-doped thin films was demonstrated by temperature dependence of longitudinal resistivity. The Fe-doped CoTiSb films with a wide range of doping concentrations can maintain semiconducting-like and magnetic properties simultaneously, while the semiconducting behavior is weakening with the increasing Fe concentration. For 21 at. % Fe-doped film, low lattice magnetic moment (around 0.65 μ{sub B}) and high resistivity (larger than 800 μΩ cm) are beneficial to its application as a magnetic electrode in spintronic devices. Anomalous Hall effect of 21 at. % Fe-doped film was also investigated and its behaviors can be treated well by recent-reported anomalous Hall scaling including the contribution of spin-phonon skew scattering.
ARM: 1290-MHz Radar Wind Profiler, precipitation moments data...
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1290-MHz Radar Wind Profiler, precipitation moments data Title: ARM: 1290-MHz Radar Wind Profiler, precipitation moments data 1290-MHz Radar Wind Profiler, precipitation moments ...
Parametric probability distributions for anomalous change detection
Theiler, James P; Foy, Bernard R; Wohlberg, Brendt E; Scovel, James C
2010-01-01
The problem of anomalous change detection arises when two (or possibly more) images are taken of the same scene, but at different times. The aim is to discount the 'pervasive differences' that occur thoughout the imagery, due to the inevitably different conditions under which the images were taken (caused, for instance, by differences in illumination, atmospheric conditions, sensor calibration, or misregistration), and to focus instead on the 'anomalous changes' that actually take place in the scene. In general, anomalous change detection algorithms attempt to model these normal or pervasive differences, based on data taken directly from the imagery, and then identify as anomalous those pixels for which the model does not hold. For many algorithms, these models are expressed in terms of probability distributions, and there is a class of such algorithms that assume the distributions are Gaussian. By considering a broader class of distributions, however, a new class of anomalous change detection algorithms can be developed. We consider several parametric families of such distributions, derive the associated change detection algorithms, and compare the performance with standard algorithms that are based on Gaussian distributions. We find that it is often possible to significantly outperform these standard algorithms, even using relatively simple non-Gaussian models.
ARM - Evaluation Product - Corrected Precipitation Radar Moments...
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ProductsCorrected Precipitation Radar Moments in Antenna Coordinates Documentation Use the Data File Inventory tool to view data availability at the file level. Comments? We would...
70 proud moments in BPA's 70 years
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
computer program that can represent and evaluate fleeting moments of power system behavior. Previous programs had captured only continuing and stable conditions, not the transient...
Tuning giant anomalous Hall resistance ratio in perpendicular Hall balance
Zhang, J. Y.; Yang, G.; Wang, S. G. E-mail: ghyu@mater.ustb.edu.cn; Liu, J. L.; Wang, R. M.; Amsellem, E.; Kohn, A.; Yu, G. H. E-mail: ghyu@mater.ustb.edu.cn
2015-04-13
Anomalous Hall effect at room temperature in perpendicular Hall balance with a core structure of [Pt/Co]{sub 4}/NiO/[Co/Pt]{sub 4} has been tuned by functional CoO layers, where [Pt/Co]{sub 4} multilayers exhibit perpendicular magnetic anisotropy. A giant Hall resistance ratio up to 69 900% and saturation Hall resistance (R{sub S}{sup P}) up to 2590 mΩ were obtained in CoO/[Pt/Co]{sub 4}/NiO/[Co/Pt]{sub 4}/CoO system, which is 302% and 146% larger than that in the structure without CoO layers, respectively. Transmission electron microscopy shows highly textured [Co/Pt]{sub 4} multilayers and oxide layers with local epitaxial relations, indicating that the crystallographic structure has significant influence on spin dependent transport properties.
Search for anomalous production of events with a high energy...
Office of Scientific and Technical Information (OSTI)
for anomalous production of events with a high energy lepton and photon at the Tevatron Citation Details In-Document Search Title: Search for anomalous production of events with ...
Total least squares for anomalous change detection
Theiler, James P; Matsekh, Anna M
2010-01-01
A family of difference-based anomalous change detection algorithms is derived from a total least squares (TLSQ) framework. This provides an alternative to the well-known chronochrome algorithm, which is derived from ordinary least squares. In both cases, the most anomalous changes are identified with the pixels that exhibit the largest residuals with respect to the regression of the two images against each other. The family of TLSQ-based anomalous change detectors is shown to be equivalent to the subspace RX formulation for straight anomaly detection, but applied to the stacked space. However, this family is not invariant to linear coordinate transforms. On the other hand, whitened TLSQ is coordinate invariant, and furthermore it is shown to be equivalent to the optimized covariance equalization algorithm. What whitened TLSQ offers, in addition to connecting with a common language the derivations of two of the most popular anomalous change detection algorithms - chronochrome and covariance equalization - is a generalization of these algorithms with the potential for better performance.
Magnetic order and lattice anomalies in the J{sub 1}-J{sub 2} model system VOMoO{sub 4}
Bombardi, A.; Chapon, L.C.; Margiolaki, I.; Mazzoli, C.; Gonthier, S.; Duc, F.; Radaelli, P.G.
2005-06-01
High-resolution x-ray and neutron powder-diffraction measurements were performed on polycrystalline VOMoO{sub 4}. Below {approx_equal}40 K the system orders in a simple Neel antiferromagnetic state (propagation vector k-vector=0), indicating a dominant role of the nearest-neighbor interactions. The order is three dimensional but the reduced saturated magnetic moment m of 0.41 (1) {mu}{sub B}/V{sup 4+} at 2 K indicates strongly two-dimensional character and enhanced quantum fluctuations. On cooling, there is no evidence of a reduction of the crystal symmetry. However, neutron diffraction indicates an anomalous evolution of the lattice parameters, which can be related to the onset of magnetic correlations.
Anomalous density for Bose gases at finite temperature
Boudjemaa, A.; Benarous, M.
2011-10-15
We analyze the behavior of the anomalous density as function of the radial distance at different temperatures in a variational framework. We show that the temperature dependence of the anomalous density agrees with the Hartree-Fock-Bogoliubov (HFB) calculations. Comparisons between the normal and anomalous fractions at low temperature show that the latter remains higher and, consequently, the neglect of the anomalous density may destabilize the condensate. These results are compatible with those of Yukalov. Surprisingly, the study of the anomalous density in terms of the interaction parameter shows that the dip in the central density is destroyed for sufficiently weak interactions. We explain this effect.
Quantum Anomalous Hall Effect in Hg_1-yMn_yTe Quantum Wells
Liu, Chao-Xing; Qi, Xiao-Liang; Dai, Xi; Fang, Zhong; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.
2010-03-19
The quantum Hall effect is usually observed when the two-dimensional electron gas is subjected to an external magnetic field, so that their quantum states form Landau levels. In this work we predict that a new phenomenon, the quantum anomalous Hall effect, can be realized in Hg{sub 1-y}Mn{sub y}Te quantum wells, without the external magnetic field and the associated Landau levels. This effect arises purely from the spin polarization of the Mn atoms, and the quantized Hall conductance is predicted for a range of quantum well thickness and the concentration of the Mn atoms. This effect enables dissipationless charge current in spintronics devices.
Secretary Chu and the 'Sputnik Moment'
Broader source: Energy.gov [DOE]
U.S. Secretary of Energy Steven Chu speaks about China and the Sputnik Moment in US energy Policy at the National Press Club. Remarks followed by Q&A.
ARM - Evaluation Product - Precipitation Radar Moments Mapped...
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We would love to hear from you Send us a note below or call us at 1-888-ARM-DATA. Send Evaluation Product : Precipitation Radar Moments Mapped to a Cartesian Grid The Scanning...
Toroidal Dipole Moment of a Massless Neutrino
Cabral-Rosetti, L. G.; Mondragon, M.; Perez, E. Reyes
2009-04-20
We obtain the toroidal dipole moment of a massless neutrino {tau}{sub v{sub I}}{sup M} using the results for the anapole moment of a massless Dirac neutrino a{sub v{sub I}}{sup D}, which was obtained in the context of the Standard Model of the electroweak interactions (SM)SU(2){sub L} x U(1){sub Y}.
Method for identifying anomalous terrestrial heat flows
Del Grande, Nancy Kerr
1977-01-25
A method for locating and mapping the magnitude and extent of terrestrial heat-flow anomalies from 5 to 50 times average with a tenfold improved sensitivity over orthodox applications of aerial temperature-sensing surveys as used for geothermal reconnaissance. The method remotely senses surface temperature anomalies such as occur from geothermal resources or oxidizing ore bodies by: measuring the spectral, spatial, statistical, thermal, and temporal features characterizing infrared radiation emitted by natural terrestrial surfaces; deriving from these measurements the true surface temperature with uncertainties as small as 0.05 to 0.5 K; removing effects related to natural temperature variations of topographic, hydrologic, or meteoric origin, the surface composition, detector noise, and atmospheric conditions; factoring out the ambient normal-surface temperature for non-thermally enhanced areas surveyed under otherwise identical environmental conditions; distinguishing significant residual temperature enhancements characteristic of anomalous heat flows and mapping the extent and magnitude of anomalous heat flows where they occur.
Moment enhancement in dilute magnetic semiconductors: MnxSi1...
Office of Scientific and Technical Information (OSTI)
Authors: Shaughnessy, M ; Fong, C Y ; Snow, R ; Liu, K ; Pask, J E ; Yang, L H Publication Date: 2009-03-12 OSTI Identifier: 965070 Report Number(s): LLNL-JRNL-411279 Journal ID: ...
Stabilizing and increasing the magnetic moment of half-metals...
Office of Scientific and Technical Information (OSTI)
Type: Publisher's Accepted Manuscript Journal Name: Physical Review B Additional Journal ... Export Metadata Endnote Excel CSV XML Save to My Library Send to Email Send to Email ...
Anomalous Charge Transport in Disordered Organic Semiconductors
Muniandy, S. V.; Woon, K. L.; Choo, K. Y.
2011-03-30
Anomalous charge carrier transport in disordered organic semiconductors is studied using fractional differential equations. The connection between index of fractional derivative and dispersion exponent is examined from the perspective of fractional Fokker-Planck equation and its link to the continuous time random walk formalism. The fractional model is used to describe the bi-scaling power-laws observed in the time-of flight photo-current transient data for two different types of organic semiconductors.
Metal-to-insulator switching in quantum anomalous Hall states
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Kou, Xufeng; Pan, Lei; Wang, Jing; Fan, Yabin; Choi, Eun Sang; Lee, Wei -Li; Nie, Tianxiao; Murata, Koichi; Shao, Qiming; Zhang, Shou -Cheng; et al
2015-10-07
After decades of searching for the dissipationless transport in the absence of any external magnetic field, quantum anomalous Hall effect (QAHE) was recently achieved in magnetic topological insulator films. However, the universal phase diagram of QAHE and its relation with quantum Hall effect (QHE) remain to be investigated. Here, we report the experimental observation of the giant longitudinal resistance peak and zero Hall conductance plateau at the coercive field in the six quintuple-layer (Cr0.12Bi0.26Sb0.62)2Te3 film, and demonstrate the metal-to-insulator switching between two opposite QAHE plateau states up to 0.3 K. Moreover, the universal QAHE phase diagram is confirmed through themore » angle-dependent measurements. Our results address that the quantum phase transitions in both QAHE and QHE regimes are in the same universality class, yet the microscopic details are different. Additionally, the realization of the QAHE insulating state unveils new ways to explore quantum phase-related physics and applications.« less
Metal-to-insulator switching in quantum anomalous Hall states
Kou, Xufeng; Pan, Lei; Wang, Jing; Fan, Yabin; Choi, Eun Sang; Lee, Wei -Li; Nie, Tianxiao; Murata, Koichi; Shao, Qiming; Zhang, Shou -Cheng; Wang, Kang L.
2015-10-07
After decades of searching for the dissipationless transport in the absence of any external magnetic field, quantum anomalous Hall effect (QAHE) was recently achieved in magnetic topological insulator films. However, the universal phase diagram of QAHE and its relation with quantum Hall effect (QHE) remain to be investigated. Here, we report the experimental observation of the giant longitudinal resistance peak and zero Hall conductance plateau at the coercive field in the six quintuple-layer (Cr_{0.12}Bi_{0.26}Sb_{0.62})_{2}Te_{3} film, and demonstrate the metal-to-insulator switching between two opposite QAHE plateau states up to 0.3 K. Moreover, the universal QAHE phase diagram is confirmed through the angle-dependent measurements. Our results address that the quantum phase transitions in both QAHE and QHE regimes are in the same universality class, yet the microscopic details are different. Additionally, the realization of the QAHE insulating state unveils new ways to explore quantum phase-related physics and applications.
CFD Combustion Modeling with Conditional Moment Closure using...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Combustion Modeling with Conditional Moment Closure using Tabulated Chemistry CFD Combustion Modeling with Conditional Moment Closure using Tabulated Chemistry A method is ...
Momentive Performance Materials Inc MPM | Open Energy Information
Momentive Performance Materials Inc MPM Jump to: navigation, search Name: Momentive Performance Materials Inc (MPM) Place: Albany, New York Zip: 12211 Product: New York-based...
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Xu, X. Q.; Dudson, B.; Snyder, P. B.; Umansky, M. V.; Wilson, H.
2010-10-22
A minimum set of equations based on the peeling-ballooning (P-B) model with nonideal physics effects (diamagnetic drift, E×B drift, resistivity, and anomalous electron viscosity) is found to simulate pedestal collapse when using the new BOUT++ simulation code, developed in part from the original fluid edge code BOUT. Nonlinear simulations of P-B modes demonstrate that the P-B modes trigger magnetic reconnection, which leads to the pedestal collapse. With the addition of a model of the anomalous electron viscosity under the assumption that the electron viscosity is comparable to the anomalous electron thermal diffusivity, it is found from simulations using a realisticmore » high-Lundquist number that the pedestal collapse is limited to the edge region and the edge localized mode (ELM) size is about 5–10% of the pedestal stored energy. Furthermore, this is consistent with many observations of large ELMs.« less
TIMING NOISE IN PULSARS AND MAGNETARS AND THE MAGNETOSPHERIC MOMENT OF INERTIA
Tsang, David; Gourgouliatos, Konstantinos N. E-mail: kostasg@physics.mcgill.ca
2013-08-10
We examine timing noise in both magnetars and regular pulsars, and find that there exists a component of the timing noise ({sigma}{sub TN}) with strong magnetic field dependence ({sigma}{sub TN}{approx}B{sub o}{sup 2}{Omega}T{sup 3/2}) above B{sub o} {approx} 10{sup 12.5} G. The dependence of the timing noise floor on the magnetic field is also reflected in the smallest observable glitch size. We find that magnetospheric torque variation cannot explain this component of timing noise. We calculate the moment of inertia of the magnetic field outside of a neutron star and show that this timing noise component may be due to variation of this moment of inertia, and could be evidence of rapid global magnetospheric variability.
First moments of nucleon generalized parton distributions
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Wang, P.; Thomas, A. W.
2010-06-01
We extrapolate the first moments of the generalized parton distributions using heavy baryon chiral perturbation theory. The calculation is based on the one loop level with the finite range regularization. The description of the lattice data is satisfactory, and the extrapolated moments at physical pion mass are consistent with the results obtained with dimensional regularization, although the extrapolation in the momentum transfer to t=0 does show sensitivity to form factor effects, which lie outside the realm of chiral perturbation theory. We discuss the significance of the results in the light of modern experiments as well as QCD inspired models.
Nuclear moments of inertia at high spin
Deleplanque, M.A.
1982-10-01
The competition between collective motion and alignment at high spin can be evaluated by measuring two complementary dynamic moments of inertia. The first, I band, measured in ..gamma..-..gamma.. correlation experiments, relates to the collective properties of the nucleus. A new moment of inertia I/sub eff/ is defined here, which contains both collective and alignment effects. Both of these can be measured in continuum ..gamma..-ray spectra of rotational nuclei up to high frequencies. The evolution of ..gamma..-ray spectra for Er nuclei from mass 160 to 154 shows that shell effects can directly be observed in the spectra of the lighter nuclei.
Spin and orbital moments in actinide compounds (invited)
Lebech, B. ); Wulff, M.; Lander, G.H. )
1991-04-15
The extended spatial distribution of both the transition-metal 3{ital d} electrons and the actinide 5{ital f} electrons results in a strong interaction between these electron states when the relevant elements are alloyed. A particular interesting feature of this hybridization, which is predicted by single-electron band-structure calculations, is that the orbital moments of the actinide 5{ital f} electrons are considerably reduced from the values anticipated by a simple application of Hund's rules. To test these ideas, and thus to obtain a measure of the hybridization, we have performed a series of neutron scattering experiments designed to determine the magnetic moments at the actinide and transition-metal sublattice sites in compounds such as UFe{sub 2}, NpCo{sub 2}, and PuFe{sub 2} and to separate the spin and orbital components at the actinide sites. The results show, indeed, that the ratio of the orbital to spin moment is reduced as compared to the free-ion expectations. In addition there is qualitative agreement with theory, although the latter predicts values of both components that are larger than those found by experiment. Because {bold L} and {bold S} are opposed in the light actinides, and {ital L} is usually greater than {ital S}, the reduction of {ital L} can result in a situation for which {ital L}{minus}{ital S}{congruent}0. This almost occurs in UFe{sub 2}. However, neutrons are capable of observing the individual components at finite wave vector ({bold Q}), although the total component (observed at {bold Q}={bold 0}) may indeed be close to zero.
Anomalous Dimensions and Non-Gaussianity (Journal Article) |...
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Title: Anomalous Dimensions and Non-Gaussianity Authors: Green, Daniel ; Lewandowski, ... Sponsoring Org: US DOE Office of Science (DOE SC);High Energy Physics (HEP);National ...
Anomalous Zeeman response of the coexisting superconducting and...
Office of Scientific and Technical Information (OSTI)
s -wave pairing in ferropnictide superconductors Title: Anomalous Zeeman response of ... s -wave pairing in ferropnictide superconductors Authors: Ghaemi, Pouyan ; Vishwanath, ...
Evidence for an anomalous quantum state of protons in nanoconfined...
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of protons in nanoconfined water Citation Details In-Document Search Title: Evidence for an anomalous quantum state of protons in nanoconfined water Deep inelastic neutron ...
Phase-space jets drive transport and anomalous resistivity (Journal...
Office of Scientific and Technical Information (OSTI)
transport and anomalous resistivity In the presence of wave dissipation, phase-space structures spontaneously emerge in nonlinear Vlasov dynamics. These structures include not only...
Anomalous shear wave attenuation in the shallow crust beneath...
volcanic region, California Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Anomalous shear wave attenuation in the shallow crust beneath the...
Surface magnetism of Gd(0001): Evidence of ferromagnetic coupling to bulk
Mulhollan, G.A.; Garrison, K.; Erskine, J.L. )
1992-11-30
Previous polarized electron experiments and recent {ital ab} {ital initio} calculations suggest that the surface layer magnetic moments of Gd(0001) are antiferromagnetically coupled to the bulk magnetic moments. Spin-polarized photoemission data are presented which show that the spin polarization of the magnetic surface state and the surface 4{ital f} states of Gd(0001) are coupled ferromagnetically to the bulk magnetic moment.
The electric dipole moment of cobalt monoxide, CoO
Zhuang, Xiujuan; Steimle, Timothy C.
2014-03-28
A number of low-rotational lines of the E{sup 4}?{sub 7/2}???X{sup 4}?{sub 7/2} (1,0) band system of cobalt monoxide, CoO, were recorded field free and in the presence of a static electric field. The magnetic hyperfine parameter, h{sub 7/2}, and the electron quadrupole parameter, eQq{sub 0}, for the E{sup 4}?{sub 7/2}(? = 1) state were optimized from the analysis of the field-free spectrum. The permanent electric dipole moment, ?{sup -vector}{sub el}, for the X{sup 4}?{sub 7/2} (? = 0) and E{sup 4}?{sub 7/2} (? = 1) states were determined to be 4.18 0.05 D and 3.28 0.05 D, respectively, from the analysis of the observed Stark spectra of F? = 7???F? = 6 branch feature in the Q(7/2) line and the F? = 8???F? = 7 branch feature in the R(7/2) line. The measured dipole moments of CoO are compared to those from theoretical predictions and the trend across the 3d-metal monoxide series discussed.
The influence of Nd dopants on spin and orbital moments in Nd-doped permalloy thin films
Luo, Chen Zhang, Wen E-mail: yazhai@seu.edu.cn; Zhai, Ya E-mail: yazhai@seu.edu.cn; Wong, P. K. J.; You, Biao; Du, Jun; Zhai, Hongru
2014-08-25
Magnetic properties of Nd{sub X}-Ni{sub 80}Fe{sub 20(1?X)} thin films have been investigated using x-ray absorption spectroscopy and x-ray magnetic circular dichroism (XMCD) at room temperature. With the Nd concentration increasing, the ratio of orbital-to-spin moment of Ni and Fe increases significantly, indicating that the spin-orbit coupling in permalloy thin films is enhanced due to the Nd impurities. The spin and orbital moments have been obtained by the sum rules analysis, which shows that the Nd impurities lead to a strong dispersion of spin moments of Fe and Ni while have no effect on orbital moments in Nd-doped permalloy thin films. Element-specific XMCD hysteresis loops suggest an antiferromagnetic coupling between the magnetic moments of Nd and permalloy at room temperature. The static magnetic properties have been studied by vibrating sample magnetometer for comparison, which shows a nice agreement with the XMCD results.
Investigation into the semimagic nature of the tin isotopes through electromagnetic moments
Allmond, J. M.; Stuchbery, A. E.; Galindo-Uribarri, A.; Padilla-Rodal, E.; Radford, D. C.; Batchelder, J. C.; Bingham, C. R.; Howard, M. E.; Liang, J. F.; Manning, B.; Pain, S. D.; Stone, N. J.; Varner, R. L.; Yu, C. -H.
2015-10-19
A complete set of electromagnetic moments, B(E2;0^{+}_{1} 2^{+}_{1}), Q(2^{+}_{1}), and g(2^{+}_{1}), have been measured from Coulomb excitation of semi-magic ^{112,114,116,118,120,122,124}Sn (Z = 50) on natural carbon and titanium targets. The magnitude of the B(E2) values, measured to a precision of ~4%, disagree with a recent lifetime study [Phys. Lett. B 695, 110 (2011)] that employed the Doppler- shift attenuation method. The B(E2) values show an overall enhancement compared with recent theoretical calculations and a clear asymmetry about midshell, contrary to naive expectations. A new static electric quadrupole moment, Q(2^{+}_{1}), has been measured for ^{114}Sn. The static quadrupole moments are generally consistent with zero but reveal an enhancement near midshell; this had not been previously observed. The magnetic dipole moments are consistent with previous measurements and show a near monotonic decrease in value with neutron number. The current theory calculations fail to reproduce the electromagnetic moments of the tin isotopes. The role of 2p-2h and 4p-4h intruders, which are lowest in energy at mid shell and outside of current model spaces, needs to be investigated in the future.
Investigation into the semimagic nature of the tin isotopes through electromagnetic moments
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Allmond, J. M.; Stuchbery, A. E.; Galindo-Uribarri, A.; Padilla-Rodal, E.; Radford, D. C.; Batchelder, J. C.; Bingham, C. R.; Howard, M. E.; Liang, J. F.; Manning, B.; et al
2015-10-19
A complete set of electromagnetic moments, B(E2;0+1 2+1), Q(2+1), and g(2+1), have been measured from Coulomb excitation of semi-magic 112,114,116,118,120,122,124Sn (Z = 50) on natural carbon and titanium targets. The magnitude of the B(E2) values, measured to a precision of ~4%, disagree with a recent lifetime study [Phys. Lett. B 695, 110 (2011)] that employed the Doppler- shift attenuation method. The B(E2) values show an overall enhancement compared with recent theoretical calculations and a clear asymmetry about midshell, contrary to naive expectations. A new static electric quadrupole moment, Q(2+1), has been measured for 114Sn. The static quadrupole moments are generallymore » consistent with zero but reveal an enhancement near midshell; this had not been previously observed. The magnetic dipole moments are consistent with previous measurements and show a near monotonic decrease in value with neutron number. The current theory calculations fail to reproduce the electromagnetic moments of the tin isotopes. The role of 2p-2h and 4p-4h intruders, which are lowest in energy at mid shell and outside of current model spaces, needs to be investigated in the future.« less
Electric dipole moment of light nuclei
Afnan, Iraj R.; Gibson, Benjamin F.
2010-07-27
We examine the sensitivity of the deuteron Electric Dipole Moment (EDM) to variation in the nucleon-nucleon interaction. In particular, we write the EDM as a sum of two terms, one depends on the target wave function, the second on intermediate multiple scattering states in the {sup 3}P{sub 1} channel. This second contribution is sensitive to off-shell behavior of the {sup 3}P{sub 1} amplitude.
Electric dipole moment of light nuclei
Gibson, Benjamin; Afnan, I R
2010-01-01
We examine the sensitivity of the deuteron Electric Dipole Moment (EDM) to variation in the nucleon-nucleon interaction. In particular, we write the EDM as a sum of two terms, one depends on the target wave function, the second on intermediate multiple scattering states in the {sup 3}P{sub 1} channel. This second contribution is sensitive to off-shell behavior of the {sup 3}P{sub 1} amplitude.
Anomalous expansion of the copper-apical-oxygen distance in supercondu...
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Anomalous expansion of the copper-apical-oxygen distance in superconducting cuprate bilayers Citation Details In-Document Search Title: Anomalous expansion of the copper-apical-oxy...
The MOMENT to search for CP violation
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Blennow, Mattias; Coloma, Pilar; Fernández-Martinez, Enrique
2016-03-30
In this letter, we analyze for the first time the physics reach in terms of sensitivity to leptonic CP violation of the proposed MuOn-decay MEdium baseline NeuTrino beam (MOMENT) experiment, a novel neutrino oscillation facility that would operate with neutrinos from muon decay. Apart from obtaining a sufficiently intense flux, the bottlenecks to the physics reach of this experiment will be achieving a high enough suppression of the atmospheric background and, particularly, attaining a sufficient level of charge identification. We thus present our results as a function of these two factors. We consider a very massive Gd-doped Water Cherenkov detector.more » We also find that MOMENT will be competitive with other currently planned future oscillation experiments if a charge identification of at least 80 % can be achieved at the same time that the atmospheric background can be suppressed by at least a factor of ten. We also find a large synergy of MOMENT with the current generation of neutrino oscillation experiments, T2K and NOvA, which significantly enhances its final sensitivity.« less
The MOMENT to search for CP violation
Blennow, Mattias; Coloma, Pilar; Fernández-Martinez, Enrique
2015-11-09
In this letter, we analyze for the first time the physics reach in terms of sensitivity to leptonic CP violation of the proposed MuOn-decay MEdium baseline NeuTrino beam (MOMENT) experiment, a novel neutrino oscillation facility that would operate with neutrinos from muon decay. Apart from obtaining a sufficiently intense flux, the bottlenecks to the physics reach of this experiment will be achieving a high enough suppression of the atmospheric background and, particularly, attaining a sufficient level of charge identification. We thus present our results as a function of these two factors. We consider a very massive Gd-doped Water Cherenkov detector. We also find that MOMENT will be competitive with other currently planned future oscillation experiments if a charge identification of at least 80 % can be achieved at the same time that the atmospheric background can be suppressed by at least a factor of ten. We also find a large synergy of MOMENT with the current generation of neutrino oscillation experiments, T2K and NOvA, which significantly enhances its final sensitivity.
Spin and orbital moments of nanoscale Fe{sub 3}O{sub 4} epitaxial thin film on MgO/GaAs(100)
Liu, W. Q.; Xu, Y. B. E-mail: rzhang@nju.edu.cn; Wong, P. K. J.; Maltby, N. J.; Li, S. P.; Wang, X. F.; Zhang, R. E-mail: rzhang@nju.edu.cn; Du, J.; You, B.; Wu, J.; Bencok, P.
2014-04-07
Nanoscale Fe{sub 3}O{sub 4} epitaxial thin film has been synthesized on MgO/GaAs(100) spintronic heterostructure, and studied with X-ray magnetic circular dichroism. We have observed a total magnetic moment (m{sub l+s}) of (3.32 ± 0.1)μ{sub B}/f.u., retaining 83% of the bulk value. Unquenched orbital moment (m{sub l}) of (0.47 ± 0.05)μ{sub B}/f.u. has been confirmed by carefully applying the sum rule. The results offer direct experimental evidence of the bulk-like total magnetic moment and a large orbital moment in the nanoscale fully epitaxial Fe{sub 3}O{sub 4}/MgO/GaAs(100) heterostructure, which is significant for spintronics applications.
Spin-orbit coupled jeff=1/2 iridium moments on the geometrically frustrated fcc lattice
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Cook, A. M.; Matern, S.; Hickey, C.; Aczel, A. A.; Paramekanti, A.
2015-07-01
Motivated by experiments on La2ZnIrO6 and La2MgIrO6, we study the magnetism of spin-orbit coupled jeff = 1/2 iridium moments on the three-dimensional geometrically-frustrated face-centered cubic lattice. The symmetry-allowed nearest-neighbor interaction includes Heisenberg, Kitaev, and symmetric off-diagonal exchange. Using Luttinger-Tisza and Monte Carlo simulations, we find a rich variety of orders, including collinear A-type antiferromagnetism, collinear stripe order with moments along the {111}-direction, and incommensurate non-coplanar spirals, and determine their magnetic ordering transition temperatures. We argue that thermodynamic data on these iridates underscore the presence of a dominant Kitaev exchange, and suggest a possible resolution to the puzzle of why La2ZnIrO6,more » but not La2MgIrO6, exhibits 'weak' ferromagnetism.« less
ARM: 915-MHz Radar Wind Profiler: Wind Moments, operating in...
Office of Scientific and Technical Information (OSTI)
915-MHz Radar Wind Profiler: Wind Moments, operating in low power mode Title: ARM: 915-MHz Radar Wind Profiler: Wind Moments, operating in low power mode 915-MHz Radar Wind ...
Merged and corrected 915 MHz Radar Wind Profiler moments (Dataset...
Office of Scientific and Technical Information (OSTI)
Merged and corrected 915 MHz Radar Wind Profiler moments Title: Merged and corrected 915 MHz Radar Wind Profiler moments The radar wind profiler (RWP) present at the SGP central ...
Community Reflects on Pivotal Moment in History with B Reactor...
Office of Environmental Management (EM)
Reflects on Pivotal Moment in History with B Reactor Community Reflects on Pivotal Moment in History with B Reactor September 29, 2014 - 12:00pm Addthis David Klaus, Deputy Under ...
Electric dipole moments (EDM) of ionic atoms
Oshima, Sachiko
2010-03-15
Recent investigations show that the second-order perturbation calculations of electric dipole moments (EDM) from the finite nuclear size as well as the relativistic effects are all canceled out by the third-order perturbation effects and that this is due to electron screening. To derive the nucleon EDM from the nucleus, we propose to measure the EDM of an ionic system. In this case, it is shown that the nucleon EDM can survive by the reduction factor of 1/Z for the ionic system with one electron stripped off.
Diagnosing Anomalous Network Performance with Confidence
Settlemyer, Bradley W; Hodson, Stephen W; Kuehn, Jeffery A; Poole, Stephen W
2011-04-01
Variability in network performance is a major obstacle in effectively analyzing the throughput of modern high performance computer systems. High performance interconnec- tion networks offer excellent best-case network latencies; how- ever, highly parallel applications running on parallel machines typically require consistently high levels of performance to adequately leverage the massive amounts of available computing power. Performance analysts have usually quantified network performance using traditional summary statistics that assume the observational data is sampled from a normal distribution. In our examinations of network performance, we have found this method of analysis often provides too little data to under- stand anomalous network performance. Our tool, Confidence, instead uses an empirically derived probability distribution to characterize network performance. In this paper we describe several instances where the Confidence toolkit allowed us to understand and diagnose network performance anomalies that we could not adequately explore with the simple summary statis- tics provided by traditional measurement tools. In particular, we examine a multi-modal performance scenario encountered with an Infiniband interconnection network and we explore the performance repeatability on the custom Cray SeaStar2 interconnection network after a set of software and driver updates.
Berkolaiko, G.; Kuipers, J.
2013-12-15
Electronic transport through chaotic quantum dots exhibits universal behaviour which can be understood through the semiclassical approximation. Within the approximation, calculation of transport moments reduces to codifying classical correlations between scattering trajectories. These can be represented as ribbon graphs and we develop an algorithmic combinatorial method to generate all such graphs with a given genus. This provides an expansion of the linear transport moments for systems both with and without time reversal symmetry. The computational implementation is then able to progress several orders further than previous semiclassical formulae as well as those derived from an asymptotic expansion of random matrix results. The patterns observed also suggest a general form for the higher orders.
Quantum transport, anomalous dephasing, and spin-orbit coupling...
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Quantum transport, anomalous dephasing, and spin-orbit coupling in an open ballistic bismuth nanocavity Home Author: B. Hackens, J. P. Minet, S. Faniel, G. Farhi, C. Gustin, J. P....
Understanding the anomalous dispersion of doubly-ionized carbon...
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of doubly-ionized carbon plasmas near 47 nm Citation Details In-Document Search Title: Understanding the anomalous dispersion of doubly-ionized carbon plasmas near 47 nm Over ...
Apparatus for responding to an anomalous change in downhole pressure
Hall, David R.; Fox, Joe; Wilde, Tyson; Barlow, Jonathan S.
2010-04-13
A method of responding to an anomalous change in downhole pressure in a bore hole comprises detecting the anomalous change in downhole pressure, sending a signal along the segmented electromagnetic transmission path, receiving the signal, and performing a automated response. The anomalous change in downhole pressure is detected at a first location along a segmented electromagnetic transmission path, and the segmented electromagnetic transmission path is integrated into the tool string. The signal is received by at least one receiver in communication with the segmented electromagnetic transmission path. The automated response is performed along the tool string. Disclosed is an apparatus for responding to an anomalous change in downhole pressure in a downhole tool string, comprising a segmented electromagnetic transmission path connecting one or more receivers and at least one pressure sensor.
NLO BFKL and anomalous dimensions of light-ray operators
Balitsky, Ian
2013-05-01
This presentation covers: Regge limit in the coordinate space; BFKL representation of 4-point correlation function in N = 4 SYM; light-ray operators; DGLAP representation of 4-point correlation function; and anomalous dimensions from DGAP vs BFKL representations.
CP violating anomalous top-quark couplings at the LHC
Gupta, Sudhir Kumar; Mete, Alaettin Serhan; Valencia, G.
2009-08-01
We study the T odd correlations induced by CP violating anomalous top-quark couplings at both production and decay level in the process gg{yields}tt{yields}(b{mu}{sup +}{nu}{sub {mu}})(b{mu}{sup -}{nu}{sub {mu}}). We consider several counting asymmetries at the parton level and find the ones with the most sensitivity to each of these anomalous couplings at the LHC.
Simulation framework for spatio-spectral anomalous change detection
Theiler, James P; Harvey, Neal R; Porter, Reid B; Wohlberg, Brendt E
2009-01-01
The authors describe the development of a simulation framework for anomalous change detection that considers both the spatial and spectral aspects of the imagery. A purely spectral framework has previously been introduced, but the extension to spatio-spectral requires attention to a variety of new issues, and requires more careful modeling of the anomalous changes. Using this extended framework, they evaluate the utility of spatial image processing operators to enhance change detection sensitivity in (simulated) remote sensing imagery.
Method for processing seismic data to identify anomalous absorption zones
Taner, M. Turhan
2006-01-03
A method is disclosed for identifying zones anomalously absorptive of seismic energy. The method includes jointly time-frequency decomposing seismic traces, low frequency bandpass filtering the decomposed traces to determine a general trend of mean frequency and bandwidth of the seismic traces, and high frequency bandpass filtering the decomposed traces to determine local variations in the mean frequency and bandwidth of the seismic traces. Anomalous zones are determined where there is difference between the general trend and the local variations.
Structural and magnetic stability of Fe{sub 2}NiSi
Gupta, Dinesh C. Bhat, Idris Hamid Chauhan, Mamta
2014-04-24
Full-potential ab-initio calculations in the stable F-43m phase have been performed to investigate the structural and magnetic properties of Fe{sub 2}NiSi inverse Heusler alloys. The spin magnetic moment distributions show that present material is ferromagnetic in stable F-43m phase. Further, spin resolved electronic structure calculations show that the discrepancy in magnetic moments of Fe-I and Fe-II depend upon the hybridization of Fe with the main group element. It is found that the main group electron concentration is predominantly responsible in establishing the magnetic properties, formation of magnetic moments and the magnetic order for present alloy.
Magnetic and dielectric behavior in YMn{sub 1?x}Fe{sub x}O{sub 3} (x???0.5)
Sharma, Neetika; Das, A. Mishra, S. K.; Meena, S. S.; Prajapat, C. L.; Singh, M. R.
2014-06-07
The role of doping Fe on the structural, magnetic, and dielectric properties of frustrated antiferromagnet YMn{sub 1?x}Fe{sub x}O{sub 3} (x ? 0.5) has been investigated. The neutron diffraction analysis shows that the structure of these polycrystalline samples changes from hexagonal phase (space group P6{sub 3}cm) to orthorhombic phase (space group Pnma) for x?>?0.2. The frustration parameter decreases with Fe substitution. All the compounds are antiferromagnetic, and the magnetic structure is described as a mixture of ?3 and ?4 irreducible representation (IR) in the hexagonal phase, and the ratio of these two IRs is found to vary with Fe doping (x???0.2). A continuous spin reorientation as a function of temperature is observed in these samples. The magnetic ground state in the orthorhombic phase of the higher doped samples (x???0.3) is explained by taking ?1 (G{sub x}C{sub y}A{sub z}) representation of Pnma setting. In YMnO{sub 3} suppression of dielectric constant ?? is observed below T{sub N} indicative of magnetoelectric coupling. This anomalous behavior reduces in Fe doped samples. The dielectric constant is found to be correlated with the magnetic moment (M) obtained from neutron diffraction experiments and follows a M{sup 2} behavior close to T{sub N} in agreement with Landau theory.
Kikuchi, N. Furuta, M.; Okamoto, S.; Kitakami, O.; Shimatsu, T.
2014-12-15
Anomalous Hall effect (AHE) based ferromagnetic resonance (FMR) measurements were carried out on perpendicularly magnetized Co/Pt multilayer single dots of 0.4–3 μm in diameter. The resonance behavior was measured by detecting the decrease of perpendicular magnetization component due to magnetization precession. Resonance behavior was observed as a clear decrease of Hall voltages, and the obtained resonance fields were consistent with the results of vector-network-analyzer FMR. Spin-waves with cylindrical symmetry became significant by decreasing the dot diameter, and quantized multiple resonances were observed in the dot of 0.4 μm in diameter. The AHE based FMR proposed here is a powerful method to approach magnetization dynamics including spin waves and non-linear behavior excited in a finite nanostructure.
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... for the muon anomalous magnetic moment Porter, Frank C. The BABAR collaboration has an ... CP Violation and the Determination of the CKM Matrix Porter, Frank ; Caltech Full Text ...
Intrinsic quantum anomalous Hall effect in the kagome lattice Cs2LiMn3F12
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Xu, Gang; Lian, Biao; Zhang, Shou -Cheng
2015-10-27
In a kagome lattice, the time reversal symmetry can be broken by a staggered magnetic flux emerging from ferromagnetic ordering and intrinsic spin-orbit coupling, leading to several well-separated nontrivial Chern bands and intrinsic quantum anomalous Hall effect. Based on this idea and ab initio calculations, we propose the realization of the intrinsic quantum anomalous Hall effect in the single layer Cs2Mn3F12 kagome lattice and on the (001) surface of a Cs2LiMn3F12 single crystal by modifying the carrier coverage on it, where the band gap is around 20 meV. Furthermore, a simplified tight binding model based on the in-plane ddσ antibondingmore » states is constructed to understand the topological band structures of the system.« less
Search for the Neutron Electric Dipole Moment
Plaster, Brad
2010-08-04
Searches for the neutron electric dipole moment (EDM) are motivated by their highly suppressed Standard Model value. The observation of a non-zero signal in the next generation of experiments would point unambiguously to the existence of new physics beyond the Standard Model. Several ongoing efforts worldwide hold the potential for an up to two-orders-of-magnitude improvement beyond the current upper limit on the neutron EDM of 2.9x10{sup -6} e-cm. In this talk, I review the basic measurement principles of neutron EDM searches, then discuss a new experiment to be carried out in the United States at the Spallation Neutron Source with ultracold neutrons and an in-situ '3He''co-magnetometer'.
Magnetic measurements on ??CS{sub 2}U{sub 4}O{sub 12}
Kanrar, Buddhadev Misra, N. L.; Sastry, P. U.; Dube, V.; Ravikumar, G.
2014-04-24
Magnetic and XRD measurements on ??CS{sub 2}U{sub 4}O{sub 12} having uranium in mixed valent states of U (V) and U (VI) have been made. The study reveals that the compound undergoes an antiferromagnetic transition below 25K and an anomalous magnetic behavior was seen around 75K. This anomalous behavior indicates towards a structural phase transition. However, the low temperature XRD could not confirm this observation.
Probing top-Z dipole moments at the LHC and ILC
Röntsch, Raoul; Schulze, Markus
2015-08-11
We investigate the weak electric and magnetic dipole moments of top quark-Z boson interactions at the Large Hadron Collider (LHC) and the International Linear Collider (ILC). Their vanishingly small magnitude in the Standard Model makes these couplings ideal for probing New Physics interactions and for exploring the role of top quarks in electroweak symmetry breaking. In our analysis, we consider the production of two top quarks in association with a Z boson at the LHC, and top quark pairs mediated by neutral gauge bosons at the ILC. These processes yield direct sensitivity to top quark-Z boson interactions and complement indirect constraints from electroweak precision data. Our computation is accurate to next-to-leading order in QCD, we include the full decay chain of top quarks and the Z boson, and account for theoretical uncertainties in our constraints. Furthermore, we find that LHC experiments will soon be able to probe weak dipole moments for the first time.
On the moment of inertia of a quantum harmonic oscillator
Khamzin, A. A. Sitdikov, A. S.; Nikitin, A. S.; Roganov, D. A.
2013-04-15
An original method for calculating the moment of inertia of the collective rotation of a nucleus on the basis of the cranking model with the harmonic-oscillator Hamiltonian at arbitrary frequencies of rotation and finite temperature is proposed. In the adiabatic limit, an oscillating chemical-potential dependence of the moment of inertia is obtained by means of analytic calculations. The oscillations of the moment of inertia become more pronounced as deformations approach the spherical limit and decrease exponentially with increasing temperature.
CFD Combustion Modeling with Conditional Moment Closure using Tabulated
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Chemistry | Department of Energy Combustion Modeling with Conditional Moment Closure using Tabulated Chemistry CFD Combustion Modeling with Conditional Moment Closure using Tabulated Chemistry A method is presented that allows for efficient conditional moment closure combustion simulations through the use of a progress variable based parameterization of the combustion chemistry. p-15_borg.pdf (228.78 KB) More Documents & Publications Advanced CFD Models for High Efficiency Compression
Heiba, Zein K.; Taif University, Faculty of Science, Physics Department ; Mohamed, Mohamed Bakr; Fuess, H.
2012-12-15
Graphical abstract: Display Omitted Highlights: ? Er{sub 2?x}Mn{sub x}O{sub 3} (0.0 ? x ? 0.20) prepared by solgel method. ? The change in lattice parameter is not linear with x due to the change in crystallite size with doping. ? Anomalous concentration dependence is found in magnetic susceptibility. ? The effective magnetic moment ?{sub eff} is found to decrease with composition parameter x. ? Superexchange interactions between Er ions depending on the amount of Mn or Er in different sites. -- Abstract: The manganese doped rare earth oxides Er{sub 2?x}Mn{sub x} O{sub 3} (0.0 ? x ? 0.20) were synthesized by a solgel process and analyzed by X-ray diffraction using Rietveld refinement methods. A single phase solid solution is formed up to x = 0.15 while for x ? 0.2 a manganese oxide phase appears in the diffraction pattern. Preferential cationic distribution between the non-equivalent sites 8b and 24d of space group Ia3{sup } is found for all samples but to a different extent. The octahedral volume and average bond length of Er{sub 1}-O for 8b site decrease while both octahedral volume and bond length of Er{sub 2}-O for 24d site increase. Magnetization measurements were done in the temperature range 5300 K. The effective magnetic moment ?{sub eff} is found to decrease with composition parameter x, except for sample x = 0.05 where the magnetization is enhanced. The Curie-Weiss paramagnetic temperatures indicate antiferromagnetic interaction.
Neutron Electric Dipole Moments from Beyond the Standard Model...
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Electric Dipole Moments from Beyond the Standard Model Physics Bhattacharya, Tanmoy Los Alamos National Laboratory Los Alamos National Laboratory; Cirigliano, Vincenzo Los...
Separating Cloud and Drizzle Radar Moments during Precipitation...
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Onset using Doppler Spectra Citation Details In-Document Search Title: Separating Cloud and Drizzle Radar Moments during Precipitation Onset using Doppler Spectra Authors: ...
Neutron Electric Dipole Moments from Beyond the Standard Model...
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Beyond the Standard Model Physics Citation Details In-Document Search Title: Neutron Electric Dipole Moments from Beyond the Standard Model Physics Authors: Bhattacharya, Tanmoy ...
Neutron Electric Dipole Moments from Beyond the Standard Model...
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Beyond the Standard Model Physics Citation Details In-Document Search Title: Neutron Electric Dipole Moments from Beyond the Standard Model Physics You are accessing a ...
Comment on Pion-nucleon bremsstrahlung and. Delta. electromagnetic moments''
Weyrauch, M. )
1989-11-01
We analyze the definition of the electromagnetic moments of the dressed'' {Delta} introduced by Heller, Kumano, Martinez, and Moniz with respect to gauge invariance.
Magnetic Systems Mimic Granular Materials | U.S. DOE Office of...
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... magnetic x-ray photon correlation spectroscopy" that uses coherent x-ray beams (similar to laser light) whose energy is tuned to resonantly interact with atomic magnetic moments. ...
The search for permanent electric dipole moments
Kirch, Klaus
2013-02-13
Permanent electric dipole moments (EDMs) of fundamental systems with spin - particles, nuclei, atoms or molecules violate parity and time reversal invariance. Invoking the CPT theorem, time reversal violation implies CP violation. Although CP-violation is implemented in the standard electro-weak theory, EDM generated this way remain undetectably small. However, this CP-violation also appears to fail explaining the observed baryon asymmetry of our universe. Extensions of the standard theory usually include new sources of CP violation and often predict sizeable EDMs. EDM searches in different systems are complementary and various efforts worldwide are underway and no finite value has been established yet. The prototype of an EDM search is the pursuit of the EDM of the neutron. It has the longest history and at the same time is at the forefront of present research. The talk aims at giving an overview of the field with emphasis on our efforts within an international collaboration at PSI, nedm.web.psi.ch.
Moment Closures on Two-Dimensional Cartesian Grids
Garrett, Charles K.
2015-07-31
Some moment methods for kinetic equations are complicated and take time to develop. Over the course of a couple years, this software was developed to test different closures on standard test problems in the literature. With this software, researchers in the field of moment closures will be able to rapidly test new methods.
Proximity-induced magnetism in transition-metal substituted graphene
Crook, Charles B.; Constantin, Costel; Ahmed, Towfiq; Zhu, Jian -Xin; Balatsky, Alexander V.; Haraldsen, Jason T.
2015-08-03
We investigate the interactions between two identical magnetic impurities substituted into a graphene superlattice. Using a first-principles approach, we calculate the electronic and magnetic properties for transition-metal substituted graphene systems with varying spatial separation. These calculations are compared for three different magnetic impurities, manganese, chromium, and vanadium. We determine the electronic band structure, density of states, and Millikan populations (magnetic moment) for each atom, as well as calculate the exchange parameter between the two magnetic atoms as a function of spatial separation. We find that the presence of magnetic impurities establishes a distinct magnetic moment in the graphene lattice, where the interactions are highly dependent on the spatial and magnetic characteristic between the magnetic and carbon atoms, which leads to either ferromagnetic or antiferromagnetic behavior. Furthermore, through an analysis of the calculated exchange energies and partial density of states, it is determined that interactions between the magnetic atoms can be classified as an RKKY interaction.
Cancellation of orbital and spin magnetism in UFe/sub 2/
Wulff, M.; Lander, G.H.; Lebech, B.; Delapalme, A.
1989-03-01
Polarized-neutron measurements have shown that the orbital and spin magnetic moments, which individually have a value of approx.0.23..mu../sub B/, almost completely cancel on the U sublattice in the ordered Laves phase UFe/sub 2/. This confirms a recent theoretical predicton and raises the possibility of ''magnetic'' compounds with zero total moment.
Local spin torque induced by electron electric dipole moment in the YbF molecule
Fukuda, Masahiro; Senami, Masato; Ogiso, Yoji; Tachibana, Akitomo
2014-10-06
In this study, we show the modification of the equation of motion of the electronic spin, which is derived by the quantum electron spin vorticity principle, by the effect of the electron electric dipole moment (EDM). To investigate the new contribution to spin torque by EDM, using first principle calculations, we visualize distributions of the local spin angular momentum density and local spin torque density of the YbF molecule on which the static electric field and magnetic field are applied at t = 0.
Anomalous fast ion losses at high β on the tokamak fusion test...
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Anomalous fast ion losses at high on the tokamak fusion test reactor Citation Details In-Document Search Title: Anomalous fast ion losses at high on the tokamak fusion test ...
Quantum anomalous Hall effect in single-layer and bilayer graphene...
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Quantum anomalous Hall effect in single-layer and bilayer graphene Citation Details In-Document Search Title: Quantum anomalous Hall effect in single-layer and bilayer graphene ...
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Terwilliger, Thomas C.; Bunkóczi, Gábor; Hung, Li-Wei; Zwart, Peter H.; Smith, Janet L.; Akey, David L.; Adams, Paul D.
2016-03-01
A key challenge in the SAD phasing method is solving a structure when the anomalous signal-to-noise ratio is low. Here, we describe algorithms and tools for evaluating and optimizing the useful anomalous correlation and the anomalous signal in a SAD experiment. A simple theoretical framework [Terwilliger et al.(2016),Acta Cryst.D72, 346–358] is used to develop methods for planning a SAD experiment, scaling SAD data sets and estimating the useful anomalous correlation and anomalous signal in a SAD data set. Thephenix.plan_sad_experimenttool uses a database of solved and unsolved SAD data sets and the expected characteristics of a SAD data set to estimatemore » the probability that the anomalous substructure will be found in the SAD experiment and the expected map quality that would be obtained if the substructure were found. Thephenix.scale_and_mergetool scales unmerged SAD data from one or more crystals using local scaling and optimizes the anomalous signal by identifying the systematic differences among data sets, and thephenix.anomalous_signaltool estimates the useful anomalous correlation and anomalous signal after collecting SAD data and estimates the probability that the data set can be solved and the likely figure of merit of phasing.« less
Exact linearized Coulomb collision operator in the moment expansion
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Ji, Jeong -Young; Held, Eric D.
2006-10-05
In the moment expansion, the Rosenbluth potentials, the linearized Coulomb collision operators, and the moments of the collision operators are analytically calculated for any moment. The explicit calculation of Rosenbluth potentials converts the integro-differential form of the Coulomb collision operator into a differential operator, which enables one to express the collision operator in a simple closed form for any arbitrary mass and temperature ratios. In addition, it is shown that gyrophase averaging the collision operator acting on arbitrary distribution functions is the same as the collision operator acting on the corresponding gyrophase averaged distribution functions. The moments of the collisionmore » operator are linear combinations of the fluid moments with collision coefficients parametrized by mass and temperature ratios. Furthermore, useful forms involving the small mass-ratio approximation are easily found since the collision operators and their moments are expressed in terms of the mass ratio. As an application, the general moment equations are explicitly written and the higher order heat flux equation is derived.« less
Can I solve my structure by SAD phasing? Anomalous signal in SAD phasing
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Terwilliger, Thomas C.; Bunkóczi, Gábor; Hung, Li-Wei; Zwart, Peter H.; Smith, Janet L.; Akey, David L.; Adams, Paul D.
2016-03-01
A key challenge in the SAD phasing method is solving a structure when the anomalous signal-to-noise ratio is low. We present a simple theoretical framework for describing measurements of anomalous differences and the resulting useful anomalous correlation and anomalous signal in a SAD experiment. Here, the useful anomalous correlation is defined as the correlation of anomalous differences with ideal anomalous differences from the anomalous substructure. The useful anomalous correlation reflects the accuracy of the data and the absence of minor sites. The useful anomalous correlation also reflects the information available for estimating crystallographic phases once the substructure has been determined.more » In contrast, the anomalous signal (the peak height in a model-phased anomalous difference Fourier at the coordinates of atoms in the anomalous substructure) reflects the information available about each site in the substructure and is related to the ability to find the substructure. A theoretical analysis shows that the expected value of the anomalous signal is the product of the useful anomalous correlation, the square root of the ratio of the number of unique reflections in the data set to the number of sites in the substructure, and a function that decreases with increasing values of the atomic displacement factor for the atoms in the substructure. In conclusion, this means that the ability to find the substructure in a SAD experiment is increased by high data quality and by a high ratio of reflections to sites in the substructure, and is decreased by high atomic displacement factors for the substructure.« less
Kanai, Shun; Tsujikawa, Masahito; Shirai, Masafumi; Miura, Yoshio; Matsukura, Fumihiro Ohno, Hideo
2014-12-01
We study the spin and orbital magnetic moments in Ta/Co{sub 0.4}Fe{sub 0.4}B{sub 0.2}/MgO by x-ray magnetic circular dichroism measurements as well as first-principles calculations, in order to clarify the origin of the perpendicular magnetic anisotropy. Both experimental and theoretical results show that orbital magnetic moment of Fe is more anisotropic than that of Co with respect to the magnetization direction. The anisotropy is larger for thinner CoFeB, indicating that Fe atoms at the interface with MgO contribute more than Co to the observed perpendicular magnetic anisotropy.
Evaluation of Double-moment Microphysical Parameterization with...
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model?" Because of the lack of data with detailed MCS cloud components, a detailed evaluation of double-moment schemes has not yet been undertaken. During April and May of 2011,...
Neutron Electric Dipole Moments from Beyond the Standard Model Physics
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(Conference) | SciTech Connect Conference: Neutron Electric Dipole Moments from Beyond the Standard Model Physics Citation Details In-Document Search Title: Neutron Electric Dipole Moments from Beyond the Standard Model Physics Authors: Bhattacharya, Tanmoy [1] ; Cirigliano, Vincenzo [1] ; Gupta, Rajan [1] + Show Author Affiliations Los Alamos National Laboratory Publication Date: 2013-11-18 OSTI Identifier: 1107163 Report Number(s): LA-UR-13-28859 DOE Contract Number: AC52-06NA25396
Searching for the corner seismic moment in worldwide data
Felgueiras, Miguel; Santos, Rui; Martins, João Paulo
2015-12-31
In this paper the existence of the corner frequency value for the seismic moment distribution is investigated, analysing worldwide data. Pareto based distributions, usually considered as the most suitable to this type of data, are fitted to the most recent data, available in a global earthquake catalog. Despite the undeniable finite nature of the seismic moment data, we conclude that no corner frequency can be established considering the available data set.
Forces and moments on a slender, cavitating body
Hailey, C.E.; Clark, E.L.; Buffington, R.J.
1988-01-01
Recently a numerical code has been developed at Sandia National Laboratories to predict the pitching moment, normal force, and axial force of a slender, supercavitating shape. The potential flow about the body and cavity is calculated using an axial distribution of source/sink elements. The cavity surface is assumed to be a constant pressure streamline, extending beyond the base of the model. Slender body approximation is used to model the crossflow for small angles of attack. A significant extension of previous work in cavitation flow is the inclusion of laminar and turbulent boundary layer solutions on the body. Predictions with this code, for axial force at zero angle of attack, show good agreement with experiments. There are virtually no published data availble with which to benchmark the pitching moment and normal force predictions. An experiment was designed to measure forces and moments on a supercavitation shape. The primary reason for the test was to obtain much needed data to benchmark the hydrodynamic force and moment predictions. Since the numerical prediction is for super cavitating shapes at very small cavitation numbers, the experiment was designed to be a ventilated cavity test. This paper describes the experimental procedure used to measure the pitching moment, axial and normal forces, and base pressure on a slender body with a ventilated cavity. Limited results are presented for pitching moment and normal force. 5 refs., 7 figs.
Shen, Xi; Shigematsu, Kei; Chikamatsu, Akira Fukumura, Tomoteru; Hirose, Yasushi; Hasegawa, Tetsuya
2014-08-18
We report the electrical transport properties of ferrimagnetic Mn{sub 4}N (001) epitaxial thin films grown by pulsed laser deposition on MgO (001) substrates. The Mn{sub 4}N thin films were tetragonally distorted with a ratio of out-of-plane to in-plane lattice constants of 0.987 and showed perpendicular magnetic anisotropy with an effective magnetic anisotropy constant of 0.16 MJ/m{sup 3}, which is comparable with that of a recently reported molecular-beam-epitaxy-grown film. The thin films exhibited metallic transport with a room temperature resistivity of 125 μΩ cm in addition to a large anomalous Hall effect with a Hall angle tangent of 0.023.
Effective field theory: A modern approach to anomalous couplings
Degrande, Cline; Centre for Particle Physics and Phenomenology , Universit Catholique de Louvain, Chemin du Cyclotron 2, B-1348 Louvain-la-Neuve ; Greiner, Nicolas; Max-Planck-Institut fr Physik, Fhringer Ring 6, 80805 Mnchen ; Kilian, Wolfgang; University of Siegen, Fachbereich Physik, D-57068 Siegen ; Mattelaer, Olivier; Mebane, Harrison; Stelzer, Tim; Willenbrock, Scott; Zhang, Cen; Centre for Particle Physics and Phenomenology , Universit Catholique de Louvain, Chemin du Cyclotron 2, B-1348 Louvain-la-Neuve
2013-08-15
We advocate an effective field theory approach to anomalous couplings. The effective field theory approach is the natural way to extend the standard model such that the gauge symmetries are respected. It is general enough to capture any physics beyond the standard model, yet also provides guidance as to the most likely place to see the effects of new physics. The effective field theory approach also clarifies that one need not be concerned with the violation of unitarity in scattering processes at high energy. We apply these ideas to pair production of electroweak vector bosons. -- Highlights: We discuss the advantages of effective field theories compared to anomalous couplings. We show that one need not be concerned with unitarity violation at high energy. We discuss the application of effective field theory to weak boson physics.
ARM: 1290-MHz Beam-Steered Radar Wind Profiler: Wind and Moment...
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Wind and Moment Averages Title: ARM: 1290-MHz Beam-Steered Radar Wind Profiler: Wind and Moment Averages 1290-MHz Beam-Steered Radar Wind Profiler: Wind and Moment Averages ...
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Hussein, Khalid
2012-02-01
Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Warm Modeled Temperature Archuleta Note: This “Weakly Anomalous to Anomalous Surface Temperature” dataset differs from the “Anomalous Surface Temperature” dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1σ and 2σ above the mean, as opposed to the greater than 2σ temperatures contained in the “Anomalous Surface Temperature” dataset. Edition: First Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains areas of anomalous surface temperature in Archuleta County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature between 1σ and 2σ were considered ASTER modeled warm surface exposures (thermal anomalies). Spatial Domain: Extent: Top: 4144825.235807 m Left: 285446.256851 m Right: 350577.338852 m Bottom: 4096962.250137 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Hussein, Khalid
2012-02-01
Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Warm Modeled Temperature Routt Edition: First Note: This “Weakly Anomalous to Anomalous Surface Temperature” dataset differs from the “Anomalous Surface Temperature” dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1σ and 2σ above the mean, as opposed to the greater than 2σ temperatures contained in the “Anomalous Surface Temperature” dataset. Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains areas of anomalous surface temperature in Routt County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature between 1σ and 2σ were considered ASTER modeled warm surface exposures (thermal anomalies) Spatial Domain: Extent: Top: 4501071.574000 m Left: 311351.975000 m Right: 359411.975000 m Bottom: 4447521.574000 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO Postal Code
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Hussein, Khalid
2012-02-01
Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Warm Modeled Temperature Garfield Edition: First Note: This “Weakly Anomalous to Anomalous Surface Temperature” dataset differs from the “Anomalous Surface Temperature” dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1σ and 2σ above the mean, as opposed to the greater than 2σ temperatures contained in the “Anomalous Surface Temperature” dataset. Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains areas of anomalous surface temperature in Garfield County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature between 1σ and 2σ were considered ASTER modeled warm surface exposures (thermal anomalies) Spatial Domain: Extent: Top: 4442180.552290 m Left: 268655.053363 m Right: 359915.053363 m Bottom: 4312490.552290 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO Postal
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Hussein, Khalid
2012-02-01
Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Very Warm Modeled Temperature Dolores Edition: First Note: This “Weakly Anomalous to Anomalous Surface Temperature” dataset differs from the “Anomalous Surface Temperature” dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1σ and 2σ above the mean, as opposed to the greater than 2σ temperatures contained in the “Anomalous Surface Temperature” dataset. Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains areas of anomalous surface temperature in Dolores County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature greater than 2σ were considered ASTER modeled very warm surface exposures (thermal anomalies) Spatial Domain: Extent: Top: 4186234.213315 m Left: 212558.673056 m Right: 232922.811862 m Bottom: 4176781.467043 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Hussein, Khalid
2012-02-01
Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Very Warm Modeled Temperature Alamosa Saguache Edition: First Note: This “Weakly Anomalous to Anomalous Surface Temperature” dataset differs from the “Anomalous Surface Temperature” dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1σ and 2σ above the mean, as opposed to the greater than 2σ temperatures contained in the “Anomalous Surface Temperature” dataset. Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains areas of anomalous surface temperature in Alamosa and Saguache Counties identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature greater than 2σ were considered ASTER modeled very warm surface exposures (thermal anomalies) Spatial Domain: Extent: Top: 4217727.601630 m Left: 394390.400264 m Right: 460179.841813 m Bottom: 4156258.036086 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Hussein, Khalid
2012-02-01
Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Very Warm Modeled Temperature Chaffee Edition: First Note: This “Weakly Anomalous to Anomalous Surface Temperature” dataset differs from the “Anomalous Surface Temperature” dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1σ and 2σ above the mean, as opposed to the greater than 2σ temperatures contained in the “Anomalous Surface Temperature” dataset. Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains areas of anomalous surface temperature in Chaffee County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature greater than 2σ were considered ASTER modeled very warm surface exposures (thermal anomalies) Spatial Domain: Extent: Top: 4333432.368072 m Left: 366907.700763 m Right: 452457.816015 m Bottom: 4208271.566715 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO
Bieron, Jacek; Gaigalas, Gediminas; Gaidamauskas, Erikas; Fritzsche, Stephan; Indelicato, Paul; Joensson, Per
2009-07-15
The multiconfiguration Dirac-Hartree-Fock theory has been employed to calculate the electric dipole moment of the 7s6d {sup 3}D{sub 2} state of radium induced by the nuclear Schiff moment. The results are dominated by valence and core-valence electron correlation effects. We show that the correlation effects can be evaluated in a converged series of multiconfiguration expansions.
On The Anomalous Fast Ion Energy Diffusion in Toroidal Plasmas Due to Cavity Modes
N.N. Gorelenkov, N.J. Fisch and E. Fredrickson
2010-03-09
An enormous wave-particle diffusion coefficient along paths suitable for alpha channeling had been deduced in mode converted ion Bernstein wave experiments on Tokamak Fusion Test Reactor (TFTR) the only plausible explanation advanced for such a large diffusion coefficient was the excitation of internal cavity modes which induce particle diffusion along identical diffusion paths, but at much higher rates. Although such a mode was conjectured, it was never observed. However, recent detailed observations of high frequency compressional Alfven eigenmodes (CAEs) on the National Spherical torus Experiment (NSTX) indirectly support the existence of the related conjectured modes on TFTR. The eigenmodes responsible for the high frequency magnetic activity can be identified as CAEs through the polarization of the observed magnetic field oscillations in NSTX and through a comparison with the theoretically derived freuency dispersion relation. Here, we show how these recent observations of high frequency CAEs lend support to this explanation of the long-standing puzzle of anomalous fast ion energy diffusion on TFTR. The support of the conjecure that these internal modes could have caused the remarkable ion energy diffusion on TFTR carries significant and favorable implications for the possibilities in achieving the alpha channeling effect with small injected power in a tokamak reactor.
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Print Using spectroscopic information for magnetometry and magnetic microscopy obviously requires detailed theoretical understanding of spectral shape and magnitude of dichroism signals. A research team at ALS Beamline 4.0.2 has now shown unambiguously that, contrary to common belief, spectral shape and magnitude of x-ray magnetic linear dichroism (XMLD) are not only determined by the relative orientation of magnetic moments and
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Print Using spectroscopic information for magnetometry and magnetic microscopy obviously requires detailed theoretical understanding of spectral shape and magnitude of dichroism signals. A research team at ALS Beamline 4.0.2 has now shown unambiguously that, contrary to common belief, spectral shape and magnitude of x-ray magnetic linear dichroism (XMLD) are not only determined by the relative orientation of magnetic moments and
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Print Using spectroscopic information for magnetometry and magnetic microscopy obviously requires detailed theoretical understanding of spectral shape and magnitude of dichroism signals. A research team at ALS Beamline 4.0.2 has now shown unambiguously that, contrary to common belief, spectral shape and magnitude of x-ray magnetic linear dichroism (XMLD) are not only determined by the relative orientation of magnetic moments and
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Print Using spectroscopic information for magnetometry and magnetic microscopy obviously requires detailed theoretical understanding of spectral shape and magnitude of dichroism signals. A research team at ALS Beamline 4.0.2 has now shown unambiguously that, contrary to common belief, spectral shape and magnitude of x-ray magnetic linear dichroism (XMLD) are not only determined by the relative orientation of magnetic moments and
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Print Using spectroscopic information for magnetometry and magnetic microscopy obviously requires detailed theoretical understanding of spectral shape and magnitude of dichroism signals. A research team at ALS Beamline 4.0.2 has now shown unambiguously that, contrary to common belief, spectral shape and magnitude of x-ray magnetic linear dichroism (XMLD) are not only determined by the relative orientation of magnetic moments and
Intrinsic quantum anomalous Hall effect in the kagome lattice Cs_{2}LiMn_{3}F_{12}
Xu, Gang; Lian, Biao; Zhang, Shou -Cheng
2015-10-27
In a kagome lattice, the time reversal symmetry can be broken by a staggered magnetic flux emerging from ferromagnetic ordering and intrinsic spin-orbit coupling, leading to several well-separated nontrivial Chern bands and intrinsic quantum anomalous Hall effect. Based on this idea and ab initio calculations, we propose the realization of the intrinsic quantum anomalous Hall effect in the single layer Cs_{2}Mn_{3}F_{12} kagome lattice and on the (001) surface of a Cs_{2}LiMn_{3}F_{12} single crystal by modifying the carrier coverage on it, where the band gap is around 20 meV. Furthermore, a simplified tight binding model based on the in-plane ddσ antibonding states is constructed to understand the topological band structures of the system.
Anomalous Hall effect in epitaxial ferrimagnetic anti-perovskite Mn{sub 4−x}Dy{sub x}N films
Meng, M.; Wu, S. X. Zhou, W. Q.; Ren, L. Z.; Wang, Y. J.; Wang, G. L.; Li, S. W.
2015-08-07
Anomalous Hall effect (AHE) has been studied for ferrimagnetic antiperovskite Mn{sub 4−x}Dy{sub x}N films grown by molecular-beam epitaxy. The introduction of Dy changes the AHE dramatically, even changes its sign, while the variations in magnetization are negligible. Two sign reversals of the AHE (negative-positive-negative) are ascribed to the variation of charge carriers as a result of Fermi surface reconstruction. We further demonstrate that the AHE current J{sub AH} is dissipationless (independent of the scattering rate), by confirming that anomalous Hall conductivity, σ{sub AH}, is proportional to the carrier density n at 5 K. Our study may provide a route to further utilize antiperovskite manganese nitrides in spintronics.
Minimizing magnetic fields for precision experiments
Altarev, I.; Fierlinger, P.; Lins, T.; Marino, M. G.; Nießen, B.; Petzoldt, G.; Reisner, M.; Stuiber, S. Sturm, M.; Taggart Singh, J.; Taubenheim, B.; Rohrer, H. K.; Schläpfer, U.
2015-06-21
An increasing number of measurements in fundamental and applied physics rely on magnetically shielded environments with sub nano-Tesla residual magnetic fields. State of the art magnetically shielded rooms (MSRs) consist of up to seven layers of high permeability materials in combination with highly conductive shields. Proper magnetic equilibration is crucial to obtain such low magnetic fields with small gradients in any MSR. Here, we report on a scheme to magnetically equilibrate MSRs with a 10 times reduced duration of the magnetic equilibration sequence and a significantly lower magnetic field with improved homogeneity. For the search of the neutron's electric dipole moment, our finding corresponds to a 40% improvement of the statistical reach of the measurement. However, this versatile procedure can improve the performance of any MSR for any application.
Platinum dendritic nanoparticles with magnetic behavior
Li, Wenxian; Sun, Ziqi; Nevirkovets, Ivan P.; Dou, Shi-Xue; Tian, Dongliang
2014-07-21
Magnetic nanoparticles have attracted increasing attention for biomedical applications in magnetic resonance imaging, high frequency magnetic field hyperthermia therapies, and magnetic-field-gradient-targeted drug delivery. In this study, three-dimensional (3D) platinum nanostructures with large surface area that features magnetic behavior have been demonstrated. The well-developed 3D nanodendrites consist of plentiful interconnected nano-arms ?4?nm in size. The magnetic behavior of the 3D dendritic Pt nanoparticles is contributed by the localization of surface electrons due to strongly bonded oxygen/Pluronic F127 and the local magnetic moment induced by oxygen vacancies on the neighboring Pt and O atoms. The magnetization of the nanoparticles exhibits a mixed paramagnetic and ferromagnetic state, originating from the core and surface, respectively. The 3D nanodendrite structure is suitable for surface modification and high amounts of drug loading if the transition temperature was enhanced to room temperature properly.
Filament capturing with the multimaterial moment-of-fluid method*
Jemison, Matthew; Sussman, Mark; Shashkov, Mikhail
2015-01-15
A novel method for capturing two-dimensional, thin, under-resolved material configurations, known as “filaments,” is presented in the context of interface reconstruction. This technique uses a partitioning procedure to detect disconnected regions of material in the advective preimage of a cell (indicative of a filament) and makes use of the existing functionality of the Multimaterial Moment-of-Fluid interface reconstruction method to accurately capture the under-resolved feature, while exactly conserving volume. An algorithm for Adaptive Mesh Refinement in the presence of filaments is developed so that refinement is introduced only near the tips of filaments and where the Moment-of-Fluid reconstruction error is still large. Comparison to the standard Moment-of-Fluid method is made. As a result, it is demonstrated that using filament capturing at a given resolution yields gains in accuracy comparable to introducing an additional level of mesh refinement at significantly lower cost.
Electric dipole moments from flavored CP violation in supersymmetry
Calibbi, L.; Perez, J. Jones; Vives, O.
2008-10-01
The so-called supersymmetric flavor and CP problems are deeply related to the origin of flavor and hence to the origin of the standard model Yukawa couplings themselves. We show that realistic SU(3) flavor symmetries with spontaneous CP violation reproducing correctly the standard model Yukawa matrices can simultaneously solve both problems without ad hoc modifications of the supersymmetric model. We analyze the leptonic electric dipole moments and lepton flavor violation processes in these models. We show that the electron electric dipole moment and the decay {mu}{yields}e{gamma} are naturally within reach of the proposed experiments if the sfermion masses are measurable at the LHC.
A Peek Inside the Earliest Moments of the Universe
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
A Peek Inside the Earliest Moments of the Universe A Peek Inside the Earliest Moments of the Universe LQCD Calculations Help Physicists Probe Big Bang Nucleosynthesis July 5, 2016 Contact: Kathy Kincade, kkincade@lbl.gov, +1 510 495 2124 musun The MuSun experiment at the Paul Scherrer Institute is measuring the rate for muon capture on the deuteron to better than 1.5% precision. This process is the simplest weak interaction on a nucleus that can be measured to a high degree of precision. The Big
Anomalous diffusion and Tsallis statistics in an optical lattice
Lutz, Eric
2003-05-01
We point out a connection between anomalous transport in an optical lattice and Tsallis' generalized statistics. Specifically, we show that the momentum equation for the semiclassical Wigner function which describes atomic motion in the optical potential, belongs to a class of transport equations recently studied by Borland [Phys. Lett. A 245, 67 (1998)]. The important property of these ordinary linear Fokker-Planck equations is that their stationary solutions are exactly given by Tsallis distributions. An analytical expression of the Tsallis index q in terms of the microscopic parameters of the quantum-optical problem is given and the spatial coherence of the atomic wave packets is discussed.
A fractional Fokker-Planck model for anomalous diffusion
Anderson, Johan; Kim, Eun-jin; Moradi, Sara
2014-12-15
In this paper, we present a study of anomalous diffusion using a Fokker-Planck description with fractional velocity derivatives. The distribution functions are found using numerical means for varying degree of fractionality of the stable Lévy distribution. The statistical properties of the distribution functions are assessed by a generalized normalized expectation measure and entropy in terms of Tsallis statistical mechanics. We find that the ratio of the generalized entropy and expectation is increasing with decreasing fractionality towards the well known so-called sub-diffusive domain, indicating a self-organising behavior.
Crowding and Anomalous Capacitance at an ElectrodeIonic Liquid...
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Crowding and Anomalous Capacitance at an ElectrodeIonic Liquid Interface Observed Using Operando X-ray Scattering Citation Details In-Document Search Title: Crowding and ...