WorldWideScience

Sample records for anomalous magnetic properties

  1. Anomalous magnetic properties of VOx multiwall nanotubes

    Science.gov (United States)

    Demishev, S. V.; Chernobrovkin, A. L.; Glushkov, V. V.; Goodilin, E. A.; Grigorieva, A. V.; Ishchenko, T. V.; Kuznetsov, A. V.; Sluchanko, N. E.; Tretyakov, Yu D.; Semeno, A. V.

    2010-01-01

    Basing on the high frequency (60 GHz) electron spin resonance (ESR) and magnetic susceptibility study of the VOx multiwall nanotubes (VOx-NTs) in the range 4.2-300 K we report the ESR evidence of the presence of the antiferromagnetic V4+ dimers in VOx-NTs and the observation of an anomalous low temperature (T<50 K) growth of the magnetic susceptibility for V4+ quasi-free spins, which obey power law χ(T)~1/Tα with the exponent αapprox0.6. The estimates of the concentrations for various spin species (clusters) indicate that the non-interacting dimers should be an essential element in the VOx-NTs structure. The possibility of the disorder driven quantum critical regime in VOx-NTs is discussed.

  2. Anomalous magnetic properties in Ni50Mn35In15

    International Nuclear Information System (INIS)

    We present here a comprehensive investigation of the magnetic ordering in Ni50Mn35In15 composition. A concomitant first order martensitic transition and the magnetic ordering occurring in this off-stoichiometric Heusler compound at room temperature signify the multifunctional character of this magnetic shape memory alloy. Unusual features are observed in the dependence of the magnetization on temperature that can be ascribed to a frustrated magnetic order. It is compelling to ascribe these features to the cluster type description that may arise due to inhomogeneity in the distribution of magnetic atoms. However, evidence is presented from our ac susceptibility, electrical resistivity and dc magnetization studies that there exists a competing ferromagnetic and antiferromagnetic order within the crystal structure of this system. We show that excess Mn atoms that substitute the In atoms have a crucial bearing on the magnetic order of this compound. These excess Mn atoms are antiferromagnetically aligned to the other Mn, which explains the peculiar dependence of magnetization on temperature.

  3. Anomalous increase in the magnetorheological properties of magnetic fluid induced by silica nanoparticles

    Science.gov (United States)

    Desai, Rucha; Upadhyay, R. V.

    2014-12-01

    Magnetorheological properties are experimentally investigated in aqueous magnetic fluid containing spherical silica nanoparticles. A bi-dispersed system is prepared using aqueous suspension of silica nanoparticles and aqueous magnetic fluid. Both these fluids exhibit Newtonian viscosity with nominal values of 1.3 and 5.8 mPa\\cdot s at 20 °C. Three different samples are prepared by varying silica and magnetic fluid concentrations and keeping the total volume constant. The addition of silica nanoparticles leads to enhancement of the magnetic field induced viscosity up to the order 107 Pa\\cdot s. The magnetic field induced viscosity is analyzed using the structural viscosity model. Magnetic field induced static and dynamic yield stress values to reveal the existence of field induced clustering. An attempt is made to explain this yielding behavior using chain-like and micromechanical models. It is found that high silica fraction leads to the formation of chain-like structure. At low silica fraction, chains overlap and result into layer aggregates, which are responsible for the anomalous increase in the magnetorheological properties. This is further confirmed using magnetic field microscopic chain formations.

  4. Anomalous increase in the magnetorheological properties of magnetic fluid induced by silica nanoparticles

    International Nuclear Information System (INIS)

    Magnetorheological properties are experimentally investigated in aqueous magnetic fluid containing spherical silica nanoparticles. A bi-dispersed system is prepared using aqueous suspension of silica nanoparticles and aqueous magnetic fluid. Both these fluids exhibit Newtonian viscosity with nominal values of 1.3 and 5.8 mPa⋅s at 20 °C. Three different samples are prepared by varying silica and magnetic fluid concentrations and keeping the total volume constant. The addition of silica nanoparticles leads to enhancement of the magnetic field induced viscosity up to the order 107 Pa⋅s. The magnetic field induced viscosity is analyzed using the structural viscosity model. Magnetic field induced static and dynamic yield stress values to reveal the existence of field induced clustering. An attempt is made to explain this yielding behavior using chain-like and micromechanical models. It is found that high silica fraction leads to the formation of chain-like structure. At low silica fraction, chains overlap and result into layer aggregates, which are responsible for the anomalous increase in the magnetorheological properties. This is further confirmed using magnetic field microscopic chain formations. (paper)

  5. ANOMALOUS ELECTRODEPOSITION OF Fe-Ni ALLOY COATING FROM SIMPLE AND COMPLEX BATHS AND ITS MAGNETIC PROPERTY

    Directory of Open Access Journals (Sweden)

    M A Islam

    2010-03-01

    Full Text Available Electrodeposition of Fe-Ni thin films has been carried on copper substrate under various electrodeposition conditions from two simple and six complex baths. Sulfate baths composing of NiSO4. 7H2O, FeSO4.7H2O, H3BO3 and Na2SO4KEYWORDS: Anomalous Electrodeposition, Fe-Ni Coating, Complexing agent, Current Density, Magnetic Property. 1. INTRODUCTION Alloy electrodeposition technologies can extend tremendously the potential of electrochemical deposition processes to provide coatings that require unique mechanical, chemical and physical properties [1]. There has been a great research interest in the development and characterization of iron-nickel (Fe-Ni thin films due to their operational capacity, economic interest, magnetic and other properties [2]. Due to their unique low coefficient of thermal expansion (CTE and soft magnetic properties, Fe-Ni alloys have been used in industrial applications for over 100 years [3]. Typical examples of applications that are based on the low CTE of Fe-Ni alloys include: thermostatic bimetals, glass sealing, integrated circuit packaging, cathode ray tube, shadow masks, membranes for liquid natural gas tankers; applications based on the soft magnetic properties include: read-write heads for magnetic storage, magnetic actuators, magnetic shielding, high performance transformer cores. comprise the simple baths whereas complex baths were prepared by adding ascorbic acid, saccharin and citric acid in simple baths. The effect of bath composition, pH and applied current density on coating appearance, composition, morphology and magnetic property were studied. Wet chemical analysis technique was used to analyze the coating composition whereas SEM and VSM were used to study the deposit morphology and magnetic property respectively. Addition of complexing agents in plating baths suppressed the anomalous nature of Fe-Ni alloy electrodeposition. Coatings obtained from simple baths were characterized by coarse grained non

  6. ANOMALOUS ELECTRODEPOSITION OF Fe-Ni ALLOY COATING FROM SIMPLE AND COMPLEX BATHS AND ITS MAGNETIC PROPERTY

    OpenAIRE

    M A Islam

    2010-01-01

    Electrodeposition of Fe-Ni thin films has been carried on copper substrate under various electrodeposition conditions from two simple and six complex baths. Sulfate baths composing of NiSO4. 7H2O, FeSO4.7H2O, H3BO3 and Na2SO4KEYWORDS: Anomalous Electrodeposition, Fe-Ni Coating, Complexing agent, Current Density, Magnetic Property. 1. INTRODUCTION Alloy electrodeposition technologies can extend tremendously the potential of electrochemical deposition processes to provide coatings that require ...

  7. Magnetic and anomalous electronic transport properties of the quaternary Heusler alloys Co2Ti1-xFexGe

    Science.gov (United States)

    Venkateswarlu, B.; Midhunlal, P. V.; Babu, P. D.; Kumar, N. Harish

    2016-06-01

    The half-metallic Heusler alloy Co2TiGe has a ferromagnetic ground state with a low magnetic moment (2 μB). It is free of atomic antisite disorder but has low Curie temperature (~390 K). In contrast the other cobalt based Heusler alloy Co2FeGe has high Curie temperature (~980 K) and high magnetic moment (5.6 μB) while exhibiting antisite disorder and lack of half-metallicity. Hence it is of interest to investigate the magnetic and transport properties of solid solutions of these two materials with contrasting characteristics. We report the structural, magnetic and electronic transport properties of quaternary Co2Ti1-x FexGe (x=0.2, 0.4, 0.6, 0.8) Heusler alloys. The alloys crystallize in L21 structure but with antisite disorder. The magnetization measurements revealed that the alloys were of soft ferromagnetic type with high Curie temperatures. Deviation from Slater-Pauling behavior and drastic change in electronic transport properties with some anomalous features were observed.The complex electronic transport properties have been explained using different scattering mechanisms.

  8. Synthesis and anomalous magnetic properties of hexagonal CoO nanoparticles

    International Nuclear Information System (INIS)

    Highlights: → The as-synthesized CoO nanoparticles are of pyramid configuration with hcp structure. → The hexagonal CoO particles do not exhibit antiferromagnetic transition around 300 K. → The CoO particles have relative large saturation magnetization and coercivity at 5 K. → The shift of hysteresis loops is consistent with the result of multisublattice model. → 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.

  9. Anomalous magnetic moment of anyons

    CERN Document Server

    Gat, G; Gat, Gil; Ray, Rashmi

    1994-01-01

    The anomalous magnetic moment of anyons is calculated to leading order in a 1/N expansion. It is shown that the gyromagnetic ratio g remains 2 to the leading order in 1/N. This result strongly supports that obtained in \\cite{poly}, namely that g=2 is in fact exact.

  10. Minimal muon anomalous magnetic moment

    CERN Document Server

    Biggio, Carla

    2014-01-01

    We classify all possible one-particle (scalar and fermion) extensions of the Standard Model that can contribute to the anomalous magnetic moment of leptons. We review the cases already discussed in the literature and complete the picture by performing the calculation for a fermionic doublet with hypercharge -3/2. We conclude that, out of the listed possibilities, only two scalar leptoquarks and the pseudoscalar of a peculiar two-Higgs-doublet model could be the responsibles for the muon anomalous magnetic moment discrepancy. Were this the case, this particles could be seen in the next LHC run. To this aim, especially to test the leptoquark hypothesis, we suggest to look for final states with tops and muons.

  11. Anomalous magnetic moment with heavy virtual leptons

    Energy Technology Data Exchange (ETDEWEB)

    Kurz, Alexander [Karlsruher Institut fuer Technologie (Germany). Inst. fuer Theoretische Teilchenphysik; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Liu, Tao; Steinhauser, Matthias [Karlsruher Institut fuer Technologie (Germany). Inst. fuer Theoretische Teilchenphysik; Marquard, Peter [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2013-11-15

    We compute the contributions to the electron and muon anomalous magnetic moment induced by heavy leptons up to four-loop order. Asymptotic expansion is applied to obtain three analytic expansion terms which show rapid convergence.

  12. Nanodomain induced anomalous magnetic and electronic transport properties of LaBaCo2O5.5+δ highly epitaxial thin films

    International Nuclear Information System (INIS)

    A giant magnetoresistance effect (∼46% at 20 K under 7 T) and anomalous magnetic properties were found in a highly epitaxial double perovskite LaBaCo2O5.5+δ (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)LBCO || (001)MgO and [001]LBCO || [100]MgO or [010]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

  13. On the photon anomalous magnetic moment

    CERN Document Server

    Villalba, S; Villalba, Selym; Rojas, Hugo Perez

    2006-01-01

    It is shown that due to radiative corrections a photon having a non vanishing component of its momentum perpendicular to it, bears a non-zero magnetic moment. All modes of propagation of the polarization operator in one loop approximation are discussed and in this field regime the dispersion equation and the corresponding magnetic moment are derived. Near the first thresholds of cyclotron resonance the photon magnetic moment has a peak larger than the electron anomalous magnetic moment. Related to this magnetic moment, the arising of some sort of photon "dynamical mass" and a gyromagnetic ratio are discussed. These latter results might be interesting in an astrophysical context.

  14. Anomalous magnetoresistance in magnetized topological insulator cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Siu, Zhuo Bin, E-mail: a0018876@nus.edu.sg [NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456 (Singapore); Data Storage Institute, Agency for Science, Technology and Research, Singapore 117608 (Singapore); Jalil, Mansoor B. A. [NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456 (Singapore)

    2015-05-07

    The close coupling between the spin and momentum degrees of freedom in topological insulators (TIs) presents the opportunity for the control of one to manipulate the other. The momentum can, for example, be confined on a curved surface and the spin influenced by applying a magnetic field. In this work, we study the surface states of a cylindrical TI magnetized in the x direction perpendicular to the cylindrical axis lying along the z direction. We show that a large magnetization leads to an upwards bending of the energy bands at small |k{sub z}|. The bending leads to an anomalous magnetoresistance where the transmission between two cylinders magnetized in opposite directions is higher than when the cylinders are magnetized at intermediate angles with respect to each other.

  15. Anomalous Josephson Hall effect in magnet/triplet superconductor junctions

    OpenAIRE

    Yokoyama, Takehito

    2015-01-01

    We investigate anomalous Hall effect in a magnet coupled to a triplet superconductor under phase gradient. It is found that the anomalous Hall supercurrent arises from non-trivial structure of the magnetization. The magnetic structure manifested in the Hall supercurrent is characterized by even order terms of the exchange coupling, essentially different from that discussed in the context of anomalous Hall effect, reflecting the disspationless nature of supercurrent. We also discuss a possible...

  16. Anomalous magnetic field effects on graphene

    International Nuclear Information System (INIS)

    Full text: Graphene exhibits anomalous properties in externally applied magnetic field. The orbital susceptibility of graphene has a singularity expressed as a delta function in Fermi energy EF, which diverges at Dirac point (EF =0) and vanishes otherwise. The singular diamagnetism is modified by various external factors such as the disorder potential [1], and the band gap opening [2,3], the finite-size effect [4] and the multilayer stacking [5], and studying those effects give deeper insights into the origin of the diamagnetic singularity of Dirac electron. The delta-function singularity is generally weakened by the electronic coupling between different graphene layers. In usual AB-stacked multilayer graphite, the interlayer coupling changes monlayer's linear band to quadratic, and then the susceptibility peak is broadened into a less singular logarithmic curve [5]. In a turbostratic (randomly-stacked) graphene multilayer, on the other hand, the diamagnetism generally becomes much stronger than in AB-stacked graphite, because the interlayer coupling is significantly reduced in misoriented lattice structure. There the external magnetic field is significantly screened inside the sample in low temperatures, and even a perfect screening is achieved at zero temperature in an ideal sample [4]. When the stacking angle between two graphene layers becomes as small as a few degree, the electronic structure is strongly modified by the long-period lattice structure with a Moire pattern. In increasing magnetic field, the spectrum gradually evolves into a fractal band structure called Hofstadter's butterfly, where the Hall conductivity exhibits a nonmonotonic behavior as a function of Fermi energy [6]. In finite-sized graphene system such as graphene ribbon and graphene nano-islands, the finite-size effect also changes the singular diamagnetism.[4] At T=0, the susceptibility χ(EF) oscillates between diamagnetism and paramagnetism in accordance with the subband structure formed

  17. The peak in anomalous magnetic viscosity

    International Nuclear Information System (INIS)

    Anomalous magnetic viscosity, where the magnetization as a function of time exhibits non-monotonic behaviour, being seen to increase, reach a peak, and then decrease, is observed on recoil lines in bulk amorphous ferromagnets, for certain magnetic prehistories. A simple geometrical approach based on the motion of the state line on the Preisach plane gives a theoretical framework for interpreting non-monotonic behaviour and explains the origin of the peak. This approach gives an expression for the time taken to reach the peak as a function of the applied (or holding) field. The theory is applied to experimental data for bulk amorphous ferromagnet alloys of composition Nd60−xFe30Al10Dyx, x = 0, 1, 2, 3 and 4, and it gives a reasonable description of the observed behaviour. The role played by other key magnetic parameters, such as the intrinsic coercivity and fluctuation field, is also discussed. When the non-monotonic behaviour of the magnetization of a number of alloys is viewed in the context of the model, features of universal behaviour emerge, that are independent of alloy composition. - Highlights: • Development of a simple geometrical model based on the Preisach model which gives a complete explanation of the peak in the magnetic viscosity. • Geometrical approach is extended by considering equations that govern the motion of the state line. • The model is used to deduce the relationship between the holding field and the time it takes to reach the peak. • The model is tested with experimental results for a range of Nd–Fe–Al–Dy bulk amorphous ferromagnets. • There is good agreement between the model and the experimental data

  18. ''Anomalous'' properties of technetium clusters

    International Nuclear Information System (INIS)

    The authors show how some properties of technetium clusters can be explained on the basis of a qualitative model of the electrostatic repulsion of the metal atoms in the clusters. The position of technetium in the periodic table, as well as the experimentally recently discovered ability of technetium to lower the effective charge on its atoms when M-M bonds are formed by them, impart a high capacity to this element to form clusters with both weak-field ligands and strong field ligands

  19. Spectral Properties of Anomalous X-ray Pulsars

    Institute of Scientific and Technical Information of China (English)

    Ye Lu; Wei Wang; Yong-Heng Zhao

    2003-01-01

    We examine the spectra of the persistent emission from anomalous X-ray pulsars (AXPs) and their variation with the spin-down rate Ω. Based on an accretion-powered model, the influences of both the magnetic field and the mass accretion rate on the spectral properties of AXPs are addressed. We then investigate the relation between the spectral property of AXPs and mass accretion rate M. The result shows that there exists a linear correlation between the photon index and the mass accretion rate: the spectral hardness increases with increasing M. A possible emission mechanism for the explanation of the spectral properties of AXPs is also discussed.

  20. Anomalous hysteresis properties of iron films deposited on liquid surfaces

    Science.gov (United States)

    Ye, Quan-Lin; Feng, Chun-Mu; Xu, Xiao-Jun; Jin, Jin-Sheng; Xia, A.-Gen; Ye, Gao-Xiang

    2005-07-01

    A nearly free sustained iron film system, deposited on silicone oil surfaces by vapor-phase deposition method, has been fabricated and its crystal structure as well as magnetic properties has been studied. Both the temperature-dependent coercivity Hc(T) and exchange anisotropy field HE(T) of the iron films possess a maximum peak around the critical temperature Tcrit=10-15 and 4K, respectively. Our experimental results show that the anomalous hysteresis properties mainly result from the oxide surfaces of the films with spin-glass-like phase below freezing temperature Tf=30-50K.

  1. Anomalous transport effects in magnetically-confined plasma columns

    International Nuclear Information System (INIS)

    The evolution of density structure in a magnetized plasma column is analyzed accounting for anomalous diffusion due to the lower hybrid drift instability. The plasma column is found to be divided into regions of classical, anomalous, and intermediate diffusivity. The bulk behavior, described in terms of radial confinement time, depends most sensitively upon the particle line density (ion/cm). For broad plasmas (large line density), the transport is characteristic of classical diffusion, and for slender plasmas (small line density) the transport is characteristic of anomalous diffusion. For intermediate line densities, the transport undertakes a rapid transition from classical to anomalous. Correlations between the theoretical results and past experiments are described

  2. A note on the anomalous magnetic moment of the muon

    CERN Document Server

    Palle, Davor

    2016-01-01

    The anomalous magnetic moment of the muon is an important observable that tests radiative corrections of all three observed local gauge forces: electromagnetic, weak and strong interactions. High precision measurements reveal some discrepancy with the most accurate theoretical evaluations of the anomalous magnetic moment. We show in this note that the UV finite theory cannot resolve this discrepancy. We believe that more reliable estimate of the nonperturbative hadronic contribution and the new measurements can resolve the problem.

  3. Quantization of Spinning Particle with Anomalous Magnetic Momentum

    OpenAIRE

    Gitman, D. M.; Saa, A. V.

    1992-01-01

    A generalization of the pseudoclassical action of a spinning particle in the presence of an anomalous magnetic moment is given. The leading considerations, to write the action, are gotten from the path integral representation for the causal Green's function of the generalized (by Pauli) Dirac equation for the particle with anomalous magnetic momentum in an external electromagnetic field. The action can be written in reparametrization and supergauge invariant form. Both operator (Dirac) and pa...

  4. Quasi-periodic table and anomalous metallic properties

    International Nuclear Information System (INIS)

    The electron states in atoms and solids are compared in an attempt to gain some insight into the quasi-localized behavior of the heavy-electron materials. These materials occur in compounds containing elements that have uncertainties in their electronic configurations both in the free atoms and in the metals. It is found that unlike the long range phenomena of conventional superconductivity in the transition metals and local-moment magnetism in the rare-earth systems, the site quantum numbers in the heavy-electron systems have not yet been determined. These uncertainties lead to the anomalous properties of these systems. 22 references, 3 figures, 1 table

  5. Magnetic Topological Insulators and Quantum Anomalous Hall Effect

    Science.gov (United States)

    Kou, Xufeng

    The engineering of topological surface states is a key to realize applicable devices based on topological insulators (TIs). Among various proposals, introducing magnetic impurities into TIs has been proven to be an effective way to open a surface gap and integrate additional ferromagnetism with the original topological order. In this Dissertation, we study both the intrinsic electrical and magnetic properties of the magnetic TI thin films grown by molecular beam epitaxy. By doping transition element Cr into the host tetradymite-type V-VI semiconductors, we achieve robust ferromagnetic order with a strong perpendicular magnetic anisotropy. With additional top-gating capability, we realize the electric-field-controlled ferromagnetism in the magnetic TI systems, and demonstrate such magneto-electric effects can be effectively manipulated, depending on the interplays between the band topology, magnetic exchange coupling, and structural engineering. Most significantly, we report the observation of quantum anomalous Hall effect (QAHE) in the Cr-doped (BiSb)2Te3 samples where dissipationless chiral edge conduction is realized in the macroscopic millimeter-size devices without the presence of any external magnetic field, and the stability of the quantized Hall conductance of e2/h is well-maintained as the film thickness varies across the 2D hybridization limit. With additional quantum confinement, we discover the metal-to-insulator switching between two opposite QAHE states, and reveal the universal QAHE phase diagram in the thin magnetic TI samples. In addition to the uniform magnetic TIs, we further investigate the TI/Cr-doped TI bilayer structures prepared by the modulation-doped growth method. By controlling the magnetic interaction profile, we observe the Dirac hole-mediated ferromagnetism and develop an effective way to manipulate its strength. Besides, the giant spin-orbit torque in such magnetic TI-based heterostructures enables us to demonstrate the current

  6. Pseudoclassical Model of Spinning Particle with Anomalous Magnetic Momentum

    CERN Document Server

    Gitman, D M

    1993-01-01

    A generalization of the pseudoclassical action of a spinning particle in the presence of an anomalous magnetic momentum is given. The action is written in reparametrization and supergauge invariant form. The Dirac quantization, based on the Hamiltonian analyses of the model, leads to the Dirac-Pauli equation for a particle with an anomalous magnetic momentum in an external electromagnetic field. Due to the structure of first-class constraints in that case, the Dirac quantization demands for consistency to take into account an operators ordering problem.

  7. Anomalous Magnetic Moments and Quark Orbital Angular Momentum

    OpenAIRE

    Burkardt, M.; Schnell, G.(University of the Basque Country UPV/EHU, 48080 Bilbao, Spain)

    2005-01-01

    We derive an inequality for the distribution of quarks with non-zero orbital angular momentum, and thus demonstrate, in a model-independent way, that a non-vanishing anomalous magnetic moment requires both a non-zero size of the target as well as the presence of wave function components with quark orbital angular momentum L_z>0.

  8. Composite scalar contributions to the anomalous magnetic moments

    International Nuclear Information System (INIS)

    It is shown that the composite scalars recently introduced to explain the high Z0 → e+e-γ rate contribute too much to the lepton anomalous magnetic moments, unless one uses very accurate chiral symmetry or composite models with two preonic scales. (Author)

  9. Magnetic Instability in Accretion Disks with Anomalous Viscosity

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ai-Ping; LI Xiao-Qing

    2004-01-01

    @@ Using the new model of anomalous viscosity, we investigate the magnetic instability in the accretion disks and give the dispersion formula. On the basis of the dispersion relation obtained, it is numerically shown that the instability condition of viscous accretion disk is well consistent with that of the ideal accretion disk, namely there would be magneto-rotational instability in the presence of a vertical weak magnetic field. For a given distance R from the centre of the disk, the growth rate in the anomalous case deviates from the ideal case more greatly when the vertical magnetic field is smaller. The large viscosity limits to the instability. In the two cases, the distributions of growth rate with wave number k approach each other when the magnetic field increases. It greatly represses the effect of viscosity.

  10. Quantum Anomalous Hall Effect in Magnetic Insulator Heterostructure

    OpenAIRE

    Xu, Gang; Jing WANG; FELSER, CLAUDIA; Qi, Xiao-Liang; Zhang, Shou-Cheng

    2014-01-01

    Based on ab initio calculations, we predict that a monolayer of Cr-doped (Bi,Sb)2Te3 and GdI2 heterostructure is a quantum anomalous Hall insulator with a non-trivial band gap up to 38 meV. The principle behind our prediction is that the band inversion between two topologically trivial ferromagnetic insulators can result in a non-zero Chern number, which offers a better way to realize the quantum anomalous Hall state without random magnetic doping. In addition, a simple effective model is pre...

  11. Anomalous magnetic moment and Compton wavelength

    OpenAIRE

    Heyrovska, Raji

    2004-01-01

    The relativistic and quantum theoretical explanations of the magnetic moment anomaly of the electron (or proton) show that it is a complicated function of the fine structure constant. In this work, a simple non-relativistic approach shows that the translational motion of the particle during its spin is responsible for the observed effects.

  12. Anomalous Hall Effect in Geometrically Frustrated Magnets

    Directory of Open Access Journals (Sweden)

    D. Boldrin

    2012-01-01

    space mechanism based on spin chirality that was originally applied to the pyrochlore Nd2Mo2O7 appears unsatisfactory. Recently, an orbital description based on the Aharonov-Bohm effect has been proposed and applied to both the ferromagnetic pyrochlores Nd2Mo2O7 and Pr2Ir2O7; the first of which features long-ranged magnetic order while the latter is a chiral spin liquid. Two further examples of geometrically frustrated conducting magnets are presented in this paper—the kagome-like Fe3Sn2 and the triangular PdCrO2. These possess very different electronic structures to the 3-dimensional heavy-metal pyrochlores and provide new opportunities to explore the different origins of the AHE. This paper summarises the experimental findings in these materials in an attempt to unite the conflicting theoretical arguments.

  13. Millicharged neutrino with anomalous magnetic moment in rotating magnetized matter

    CERN Document Server

    Studenikin, Alexander

    2014-01-01

    We consider a millicharged neutrino with nonzero magnetic moment in the presence of rotating and magnetized background matter. The exact solution of the corresponding modified Dirac equation for the neutrino wave function is found. The neutrino energy spectrum is obtained and the effect of neutrino energy quantization is discussed in details. We introduce a new kind of spin operator which is a superposition of longitudinal and transverse polarizations operators for description of the neutrino spin properties in the considered background environment. Within the quasi-classical approach to the problem, radius of the neutrino orbits is derived and the effective "matter induced Lorentz force" is introduced. It is shown that in the considered environment, and also in matter with nonzero gradient of density, neutrino moves with acceleration. In this case a new type of the electromagnetic neutrino radiation (termed "light of millicharged neutrino") can be produced. The considered problem is of interest for astrophys...

  14. Quantization of Spinning Particle with Anomalous Magnetic Momentum

    CERN Document Server

    Gitman, D M

    1993-01-01

    A generalization of the pseudoclassical action of a spinning particle in the presence of an anomalous magnetic moment is given. The leading considerations, to write the action, are gotten from the path integral representation for the causal Green's function of the generalized (by Pauli) Dirac equation for the particle with anomalous magnetic momentum in an external electromagnetic field. The action can be written in reparametrization and supergauge invariant form. Both operator (Dirac) and path-integral (BFV) quantization are discussed. The first one leads to the Dirac-Pauli equation, whereas the second one gives the corresponding propagator. One of the nontrivial points in this case is that both quantizations schemes demand for consistency to take into account an operators ordering problem.

  15. Searches for Magnetic Monopoles and Anomalously Charged Objects with ATLAS

    CERN Document Server

    Katre, Akshay; The ATLAS collaboration

    2016-01-01

    Results of searches for highly ionising particles and particles with anomalously high electric charge produced in proton-proton collisions in the ATLAS detector are presented. Such signatures, encompassing particles with charges from 10 to 60 times the electron charge, involve high levels of ionization in the ATLAS detector and can arise from magnetic monopoles or models involving technicolor, doubly charged Higgs bosons or composite dark matter models.

  16. Quantum anomalous Hall effect in magnetic topological insulators

    OpenAIRE

    Jing WANG; Lian, Biao; Zhang, Shou-Cheng

    2014-01-01

    The search for topologically non-trivial states of matter has become an important goal for condensed matter physics. Here, we give a theoretical introduction to the quantum anomalous Hall (QAH) effect based on magnetic topological insulators in two-dimension (2D) and three-dimension (3D). In 2D topological insulators, magnetic order breaks the symmetry between the counter-propagating helical edge states, and as a result, the quantum spin Hall effect can evolve into the QAH effect. In 3D, magn...

  17. Quantized Anomalous Hall Effect in Magnetic Topological Insulators

    Institute of Scientific and Technical Information of China (English)

    YU Rui

    2011-01-01

    The Hall effect, the anomalous Hall effect (AHE) and the spin Hall effect are thndamental transport processes in solids arising from the Lorentz force and the spin-orbit coupling respectively. The AHE, in which a voltage transverse to the electric current appears even in the absence of an external magnetic field, was first detected in ferromagnetic (FM) metals in 1881 and later found to arise from the spin-orbit coupling (SOC) between the current and magnetic moments.

  18. Quantized Anomalous Hall Effect in Magnetic Topological Insulators

    Institute of Scientific and Technical Information of China (English)

    YU Rui

    2011-01-01

    @@ The Hall effect, the anomalous Hall effect (AHE) and the spin Hall effect are fundamental transport processes in solids arising from the Lorentz force and the spin-orbit coupling respectively.The AHE, in which a voltage transverse to the electric current appears even in the absence of an external magnetic field, was first detected in ferromagnetic (FM) metals in 1881 and later found to arise from the spin-orbit coupling (SOC) between the current and magnetic moments.Recent progress on the mechanism of AHE has established a link between the AHE and the topological nature of the Hall current by adopting the Berry-phase concepts in close analogy to the intrinsic spin Hall effect.Given the experimental discovery of the quantum Hall and the quantum spin Hall effects, it is natural to ask whether the AHE can also be quantized.In a quantized anomalous Hall (QAH) insulator, spontaneous magnetic moments and spin-orbit coupling combine to give rise to a topologically non-trivial electronic structure, leading to the quantized Hall effect without any external magnetic field.

  19. Tau anomalous magnetic moment in γγ colliders

    Science.gov (United States)

    Peressutti, Javier; Sampayo, Oscar A.

    2012-08-01

    We investigate the possibility of setting model independent limits for a nonstandard anomalous magnetic moment aτNP of the tau lepton, in future γγ colliders based on Compton backscattering. For a hypothetical collider we find that, at various levels of confidence, the limits for aτNP could be improved, compared to previous studies based on LEP1, LEP2 and SLD data. We show the results for a realistic range of the center of mass energy of the e+e- collider. As a more direct application, we also present the results of the simulation for the photon collider at the TESLA project.

  20. Quantum anomalous Hall effect in magnetic topological insulators

    Science.gov (United States)

    Wang, Jing; Lian, Biao; Zhang, Shou-Cheng

    2015-12-01

    The search for topologically non-trivial states of matter has become an important goal for condensed matter physics. Here, we give a theoretical introduction to the quantum anomalous Hall (QAH) effect based on magnetic topological insulators in two-dimensions (2D) and three-dimensions (3D). In 2D topological insulators, magnetic order breaks the symmetry between the counter-propagating helical edge states, and as a result, the quantum spin Hall effect can evolve into the QAH effect. In 3D, magnetic order opens up a gap for the topological surface states, and chiral edge state has been predicted to exist on the magnetic domain walls. We present the phase diagram in thin films of a magnetic topological insulator and review the basic mechanism of ferromagnetic order in magnetically doped topological insulators. We also review the recent experimental observation of the QAH effect. We discuss more recent theoretical work on the coexistence of the helical and chiral edge states, multi-channel chiral edge states, the theory of the plateau transition, and the thickness dependence in the QAH effect.

  1. An interpolation of the vacuum polarization function for the evaluation of hadronic contributions to the muon anomalous magnetic moment

    International Nuclear Information System (INIS)

    We propose a simple parameterization of the two-point correlator of hadronic electromagnetic currents for the evaluation of the hadronic contributions to the muon anomalous magnetic moment. The parameterization is explicitly done in the Euclidean domain. The model function contains a phenomenological parameter which provides an infrared cutoff to guarantee the smooth behavior of the correlator at the origin in accordance with experimental data in e+e- annihilation. After fixing a numerical value for this parameter from the leading order hadronic contribution to the muon anomalous magnetic moment, the next-to-leading order results related to the vacuum polarization function are accurately reproduced. The properties of the four-point correlator of hadronic electromagnetic currents as for instance the so-called light-by-light scattering amplitude relevant for the calculation of the muon anomalous magnetic moment are briefly discussed. (orig.)

  2. Progress in analytical calculations for the anomalous magnetic moment of the muon

    Energy Technology Data Exchange (ETDEWEB)

    Baikov, P.A. [Moscow State Univ. (Russian Federation). Skobeltsyn Inst. of Nuclear Physics; Maier, A. [Technische Univ. Muenchen (Germany). Physik Dept. T31; Marquard, P. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2013-11-15

    We present results for certain classes of diagrams contributing to the anomalous magnetic moment of the muon at five-loop order. Our method is based on first constructing an approximating function for the vacuum polarization function of the photon at four loop order which later can be numerically integrated to obtain the anomalous magnetic moment of the muon.

  3. Anomalous wave structure in magnetized materials described by non-convex equations of state

    Energy Technology Data Exchange (ETDEWEB)

    Serna, Susana, E-mail: serna@mat.uab.es [Departament de Matematiques, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain); Marquina, Antonio, E-mail: marquina@uv.es [Departamento de Matematicas, Universidad de Valencia, 46100 Burjassot, Valencia (Spain)

    2014-01-15

    We analyze the anomalous wave structure appearing in flow dynamics under the influence of magnetic field in materials described by non-ideal equations of state. We consider the system of magnetohydrodynamics equations closed by a general equation of state (EOS) and propose a complete spectral decomposition of the fluxes that allows us to derive an expression of the nonlinearity factor as the mathematical tool to determine the nature of the wave phenomena. We prove that the possible formation of non-classical wave structure is determined by both the thermodynamic properties of the material and the magnetic field as well as its possible rotation. We demonstrate that phase transitions induced by material properties do not necessarily imply the loss of genuine nonlinearity of the wavefields as is the case in classical hydrodynamics. The analytical expression of the nonlinearity factor allows us to determine the specific amount of magnetic field necessary to prevent formation of complex structure induced by phase transition in the material. We illustrate our analytical approach by considering two non-convex EOS that exhibit phase transitions and anomalous behavior in the evolution. We present numerical experiments validating the analysis performed through a set of one-dimensional Riemann problems. In the examples we show how to determine the appropriate amount of magnetic field in the initial conditions of the Riemann problem to transform a thermodynamic composite wave into a simple nonlinear wave.

  4. Anomalous wave structure in magnetized materials described by non-convex equations of state

    International Nuclear Information System (INIS)

    We analyze the anomalous wave structure appearing in flow dynamics under the influence of magnetic field in materials described by non-ideal equations of state. We consider the system of magnetohydrodynamics equations closed by a general equation of state (EOS) and propose a complete spectral decomposition of the fluxes that allows us to derive an expression of the nonlinearity factor as the mathematical tool to determine the nature of the wave phenomena. We prove that the possible formation of non-classical wave structure is determined by both the thermodynamic properties of the material and the magnetic field as well as its possible rotation. We demonstrate that phase transitions induced by material properties do not necessarily imply the loss of genuine nonlinearity of the wavefields as is the case in classical hydrodynamics. The analytical expression of the nonlinearity factor allows us to determine the specific amount of magnetic field necessary to prevent formation of complex structure induced by phase transition in the material. We illustrate our analytical approach by considering two non-convex EOS that exhibit phase transitions and anomalous behavior in the evolution. We present numerical experiments validating the analysis performed through a set of one-dimensional Riemann problems. In the examples we show how to determine the appropriate amount of magnetic field in the initial conditions of the Riemann problem to transform a thermodynamic composite wave into a simple nonlinear wave

  5. On anomalously magnetic basalt lavas from Stardalur, Iceland

    International Nuclear Information System (INIS)

    In an attempt to explain an exceptionally strong magnetic anomaly near Stardalur, SW-Iceland, a 200 m deep hole was drilled into its centre and the core subjected to various mineralogical and geophysical measurements. In Moessbauer spectra of bulk samples from depths between 45 and 170 m the magnetic phase is predominant and consists of very pure magnetite. The area ratio for the components with hyperfine fields of 46 and 49 T is approximately 2. Comparison with spectra of selected basalt lavas showing similar magnetic properties indicates a distinctive difference. The strong remanent magnetism of the Stardalur samples can be explained by a combination of unusually high concentration in the rocks of pure magnetite, its small grain size and a strong magnetic field appending its formation. It is suggested that both the composition of the magnetic phase and the strong magnetic field were brought about by hydrothermal alteration. (orig.)

  6. Anomalous dispersion properties of TM waves in subwavelength metallic waveguides loaded by uniaxial metamaterials

    International Nuclear Information System (INIS)

    Dispersion properties of transverse magnetic (TM) waves in a subwavelength metallic waveguide loaded by uniaxial metamaterials are investigated, based on two kinds of uniaxial metamaterials with different orientations of optical axis. The numerical results show that the existence of fundamental TM0 mode and high-order TM modes in the waveguide system is dependent on the orientation of optical axis. In addition, their anomalous dispersion properties are clarified. When the orientation of optical axis is selected properly, there are two branches of dispersion curves for each high-order mode—one is normal dispersion and another belongs to anomalous dispersion, showing a transition from a backward wave to a forward one with the increase of working frequency. Moreover, the group velocity and energy flow distribution for TM1 mode are also demonstrated. These properties may have potential applications in optical information storage, integrated optics and nanophotonic devices. - Highlights: • Two kinds of subwavelength uniaxial metamaterial waveguides are constructed. • We demonstrate anomalous dispersion properties of transverse magnetic (TM) guided modes. • There are two branches of dispersion curves for high-order TM modes, showing a transition from a backward wave to a forward one. • Group velocity can approach to zero, having potential application in optical information storage. • Negative group velocity and energy flow distribution for TM modes are shown

  7. Lepton anomalous magnetic moments from twisted mass fermions

    CERN Document Server

    Burger, Florian; Jansen, Karl; Petschlies, Marcus

    2014-01-01

    We present our results for the leading-order hadronic quark-connected contributions to the electron, the muon, and the tau anomalous magnetic moments obtained with four dynamical quarks. Performing the continuum limit and an analysis of systematic effects, full agreement with phenomenological results is found. To estimate the impact of omitting the quark-disconnected contributions to the hadronic vacuum polarisation we investigate them on one of the four-flavour ensembles. Additionally, the light quark contributions on the four-flavour sea are compared to the values obtained for $N_f=2$ physically light quarks. In the latter case different methods to fit the hadronic vacuum polarisation function are tested.

  8. Precise quantization of anomalous Hall effect near zero magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Bestwick, A. J. [Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Fox, E. J. [Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Kou, Xufeng [Univ. of California, Los Angeles, CA (United States); Pan, Lei [Univ. of California, Los Angeles, CA (United States); Wang, Kang L. [Univ. of California, Los Angeles, CA (United States); Goldhaber-Gordon, D. [Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)

    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.

  9. Precision Measurement of the Anomalous Magnetic Moment of the Muon

    CERN Document Server

    Ozben, C S

    2002-01-01

    The muon g-2 experiment at Brookhaven National Laboratory measures the anomalous magnetic moment of the muon, $a_\\mu$, very precisely. This measurement tests the Standard Model theory. The analysis for the data collected in 2000 (a $\\mu^+$ run) is completed and the accuracy on $a_\\mu$ is improved to 0.7 ppm, including statistical and systematic errors. The data analysis was performed blindly between the precession frequency and the field analysis groups in order to prevent a possible bias in the $a_\\mu$ result. The observed difference between the theory and our most recent experimental result is quite important for further studies of the Standard Model theory. In 2001, we ran for the first time with $\\mu^-$ and the analysis of this data will provide $a_\\mu$ with similar statistical power.

  10. Rosenbluth scattering and Pauli's approach to anomalous magnetic moments

    International Nuclear Information System (INIS)

    In standard QED particle interactions are evaluated using minimal coupling, coupling the particles solely through their (electric monopole) charges. The Direc Hamiltonian is used to describe the interaction of a single spin-1/2 particle with an electromagnetic field. Pauli suggested the addition of a further gauge-invariant term to the Dirac Hamiltonian where the coupling constant for this extra term should not be directly linked to the particle's electric charge. We study some of the effects of this additional term and show that for the scattering of electrons off protons, the first-order Pauli-Dirac analysis has at least as good agreement with experiment as previous analyses based on the Dirac Hamiltonian. We show that Rosenbluth used the incorrect sign on the anomalous magnetic moment of the proton. (author)

  11. Anomalous Nernst Effect of Perpendicularly Magnetic Anisotropy TbFeCo Thin Films

    Science.gov (United States)

    Ando, Ryo; Komine, Takashi; Hasegawa, Yasuhiro

    2016-07-01

    In this study, we investigated anomalous Nernst effect (ANE) of perpendicularly magnetized TbFeCo thin films with various Tb content, and especially studied the relation between ANE and anomalous Hall effect. As a result, the hysteresis of anomalous Nernst coefficient showed the same behavior as that of anomalous Hall resistivity, and the sign of anomalous Nernst coefficient was consistent with that of anomalous Hall voltage in any Tb content, whereas the Seebeck coefficient and the resistivity were almost constant even if the applied magnetic field was varied. Taking into account of thermoelectric coefficient tensor, it was revealed that the off-diagonal thermopower corresponding to the ANE in TbFeCo thin films is the product of Hall angle and Seebeck coefficient.

  12. Light-by-light scattering and muon's anomalous magnetic moment

    International Nuclear Information System (INIS)

    implications of these results for mesons in both the light-quark sector and the charm-quark sector. In the second part of this thesis we develop the formalism to provide an improved estimate for the hadronic light-by-light (HLbL) correction to the muon's anomalous magnetic moment aμ, by considering single meson contributions beyond the leading pseudo-scalar mesons. This is motivated by the present 3σ deviation between the measurement of aμ and its estimate in the Standard Model. Furthermore, a forthcoming new experiment at Fermilab aims to improve the experimental precision by a factor of 4 which also requires a similar theoretical improvement. We incorporate available experimental input as well as constraints from light-by-light scattering sum rules to estimate the effects of axial-vector, scalar, and tensor mesons. We give numerical evaluations for the HLbL contribution of these states to aμ. The presented formalism allows to further improve on these estimates, once new data for such meson states will become available. In the last part of this work, we present a new dispersion formalism developed for the HLbL contribution to aμ and test the formalism for the case of scalar field theory. The new framework opens a unique possibility for a consistent incorporation of data from e+e- colliders for single- as well as multi-meson contributions. Furthermore, it allows to systematically control the HLbL uncertainty in the aμ which is a crucial step in searches of new physics using this precision quantity.

  13. New Physics Contributions to the Muon Anomalous Magnetic Moment

    CERN Document Server

    Queiroz, Farinaldo S

    2014-01-01

    We consider the contributions of individual new particles to the anomalous magnetic moment of the muon, utilizing the generic framework of simplified models. We also present analytic results for all possible one-loop contributions, allowing easy application of these results for more complete models which predict more than one particle capable of correcting the muon magnetic moment. Additionally, we provide a Mathematica code to allow the reader straightforwardly compute any 1-loop contribution. Furthermore, we derive bounds on each new particle considered, assuming either the absence of other significant contributions to $a_\\mu$ or that the anomaly has been resolved by some other mechanism. In summary we found the following particles capable of explaining the current discrepancy, assuming unit couplings: $2$TeV ($0.3$TeV) neutral scalar with pure scalar (chiral) couplings, $4$TeV doubly charged scalar with pure pseudoscalar coupling, $0.3-1$TeV neutral vector boson depending on what couplings are used (vector...

  14. Anomalous-Magnetic-Moment Effects in a Strongly Magnetized and Dense Medium

    CERN Document Server

    Ferrer, E J; Paret, D Manreza; Martínez, A Pérez

    2013-01-01

    We investigate the quantum corrections of the anomalous magnetic moment (AMM) for fermions in the presence of a strong magnetic field using the Ritus's approach. At strong fields the particles get different AMM's depending on the LL's. This result is different from what is obtained with the Schwinger's approximation at weak field where the AMM is independent of the LL. We analyze the significance of the AMM contribution to the Equation of State (EoS) of the magnetized system, in the weak and strong field approximations.

  15. Texture and Magnetic Properties

    OpenAIRE

    Morris, P. R.; Flowers, J. W.

    1981-01-01

    Expressions are derived for the dependence of the magnetic properties of cubic materials on texture. The theoretical development generally parallels that of Bunge, but employs Roe's formalism. The expressions, together with limited experimental data, enable one to express magnetic property variations in the plane of the sheet, to obtain property values for comparable texture-free specimens, and to separate magnetic properties into texture-dependent and texture-independent components. Core los...

  16. Soft gamma-ray repeaters and anomalous X-ray pulsars as highly magnetized white dwarfs

    CERN Document Server

    Mukhopadhyay, Banibrata

    2016-01-01

    We explore the possibility that soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are powered by highly magnetized white dwarfs (B-WDs). We take a sample of SGRs and AXPs and provide the possible parameter space in mass, radius, and surface magnetic field based on their observed properties (period and its derivative) and the assumption that these sources obey the mass-radius relation derived for the B-WDs. The radius and magnetic field of B-WDs are adequate to explain energies in SGRs/AXPs as the rotationally powered energy. In addition, B-WDs also adequately explain the perplexing radio transient GCRT J1745-3009 as a white dwarf pulsar. Note that the radius and magnetic fields of B-WDs are neither extreme (unlike of highly magnetized neutron stars) nor ordinary (unlike of magnetized white dwarfs, yet following the Chandrasekhar's mass-radius relation (C-WDs)). In order to explain SGRs/AXPs, while the highly magnetized neutron stars require an extra, observationally not well established yet, ...

  17. Particle with spin 2 and anomalous magnetic moment in external electromagnetic and gravitational fields

    CERN Document Server

    Kisel, V V; Red'kov, V M

    2011-01-01

    Tensor 50-component form of the first order relativistic wave equation for a particle with spin 2 and anomalous magnetic moment is extended to the case of an arbitrary curved space-time geometry. An additional parameter considered in the presence of only electromagnetic field as related to anomalous magnetic moment, turns to determine additional interaction terms with external geometrical background through Ricci R_{kl} and Riemann R_{klmn} tensors.

  18. Anomalously elastic intermediate phase in randomly layered superfluids, superconductors, and planar magnets.

    Science.gov (United States)

    Mohan, Priyanka; Goldbart, Paul M; Narayanan, Rajesh; Toner, John; Vojta, Thomas

    2010-08-20

    We show that layered quenched randomness in planar magnets leads to an unusual intermediate phase between the conventional ferromagnetic low-temperature and paramagnetic high-temperature phases. In this intermediate phase, which is part of the Griffiths region, the spin-wave stiffness perpendicular to the random layers displays anomalous scaling behavior, with a continuously variable anomalous exponent, while the magnetization and the stiffness parallel to the layers both remain finite. Analogous results hold for superfluids and superconductors. We study the two phase transitions into the anomalous elastic phase, and we discuss the universality of these results, and implications of finite sample size as well as possible experiments. PMID:20868107

  19. Anomalous Temperature Dependence of Magnetic Moment in Monodisperse Antiferromagnetic Nanoparticles

    Science.gov (United States)

    Gillaspie, Dane; Gu, B.; Wang, W.; Shen, J.

    2005-03-01

    1 Condensed Matter Sciences Division, Oak Ridge National Laboratory*, TN 37831 2 Department of Physics and Astronomy, The University of Tennessee, TN 37996 3 Environmental Sciences Division, Oak Ridge National Laboratory*, TN 37831 Recent experiments [1] and theory [2] from AFM nanoparticles showed that they exhibit sizable net magnetization, which increases with increasing temperature. In order to further understand such peculiar temperature dependence, we have measured the magnetic properties of monodisperse hematite (α-Fe2O3) nanoparticles, grown using a microemulsion precipitation technique, which minimizes the impact of the particle moment distribution on the measured properties of the samples. Our measured results indicate that the net magnetization of these nanoparticles, when small, indeed increases linearly with increasing temperature. This is in sharp contrast to the bulk-like behavior of α-Fe2O3, which was observed in particles with size larger than 120 nm. [1] M. Seehra et al, Phys. Rev. B 61, 3513 (2000) [2] S. Mørup, C. Frandsen, Phys. Rev. Lett. 92, 217201 (2004) *Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Dept. of Energy under contract DE-AC05-00OR22725

  20. Rock magnetic properties

    International Nuclear Information System (INIS)

    In 1978 the Nuclear Fuel Waste Management Program began the long task of site selection and evaluation for nuclear waste disposal. The Canadian Nuclear Fuel Waste Management Program, administered by Atomic Energy of Canada Limited, Research Company has provided the geophysicist with the unique opportunity to evaluate many modes of geophysical investigation in conjunction with detailed geologic mapping at a number of research areas. Of particular interest is research area RA-7, East Bull Lake, Algoma District, Ontario. Geophysical survey methods applied to the study of this included detailed gravity, ground magnetics, VLF, an airborne magnetic gradiometer survey and an airborne helicopter magnetic and EM survey. A comprehensive suite of rock property studies was also undertaken providing information on rock densities and magnetic rock properties. Preliminary modeling of the magnetic data sets assuming only induced magnetization illustrated the difficulty of arriving at a magnetic source geometry consistent with the mapped surficial and borehole geology. Integration of the magnetic rock properties observations and industry standard magnetic modelling techniques provides a source model geometry that is consistent with other geophysical/geological data sets, e.g. gravity and observed geology. The genesis of individual magnetic signatures in the East Bull Lake gabbro-anorthosite record the intrusion, metamorphism and fracture alteration of the pluton. As shown by this paper, only by understanding the rock magnetic signatures associated with each of these events is it possible to obtain geologically meaningful interpretative models

  1. Carrier-independent ferromagnetism and giant anomalous Hall effect in magnetic topological insulator

    OpenAIRE

    Chang, Cui-Zu; Zhang, Jin-song; Liu, Min-Hao; Zhang, Zuo-Cheng; Feng, Xiao; Li, Kang; Wang, Li-Li; Chen, Xi; Dai, Xi; Fang, Zhong; Qi, Xiao-Liang; Zhang, Shou-Cheng; Wang, Yayu; He, Ke; Ma, Xu-Cun

    2011-01-01

    Breaking the time-reversal symmetry of a topological insulator (TI) by ferromagnetism can induce exotic magnetoelectric phenomena such as quantized anomalous Hall (QAH) effect. Experimental observation of QAH effect in a magnetically doped TI requires ferromagnetism not relying on the charge carriers. We have realized the ferromagnetism independent of both polarity and density of carriers in Cr-doped BixSb2-xTe3 thin films grown by molecular beam epitaxy. Meanwhile, the anomalous Hall effect ...

  2. Thickness Dependence of the Quantum Anomalous Hall Effect in Magnetic Topological Insulator Films.

    Science.gov (United States)

    Feng, Xiao; Feng, Yang; Wang, Jing; Ou, Yunbo; Hao, Zhenqi; Liu, Chang; Zhang, Zuocheng; Zhang, Liguo; Lin, Chaojing; Liao, Jian; Li, Yongqing; Wang, Li-Li; Ji, Shuai-Hua; Chen, Xi; Ma, Xucun; Zhang, Shou-Cheng; Wang, Yayu; He, Ke; Xue, Qi-Kun

    2016-08-01

    The evolution of the quantum anomalous Hall effect with the thickness of Cr-doped (Bi,Sb)2 Te3 magnetic topological insulator films is studied, revealing how the effect is caused by the interplay of the surface states, band-bending, and ferromagnetic exchange energy. Homogeneity in ferromagnetism is found to be the key to high-temperature quantum anomalous Hall material. PMID:27166762

  3. `Anomalous' magnetic fabrics of dikes in the stable single domain/superparamagnetic threshold

    Science.gov (United States)

    Soriano, Carles; Beamud, Elisabet; Garcés, Miguel; Ort, Michael H.

    2016-02-01

    `Anomalous' magnetic fabrics in dikes that appear to indicate flow into the wall confound many workers. Here, we present extensive magnetic data on five dikes from Tenerife, Canary Islands, and use these to interpret the causes of the anomalous fabrics. Comparison of the anisotropy of magnetic susceptibility (AMS) and anhysteretic magnetization (AARM) results show that, in some cases, the anomalous fabrics are caused by single-domain grains, which produce AMS fabrics perpendicular to the grain elongation, whereas AARM fabrics are parallel. To check this, hysteresis experiments were used to characterize the domain state. These show most are mixtures of pseudo-single-domain or single-domain plus multi-domain particles, but many have wasp-waisted hysteresis loops, likely indicating mixed populations of stable single-domain and superparamagnetic grains. First-order reversal curves were used to better characterize this and show mixtures of stable single-domain and superparamagnetic grains dominate the magnetic signal. Magnetic particles at the stable single-domain/superparamagnetic threshold are unstable at timespans relevant to the analytical techniques, so they produce complicated results. This suggests that anomalous AMS fabrics in dikes cannot simply be attributed to elongated stable single-domain particles and that mixtures of the different grain types can produce hybrid fabrics, in which the fabrics are neither perpendicular or parallel to the dike plane, that are difficult to interpret without extensive magnetic analysis.

  4. Solution of Dirac Equation for Charged and Neutral Fermions with Anomalous Magnetic Moments in Uniform Magnetic Field

    OpenAIRE

    Pitschmann, M.; A. N. Ivanov

    2012-01-01

    The Dirac equation for charged and neutral fermions with anomalous magnetic moments is solved in a uniform magnetic field. We find the relativistic wave functions and energy spectra. In the non-relativistic limit the wave functions and energy spectra of charged fermions agree with the known solutions of the Schroedinger equation.

  5. Vacuum effects in magnetic field with with account for fermion anomalous magnetic moment and axial-vector interaction

    Science.gov (United States)

    Bubnov, Andrey; Gubina, Nadezda; Zhukovsky, Vladimir

    2016-05-01

    We study vacuum polarization effects in the model of Dirac fermions with additional interaction of an anomalous magnetic moment with an external magnetic field and fermion interaction with an axial-vector condensate. The proper time method is used to calculate the one-loop vacuum corrections with consideration for different configurations of the characteristic parameters of these interactions.

  6. The QED vacuum polarization function at four loops and the anomalous magnetic moment at five loops

    International Nuclear Information System (INIS)

    The anomalous magnetic moment of the muon is one of the most fundamental observables. It has been measured experimentally with a very high precision and on theory side the contributions from perturbative QED have been calculated up to five-loop level by numerical methods. Contributions to the muon anomalous magnetic moment from certain diagram classes are also accessible by alternative methods. In this paper we present the evaluation of contributions to the QED corrections due to insertions of the vacuum polarization function at five-loop level

  7. Microstructure and magnetic properties

    International Nuclear Information System (INIS)

    The relationship between the microstructure and magnetic properties of heat treated Fe-23 wt percent Cr--15 wt percent Co--5 wt percent V has been studied by transmission electron microscopy and Lorentz microscopy. Three different heat treatments were adopted for the present investigations viz., (1) isothermal aging, (2) TMT (thermomagnetic treatment) + step-aging, (3) continuous cooling. It has been found that the magnetic properties of the alloy are very sensitive to the temperature of the thermomagnetic treatment. Step-aging gave the best magnetic properties, producing an elongated ferromagnetic phase, 300 A in diameter and 1200 A in length. Lorentz microscopy revealed domain walls and these lie within the Cr-rich phase and pinned by the Fe-rich phase in the isothermally aged alloy at 6500C. Magnetic domains of optimally step-aged alloy, 0.5 μm in width, are elongated along the direction of the applied magnetic field. The results suggest that the magnetic anisotropy is introduced parallel to the direction of the applied magnetic field during TMT and step-aging treatments

  8. Is the anomalous magnetic moment the consequence of a non-classical transformation for rotating frames?

    Energy Technology Data Exchange (ETDEWEB)

    Gisin, B V [Department of Electrical Engineering - Physical Electronics, Faculty of Engineering, Tel-Aviv University Tel-Aviv 69978 (Israel)

    2002-08-01

    We consider the anomalous magnetic moment from an 'optical viewpoint' using an analogy between the motion of a particle with a magnetic moment in a magnetic field and the propagation of an optical pulse through an electro-optical crystal in an electric field. We show that an optical experiment similar to electron magnetic resonance is possible in some electro-optical crystals possessing the Faraday effect. This phenomenon is described by an analogue of the Pauli equation extracted from the Maxwell equation in the slowly varied amplitude approximation. In such an experiment the modulation by rotating fields plays a significant role. From the optical viewpoint the modulation assumes introducing the concept of a point rotation frame with the rotation axis at every point originated from the concept of the optical indicatrix (index ellipsoid). We discuss the connection between the non-classical transformation by transition from one such frame to another and an anomalous magnetic moment.

  9. Anomalous sound propagation due to the horizontal variation of seabed acoustic properties

    Institute of Scientific and Technical Information of China (English)

    LI; Zhenglin; ZHANG; Renhe; PENG; Zhaohui; LI; Xilu

    2004-01-01

    The sound propagation in shallow water is greatly influenced by the acoustic properties of seabed. An anomalous transmission loss was observed in an experiment, and a range dependent bottom model with horizontal variation of seabed acoustic property is proposed and could be well used to explain the anomalous phenomena. It is shown that the horizontal variation of bottom properties has a great effect on underwater sound propagation, and it should be given much attention in sound propagation and geoacoustic inversion problems.

  10. Spontaneous magnetization and anomalous Hall effect in an emergent Dice lattice

    Science.gov (United States)

    Dutta, Omjyoti; Przysiężna, Anna; Zakrzewski, Jakub

    2015-06-01

    Ultracold atoms in optical lattices serve as a tool to model different physical phenomena appearing originally in condensed matter. To study magnetic phenomena one needs to engineer synthetic fields as atoms are neutral. Appropriately shaped optical potentials force atoms to mimic charged particles moving in a given field. We present the realization of artificial gauge fields for the observation of anomalous Hall effect. Two species of attractively interacting ultracold fermions are considered to be trapped in a shaken two dimensional triangular lattice. A combination of interaction induced tunneling and shaking can result in an emergent Dice lattice. In such a lattice the staggered synthetic magnetic flux appears and it can be controlled with external parameters. The obtained synthetic fields are non-Abelian. Depending on the tuning of the staggered flux we can obtain either anomalous Hall effect or its quantized version. Our results are reminiscent of Anomalous Hall conductivity in spin-orbit coupled ferromagnets.

  11. Leading-order hadronic contributions to the electron and tau anomalous magnetic moments

    CERN Document Server

    Burger, Florian; Jansen, Karl; Petschlies, Marcus

    2015-01-01

    The leading hadronic contributions to the anomalous magnetic moments of the electron and the $\\tau$-lepton are determined by a four-flavour lattice QCD computation with twisted mass fermions. The continuum limit is taken and systematic uncertainties are quantified. Full agreement with results obtained by phenomenological analyses is found.

  12. Leading-order hadronic contributions to the electron and tau anomalous magnetic moments

    Energy Technology Data Exchange (ETDEWEB)

    Burger, Florian; Hotzel, Grit [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Petschlies, Marcus [The Cyprus Institute, Nicosia (Cyprus)

    2015-01-15

    The leading hadronic contributions to the anomalous magnetic moments of the electron and the τ-lepton are determined by a four-flavour lattice QCD computation with twisted mass fermions. The continuum limit is taken and systematic uncertainties are quantified. Full agreement with results obtained by phenomenological analyses is found.

  13. Anomalous magnetic behavior of CuO nanoparticles

    OpenAIRE

    Bisht, Vijay; Rajeev, K. P.; Banerjee, Sangam

    2009-01-01

    We report studies on temperature, field and time dependence of magnetization on cupric oxide nanoparticles of sizes 9 nm, 13 nm and 16 nm. The nanoparticles show unusual features in comparison to other antiferromagnetic nanoparticle systems. The field cooled (FC) and zero field cooled (ZFC) magnetization curves bifurcate well above the N\\'eel temperature and the usual peak in the ZFC magnetization curve is absent. The system does not show any memory effects which is in sharp contrast to the u...

  14. Texture and Magnetic Properties

    OpenAIRE

    Bunge, H. J.

    1989-01-01

    The magnetic properties of ferromagnetic materials are closely related to the crystallographic texture, i.e. the orientation distribution of the crystallites, they are, however, not uniquely determined by the texture. Higher order “textural quantities” such as, for instance, orientation correlation functions are additionally needed for a more complete description.The properties in saturation are uniquely determined by the texture. They can be expressed by a fourth—or sixth—order approximation...

  15. The effect of interfacial intermixing on magnetization and anomalous Hall effect in Co/Pd multilayers

    KAUST Repository

    Guo, Zaibing

    2015-05-01

    The effect of interfacial intermixing on magnetization and anomalous Hall effect (AHE) in Co/Pd multilayers is studied by using rapid thermal annealing to enhance the interfacial diffusion. The dependence of saturation magnetization and coercivity on the temperature of rapid thermal annealing at 5 K is discussed. It is found that AHE is closely related to the relative thickness of the Co and Pd layers. Localized paramagnetism has been observed which destroys AHE, while AHE can be enhanced by annealing.

  16. Anomalous Magnetic Excitations of Cooperative Tetrahedral Spin Clusters

    DEFF Research Database (Denmark)

    Prsa, K.; Rønnow, H.M.; Zaharko, O.; Christensen, Niels Bech; Jensen, J.; Chang, J.; Streule, S.; Jimenez-Ruiz, M.; Berger, H.; Prester, M.; Mesot, J.

    2009-01-01

    An inelastic neutron scattering study of Cu2Te2O5X2 (X=Cl, Br) shows strong dispersive modes with large energy gaps persisting far above T-N, notably in Cu2Te2O5Br2. The anomalous features: a coexisting unusually weak Goldstone-like mode observed in Cu2Te2O5Cl2 and the size of the energy gaps can...... cannot be explained by existing theories, such as our mean-field or random-phase approximation. We argue that our findings represent a new general type of behavior due to intercluster quantum fluctuations and call for development of a new theoretical approach....

  17. MAGNETIC WOVEN FABRICS - PHYSICAL AND MAGNETIC PROPERTIES

    Directory of Open Access Journals (Sweden)

    GROSU Marian C

    2015-05-01

    Full Text Available A coated material is a composite structure that consists of at least two components: base material and coating layer. The purpose of coating is to provide special properties to base material, with potential to be applied in EMI shielding and diverse smart technical fields. This paper reports the results of a study about some physical and magnetic properties of coated woven fabrics made from cotton yarns with fineness of 17 metric count. For this aim, a plain woven fabric was coated with a solution hard magnetic polymer based. As hard magnetic powder, barium hexaferrite (BaFe12O19 was selected. The plain woven fabric used as base has been coated with five solutions having different amounts of hard magnetic powder (15% - 45% in order to obtain five different magnetic woven fabrics. A comparison of physical properties regarding weight (g/m2, thickness (mm, degree of charging (% and magnetic properties of magnetic woven samples were presented. Saturation magnetizing (emu/g, residual magnetizing (emu/g and coercive force (kA/m of pure hard magnetic powder and woven fabrics have been studied as hysteresis characteristics. The magnetic properties of the woven fabrics depend on the mass percentage of magnetic powder from coating solution. Also, the residual magnetism and coercive field of woven fabrics represents only a part of bulk barium hexafferite residual magnetism and coercive field.

  18. Soft gamma-ray repeaters and anomalous X-ray pulsars as highly magnetized white dwarfs

    CERN Document Server

    Mukhopadhyay, Banibrata

    2016-01-01

    We show that the soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) can be explained as recently proposed highly magnetized white dwarfs (B-WDs). The radius and magnetic field of B-WDs are perfectly adequate to explain energies in SGRs/AXPs as the rotationally powered energy. While the highly magnetized neutron stars require an extra, observationally not well established yet, source of energy, the magnetized white dwarfs, yet following Chandrasekhar's theory (C-WDs), exhibit large ultra-violet luminosity which is observationally constrained from a strict upper limit.

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

    Science.gov (United States)

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

    2016-05-01

    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. We propose that complex structures at magnetic domain walls may be responsible for the hysteretic MR and may also lead to the AHE.

  20. Anomalous metamagnetic-like transition in a FeRh/Fe3Pt interface occurring at T ≈ 120 K in the field-cooled-cooling curves for low magnetic fields

    Directory of Open Access Journals (Sweden)

    S. Salem-Sugui Jr.

    2012-09-01

    Full Text Available We report on the magnetic properties of a special configuration of a FeRh thin film. An anomalous behavior on the magnetisation vs. temperature was observed when low magnetic fields are applied in the plane of a thin layer of FeRh deposited on ordered Fe3Pt. The anomalous effect resembles a metamagnetic transition and occur only in the field-cooled-cooling magnetisation curve at temperatures near 120 K in samples without any heat treatment.

  1. Anomalous metamagnetic-like transition in a FeRh/Fe$_3$Pt interface occurring at T120 K in the field-cooled-cooling curves for low magnetic fields

    OpenAIRE

    Salem-Sugui Jr., S.; Alvarenga, A. D.; R. D. Noce; Guimarães, R. B.; Salazar Mejia, C.; Salim, H.; Gandra, F. G.

    2012-01-01

    We report on the magnetic properties of a special configuration of a FeRh thin film. An anomalous behavior on the magnetisation vs. temperature was observed when low magnetic fields are applied in the plane of a thin layer of FeRh deposited on ordered Fe$_3$Pt. The anomalous effect resembles a metamagnetic transition and occur only in the field-cooled-cooling magnetisation curve at temperatures near 120 K in samples without any heat treatment.

  2. Anomalous metamagnetic-like transition in a FeRh/Fe3Pt interface occurring at T ≈ 120 K in the field-cooled-cooling curves for low magnetic fields

    Science.gov (United States)

    Salem-Sugui, S.; Alvarenga, A. D.; Noce, R. D.; Guimarães, R. B.; Mejia, C. Salazar; Salim, H.; Gandra, F. G.

    2012-09-01

    We report on the magnetic properties of a special configuration of a FeRh thin film. An anomalous behavior on the magnetisation vs. temperature was observed when low magnetic fields are applied in the plane of a thin layer of FeRh deposited on ordered Fe3Pt. The anomalous effect resembles a metamagnetic transition and occur only in the field-cooled-cooling magnetisation curve at temperatures near 120 K in samples without any heat treatment.

  3. Composite Higgs Models, Technicolor and The Muon Anomalous Magnetic Moment

    OpenAIRE

    Doff, A.(Universidade Tecnológica Federal do Paraná – UTFPR – DAFIS, Av. Monteiro Lobato Km 04, 84016-210 Ponta Grossa, PR, Brazil); Clarissa Siqueira

    2015-01-01

    We revisit the muon magnetic moment (g-2) in the context of Composite Higgs models and Technicolor, and provide general analytical expressions for computing the muon magnetic moment stemming from new fields such as, neutral gauge bosons, charged gauge bosons, neutral scalar, charged scalars, and exotic charged leptons type of particles. Under general assumptions we assess which particle content could address the $g-2_{\\mu}$ excess. Moreover, we take a conservative approach and derive stringen...

  4. Anomalous origin of the occipital artery diagnosed by magnetic resonance angiography

    Energy Technology Data Exchange (ETDEWEB)

    Uchino, Akira; Saito, Naoko; Mizukoshi, Waka; Okada, Yoshitaka [Saitama Medical University International Medical Center, Department of Diagnostic Radiology, Hidaka, Saitama (Japan)

    2011-11-15

    It is well known that the occipital artery (OA) can arise from the internal carotid artery (ICA) or vertebral artery (VA). However, the incidence of an anomalously originating OA has not been reported. We investigate its incidence and characteristic features on magnetic resonance angiography (MRA). We retrospectively reviewed MRA images of 2,866 patients that included the carotid bifurcation; images were obtained using a standard noncontrast MRA protocol and two 1.5-T MR units. We diagnosed six cases (seven arteries) of anomalously originating OA, which represented an incidence of 0.21%. The OA arose from the ICA in four patients (five arteries), from the carotid bifurcation in one, and from the VA in one. Five of the seven arteries occurred on the right. Anomalously originating OA is rare and occurs with right-side predominance. Correct diagnosis is necessary before or during cerebral angiography, especially when selective catheterization to the OA is required. (orig.)

  5. Effects of anomalous magnetic moment in the quantum motion of neutral particle in magnetic and conical spacetime electric fields produced by a linear source in a conical spacetime

    International Nuclear Information System (INIS)

    In this paper we analyse the effect of the anomalous magnetic moment on the non-relativistic quantum motion of a neutral particle in magnetic and electric fields produced by linear sources of constant current and charge density, respectively. (author)

  6. Anomalous shift of magnetic diffuse scattering studied by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Prokes, K [Helmholtz Centre Berlin for Materials and Energy, SF-2, Glienicker Strasse 100, 14109 Berlin (Germany); Lander, G H [European Commission, JRC, Institute for Transuranium Elements, Postfach 2340, 76125 Karlsruhe (Germany); Bernhoeft, N [CEA Grenoble, DRFMC/SPSMS, F-38054 Grenoble (France)], E-mail: prokes@helmholtz-berlin.de

    2009-07-15

    Neutron diffraction results, in the vicinity of the magnetic phase transition of USb and MnF{sub 2}, are reported. The thermal evolution of the magnetic diffuse signal and nuclear Bragg reflections demonstrate that the centre of gravity of the magnetic signals does not lie at the predicted position as calculated from nuclear reflections. This phenomenon, called the q-shift, was first found using resonance x-ray scattering (RXS). The present results show that, (i) the effect is not an artefact of RXS and is also found with neutrons (ii) that the effect arises from the bulk of the sample and is not restricted to the near surface layer ({approx}2000 A) associated with the RXS probe in actinide systems, (iii) the effect is not restricted to actinide compounds.

  7. Composite Higgs Models, Technicolor and The Muon Anomalous Magnetic Moment

    CERN Document Server

    Doff, A

    2015-01-01

    We revisit the muon magnetic moment (g-2) in the context of Composite Higgs models and Technicolor, and provide general analytical expressions for computing the muon magnetic moment stemming from new fields such as, neutral gauge bosons, charged gauge bosons, neutral scalar, charged scalars, and exotic charged leptons type of particles. Under general assumptions we assess which particle content could address the $g-2_{\\mu}$ excess. Moreover, we take a conservative approach and derive stringent limits on the particle masses in case the anomaly is otherwise resolved and comment on electroweak and collider bounds. Lastly, for concreteness we apply our results to a particular Technicolor model.

  8. Semiclassical description of anomalous magnetic moment and chiral anomaly

    International Nuclear Information System (INIS)

    It is shown that the same term of a modified Bargmann-Michel-Telegdi equation which explains the first-order radiative correction to the electronic magnetic moment accounts for the helicity variation in the infinite momentum limit. (author). 6 refs

  9. Anomalous transport model study of chiral magnetic effects in heavy ion collisions

    CERN Document Server

    Sun, Yifeng; Li, Feng

    2016-01-01

    Using an anomalous transport model for massless quarks, we study the effect of magnetic field on the elliptic flows of quarks and antiquarks in relativistic heavy ion collisions. With initial conditions from a blast wave model and assuming that the strong magnetic field produced in non-central heavy ion collisions can last for a sufficiently long time, we obtain an appreciable electric quadrupole moment in the transverse plane of a heavy ion collision, which subsequently leads to a splitting between the elliptic flows of quarks and antiquarks as expected from the chiral magnetic wave formed in the produced QGP and observed in experiments at the Relativistic Heavy Ion Collider (RHIC).

  10. Anomalous electron trapping by magnetic flux tubes and electric current vortices

    OpenAIRE

    Bentosela, F.; Exner, P.; Zagrebnov, V. A.

    1998-01-01

    We consider an electron with an anomalous magnetic moment, g>2, confined to a plane and interacting with a nonhomogeneous magnetic field B, and investigate the corresponding Pauli Hamiltonian. We prove a lower bound on the number of bound states for the case when B is of a compact support and the related flux is $N+\\epsilon, \\epsilon\\in(0,1]$. In particular, there are at least N+1 bound states if B does not change sign. We also consider the situation where the magnetic field is due to a local...

  11. Constraining Natural SUSY via the Higgs Coupling and the Muon Anomalous Magnetic Moment Measurements

    CERN Document Server

    Li, Tianjun; Wang, Kechen

    2016-01-01

    We use the Higgs coupling and the muon anomalous magnetic moment measurements to constrain the parameter space of the natural supersymmetry (SUSY) in the Generalized Minimal Supergravity (GmSUGRA) model. We scan the parameter space of the GmSUGRA model with small electroweak fine-tuning measure ($\\Delta_{\\rm EW} \\leq 100$). The parameter space after applying various sparticle mass bounds, Higgs mass bounds, B-physics bounds, the muon magnetic moment constraint, and the Higgs coupling constraint from measurements at HL-LHC, ILC, and CEPC, is shown in the planes of various interesting model parameters and sparticle masses. Our study indicates that the Higgs coupling and muon anomalous magnetic moment measurements can constrain the parameter space effectively. It is shown that $\\Delta_{\\rm EW}\\sim$ 30, consistence with all constraints, and having supersymmetric contributions to the muon anomalous magnetic moment within 1$\\sigma$ can be achieved. The precision of $k_b$ and $k_{\\tau}$ measurements at CEPC can boun...

  12. Constraining natural SUSY via the Higgs coupling and the muon anomalous magnetic moment measurements

    Science.gov (United States)

    Li, Tianjun; Raza, Shabbar; Wang, Kechen

    2016-03-01

    We use the Higgs coupling and the muon anomalous magnetic moment measurements to constrain the parameter space of the natural supersymmetry in the generalized minimal supergravity (GmSUGRA) model. We scan the parameter space of the GmSUGRA model with small electroweak fine-tuning measure (ΔEW≤100 ). The parameter space after applying various sparticle mass bounds; Higgs mass bounds; B-physics bounds; the muon magnetic moment constraint; and the Higgs coupling constraint from measurements at HL-LHC, ILC, and CEPC is shown in the planes of various interesting model parameters and sparticle masses. Our study indicates that the Higgs coupling and muon anomalous magnetic moment measurements can constrain the parameter space effectively. It is shown that ΔEW˜30 , consistent with all constraints, and having supersymmetric contributions to the muon anomalous magnetic moment within 1 σ can be achieved. The precision of kb and kτ measurements at CEPC can bound mA to be above 1.2 TeV and 1.1 TeV respectively. The combination of the Higgs coupling measurement and muon anomalous magnetic moment measurement constrain the e˜R mass to be in the range from 0.6 TeV to 2 TeV. The range of both e˜L and ν˜e masses is 0.4 TeV-1.2 TeV. In all cases, the χ˜10 mass needs to be small (mostly ≤400 GeV ). The comparison of bounds in the tan β -mA plane shows that the Higgs coupling measurement is complementary to the direct collider searches for heavy Higgs when constraining the natural SUSY. A few mass spectra in the typical region of parameter space after applying all constraints are shown as well.

  13. The hadronic light-by-light contribution to the muon anomalous magnetic moment and renormalization group for EFT

    OpenAIRE

    Abyaneh Mehran Zahiri; Bijnens Johan

    2012-01-01

    We give a short overview of the theory of the muon anomalous magnetic moment with emphasis on the hadronic light-by-light and the pion loop contribution. We explain the difference between the hidden local symmetry and full VMD pion loop and discuss leading logarithms in the anomalous sector of 2-flavour chiral perturbation theory.

  14. The hadronic light-by-light contribution to the muon anomalous magnetic moment and renormalization group for EFT

    Directory of Open Access Journals (Sweden)

    Abyaneh Mehran Zahiri

    2012-12-01

    Full Text Available We give a short overview of the theory of the muon anomalous magnetic moment with emphasis on the hadronic light-by-light and the pion loop contribution. We explain the difference between the hidden local symmetry and full VMD pion loop and discuss leading logarithms in the anomalous sector of 2-flavour chiral perturbation theory.

  15. Magnetic, density and radioactive properties of Rochovce granites (Slovenske Rudohorie Mts., Western Carpathians)

    International Nuclear Information System (INIS)

    The magnetic anomaly in the Rochovce area is caused by anomalously increased magnetic properties of the hidden Upper Cretaceous granite body. The granites of this body show high values of magnetic susceptibility assigning them to the magnetite series of Ishihara (1977). The analysis of physical properties of the granites points to the existence of three physically different types (intrusive phases). The inner magnetic fabric of the body is anomalous, being deformed in the near-horizontal direction as established by the authors' study of the magnetic susceptibility anisotropy tensor. (author) 4 tabs., 10 figs., 22 refs

  16. On thermodynamic properties of heavy fermion systems in magnetic field

    International Nuclear Information System (INIS)

    Using a two-conduction-band Anderson lattice model, the influence of magnetic field on thermodynamic properties of the heavy fermion systems is studied by means of the slave boson mean-field theory. The depression of the heavy fermion state by magnetic field is found. A theoretical explanation to the anomalous volume magneto-striction of heavy fermion systems is also given in this paper. (author). 27 ref, 5 figs

  17. Finite-volume effects in the muon anomalous magnetic moment on the lattice

    Science.gov (United States)

    Aubin, Christopher; Blum, Thomas; Chau, Peter; Golterman, Maarten; Peris, Santiago; Tu, Cheng

    2016-03-01

    We investigate finite-volume effects in the hadronic vacuum polarization, with an eye toward the corresponding systematic error in the muon anomalous magnetic moment. We consider both recent lattice data as well as lowest-order, finite-volume chiral perturbation theory, in order to get a quantitative understanding. Even though leading-order chiral perturbation theory does not provide a good description of the hadronic vacuum polarization, it turns out that it gives a good representation of finite-volume effects. We find that finite-volume effects cannot be ignored when the aim is a few percent level accuracy for the leading-order hadronic contribution to the muon anomalous magnetic moment, even when using ensembles with mπL ≳4 and mπ˜200 MeV .

  18. Finite-volume effects in the muon anomalous magnetic moment on the lattice

    CERN Document Server

    Aubin, Christopher; Chau, Peter; Golterman, Maarten; Peris, Santiago; Tu, Cheng

    2015-01-01

    We investigate finite-volume effects in the hadronic vacuum polarization, with an eye toward the corresponding systematic error in the muon anomalous magnetic moment. We consider both recent lattice data as well as lowest-order, finite-volume chiral perturbation theory, in order to get a quantitative understanding. Even though leading-order chiral perturbation theory does not provide a good description of the hadronic vacuum polarization, it turns out that it gives a reasonably good representation of finite-volume effects. We find that finite-volume effects cannot be ignored when the aim is a few percent level accuracy for the leading-order hadronic contribution to the muon anomalous magnetic moment, even when using ensembles with $m_\\pi L> 4$ and $m_\\pi \\sim 200$ MeV.

  19. Ambipolar radial electric field generated by anomalous transport induced by magnetic perturbations

    Science.gov (United States)

    Chen, Dunqiang; Zhu, Siqiang; Zhang, Debing; Wang, Shaojie

    2016-05-01

    The anomalous particle transport induced by magnetic perturbations in a tokamak is investigated. The correlation between the radial position and the kinetic energy of electrons, Dr K=-e ErDr r , is predicted theoretically and is verified by simulations in the presence of a mean radial electric field. This correlation leads to a radial particle flux produced by the radial electric field. The ambipolar radial electric field can thus be predicted by using the ambipolarity condition Γri=Γre .

  20. The spin and the anomalous magnetic moment of the electron in stochastic electrodynamics

    International Nuclear Information System (INIS)

    It is proposed that the zitterbewegung induced on a harmonically bound electron by the zero-point radiation field accounts for the spin of the electron. Assuming that the measurement of a spin projection may be taken into account phenomenologically by considering the action of only the subensemble of the zero-point field with the corresponding circular polarization, the theory gives a satisfactory account of both the spin projection and the anomalous magnetic moment. (orig.)

  1. Spin and the anomalous magnetic moment of the electron in stochastic electrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Jauregui, A.; de la Pena, L. (Universidad Nacional Autonoma de Mexico, Mexico City. Inst. de Fisica)

    1981-11-23

    It is proposed that the zitterbewegung induced on a harmonically bound electron by the zero-point radiation field accounts for the spin of the electron. Assuming that the measurement of a spin projection may be taken into account phenomenologically by considering the action of only the subensemble of the zero-point field with the corresponding circular polarization, the theory gives a satisfactory account of both the spin projection and the anomalous magnetic moment.

  2. N=2-Maxwell-Chern-Simons model with anomalous magnetic moment coupling via dimensional reduction

    International Nuclear Information System (INIS)

    An N=1-supersymmetric version of the Cremmer-Scherk-Kalb-Ramond model with non-minimal coupling to matter is built up both in terms of superfields and in a component field formalism. By adopting a dimensional reduction procedure, the N=2-D=3 counterpart of the model comes out, with two main features: a genuine (diagonal) Chern-Simons term and an anomalous magnetic moment coupling between matter and the gauge potential. (author)

  3. Artificial ferroelectricity due to anomalous Hall effect in magnetic tunnel junctions

    OpenAIRE

    Vedyayev, A.; Ryzhanova, N.; Strelkov, N.; Dieny, B

    2012-01-01

    We theoretically investigated Anomalous Hall Effect (AHE) and Spin Hall Effect (SHE) transversally to the insulating spacer O, in magnetic tunnel junctions of the form F/O/F where F are ferromagnetic layers and O represents a tunnel barrier. We considered the case of purely ballistic (quantum mechanical) transport, taking into account the assymetric scattering due to spin-orbit interaction in the tunnel barrier. AHE and SHE in the considered case have a surface nature due to proximity effect....

  4. Leading-order hadronic contributions to the lepton anomalous magnetic moments from the lattice

    Energy Technology Data Exchange (ETDEWEB)

    Burger, Florian [OakLabs GmbH, Hennigsdorf (Germany); Feng, Xu [Columbia University, New York, NY (United States). Dept. of Physics; Jansen, Karl [DESY Zeuthen (Germany). NIC; Petschlies, Marcus [Bonn Univ. (Germany). Inst. fuer Strahlen- und Kernphysik; Pientka, Grit [Humboldt-Univ. Berlin (Germany). Inst. fuer Physik; Renner, Dru B. [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

    2015-11-15

    The hadronic leading-order (hlo) contribution to the lepton anomalous magnetic moments a{sup hlo}{sub l} of the Standard Model leptons still accounts for the dominant source of the uncertainty of the Standard Model estimates. We present the results of an investigation of the hadronic leading order anomalous magnetic moments of the electron, muon and tau lepton from first principles in twisted mass lattice QCD. With lattice data for multiple pion masses in the range 230 MeVanomalous magnetic moments from simulations directly at the physical value of the pion mass.

  5. Leading-order hadronic contributions to the lepton anomalous magnetic moments from the lattice

    Science.gov (United States)

    Burger, Florian; Feng, Xu; Jansen, Karl; Petschlies, Marcus; Pientka, Grit; Renner, Dru B.

    2016-04-01

    The hadronic leading-order (hlo) contribution to the lepton anomalous magnetic moments alhlo of the Standard Model leptons still accounts for the dominant source of the uncertainty of the Standard Model estimates. We present the results of an investigation of the hadronic leading order anomalous magnetic moments of the electron, muon and tau lepton from first principles in twisted mass lattice QCD. With lattice data for multiple pion masses in the range 230MeV ≲ mPS ≲ 490 MeV, multiple lattice volumes and three lattice spacings we perform the extrapolation to the continuum and to the physical pion mass and check for all systematic uncertainties in the lattice calculation. As a result we calculate alhlo for the three Standard Model leptons with controlled statistical and systematic error in agreement with phenomenological determinations using dispersion relations and experimental data. In addition, we also give a first estimate of the hadronic leading order anomalous magnetic moments from simulations directly at the physical value of the pion mass.

  6. Anomalous magnetic susceptibility of antiferromagnetic TbB2C2

    International Nuclear Information System (INIS)

    We measured the magnetic susceptibilities of TbB2C2 under fields along the , and directions. The susceptibilities below TN exhibit clear twofold symmetry in the (0 0 1) plane. No spontaneous magnetization in TbB2C2 indicates that this anisotropy in the tetragonal basal plane reflects parallel and perpendicular susceptibilities of an antiferromagnet. The susceptibilities of the and [1 1 0] directions show no cusp-like anomaly but anomalous upturns below TN with decreasing temperature, though TbB2C2 is confirmed to be an antiferromagnet. (author)

  7. Analysis of anomalous electrical conductivity and magnetic permeability effects using a frequency domain controlled-source electromagnetic method

    Science.gov (United States)

    Noh, Kyubo; Oh, Seokmin; Seol, Soon Jee; Lee, Ki Ha; Byun, Joongmoo

    2016-03-01

    We present a series of processes for understanding and analysing controlled-source electromagnetic (CSEM) responses for a conductive and permeable earth. To realize the CSEM response, a new 3-D CSEM forward modelling algorithm based on an edge finite element method for both electrically conductive and magnetically permeable heterogeneities is developed. The algorithm shows highly accurate results in validation tests against a semi-analytic solution for stratified earth and an integral form of the scattered field. We describe the vector behaviour of an anomalous magnetic field originating from a conductive and permeable anomaly when the loop sources are deployed over a conductive half-space. The CSEM response of the conductive and permeable anomaly is classified into three effects originating from: conductivity perturbations, permeability perturbations and the coupling of these two effects. The separated individual results and the corresponding integral equation form of the anomalous field help to better understand the physical behaviour. We confirm the characteristic features of the CSEM response from the conductive and permeable anomaly, for example, (1) the general dominance of the induction effect in the out-of-phase response accompanied by a non-negligible magnetization effect from the magnetic anomaly in a conductive half-space and (2) the dominance of near frequency-independent magnetization effects in the in-phase response at relatively low frequencies and change in ruling part of the in-phase response into the induction effect as the frequency increases. We also demonstrate the effect of coupling mode and show that its maximum contribution is limited to a few per cent level of other two modes, induction and magnetization mode, even when the heterogeneity of our model is strong. In our synthetic survey, using examples of land-based profiling surveys of low induction number and intermediate regime, we find that the effect of magnetization can be used as an

  8. Anomalous skin effects in relativistic parallel propagating weakly magnetized electron plasma waves

    International Nuclear Information System (INIS)

    Fully relativistic analysis of anomalous skin effects for parallel propagating waves in a weakly magnetized electron plasma is presented and general expressions for longitudinal and transverse permittivites are derived. It is found that the penetration depth for R- and L-waves increases as we move from non-relativistic to highly relativistic regime. The ambient magnetic field reduces/enhances the skin effects for R-wave/L-wave as the strength of the field is increased. In general, the weak magnetic field effects are pronounced for the weakly relativistic regime as compared with other relativistic cases. The results are also graphically illustrated. On switching off the magnetic field, previous results for field free case are retrieved [A. F. Alexandrov, A. S. Bogdankevich, and A. A. Rukhadze, Priniples of Plasma Electrodynamics (Springer-Verlag, Berlin, Heidelberg, 1984), Vol. 9, p. 106].

  9. Anomalous Magnetohydrodynamics

    OpenAIRE

    Giovannini, Massimo

    2013-01-01

    Anomalous symmetries induce currents which can be parallel rather than orthogonal to the hypermagnetic field. Building on the analogy with charged liquids at high magnetic Reynolds numbers, the persistence of anomalous currents is scrutinized for parametrically large conductivities when the plasma approximation is accurate. Different examples in globally neutral systems suggest that the magnetic configurations minimizing the energy density with the constraint that the helicity be conserved co...

  10. An upper limit on the anomalous magnetic moment of the $\\tau$ lepton

    CERN Document Server

    Ackerstaff, K; Allison, J; Altekamp, N; Anderson, K J; Anderson, S; Arcelli, S; Asai, S; Ashby, S F; Axen, D A; Azuelos, Georges; Ball, A H; Barberio, E; Barlow, R J; Bartoldus, R; Batley, J Richard; Baumann, S; Bechtluft, J; Behnke, T; Bell, K W; Bella, G; Bentvelsen, Stanislaus Cornelius Maria; Bethke, Siegfried; Betts, S; Biebel, O; Biguzzi, A; Bird, S D; Blobel, Volker; Bloodworth, Ian J; Bobinski, M; Bock, P; Bonacorsi, D; Boutemeur, M; Braibant, S; Brigliadori, L; Brown, R M; Burckhart, Helfried J; Burgard, C; Bürgin, R; Capiluppi, P; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Chrisman, D; Clarke, P E L; Cohen, I; Conboy, J E; Cooke, O C; Couyoumtzelis, C; Coxe, R L; Cuffiani, M; Dado, S; Dallapiccola, C; Dallavalle, G M; Davis, R; De Jong, S; del Pozo, L A; de Roeck, A; Desch, Klaus; Dienes, B; Dixit, M S; Doucet, M; Duchovni, E; Duckeck, G; Duerdoth, I P; Eatough, D; Estabrooks, P G; Etzion, E; Evans, H G; Evans, M; Fabbri, Franco Luigi; Fanfani, A; Fanti, M; Faust, A A; Feld, L; Fiedler, F; Fierro, M; Fischer, H M; Fleck, I; Folman, R; Fong, D G; Foucher, M; Fürtjes, A; Futyan, D I; Gagnon, P; Gary, J W; Gascon, J; Gascon-Shotkin, S M; Geddes, N I; Geich-Gimbel, C; Geralis, T; Giacomelli, G; Giacomelli, P; Giacomelli, R; Gibson, V; Gibson, W R; Gingrich, D M; Glenzinski, D A; Goldberg, J; Goodrick, M J; Gorn, W; Grandi, C; Gross, E; Grunhaus, Jacob; Gruwé, M; Hajdu, C; Hanson, G G; Hansroul, M; Hapke, M; Hargrove, C K; Hart, P A; Hartmann, C; Hauschild, M; Hawkes, C M; Hawkings, R; Hemingway, Richard J; Herndon, M; Herten, G; Heuer, R D; Hildreth, M D; Hill, J C; Hillier, S J; Hobson, P R; Höcker, Andreas; Homer, R James; Honma, A K; Horváth, D; Hossain, K R; Howard, R; Hüntemeyer, P; Hutchcroft, D E; Igo-Kemenes, P; Imrie, D C; Ishii, K; Jawahery, A; Jeffreys, P W; Jeremie, H; Jimack, Martin Paul; Joly, A; Jones, C R; Jones, M; Jost, U; Jovanovic, P; Junk, T R; Kanzaki, J I; Karlen, D A; Kartvelishvili, V G; Kawagoe, K; Kawamoto, T; Kayal, P I; Keeler, Richard K; Kellogg, R G; Kennedy, B W; Kirk, J; Klier, A; Kluth, S; Kobayashi, T; Kobel, M; Koetke, D S; Kokott, T P; Kolrep, M; Komamiya, S; Kowalewski, R V; Kress, T; Krieger, P; Von Krogh, J; Kyberd, P; Lafferty, G D; Lahmann, R; Lai, W P; Lanske, D; Lauber, J; Lautenschlager, S R; Lawson, I; Layter, J G; Lazic, D; Lee, A M; Lefebvre, E; Lellouch, Daniel; Letts, J; Levinson, L; List, B; Lloyd, S L; Loebinger, F K; Long, G D; Losty, Michael J; Ludwig, J; Liu, D; Macchiolo, A; MacPherson, A L; Mannelli, M; Marcellini, S; Markopoulos, C; Markus, C; Martin, A J; Martin, J P; Martínez, G; Mashimo, T; Mättig, P; McDonald, W J; McKenna, J A; McKigney, E A; McMahon, T J; McPherson, R A; Meijers, F; Menke, S; Merritt, F S; Mes, H; Meyer, J; Michelini, Aldo; Mikenberg, G; Miller, D J; Mincer, A; Mir, R; Mohr, W; Montanari, A; Mori, T; Mihara, S; Nagai, K; Nakamura, I; Neal, H A; Nellen, B; Nisius, R; O'Neale, S W; Oakham, F G; Odorici, F; Ögren, H O; Oh, A; Oldershaw, N J; Oreglia, M J; Orito, S; Pálinkás, J; Pásztor, G; Pater, J R; Patrick, G N; Patt, J; Pérez-Ochoa, R; Petzold, S; Pfeifenschneider, P; Pilcher, J E; Pinfold, J L; Plane, D E; Poffenberger, P R; Poli, B; Posthaus, A; Rembser, C; Robertson, S; Robins, S A; Rodning, N L; Roney, J M; Rooke, A M; Rossi, A M; Routenburg, P; Rozen, Y; Runge, K; Runólfsson, O; Ruppel, U; Rust, D R; Sachs, K; Saeki, T; Sahr, O; Sang, W M; Sarkisyan-Grinbaum, E; Sbarra, C; Schaile, A D; Schaile, O; Scharf, F; Scharff-Hansen, P; Schieck, J; Schleper, P; Schmitt, B; Schmitt, S; Schöning, A; Schröder, M; Schumacher, M; Schwick, C; Scott, W G; Shears, T G; Shen, B C; Shepherd-Themistocleous, C H; Sherwood, P; Sieberg, R P B; Siroli, G P; Sittler, A; Skillman, A; Skuja, A; Smith, A M; Snow, G A; Sobie, Randall J; Söldner-Rembold, S; Springer, R W; Sproston, M; Stephens, K; Steuerer, J; Stockhausen, B; Stoll, K; Strom, D; Ströhmer, R; Szymanski, P; Tafirout, R; Talbot, S D; Taras, P; Tarem, S; Teuscher, R; Thiergen, M; Thomson, M A; Von Törne, E; Torrence, E; Towers, S; Trigger, I; Trócsányi, Z L; Tsur, E; Turcot, A S; Turner-Watson, M F; Ueda, I; Utzat, P; Van Kooten, R; Vannerem, P; Verzocchi, M; Vikas, P; Vokurka, E H; Voss, H; Wäckerle, F; Wagner, A; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wermes, N; White, J S; Wilson, G W; Wilson, J A; Wyatt, T R; Yamashita, S; Yekutieli, G; Zacek, V; Zer-Zion, D

    1998-01-01

    Using radiative Z^0 -> \\tau^+ \\tau^- \\gamma events collected with the OPAL detector at LEP at \\sqrt{s}=M_Z during 1990-95, a direct study of the electromagnetic current at the \\tau\\gamma vertex has been performed in terms of the anomalous magnetic form factor F_2 of the \\tau lepton. The analysis is based on a data sample of 1429 e^+ e^- -> \\tau^+ \\tau^- \\gamma events which are examined for a deviation from the expectation with F_2 = 0. From the non-observation of anomalous \\tau^+ \\tau^- \\gamma production a limit of -0.068 < F_2 < 0.065 is obtained. This can also be interpreted as a limit on the electric dipole form factor F_3 as -3.8 x 10^-16 e-cm < eF_3 < 3.6 x 10^-16 e-cm. The above ranges are valid at the 95% confidence level.

  11. Anomalous properties of weak-link-containing superconductors: flicker noise

    International Nuclear Information System (INIS)

    Low-frequency magnetic noise spectral density is calculated within the superconductive glass model. The model predicts the existence of both white noise and flicker-like noise ω-α with α strongly dependent on applied magnetic field and temperature. It is shown, in particular, that α increases with field from 0.5 to 1, and that in the critical region 1/√ω-law should prevail in the noise spectrum. (orig.)

  12. Ageneral approach to first order phase transitions and the anomalous behavior of coexisting phases in the magnetic case.

    Energy Technology Data Exchange (ETDEWEB)

    Gama, S.; de Campos, A.; Coelho, A. A.; Alves, C. S.; Ren, Y.; Garcia, F.; Brown, D. E.; da Silva, L. M.; Magnus, A.; Carvalho, G.; Gandra, G. C.; dos Santos, A. O.; Cardoso, L. P.; von Ranke, P. J.; X-Ray Science Division; Univ. Federal de Sao Paulo; Unv. Estadual de Champinas; Univ. Estadual de Maringa Lab. Nacional de Luz Sincrotron; Northern Univ.; Univ. de Estado do Rio de Janerio

    2009-01-01

    First order phase transitions for materials with exotic properties are usually believed to happen at fixed values of the intensive parameters (such as pressure, temperature, etc.) characterizing their properties. It is also considered that the extensive properties of the phases (such as entropy, volume, etc.) have discontinuities at the transition point, but that for each phase the intensive parameters remain constant during the transition. These features are a hallmark for systems described by two thermodynamic degrees of freedom. In this work it is shown that first order phase transitions must be understood in the broader framework of thermodynamic systems described by three or more degrees of freedom. This means that the transitions occur along intervals of the intensive parameters, that the properties of the phases coexisting during the transition may show peculiar behaviors characteristic of each system, and that a generalized Clausius-Clapeyron equation must be obeyed. These features for the magnetic case are confirmed, and it is shown that experimental calorimetric data agree well with the magnetic Clausius-Clapeyron equation for MnAs. An estimate for the point in the temperature-field plane where the first order magnetic transition turns to a second order one is obtained (the critical parameters) for MnAs and Gd{sub 5}Ge{sub 2}Si{sub 2} compounds. Anomalous behavior of the volumes of the coexisting phases during the magnetic first order transition is measured, and it is shown that the anomalies for the individual phases are hidden in the behavior of the global properties as the volume.

  13. Anomalous magnetic behavior for Mn-site doped La{sub 0.7}Ca{sub 0.3}MnO{sub 3}: internal magnetic interactions and extrinsic inhomogeneity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hong-guang, E-mail: hgzhang_njupt@hotmail.com [College of Science, Nanjing University of Posts and Telecommunications, Nanjing 210046 (China); Li, Yong-tao [College of Science, Nanjing University of Posts and Telecommunications, Nanjing 210046 (China); Xie, Liang [Department of Physical and Chemical Sciences, North China University of Technology, Beijing 100144 (China); Shi, Jiang-jian; Dong, Xue-guang; Ge, Xiao-peng; Liu, Hao [Physics Department, Southeast University, Nanjing 211189 (China); Li, Qi, E-mail: qli@seu.edu.cn [Physics Department, Southeast University, Nanjing 211189 (China)

    2015-11-01

    Magnetic properties of Mn-site doped La{sub 0.7}Ca{sub 0.3}Mn{sub 0.94}TM{sub 0.06}O{sub 3+Δ} (TM=Cu, Zn) were experimentally and theoretically studied. The low-temperature magnetization and magnetic phase transition temperature T{sub C} of the samples combining with simulations of 2D doped Ising model suggest that Cu{sup 2+} ions have an antiferromagnetic interaction with their nearest neighboring Mn ions. Interestingly, an anomalous magnetic behavior, a “step-like” magnetic phase transition, is observed. The existence and magnitude of this step vary with different doping ions and oxygen ratio, which is experimentally suggested to be relevant to the interaction between magnetic ions and oxygen content. A superposition between two independent magnetic systems with different values of an exchange integral J well explains the anomalous magnetic phase transition, which suggests that this step-like behavior results from extrinsic inhomogeneity and negligible coupling between grains in polycrystalline. - Highlights: • A “step-like” magnetic phase transition is observed in La{sub 0.7}Ca{sub 0.3}Mn{sub 0.94}TM{sub 0.06}O{sub 3}. • An anomalous magnetic property is experimentally and theoretically studied. • The evolution of T{sub C} and low T magnetization opposite to conventional behavior. • An antiferromagnetic interaction between Cu{sup 2+} and Mn ion is investigated by Ising model. • A linear superposition between magnetic behaviors explain the phase transition.

  14. Anomalous attenuation of ultrasound in ferrofluids under the influence of a magnetic field

    Science.gov (United States)

    Isler, W. E.; Chung, D. Y.

    1978-01-01

    Ultrasonic wave propagation has been studied in a water-base ferrofluid by pulse-echo methods. A commercial box-car integrator was used to measure the change in attenuation due to an external magnetic field applied at various angles relative to the ultrasonic propagation vector. Anomalous results were obtained when the attenuation was plotted as a function of the magnetic field strength. As the field increased, the attenuation reached a maximum and then decreased to a flat minimum before it approached saturation at a field of 2 KG. This variation of attenuation with magnetic field cannot be explained from the simple picture derivable from the work of McTague on the viscosity of ferrofluids. In no case was the viscosity seen to decrease with field, nor was the oscillatory behavior observed. The results of this study were compared with the theory developed by Parsons.

  15. Enhanced diffusion and anomalous transport of magnetic colloids driven above a two-state flashing potential.

    Science.gov (United States)

    Tierno, Pietro; Shaebani, M Reza

    2016-04-14

    We combine experiments and theory to investigate the diffusive and the subdiffusive dynamics of paramagnetic colloids driven above a two-state flashing potential. The magnetic potential was realized by periodically modulating the stray field of a magnetic bubble lattice in a uniaxial ferrite garnet film. At large amplitudes H0 of the driving field, the dynamics of the particle resemble an ordinary random walk with a frequency-dependent diffusion coefficient. However, subdiffusive and oscillatory dynamics at short time scales are observed when decreasing H0. We present a persistent random walk model to elucidate the underlying mechanism of motion, and perform numerical simulations to demonstrate that the anomalous motion originates from the dynamic disorder in the structure of the magnetic lattice, induced by the slightly irregular shape of bubbles. PMID:26936328

  16. From magnetically doped topological insulator to the quantum anomalous Hall effect

    Institute of Scientific and Technical Information of China (English)

    He Ke; Ma Xu-Cun; Chen Xi; Lü Li; Wang Ya-Yu; Xue Qi-Kun

    2013-01-01

    Quantum Hall effect (QHE),as a class of quantum phenomena that occur in macroscopic scale,is one of the most important topics in condensed matter physics.It has long been expected that QHE may occur without Landau levels so that neither extemal magnetic field nor high sample mobility is required for its study and application.Such a QHE free of Landau levels,can appear in topological insulators (TIs) with ferromagnetism as the quantized version of the anomalous Hall effect,i.e.,quantum anomalous Hall (QAH) effect.Here we review our recent work on experimental realization of the QAH effect in magnetically doped TIs.With molecular beam epitaxy,we prepare thin films of Cr-doped (Bi,Sb)2Te3 TIs with wellcontrolled chemical potential and long-range ferromagnetic order that can survive the insulating phase.In such thin films,we eventually observed the quantization of the Hall resistance at h/e2 at zero field,accompanied by a considerable drop in the longitudinal resistance.Under a strong magnetic field,the longitudinal resistance vanishes,whereas the Hall resistance remains at the quantized value.The realization of the QAH effect provides a foundation for many other novel quantum phenomena predicted in TIs,and opens a route to practical applications of quantum Hall physics in low-power-consumption electronics.

  17. Higgs mass and muon anomalous magnetic moment in the U(1) extended MSSM

    CERN Document Server

    Endo, Motoi; Iwamoto, Sho; Nakayama, Kazunori; Yokozaki, Norimi

    2011-01-01

    We study phenomenological aspects of the MSSM with extra U(1) gauge symmetry. We find that the lightest Higgs boson mass can be increased up to 125GeV without introducing a large SUSY scale or large A-terms, in the frameworks of the CMSSM and gauge mediated SUSY breaking (GMSB) models. This scenario can simultaneously explain the discrepancy of the muon anomalous magnetic moment (muon g-2) at the 1 sigma / 2 sigma level for U(1)-extended CMSSM / GMSB models. In the CMSSM case, the dark matter abundance can also be explained.

  18. Influence of the electron's anomalous magnetic dipole moment on high-atomic number atoms

    International Nuclear Information System (INIS)

    Super heavy atoms ( Z > 100 ) are usually studied in the context of the so-called Quantum Electrodynamics of Strong Fields. In this theory the problem of the singularity in the electron energy whenever Z > 137 is overcome. This is done by considering the finite size of the nucleus and leads to interesting phenomena, such as the spontaneous production of positrons. Here, we show that, taking into account the contribution from the Anomalous Magnetic Dipole Moment of the electron ( by means of an effective theory ), within a point nucleus model, is a sufficient condition to obtain regular wave functions and physically acceptable energy values for Z > 137. (author)

  19. Hadronic contribution to the muon anomalous magnetic moment to next-to-next-to-leading order

    International Nuclear Information System (INIS)

    We compute the next-to-next-to-leading order hadronic contribution to the muon anomalous magnetic moment originating from the photon vacuum polarization. The corresponding three-loop kernel functions are calculated using asymptotic expansion techniques which lead to analytic expressions. Our final result, aμhad,NNLO=1.24±0.01×10−10, has the same order of magnitude as the current uncertainty of the leading order hadronic contribution and should thus be included in future analyses

  20. Muon Anomalous Magnetic Moment and Gauge Symmetry in the Standard Model

    CERN Document Server

    Tsai, Er-Cheng

    2014-01-01

    No gauge invariant regularization is available for the perturbative calculation of the standard model. One has to add finite counter terms to restore gauge symmetry for the renormalized amplitudes. The muon anomalous magnetic moment can be accurately measured but the experimental result does not entirely agree with the theoretical calculation from the standard model. This paper is to compute the contributions to the muon gyromagnetic ratio $g_{\\mu}$ due to the finite counter terms. The result obtained is found to be far from sufficient to explain the discrepancy between theory and experiment.

  1. Topcolour-assisted technicolour models and the muon anomalous magnetic moment

    International Nuclear Information System (INIS)

    We discuss and estimate the contributions of the new particles predicted by topcolour-assisted technicolour (TC2) models to the muon anomalous magnetic moment aμ. Our results show that the contributions of pseudo-Goldstone bosons are very small and can be safely ignored. The main contributions come from the ETC gauge boson xμ and topcolour gauge boson Z'. If we demand that the mass of Z' is consistent with other experimental constraints, its contributions are smaller than that of xμ. With reasonable values of the parameters in TC2 models, the observed BNL results for aμ could be explained. (author)

  2. Charged spin half particle with anomalous magnetic moment in a plane wave field

    Energy Technology Data Exchange (ETDEWEB)

    Vaidya, Arvind Narayan [Universidade Federal do Rio de Janeiro, RJ (Brazil); Silva Filho, Pedro Barbosa da [Universidade Federal da Paraiba, Cajazeiras, PB (Brazil)

    2000-07-01

    Full text follows: The Dirac-Pauli equation for a charged spin half particle with anomalous magnetic moment in the presence of a plane wave external electromagnetic field is solved by an algebraic method and the solutions are shown to be simply related to the free particle ones.We also discuss the relationship of our results with the work of other authors. We show that our solutions are equivalent to those of Chakrabarti. We also show that the different results of Barut and Duru are in error. (author)

  3. Lattice Calculation of Hadronic Light-by-Light Contribution to the Muon Anomalous Magnetic Moment

    CERN Document Server

    Blum, Thomas; Hayakawa, Masashi; Izubuchi, Taku; Jin, Luchang; Lehner, Christoph

    2016-01-01

    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. 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 $(4.6\\;\\mathrm{fm})^3$ spatial volume using the $32^3\\times 64$ Iwasaki+DSDR gauge ensemble of the RBC/UKQCD Collaboration.

  4. Lattice calculation of hadronic light-by-light contribution to the muon anomalous magnetic moment

    Science.gov (United States)

    Blum, Thomas; Christ, Norman; Hayakawa, Masashi; Izubuchi, Taku; Jin, Luchang; Lehner, Christoph

    2016-01-01

    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. 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.

  5. Inverted effective SUSY with combined Z' and gravity mediation, and muon anomalous magnetic moment

    OpenAIRE

    Kim, Jihn E.

    2012-01-01

    Effective supersymmetry(SUSY) where stop is the lightest squark may run into a two-loop tachyonic problem in some Z' mediation models. In addition, a large A term or/and a large stop mass are needed to have about a 126 GeV Higgs boson with three families of quarks and leptons. Thus, we suggest an inverted effective SUSY(IeffSUSY) where stop mass is larger compared to those of the first two families. In this case, it is possible to have a significant correction to the anomalous magnetic moment...

  6. Calculation of the hadronic vacuum polarization disconnected contribution to the muon anomalous magnetic moment

    CERN Document Server

    Blum, T; Izubuchi, T; Jin, L; Jüttner, A; Lehner, C; Maltman, K; Marinkovic, M; Portelli, A; Spraggs, M

    2015-01-01

    We report the first lattice QCD calculation of the hadronic vacuum polarization disconnected contribution to the muon anomalous magnetic moment at physical pion mass. The calculation uses a refined noise-reduction technique which enabled the control of statistical uncertainties at the desired level with modest computational effort. Measurements were performed on the $48^3 \\times 96$ physical-pion-mass lattice generated by the RBC and UKQCD collaborations. We find $a_\\mu^{\\rm HVP~(LO)~DISC} = -9.6(3.3)(2.3)\\times 10^{-10}$, where the first error is statistical and the second systematic.

  7. Calculation of the Hadronic Vacuum Polarization Disconnected Contribution to the Muon Anomalous Magnetic Moment

    Science.gov (United States)

    Blum, T.; Boyle, P. A.; Izubuchi, T.; Jin, L.; Jüttner, A.; Lehner, C.; Maltman, K.; Marinkovic, M.; Portelli, A.; Spraggs, M.; Rbc; Ukqcd Collaborations

    2016-06-01

    We report the first lattice QCD calculation of the hadronic vacuum polarization (HVP) disconnected contribution to the muon anomalous magnetic moment at physical pion mass. The calculation uses a refined noise-reduction technique that enables the control of statistical uncertainties at the desired level with modest computational effort. Measurements were performed on the 483×96 physical-pion-mass lattice generated by the RBC and UKQCD Collaborations. We find the leading-order hadronic vacuum polarization aμHVP (LO )disc=-9.6 (3.3 )(2.3 )×10-10 , where the first error is statistical and the second systematic.

  8. Pauli isotonic oscillatorwith an anomalous magnetic moment in the presence of the Aharonov-Bohm effect: Laplace transform approach

    Science.gov (United States)

    Roshanzamir-Nikou, M.; Goudarzi, H.

    2016-02-01

    A strong magnetic field significantly affects the intrinsic magnetic moment of fermions. In quantum electrodynamics, it was shown that the anomalous magnetic moment of an electron arises kinematically, while it results from a dynamical interaction with an external magnetic field for hadrons (proton). Taking the anomalous magnetic moment of a fermion into account, we find an exact expression for the boundstate energy and the corresponding eigenfunctions of a two-dimensional nonrelativistic spin-1/2 harmonic oscillator with a centripetal barrier (known as the isotonic oscillator) including an Aharonov-Bohm term in the presence of a strong magnetic field. We use the Laplace transform method in the calculations. We find that the singular solution contributes to the phase of the wave function at the origin and the phase depends on the spin and magnetic flux.

  9. Magnetic modulation doping in topological insulators toward higher-temperature quantum anomalous Hall effect

    Energy Technology Data Exchange (ETDEWEB)

    Mogi, M., E-mail: mogi@cmr.t.u-tokyo.ac.jp; Yoshimi, R.; Yasuda, K.; Kozuka, Y. [Department of Applied Physics and Quantum Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656 (Japan); Tsukazaki, A. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); PRESTO, Japan Science and Technology Agency (JST), Chiyoda-ku, Tokyo 102-0075 (Japan); Takahashi, K. S. [RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan); Kawasaki, M.; Tokura, Y. [Department of Applied Physics and Quantum Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656 (Japan); RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan)

    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.

  10. Magnetic modulation doping in topological insulators toward higher-temperature quantum anomalous Hall effect

    International Nuclear Information System (INIS)

    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)2Te3. 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)2Te3 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)2Te3 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

  11. Leading-order hadronic contributions to the lepton anomalous magnetic moments from the lattice

    CERN Document Server

    Burger, Florian; Jansen, Karl; Petschlies, Marcus; Pientka, Grit; Renner, Dru B

    2015-01-01

    The hadronic leading-order (hlo) contribution to the lepton anomalous magnetic moments $a_l^\\mathrm{hlo}$ of the Standard Model leptons still accounts for the dominant source of the uncertainty of the Standard Model estimates. We present the results of an investigation of the hadronic leading order anomalous magnetic moments of the electron, muon and tau lepton from first principles in twisted mass lattice QCD. With lattice data for multiple pion masses in the range $230 \\mathrm{~MeV} \\lesssim m_{PS} \\lesssim 490 \\mathrm{~MeV}$, multiple lattice volumes and three lattice spacings we perform the extrapolation to the continuum and to the physical pion mass and check for all systematic uncertainties in the lattice calculation. As a result we calculate $a_{l}^\\mathrm{hlo}$ for the three Standard Model leptons with controlled statistical and systematic error in agreement with phenomenological determinations using dispersion relations and experimental data. In addition, we also give a first estimate of the hadronic...

  12. Spatio-temporal anomalous diffusion in heterogeneous media by nuclear magnetic resonance

    Science.gov (United States)

    Palombo, M.; Gabrielli, A.; De Santis, S.; Cametti, C.; Ruocco, G.; Capuani, S.

    2011-07-01

    In this paper, we describe nuclear magnetic resonance measurements of water diffusion in highly confined and heterogeneous colloidal systems using an anomalous diffusion model. For the first time, temporal and spatial fractional exponents, α and μ, introduced within the framework of continuous time random walk, are simultaneously measured by pulsed gradient spin-echo NMR technique in samples of micro-beads dispersed in aqueous solution. In order to mimic media with low and high level of disorder, mono-dispersed and poly-dispersed samples are used. We find that the exponent α depends on the disorder degree of the system. Conversely, the exponent μ depends on both bead sizes and magnetic susceptibility differences within samples. The new procedure proposed here may be a useful tool to probe porous materials and microstructural features of biological tissue.

  13. New Measurement of the Anomalous Magnetic Moment of the Positive Muon

    International Nuclear Information System (INIS)

    The muon anomalous magnetic moment has been measured in a new experiment at Brookhaven. Polarized muons were stored in a superferric ring, and the angular frequency difference, ωa , between the spin precession and orbital frequencies was determined by measuring the time distribution of high-energy decay positrons. The ratio R of ωa to the Larmor precession frequency of free protons, ωp , in the storage-ring magnetic field was measured. We find R=3.707 220(48)x10-3 . With μμ/μp=3.183 345 47(47) this gives aμ+=1 165 925(15)x10-9 (±13 ppm ), in good agreement with the previous CERN measurements for μ+ and μ- and of approximately the same precision. copyright 1999 The American Physical Society

  14. Quantum anomalous Hall effect in atomic crystal layers from in-plane magnetization

    Science.gov (United States)

    Ren, Yafei; Zeng, Junjie; Deng, Xinzhou; Yang, Fei; Pan, Hui; Qiao, Zhenhua

    2016-08-01

    We theoretically demonstrate that with in-plane magnetization, the quantum anomalous Hall effect (QAHE) can be realized in two-dimensional atomic crystal layers with preserved inversion symmetry but broken out-of-plane mirror reflection symmetry. By taking the honeycomb lattice system as an example, we find that the low-buckled structure satisfying the symmetry criteria is crucial to induce QAHE. The topologically nontrivial bulk gap carrying a Chern number of C =±1 opens in the vicinity of the saddle points M , where the band dispersion exhibits strong anisotropy. We further show that the QAHE with electrically tunable Chern number can be achieved in Bernal-stacked multilayer systems, and the applied interlayer potential differences can dramatically decrease the critical magnetization to make the QAHE experimentally feasible.

  15. Pair production and vacuum polarization of vector particles with electric dipole moments and anomalous magnetic moments

    International Nuclear Information System (INIS)

    The matrix 8-component Dirac-like form of the P-odd equations for boson fields of spin 1 and 0 are obtained and the GL(2,c) symmetry group of the equations is derived. We found exact solutions of the field equation for vector particles with arbitrary electric and magnetic moments in external constant and uniform electromagnetic fields. The differential probability of pair production of vector particles with electric dipole moments and anomalous magnetic moments by an external constant and uniform electromagnetic field has been found using exact solutions. We have calculated the imaginary and real parts of the electromagnetic field Lagrangian that takes into account the vacuum polarization of vector particles. (orig.)

  16. Structural, magnetic and transport properties of Co2FeAl Heusler films with varying thickness

    Science.gov (United States)

    Wang, Xiaotian; Li, Yueqing; Du, Yin; Dai, Xuefang; Liu, Guodong; Liu, Enke; Liu, Zhongyuan; Wang, Wenhong; Wu, Guangheng

    2014-08-01

    We report on a systematic study of the structural, magnetic properties and the anomalous Hall effect, in the Heusler alloy Co2FeAl (CFA) epitaxial films on MgO (001), as a function of film thickness. It was found that the epitaxial CFA films show a highly ordered B2 structure with an in-plane uniaxial magnetic anisotropy. The electrical transport properties reveal that the lattice and magnon scattering contributions to the longitudinal resistivity. Independent on the thickness of films, the anomalous Hall resistivity of CFA films is found to be dominated by skew scattering only. Moreover, the anomalous Hall resistivity shows weakly temperature dependent behavior, and its absolute value increases as the thickness decreases. We attribute this temperature insensitivity in the anomalous Hall resistivity to the weak temperature dependent of tunneling spin-polarization in the CFA films, while the thickness dependence behavior is likely due to the increasing significance of interface or free surface electronic states.

  17. Magnetic properties of hematite nanoparticles

    DEFF Research Database (Denmark)

    Bødker, Franz; Hansen, Mikkel Fougt; Bender Koch, Christian;

    2000-01-01

    The magnetic properties of hematite (alpha-Fe2O3) particles with sizes of about 16 nm have been studied by use of Mossbauer spectroscopy, magnetization measurements, and neutron diffraction. The nanoparticles are weakly ferromagnetic at temperatures at least down to 5 K with a spontaneous...

  18. Proceedings of the workshop on 'anomalous electronic states and physical properties in high-temperature superconductors'

    International Nuclear Information System (INIS)

    A workshop entitled 'Anomalous Electronic States and Physical Properties in High-Temperature Superconductors' was held on November 7-8, 2006 at Institute for Materials Research, Tohoku University. In the workshop, leading scientists in the field of high-Tc superconductivity, both experimentalists and theorists, gathered in a hall to report the recent progress of the study, clarify the problems to be solved, and discuss the future prospects. The workshop was jointly organized by Specially Promoted Research of MEXT, Development of the 4D Spaces Access Neutron Spectrometer and Elucidation of the Mechanism of Oxide High-Tc Superconductivity' (repr. by M. Arai, JAEA) and by the Inter-university Cooperative Research Program of the Institute for Materials Research, Tohoku University, 'Anomalous Electronic States and Physical Properties in High-Temperature Superconductors' (repr. by T. Tohyama, Kyoto Univ.). This report includes abstracts and materials of the presentations in the workshop. (author)

  19. Relativistic energy correction of the hydrogen atom with an anomalous magnetic moment

    International Nuclear Information System (INIS)

    The electron is known to possess an anomalous magnetic moment, which interacts with the gradient of the electric field. This makes it necessary to compute its effects on the energy spectrum. Even though the Coulomb Dirac equation can be solved in closed form, this is no longer possible when the anomalous magnetic moment is included. In fact the interaction due to this term is so strong that it changes the domain of the Hamiltonian. From a differential equation point of view, the anomalous magnetic moment term is strongly singular near the origin. As usual, one has to resort to perturbation theory. This, however, only makes sense if the eigenvalues are stable. To prove stability is therefore a challenge one has to face before actually computing the energy shifts. The first stability results in this line were shown by Behncke for angular momenta κ≥3, because the eigenfunctions of the unperturbed Hamiltonian decay fast enough near the origin. He achieved this by decoupling the system and then using the techniques available for second order differential equations. Later, Kalf and Schmidt extended Behncke's results basing their analysis on the Pruefer angle technique and a comparison result for first order differential equations. The Pruefer angle method is particularly useful because it shows a better stability and because it obeys a first order differential equation. Nonetheless, Kalf and Schmidt had to exclude some coupling constants for κ>0. This I believe is an artefact of their method. In this study, I make increasing use of asymptotic integration, a method which is rather well adapted to perturbation theory and is known to give stability results to any level of accuracy. Together with the Pruefer angle technique, this lead to a more general stability result and even allows for an energy shifts estimate. Hamiltonians traditionally treated in physics to describe the spin-orbit effect are not self adjoint i.e. they are not proper observables in quantum

  20. Direct Evidence of Anomalous Interfacial Magnetization in Metamagnetic Pd doped FeRh Thin Films

    OpenAIRE

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

    2015-01-01

    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 sys...

  1. MAGNETIC WOVEN FABRICS - PHYSICAL AND MAGNETIC PROPERTIES

    OpenAIRE

    GROSU Marian C; LUPU Iuliana G; AVRAM Dorin; TUDORACHE Florin

    2015-01-01

    A coated material is a composite structure that consists of at least two components: base material and coating layer. The purpose of coating is to provide special properties to base material, with potential to be applied in EMI shielding and diverse smart technical fields. This paper reports the results of a study about some physical and magnetic properties of coated woven fabrics made from cotton yarns with fineness of 17 metric count. For this aim, a plain woven fabric was coated with a sol...

  2. Four-Flavour Leading Hadronic Contribution To The Muon Anomalous Magnetic Moment

    CERN Document Server

    Burger, Florian; Hotzel, Grit; Jansen, Karl; Petschlies, Marcus; Renner, Dru B

    2013-01-01

    We present a four-flavour lattice calculation of the leading-order hadronic vacuum polarisation contribution to the anomalous magnetic moment of the muon, $a_{\\mu}^{\\rm hvp}$, 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 $a_{\\mu}^{\\rm hvp}$. Our final result involving an estimate of the systematic uncertainty $$a_{\\mathrm{\\mu}}^{\\rm hvp} = 6.74(21)(18) \\cdot 10^{-8}$$ shows a good overall agreement with these computations.

  3. Four-flavour leading hadronic contribution to the muon anomalous magnetic moment

    Energy Technology Data Exchange (ETDEWEB)

    Burger, Florian; Hotzel, Grit [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Feng, Xu [KEK National High Energy Physics, Tsukuba (Japan); Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Cyprus Univ. Nicosia (Cyprus). Dept. of Physics; Petschlies, Marcus [The Cyprus Institute, Nicosia (Cyprus); Renner, Dru B. [Jefferson Lab, Newport News, VA (United States)

    2013-11-15

    We present a four-flavour lattice calculation of the leading-order hadronic vacuum polarisation contribution to the anomalous magnetic moment of the muon, a{sup hvp}{sub {mu}}, arising from quark-connected Feynman graphs. It is based on ensembles featuring N{sub 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{sup hvp}{sub {mu}}. Our final result involving an estimate of the systematic uncertainty a{sup hvp}{sub {mu}}=6.74(21)(18) x 10{sup -8} shows a good overall agreement with these computations.

  4. Electric and anomalous magnetic dipole moments of the muon in the MSSM

    International Nuclear Information System (INIS)

    We study the electric dipole moment (EDM) and the anomalous magnetic dipole moment (MDM) of the muon in the CP-violating Minimal Supersymmetric extension of the Standard Model (MSSM). We take into account the contributions from the chargino- and neutralino-mediated one-loop graphs and the dominant two-loop Higgs-mediated Barr-Zee diagrams. We improve earlier calculations by incorporating CP-violating Higgs-boson mixing effects and the resummed threshold corrections to the Yukawa couplings of the charged leptons as well as that of the bottom quark. The analytic correlation between the muon EDM and MDM is explicitly presented at one- and two-loop levels and, through several numerical examples, we illustrate its dependence on the source of the dominant contributions. We have implemented the analytic expressions for the muon EDM and MDM in an updated version of the public code CPsuperH2.0.

  5. Electric and anomalous magnetic dipole moments of the muon in the MSSM

    CERN Document Server

    Cheung, Kingman; Lee Jae Sik

    2009-01-01

    We study the electric dipole moment (EDM) and the anomalous magnetic dipole moment (MDM) of the muon in the CP-violating Minimal Supersymmetric extension of the Standard Model (MSSM). We take into account the contributions from the chargino- and neutralino-mediated one-loop graphs and the dominant two-loop Higgs-mediated Barr-Zee diagrams. We improve earlier calculations by incorporating CP-violating Higgs-boson mixing effects and the resummed threshold corrections to the Yukawa couplings of the charged leptons as well as that of the bottom quark. The analytic correlation between the muon EDM and MDM is explicitly presented at one- and two-loop levels and, through several numerical examples, we illustrate its dependence on the source of the dominant contributions. We have implemented the analytic expressions for the muon EDM and MDM in an updated version of the public code CPsuperH2.0.

  6. MeV scale leptonic force for cosmic neutrino spectrum and muon anomalous magnetic moment

    CERN Document Server

    Araki, Takeshi; Ota, Toshihiko; Sato, Joe; Shimomura, Takashi

    2015-01-01

    Characteristic patterns of cosmic neutrino spectrum reported by the IceCube collaboration and long-standing inconsistency between theory and experiment in muon anomalous magnetic moment are simultaneously explained by an extra leptonic force mediated by a gauge field with a mass of the MeV scale. With different assumptions for redshift distribution of cosmic neutrino sources, diffuse neutrino flux is calculated with the scattering between cosmic neutrino and cosmic neutrino background through the new leptonic force. Our analysis sheds light on a relation among lepton physics at the three different scales, PeV, MeV, and eV, and provides possible clues to the distribution of sources of cosmic neutrino and also to neutrino mass spectrum.

  7. Anomalous character of the axion–photon coupling in a magnetic field distorted by a pp-wave gravitational background

    International Nuclear Information System (INIS)

    We study the problem of axion–photon coupling in the magnetic field influenced by gravitational radiation. We focus on exact solutions to the equations for axion electrodynamics in the pp-wave gravitational background for two models with initially constant magnetic field. The first model describes the response of an initially constant magnetic field in a gravitational-wave vacuum with unit refraction index; the second model is characterized by a non-unit refraction index prescribed to the presence of ordinary and/or dark matter. We show that both models demonstrate anomalous behavior of the electromagnetic field generated by the axion–photon coupling in the presence of magnetic field, evolving in the gravitational wave background. The role of axionic dark matter in the formation of the anomalous response of this electrodynamic system is discussed. (paper)

  8. Spin-Down Mechanisms in Neutron Stars with ``Anomalous'' Magnetic Fields

    Science.gov (United States)

    Rogers, Adam; Safi-Harb, Samar

    2015-08-01

    Energy losses from isolated neutron stars are attributed to a number of factors, the most common assumption being the emission of electromagnetic radiation from a rotating point-like magnetic dipole in vacuum. This energy loss mechanism predicts a braking index n = 3, which is not observed in highly magnetized neutron stars. Despite this fact, the assumptions of a dipole field and rapid early rotation are often assumed a priori. This typically causes a discrepancy in the characteristic age of these objects and the age of their associated Supernova Remnants (SNRs). In this work we consider neutron stars with ``anomalous'' magnetic fields - namely magnetars, high-B radio pulsars, and the Central Compact Objects (proposed to be `anti-magnetars’) that are securely associated with SNRs. Without making any assumptions about the initial spin periods of these objects and by constraining the SNR ages to match their associated pulsar ages, we compare the predictions of distinct energy loss mechanisms, such as field decay and the emission of relativistic winds using all observed data on the braking indices. This study has important implications on the proposed emission models for these exotic objects and helps in resolving the PSR-SNR age discrepancy.

  9. A study of magnetic fluctuations and their anomalous scaling in the solar wind: the Ulysses fast-latitude scan

    OpenAIRE

    Pagel, C.; Balogh, A.

    2002-01-01

    The solar wind is a highly turbulent and intermittent medium at frequencies between 10-4 and 10-1 Hz. Power spectra are used to look at fluctuations in the components of the magnetic field at high frequencies over a wide range of latitudes. Results show steady turbulence in the polar regions of the Sun and a more varied environment in the equatorial region. The magnetic field fluctuations exhibit anomalous scaling at high frequencies. Var...

  10. Local magnetism in YbCrSb3, an anomalous member of the RECrSb3 series

    International Nuclear Information System (INIS)

    The intermetallic magnetic compound YbCrSb3, which shows anomalous behavior when compared to other compounds in the RECrSb3 series, is studied near zero magnetic field using μSR. Coherent muon spin precession is observed, unambiguously establishing at the local level that a significant fraction of the sample is in a well-ordered magnetic state below ∼240K. These results confirm, at the local level, that the magnetic transition temperature in YbCrSb3 is higher than those of the other RECrSb3 compounds synthesized to date.

  11. Experimental Demonstration of Anomalous Field Enhancement in All-Dielectric Transition Magnetic Metamaterials

    Science.gov (United States)

    Sun, Jingbo; Liu, Xiaoming; Zhou, Ji; Kudyshev, Zhaxylyk; Litchinitser, Natalia M.

    2015-11-01

    Anomalous field enhancement accompanied by resonant absorption phenomenon was originally discussed in the context of plasma physics and in applications related to radio-communications between the ground and spacecraft returning to Earth. Indeed, there is a critical period of time when all communications are lost due to the reflection/absorption of electromagnetic waves by the sheath of plasma created by a high speed vehicle re-entering the atmosphere. While detailed experimental studies of these phenomena in space are challenging, the emergence of electromagnetic metamaterials enables researchers exceptional flexibility to study them in the laboratory environment. Here, we experimentally demonstrated the strong localized field enhancement of magnetic field for an electromagnetic wave propagating in Mie-resonance-based inhomogeneous metamaterials with magnetic permeability gradually changing from positive to negative values. Although these experiments were performed in the microwave frequency range, the proposed all-dielectric approach to transition metamaterials can be extended to terahertz, infrared, and visible frequencies. We anticipate that these results, besides most basic science aspects, hold the potential for numerous applications, including low-intensity nonlinear transformation optics, topological photonics, and the broader area of surface and interface science.

  12. Nonlocal Anomalous Hall Effect

    Science.gov (United States)

    Zhang, Steven S.-L.; Vignale, Giovanni

    2016-04-01

    The anomalous Hall (AH) effect is deemed to be a unique transport property of ferromagnetic metals, caused by the concerted action of spin polarization and spin-orbit coupling. Nevertheless, recent experiments have shown that the effect also occurs in a nonmagnetic metal (Pt) in contact with a magnetic insulator [yttrium iron garnet (YIG)], even when precautions are taken to ensure that there is no induced magnetization in the metal. We propose a theory of this effect based on the combined action of spin-dependent scattering from the magnetic interface and the spin-Hall effect in the bulk of the metal. At variance with previous theories, we predict the effect to be of first order in the spin-orbit coupling, just as the conventional anomalous Hall effect—the only difference being the spatial separation of the spin-orbit interaction and the magnetization. For this reason we name this effect the nonlocal anomalous Hall effect and predict that its sign will be determined by the sign of the spin-Hall angle in the metal. The AH conductivity that we calculate from our theory is in order of magnitude agreement with the measured values in Pt /YIG structures.

  13. Muon anomalous magnetic moment in a $SU(4) \\otimes U(1)_N$ model without exotic electric charges

    CERN Document Server

    Cogollo, D

    2014-01-01

    We study an electroweak gauge extension of the standard model, so called 3-4-1 model, which does not contain exotic electric charges and it is anomaly free. We discuss phenomenological constraints of the model and compute all the corrections to the muon magnetic moment. Mainly, we discuss different mass regimes and their impact on this correction, deriving for the first time direct limits on the masses of the neutral fermions and charged vector bosons. Interestingly, the model could address the reported muon anomalous magnetic moment excess, however it would demands a rather low scale of symmetry breaking, far below the current electroweak constraints on the model. Thus, if this excess is confirmed in the foreseeable future by the g-2 experiment at FERMILAB, this 3-4-1 model can be decisively ruled out since the model cannot reproduce a sizeable and positive contribution to the muon anomalous magnetic moment consistent with current electroweak limits.

  14. Anomalous D'yakonov-Perel' spin relaxation in semiconductor quantum wells under a strong magnetic field in the Voigt configuration

    Science.gov (United States)

    Zhou, Y.; Yu, T.; Wu, M. W.

    2013-06-01

    We report an anomalous scaling of the D’yakonov-Perel’ spin relaxation with the momentum relaxation in semiconductor quantum wells under a strong magnetic field in the Voigt configuration. We focus on the case in which the external magnetic field is perpendicular to the spin-orbit-coupling-induced effective magnetic field and its magnitude is much larger than the latter one. It is found that the longitudinal spin relaxation time is proportional to the momentum relaxation time even in the strong-scattering limit, indicating that the D’yakonov-Perel’ spin relaxation demonstrates Elliott-Yafet-like behavior. Moreover, the transverse spin relaxation time is proportional (inversely proportional) to the momentum relaxation time in the strong- (weak-) scattering limit, both in the opposite trends against the well-established conventional D’yakonov-Perel’ spin relaxation behaviors. We further demonstrate that all the above anomalous scaling relations come from the unique form of the effective inhomogeneous broadening.

  15. Magnetic properties in the inhomogeneous chiral phase

    CERN Document Server

    Yoshiike, Ryo; Tatsumi, Toshitaka

    2016-01-01

    We investigate the magnetic properties of quark matter in the inhomogeneous chiral phase, where both scalar and pseudoscalar condensates spatially modulate. The energy spectrum of the lowest Landau level becomes asymmetric about zero in the external magnetic field, and gives rise to the remarkably magnetic properties: quark matter has a spontaneous magnetization, while the magnetic susceptibility does not diverge on the critical point.

  16. Anomalous magnetic ordering phenomena in tetragonal TbB sub 2 C sub 2 observed by neutron diffraction

    CERN Document Server

    Kaneko, K; Onodera, H; Yamaguchi, Y; Katano, S; Matsuda, M

    2002-01-01

    Detailed neutron diffraction measurements on a single crystalline TbB sub 2 C sub 2 in which magnetic field induced antiferroquadrupolar orderings are realised have been performed to understand characteristics of the transition under zero magnetic field. The results indicate that the magnetic transition phenomena consist of development of at least three magnetic components: (1) a dominant antiferromagentic component which develops below T sub N = 21.7 K, (2) a weak long periodic component which develops below about 18 K, and (3) anomalous components with broad magnetic scatterings which develop below about 50 K, which can not be understood by only a short range magnetic ordering. Since these three components develop independently, the transition phenomena in TbB sub 2 C sub 2 are much more complicated than expected from a typical lambda-type anomaly at T sub N in the temperature dependence of magnetic specific heat. (author)

  17. Magnetic transport properties in iron/iron-oxide films

    International Nuclear Information System (INIS)

    Iron/iron-oxide granular films were fabricated using reactive dc magnetron sputtering. Their structural, magnetic and transport properties were systematically studied. XPS and TEM confirmed the coexistence of Fe, FeO and Fe2O3. A metal-insulator transition was observed with the increasing of the oxygen component in the film. The temperature dependencies of longitudinal resistivity ρxx and anomalous Hall resistivity ρxy were discussed. We found the enhancement of ρxy and investigated the scaling law between anomalous Hall coefficient Rs and ρxx. In all the samples, Rs was found to be proportional to ρxx when ρxx is small, which indicated the skew scattering is dominant

  18. Evidence of local effects in anomalous refraction and focusing properties of dodecagonal photonic quasicrystals

    CERN Document Server

    Di Gennaro, Emiliano; Savo, Salvatore; Andreone, Antonello; Morello, Davide; Galdi, Vincenzo; Castaldi, Giuseppe; Pierro, Vincenzo

    2008-01-01

    We present the key results from a comprehensive study of the refraction and focusing properties of a two-dimensional dodecagonal photonic ``quasicrystal'' (PQC), carried out via both full-wave numerical simulations and microwave measurements on a slab made of alumina rods inserted in a parallel-plate waveguide. We observe anomalous refraction and focusing in several frequency regions, confirming some recently published results. However, our interpretation, based on numerical and experimental evidence, differs substantially from the one in terms of ``effective negative refractive-index'' that was originally proposed. Instead, our study highlights the critical role played by short-range interactions associated with local order and symmetry.

  19. Magnetic properties of electrodeposited nanowires

    Science.gov (United States)

    Heydon, G. P.; Hoon, S. R.; Farley, A. N.; Tomlinson, S. L.; Valera, M. S.; Attenborough, K.; Schwarzacher, W.

    1997-04-01

    Electrodeposited multilayered nanowires grown within a polycarbonate membrane constitute a new medium in which giant magnetoresistance (GMR) perpendicular to the plane of the multilayers can be measured. These structures can exhibit a perpendicular GMR of at least 22% at ambient temperature. We performed detailed studies both of reversible magnetization and of irreversible remanent magnetization curves for CoNiCu/Cu/CoNiCu multilayered and CoNiCu pulse-deposited nanowire systems with Co:Ni ratios of 6:4 and 7:3 respectively in the range 10 - 290 K, allowing the magnetic phases of these structures to be identified. Shape anisotropy in the pulse-deposited nanowire and inter-layer coupling in the multilayered nanowire are shown to make important contributions to the magnetic properties. Dipolar-like interactions are found to predominate in both nanowire systems. Magnetic force microscope (MFM) images of individual multilayered nanowires exhibit a contrast consistent with there being a soft magnetization parallel to the layers. Switching of the magnetic layers in the multilayered structure into the direction of the MFM tip's stray field is observed.

  20. Anomalous behaviour of thermophysical properties of stoichiometric uranium dioxide by molecular dynamics simulation

    International Nuclear Information System (INIS)

    We present a classical molecular dynamics simulation of uranium dioxide in the temperature range of 300-3000 K. Temperature dependences of thermal conductivity, heat capacity and ionic conductivity are investigated. Our study shows the rise of thermal conductivity of uranium dioxide at very high temperatures (above 2500 K), which is not predicted by the former anharmonic theories. Several pair potentials are used in the simulation, and they depict similar effects. Long range forces are accounted by Ewald sums. Static thermal properties are evaluated in NPT ensemble. It is shown that a high-temperature peak on heat capacity is present and is more legible in large systems. To ensure the best reliability, transport properties are evaluated using the theory of autocorrelation functions in NVE ensemble. In order to properly define thermal conductivity in ionic systems with charge fluxes, an expression which accounts the thermoelectric effect is derived from Onsager reciprocal relations. The rise on temperature dependence of thermal conductivity is accompanied by the peak on heat capacity and an anomalous rise of ionic conductivity. However, it is shown that there is no partial melting of the oxygen sublattice, which suggests that the system does not necessarily exhibit a superionic transition. Instead, kick-out diffusion in oxygen sublattice is proposed to be the origin of such anomalous behavior of thermophysical properties. (author)

  1. A to Z of the Muon Anomalous Magnetic Moment in the MSSM with Pati-Salam at the GUT scale

    CERN Document Server

    Belyaev, Alexander S; King, Steve F; Miller, David J; Morais, António P; Schaefers, Patrick B

    2016-01-01

    We analyse the low energy predictions of the minimal supersymmetric standard model (MSSM) arising from a GUT scale Pati-Salam gauge group further constrained by an $A_4 \\times Z_5$ family symmetry, resulting in four soft scalar masses at the GUT scale: one left-handed soft mass $m_0$ and three right-handed soft masses $m_1,m_2,m_3$, one for each generation. We demonstrate that this model, which was initially developed to describe the neutrino sector, can explain collider and non-collider measurements such as the dark matter relic density, the Higgs boson mass and, in particular, the anomalous magnetic moment of the muon $(g-2)_\\mu$. Since about two decades, $(g-2)_\\mu$ suffers a puzzling about 3$\\,\\sigma$ excess of the experimentally measured value over the theoretical prediction, which our model is able to fully resolve. As the consequence of this resolution, our model predicts specific regions of the parameter space with the specific properties including light smuons and neutralinos, which could also potent...

  2. Anomalous magnetic viscosity in the bulk-amorphous ferromagnet Nd60Fe20Co10Al10

    International Nuclear Information System (INIS)

    Full text: Magnetic viscosity is the time dependence of the magnetisation, M(t), in a constant magnetic field and is the result of thermal activation of irreversible magnetisation processes. On the major hysteresis loop, and over short times, M(t) can be described by M(t) = A + S ln(t +t0), where A and t0 are fitting parameters and S is the magnetic viscosity parameter. In the second, or de-magnetisation, quadrant of the hysteresis loop S is negative and reaches its largest value near the intrinsic coercivity. On the lower branch of a recoil curve, S can sometimes be initially positive before becoming negative after a sufficiently long waiting time; this is called anomalous magnetic viscosity. Recently, it has been reported that bulk-amorphous hard magnets can be obtained in the multi-component alloy systems Nd-Fe-Al and Nd-Fe-Co-Al. Wang et al. have observed anomalous magnetic viscosity on the lower branch of minor hysteresis loops in Nd60Fe30Al10. We have studied magnetisation and de-magnetisation processes in a suction-cast rod of bulk amorphous Nd60Fe20Co10Al10. Remanence curves were measured starting from three different states: ac de-magnetised, thermally de-magnetised and fully saturated. Magnetic viscosity was measured on the major loop and on both branches of minor loops for times extending to 30 hours. A rich variety of magnetic behaviour was observed, including anomalous viscosity on the minor loops, and our results will be presented and discussed in terms of activation energy distributions

  3. Magnetic Properties of Erbium Gallium Gallate under High Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    Zhang Xijuan; Cheng Haiying; Yang Cuihong; Wang Wei

    2004-01-01

    A theoretical investigation on the magnetic properties of rare-earth Er3+ in Er3 Ga5 O12 was reported. The average magnetic moments(M) for applied magnetic field H parallel to the [001 ], [ 100], [ 110], [ 111 ] direction was studied based on the quantum theory. Temperature dependence of the magnetic properties is analyzed for H applied parallel to the [ 100] and [ 111 ] crystallographic directions. The magnetization decreases with increasing temperature,showing good agreement with thermal effect. A strong anisotropy of the magnetization is found under high magnetic field, but when the magnetic field is small, M and H are proportional.

  4. Estimate of the hadronic vacuum polarization disconnected contribution to the anomalous magnetic moment of the muon from lattice QCD

    Science.gov (United States)

    Chakraborty, Bipasha; Davies, C. T. H.; Koponen, J.; Lepage, G. P.; Peardon, M. J.; Ryan, S. M.

    2016-04-01

    The quark-line disconnected diagram is a potentially important ingredient in lattice QCD calculations of the hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon. It is also a notoriously difficult one to evaluate. Here, for the first time, we give an estimate of this contribution based on lattice QCD results that have a statistically significant signal, albeit at one value of the lattice spacing and an unphysically heavy value of the u /d quark mass. We use HPQCD's method of determining the anomalous magnetic moment by reconstructing the Adler function from time moments of the current-current correlator at zero spatial momentum. Our results lead to a total (including u , d and s quarks) quark-line disconnected contribution to aμ of -0.15 % of the u /d hadronic vacuum polarization contribution with an uncertainty which is 1% of that contribution.

  5. An estimate of the hadronic vacuum polarization disconnected contribution to the anomalous magnetic moment of the muon from lattice QCD

    CERN Document Server

    Chakraborty, Bipasha; Koponen, J; Lepage, G P; Peardon, M J; Ryan, S M

    2015-01-01

    The quark-line disconnected diagram is a potentially important ingredient in lattice QCD calculations of the hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon. It is also a notoriously difficult one to evaluate. Here, for the first time, we give an estimate of this contribution based on lattice QCD results that have a statistically significant signal, albeit at one value of the lattice spacing and an unphysically heavy value of the $u/d$ quark mass. We use HPQCD's method of determining the anomalous magnetic moment by reconstructing the Adler function from time-moments of the current-current correlator at zero spatial momentum. Our results lead to a total (including $u$, $d$ and $s$ quarks) quark-line disconnected contribution to $a_{\\mu}$ of $-0.15\\%$ of the $u/d$ hadronic vacuum polarization contribution with an uncertainty which is 1\\% of that contribution.

  6. New evaluation of hadronic contributions to the anomalous magnetic moment of charged leptons

    International Nuclear Information System (INIS)

    A re-evaluation of the lowest-order hagronic vacuum-polarization contribution to the anomalous magnetic moment of the electron, muon and tau-lepton with a higher precision in comparison with previous estimates is carried out. The latter is achieved because new data on some exclusive processes have appeared recently, more accomplished models for a description of the pion and kaon electromagnetic structure have been developed and the revised (due to a new value of the coefficient of the third power of αs) QCD formula for R=σtot (e+e-→had)/σtot (e+e-→μ+μ-) with electroweak corrections has been applied to analyze all existing data in a proper way. The final results are ae(2)had=(1.810±0.011±0.002)x10-12 aμ(2)had=(6.986±0.042±0.016)x10-8 and aτ(2)had=(3.436±0.024±0.024)x10-6. 19 refs.; 2 figs.; 3 tabs

  7. Low-Temperature Magnetic Properties of Co Antidot Array

    Institute of Scientific and Technical Information of China (English)

    LIU Qing-Fang; JIANG Chang-Jun; FAN Xiao-Long; WANG Jian-Bo; XUE De-Sheng

    2006-01-01

    Cobalt antidot arrays with different thicknesses are fabricated by rf magnetron sputtering onto porous alumina substrates. Scanning electron microscopy and grazing incidence x-ray diffraction are employed to characterize the morphology and crystal structure of the antidot array, respectively. The temperature dependence of magnetic properties shows that in the temperature range 5K-300K, coercivity and squareness increase firstly, reach their maximum values, then decrease. The anomalous temperature dependences of coercivity and squareness are discussed by considering the pinning effect of the antidot and the magnetocrystalline anisotropy.

  8. Magnetic properties of Acidithiobacillus ferrooxidans

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Lei; Zhang, Shuang [College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, 163319 (China); Chen, Peng [Gansu Institute of Business and Technology, Lanzhou, 730010 (China); Wang, Weidong; Wang, Yanjie [College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, 163319 (China); Li, Hongyu, E-mail: hekouyanlei@gmail.com [Institute of Microbiology, School of Life Sciences, Lanzhou University, Lanzhou, 730000 (China)

    2013-10-15

    Understanding the magnetic properties of magnetotactic bacteria (MTBs) is of great interest in fields of life sciences, geosciences, biomineralization, biomagnetism, and planetary sciences. Acidithiobacillus ferrooxidans (At. ferrooxidans), obtaining energy through the oxidation of ferrous iron and various reduced inorganic sulfur compounds, can synthesize intracellular magnetite magnetosomes. However, the magnetic properties of such microorganism remain unknown. Here we used transmission electronmicroscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) assay, vibrating sample magnetometer (VSM), magneto–thermogravimetric analysis (MTGA), and low temperature magnetometry to comprehensively investigate the magnetic characteristics of At. ferrooxidans. Results revealed that each cell contained only 1 to 3 magnetite magnetosomes, which were arranged irregularly. The magnetosomes were generally in a stable single-domain (SD) state, but superparamagnetic (SP) magnetite particles were also found. The calcined bacteria exhibited a ferromagnetic behavior with a Curie Temperature of 454 °C and a coercivity of 16.36 mT. Additionally, the low delta ratio (δ{sub FC}/δ{sub ZFC} = 1.27) indicated that there were no intact magnetosome chains in At. ferrooxidans. Our results provided the new insights on the biomineralization of bacterial magnetosomes and magnetic properties of At. ferrooxidans. - Highlights: • Rock magnetic investigations carried out on At.ferrooxidans in detail. • Results indicated that each cell contained 1 to 3 scattered magnetite magnetosomes. • The magnetosomes consist of SD and SP magnetite nanoparticles. • Cells showed ferromagnetic behavior with high Curie Temperature and low δ{sub FC}/δ{sub ZFC}. • Results are useful in studying the magnetosomes biomineralization.

  9. Magnetic properties of Acidithiobacillus ferrooxidans

    International Nuclear Information System (INIS)

    Understanding the magnetic properties of magnetotactic bacteria (MTBs) is of great interest in fields of life sciences, geosciences, biomineralization, biomagnetism, and planetary sciences. Acidithiobacillus ferrooxidans (At. ferrooxidans), obtaining energy through the oxidation of ferrous iron and various reduced inorganic sulfur compounds, can synthesize intracellular magnetite magnetosomes. However, the magnetic properties of such microorganism remain unknown. Here we used transmission electronmicroscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) assay, vibrating sample magnetometer (VSM), magneto–thermogravimetric analysis (MTGA), and low temperature magnetometry to comprehensively investigate the magnetic characteristics of At. ferrooxidans. Results revealed that each cell contained only 1 to 3 magnetite magnetosomes, which were arranged irregularly. The magnetosomes were generally in a stable single-domain (SD) state, but superparamagnetic (SP) magnetite particles were also found. The calcined bacteria exhibited a ferromagnetic behavior with a Curie Temperature of 454 °C and a coercivity of 16.36 mT. Additionally, the low delta ratio (δFC/δZFC = 1.27) indicated that there were no intact magnetosome chains in At. ferrooxidans. Our results provided the new insights on the biomineralization of bacterial magnetosomes and magnetic properties of At. ferrooxidans. - Highlights: • Rock magnetic investigations carried out on At.ferrooxidans in detail. • Results indicated that each cell contained 1 to 3 scattered magnetite magnetosomes. • The magnetosomes consist of SD and SP magnetite nanoparticles. • Cells showed ferromagnetic behavior with high Curie Temperature and low δFC/δZFC. • Results are useful in studying the magnetosomes biomineralization

  10. Anomalous electrical properties of Au/SrTiO3 interface

    Science.gov (United States)

    Xu, Lun; Yajima, Takeaki; Nishimura, Tomonori; Toriumi, Akira

    2016-08-01

    Metal/dielectric interface properties of Au/SrTiO3 (STO) and SrRuO3/SrTiO3 (SRO/STO) interfaces were investigated using metal/STO/heavily Nb-doped STO (0.5 wt % Nb:STO) capacitors. The observed interfacial capacitance at SRO/STO accords with results predicted theoretically, whereas that at the Au/STO interface is strongly suppressed, suggesting an intrinsic low-k (dielectric constant) interfacial layer formation at the Au/STO interface owing to in situ evaporated Au after STO film deposition. Furthermore, metal/0.01 wt % Nb:STO junctions were also analyzed. It was found that the SRO/Nb:STO junction forms an ideal Schottky dipole, whereas the Au/Nb:STO junction exhibits anomalous electrical properties.

  11. Dissipation of the sectored heliospheric magnetic field near the heliopause: a mechanism for the generation of anomalous cosmic rays

    CERN Document Server

    Drake, J F; Swisdak, M; Chamoun, J N

    2009-01-01

    The recent observations of the anomalous cosmic ray (ACR) energy spectrum as Voyagers 1 and 2 crossed the heliospheric termination shock have called into question the conventional shock source of these energetic particles. We suggest that the sectored heliospheric magnetic field, which results from the flapping of the heliospheric current sheet, piles up as it approaches the heliopause, narrowing the current sheets that separate the sectors and triggering the onset of collisionless magnetic reconnection. Particle-in-cell simulations reveal that most of the magnetic energy is released and most of this energy goes into energetic ions with significant but smaller amounts of energy going into electrons. The energy gain of the most energetic ions results from their reflection from the ends of contracting magnetic islands, a first order Fermi process. The energy gain of the ions in contracting islands increases their parallel (to the magnetic field ${\\bf B}$) pressure $p_\\parallel$ until the marginal firehose condi...

  12. Anomalously low thermal conductivity and thermoelectric properties of new cationic clathrates in the Sn-In-As-I system

    International Nuclear Information System (INIS)

    Single-crystal samples of cationic clathrates in the Sn-In-As-I system with different indium contents have been synthesized. Their crystal structure has been analyzed and their thermoelectric properties have been measured. These compounds are found to be n-type semiconductors with high absolute values of the Seebeck coefficient (S = 400–600 μV/K) and anomalously low thermal conductivity (κ ≤ 0.4 W/(m/K) at 300 K, which is characteristic of amorphous materials. The reasons for the anomalously low thermal conductivity of these semiconductors are discussed and ways for optimizing their thermoelectric properties are shown.

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

    Science.gov (United States)

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

    2015-01-01

    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 the 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. 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. PMID:25771919

  14. The magnetic properties of the hollow cylindrical ideal remanence magnet

    DEFF Research Database (Denmark)

    Bjørk, Rasmus

    2016-01-01

    We consider the magnetic properties of the hollow cylindrical ideal remanence magnet. This magnet is the cylindrical permanent magnet that generates a uniform field in the cylinder bore, using the least amount of magnetic energy to do so. The remanence distribution of this magnet is derived and the...... generated field is compared to that of a Halbach cylinder of equal dimensions. The ideal remanence magnet is shown in most cases to generate a significantly lower field than the equivalent Halbach cylinder, although the field is generated with higher efficiency. The most efficient Halbach cylinder is shown...... to generate a field exactly twice as large as the equivalent ideal remanence magnet....

  15. Evidence of local effects in anomalous refraction and focusing properties of dodecagonal photonic quasicrystals

    Science.gov (United States)

    di Gennaro, Emiliano; Miletto, Carlo; Savo, Salvatore; Andreone, Antonello; Morello, Davide; Galdi, Vincenzo; Castaldi, Giuseppe; Pierro, Vincenzo

    2008-05-01

    We present the key results from a comprehensive study of the refraction and focusing properties of a two-dimensional dodecagonal photonic “quasicrystal” (PQC), which was carried out via both full-wave numerical simulations and microwave measurements on a slab made of alumina rods inserted in a parallel-plate waveguide. We observe an anomalous refraction and focusing in several frequency regions, which confirm some recently published results. However, our interpretation, which is based on numerical and experimental evidence, substantially differs from the one in terms of “effective negative refractive index” that was originally proposed. Instead, our study highlights the critical role played by short-range interactions associated with local order and symmetry.

  16. Effects of magnetic field on fluidization properties of magnetic pearls

    Institute of Scientific and Technical Information of China (English)

    Maoming; Fan; Zhenfu; Luo; Yuemin; Zhao; Qingru; Chen; Daniel; Tao; Xiuxiang; Tao; Zhenqiang; Chen

    2007-01-01

    An experimental study of the influence of external magnetic field on the fluidization behavior of magnetic pearls was carried out. Magnetic pearls are a magnetic form of iron oxide that mainly consists of Fe2O3 which are recovered from a high-volume power plant fly ash from pulverized coal combustion. Due to its abundance, low price and particular physical and chemical properties, magnetic pearls can be used as a heavy medium for minerals or solid waste dry separation based on density difference. This paper introduces the properties of magnetic pearls and compares the performance of magnetic pearls fluidised bed operation with or without an external magnetic field. Experimental results show that an external magnetic field significantly improves the fluidization performance of magnetic pearls such as uniformity and stability.

  17. Room-temperature anomalous Hall effect and magnetroresistance in (Ga, Co)-codoped ZnO diluted magnetic semiconductor films

    Institute of Scientific and Technical Information of China (English)

    Liu Xue-Chao; Chen Zhi-Zhan; Shi Er-Wei; Liao Da-Qian; Zhou Ke-Jin

    2011-01-01

    This paper reports that the (Ga, Co)-codoped ZnO thin films have been grown by inductively coupled plasma enhanced physical vapour deposition. Room-temperature ferromagnetism is observed for the as-grown thin films. The x-ray absorption fine structure characterization reveals that Co2+ and Ga3+ ions substitute for Zn2+ ions in the ZnO lattice and exclude the possibility of extrinsic ferromagnetism origin. The ferromagnetic (Ga, Co)-codoped ZnO thin films exhibit carrier concentration dependent anomalous Hall effect and positive magnetoresistance at room temperature. The mechanism of anomalous Hall effect and magneto-transport in ferromagnetic ZnO-based diluted magnetic semiconductors is discussed.

  18. Magnetic materials fundamentals, products, properties, applications

    CERN Document Server

    Hilzinger, Rainer

    2013-01-01

    At a practical level, this compendium reviews the basics of soft and hard magnetic materials, discusses the advantages of the different processing routes for the exploitation of the magnetic properties and hence assists in proper, fail-safe and economic application of magnetic materials. Essential guidelines and formulas for the calculation of the magnetic and electrical properties, temperature and long-term stability of permanent magnets, of inductive components and magnetic shielding are compiled. Selected fields of application and case studies illustrate the large diversity of technical applications. Application engineers will appreciate the comprehensive compilation of the properties and detailed characteristic curves of modern soft and hard magnetic materials. Materials scientists will enjoy the presentation of the different processing routes and their impact on the magnetic properties and students will profit from the survey from the basics of magnetism down to the applications in inductive components, ...

  19. Magnetic properties of UCuGe

    International Nuclear Information System (INIS)

    Magnetic properties of hexagonal UCuGe in magnetic fields up to 4 T at temperatures from 4.2 to 110 K have been investigated. At temperatures below the Neel temperature a spin-flip-like dependence on magnetic field strength is shown. After magnetizing in higher fields UCuGe exhibits a small remanent magnetization. Close analogies in magnetic properties of UCuGe and that of tetragonal UGeY (Y = S, Se, Te) have been stated. Magnetic ordering in the compounds is probably only weakly influenced by differences in their crystal structures

  20. Spinel ferrite nanocrystals embedded inside ZnO: magnetic, electronic andmagneto-transport properties

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Shengqiang; Potzger, K.; Xu, Qingyu; Kuepper, K.; Talut, G.; Marko, D.; Mucklich, A.; Helm, M.; Fassbender, J.; Arenholz, E.; Schmidt, H.

    2009-08-21

    In this paper we show that spinel ferrite nanocrystals (NiFe{sub 2}O{sub 4}, and CoFe{sub 2}O{sub 4}) can be texturally embedded inside a ZnO matrix by ion implantation and post-annealing. The two kinds of ferrites show different magnetic properties, e.g. coercivity and magnetization. Anomalous Hall effect and positive magnetoresistance have been observed. Our study suggests a ferrimagnet/semiconductor hybrid system for potential applications in magneto-electronics. This hybrid system can be tuned by selecting different transition metal ions (from Mn to Zn) to obtain various magnetic and electronic properties.

  1. Modeling Magnetic Properties in EZTB

    Science.gov (United States)

    Lee, Seungwon; vonAllmen, Paul

    2007-01-01

    A software module that calculates magnetic properties of a semiconducting material has been written for incorporation into, and execution within, the Easy (Modular) Tight-Binding (EZTB) software infrastructure. [EZTB is designed to model the electronic structures of semiconductor devices ranging from bulk semiconductors, to quantum wells, quantum wires, and quantum dots. EZTB implements an empirical tight-binding mathematical model of the underlying physics.] This module can model the effect of a magnetic field applied along any direction and does not require any adjustment of model parameters. The module has thus far been applied to study the performances of silicon-based quantum computers in the presence of magnetic fields and of miscut angles in quantum wells. The module is expected to assist experimentalists in fabricating a spin qubit in a Si/SiGe quantum dot. This software can be executed in almost any Unix operating system, utilizes parallel computing, can be run as a Web-portal application program. The module has been validated by comparison of its predictions with experimental data available in the literature.

  2. Pulsed magnetic field magnetic force microscope and evaluation of magnetic properties of soft magnetic tips

    International Nuclear Information System (INIS)

    A pulsed magnetic field magnetic force microscope (PMF-MFM) is developed for evaluation of the magnetic properties of nano-scale materials and devices, as well as the characteristics of MFM tips. We present the setup of the PMF-MFM system, and focus on the evaluation of a FeCo soft magnetic tip by PMF-MFM. We find a new theoretical method to calculate tip magnetization curves (M-H curves) using MFM phase signals. We measure the MFM phase and amplitude signals for the FeCo tip during the presence of the pulsed magnetic fields oriented parallel and antiparallel to the initial tip magnetization direction, and acquire the tip coercivity H c ∼ 1.1 kOe. The tip M-H curves are also calculated using the MFM phase signals data. We obtain the basic features of the tip magnetic properties from the tip M-H curves. (paper)

  3. Anomalous Upper Critical Field in the Heavy-Fermion Superconductor UBe13 Studied by DC Magnetization Measurements

    International Nuclear Information System (INIS)

    We have studied anomalous upper critical field Bc2(T) of a single crystal of UBe13 by DC magnetization measurements down to 0.14 K and up to 8 T. We have observed a broad anomaly and a peak effect below Bc2 in magnetization curves. Although a possibility of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state has been proposed as an origin of the unusual upper critical field by previous works, our results have shown that thermal equilibrium magnetization curves reveal no step-like behavior, which could be observed at 1st-order phase transition from a superconducting mixed state to the FFLO state. We have also investigated anisotropy of Bc2 for B || and B || , and found that Bc2 for B || c2 for B || below ∼ 0.5 K. These results might indicate that the anomalous upward curvature of Bc2 in UBe13 is related to anisotropy of Bc2 rather than the FFLO state.

  4. Anomalous Contribution of Low-Frequency, Long-Wavelength Fluctuations to Spatial Plasma Diffusion in a Magnetic Held

    International Nuclear Information System (INIS)

    The diffusion coefficient D⊥ for electron diffusion across a magnetic field of strength B is calculated in terms of the spectral function of the electric-field fluctuations. For a Maxwellian plasma, we find that an effective electron-ion collision frequency defined by v = ω2e(me/Te)D⊥, where ωe = -eB/mec and Te is the electron temperature in energy units, contains an anomalous term v* in addition to the usual classical term; the diffusion coefficient arising from v* is proportional to B-1 if k 2D (Te/me) >> ωe2, and to B-2 In B when k2D (Te/me) 2e, where kD is the Debye wave-number. The electron fluctuations in the lowfrequency domain with ω e| give rise to the anomalous term. When such fluctuations are enhanced above a thermal level owing to the onset of an instability, the anomalous term will grow accordingly, resulting in an enhanced diffusion; a microscopic account of the Bohm diffusion is thereby obtained in terms of a theory of strong turbulence. The factor of enhancement of the low-frequency fluctuations necessary to produce a Bohm-diffusion rate is estimated numerically for a C-Stellarator and for a Tokamak; the comparison may offer an, at least, partial account of the difference in containment times between the two cases. (author)

  5. Light-by-light-type corrections to the muon anomalous magnetic moment at four-loop order

    Energy Technology Data Exchange (ETDEWEB)

    Kurz, Alexander [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). Inst. fuer Theoretische Teilchenphysik; Liu, Tao; Steinhauser, Matthias [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). Inst. fuer Theoretische Teilchenphysik; Marquard, Peter [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Smirnov, Alexander V. [Moscow State Univ. (Russian Federation). Scientific Research Computing Center; Smirnov, Vladimir A. [Moscow State Univ. (Russian Federation). Skobeltsyn Inst. of Nuclear Physics

    2015-08-15

    The numerically dominant QED contributions to the anomalous magnetic moment of the muon stem from Feynman diagrams with internal electron loops. We consider such corrections and present a calculation of the four-loop light-by-light-type corrections where the external photon couples to a closed electron or muon loop. We perform an asymptotic expansion in the ratio of electron and muon mass and reduce the resulting integrals to master integrals which we evaluate using analytical and numerical methods. We confirm the results present in the literature which are based on different computational methods.

  6. Light-by-light-type corrections to the muon anomalous magnetic moment at four-loop order

    International Nuclear Information System (INIS)

    The numerically dominant QED contributions to the anomalous magnetic moment of the muon stem from Feynman diagrams with internal electron loops. We consider such corrections and present a calculation of the four-loop light-by-light-type corrections where the external photon couples to a closed electron or muon loop. We perform an asymptotic expansion in the ratio of electron and muon mass and reduce the resulting integrals to master integrals which we evaluate using analytical and numerical methods. We confirm the results present in the literature which are based on different computational methods.

  7. Lattice Calculation of the Connected Hadronic Light-by-Light Contribution to the Muon Anomalous Magnetic Moment

    CERN Document Server

    Jin, Luchang; Christ, Norman; Hayakawa, Masashi; Izubuchi, Taku; Lehner, Christoph

    2015-01-01

    The anomalous magnetic moment of muon, $g-2$, is a very precisely measured quantity. However, the current measurement disagrees with standard model by about 3 standard deviations. Hadronic vacuum polarization and hadronic light by light are the two types of processes that contribute most to the theoretical uncertainty. I will describe how lattice methods are well-suited to provide a first-principle's result for the hadronic light by light contribution, the various numerical strategies that are presently being used to evaluate it, our current results and the important remaining challenges which must be overcome.

  8. Anomalous magnetisation in a Fe_3Pt-FeRh film occurring at T~120 K in the field-cooled-cooling curves for low magnetic fields

    OpenAIRE

    Salem-Sugui, Jr., S.; Alvarenga, A. D.; R. D. Noce; Mejia, C. Salazar; Salim, H.; Gandra, F. G.

    2010-01-01

    We report on an anomalous magnetization observed with temperature for low magnetic fields applied in the plane of a film formed by a thin layer of Fe-Rh deposited on a thin foil of ordered Fe$_3$Pt. The anomalous effect resembles a metamagnetic transition and occur only in the field-cooled-cooling magnetization curve at temperatures near 120 K. We also observe an aging effect which broads the metamagnetic-like transition suggesting the existence of Fe-Rh antiferromagnetic clusters which appar...

  9. Magnetic Properties of Magnetic Nanoparticles for Efficient Hyperthermia

    Directory of Open Access Journals (Sweden)

    Ihab M. Obaidat

    2015-01-01

    Full Text Available Localized magnetic hyperthermia using magnetic nanoparticles (MNPs under the application of small magnetic fields is a promising tool for treating small or deep-seated tumors. For this method to be applicable, the amount of MNPs used should be minimized. Hence, it is essential to enhance the power dissipation or heating efficiency of MNPs. Several factors influence the heating efficiency of MNPs, such as the amplitude and frequency of the applied magnetic field and the structural and magnetic properties of MNPs. We discuss some of the physics principles for effective heating of MNPs focusing on the role of surface anisotropy, interface exchange anisotropy and dipolar interactions. Basic magnetic properties of MNPs such as their superparamagnetic behavior, are briefly reviewed. The influence of temperature on anisotropy and magnetization of MNPs is discussed. Recent development in self-regulated hyperthermia is briefly discussed. Some physical and practical limitations of using MNPs in magnetic hyperthermia are also briefly discussed.

  10. Magnetic Properties of NdAl2

    DEFF Research Database (Denmark)

    Bak, P.

    1974-01-01

    The magnetic properties of NdAl2 are calculated using a Hamiltonian including crystal-field and isotropic exchange interaction terms. A two-dimensional mean-field theory is evaluated to calculate single-crystal magnetization curves. It is shown that the magnetic properties can be understood using...... the crystal-field parameters derived from the magnetic exciton spectrum measured by Houmann et al. by means of inelastic neutron scattering. The combined lambda -Schottky anomaly in the heat capacity is explained. No additional parameters are introduced.......The magnetic properties of NdAl2 are calculated using a Hamiltonian including crystal-field and isotropic exchange interaction terms. A two-dimensional mean-field theory is evaluated to calculate single-crystal magnetization curves. It is shown that the magnetic properties can be understood using...

  11. (In-)Significance of the Anomalous Magnetic Moment of Charged Fermions for the Equation of State of a Magnetized and Dense Medium

    CERN Document Server

    Ferrer, E J; Paret, D Manreza; Martinez, A Perez; Sanchez, A

    2015-01-01

    We investigate the effects of the anomalous magnetic moment (AMM) in the equation of state (EoS) of a system of charged fermions at finite density in the presence of a magnetic field. In the region of strong magnetic fields (eB>m^2) the AMM is found from the one-loop fermion self-energy. In contrast to the weak-field AMM found by Schwinger, in the strong magnetic field region the AMM depends on the Landau level and decreases with it. The effects of the AMM in the EoS of a dense medium are investigated at strong and weak fields using the appropriate AMM expression for each case. In contrast with what has been reported in other works, we find that the AMM of charged fermions makes no significant contribution to the EoS at any field value.

  12. Anomalous strain relief and physical properties of La sub 0 sub . sub 5 Ca sub 0 sub . sub 5 MnO sub 3 films

    CERN Document Server

    Choi, C; Kim, D H; Lim, K D; Noh, T W; Jung, C U; Oh, S J; Lee, K B

    2000-01-01

    La sub 0 sub . sub 5 Ca sub 0 sub . sub 5 MnO sub 3 films were grown using pulsed laser deposition. Several factors, such as variation of substrates, interface effects, and annealing effects, influencing the properties of the grown films were investigated. As-grown films on LaAlO sub 3 substrates showed anomalous strain relief; they had strained and partly relaxed layers, both of which had tetragonal structures. On SrTiO sub 3 substrates, only coherently strained layers were observed. Such a difference of growth behaviors cannot be explained solely in terms of lattice mismatch since only partly relaxed layers appeared on LaAlO sub 3 and relaxed layers were obtained after annealing. The transport and the magnetic properties of the annealed films were quite different from those of the as-grown films.

  13. The origin of anomalous magnetism of titanohematite lamellae in rhombohedral oxide assemblages inside igneous and metamorphic rocks

    Czech Academy of Sciences Publication Activity Database

    Kletetschka, Günther; Wasilewski, P.; Adachi, T.; Mikula, V.

    Geofyzikální ústav AV ČR, v. v. i.. Roč. 38, - (2006), s. 63-64 ISSN 0231-5548. [Castle Meeting New Trends in Geomagnetism, Paleo, Rock and Environmental Magnetism /10./. 03.09.2006-08.09.2006, Valtice] Institutional research plan: CEZ:AV0Z30130516 Keywords : magnetic properties * titanohematite * remanent magnetization Subject RIV: DE - Earth Magnetism, Geodesy, Geography

  14. Anisotropy of Magnetic Properties in Textured Materials

    OpenAIRE

    J. A. Szpunar

    1989-01-01

    A short survey is presented of techniques and methods used to correlate the texture with the magnetic anisotropy of various properties of soft and hard magnetic materials. Also, examples of magnetic materials are discussed with emphasis on techniques of processing which optimize the texture.

  15. Bound states, resonances, and symmetries of a neutral Dirac particle with anomalous magnetic moment, coupled to a fixed monopole

    International Nuclear Information System (INIS)

    For the system consisting of a neutral Dirac particle with anomalous magnetic moment, interacting with a fixed magnetic monopole, zero-energy bound states are constructed for each possible value of the total angular momentum. Results of Kazama and Yang for the charge--monopole system are used to deduce the existence of other bound states for this system, when the mass of the bound particle is nonzero. In the zero-mass case, there are no other bound states, but there are resonant states, and these are determined exactly. A noncompact, so(3,2) symmetry algebra of the zero-energy bound states is given for the finite-mass case and for the zero-mass case. In each case the infinite number of such states is associated with an irreducible Majorana representation of the algebra

  16. Anomalous dimension, chiral phase transition and inverse magnetic catalysis in soft-wall AdS/QCD

    Science.gov (United States)

    Fang, Zhen

    2016-07-01

    A modified soft-wall AdS/QCD model with a z-dependent bulk scalar mass is proposed. We argue for the necessity of a modified bulk scalar mass from the quark mass anomalous dimension and carefully constrain the form of bulk mass by the corresponding UV and IR asymptotics. After fixing the form of bulk scalar mass, we calculate the mass spectra of (axial-)vector and pseudoscalar mesons, which have a good agreement with the experimental data. The behavior of chiral phase transition is also investigated, and the results are consistent with the standard scenario and lattice simulations. Finally, the issue of chiral magnetic effects is addressed. We find that the inverse magnetic catalysis emerges naturally from the modified soft-wall model, which is consistent with the recent lattice simulations.

  17. Anomalous values of gravity and magnetism in the western margin of Gondwana

    Science.gov (United States)

    Weidmann, Cecilia; Gimenez, Mario; Klinger, Federico Lince; Alvarez, Orlando

    2016-01-01

    This research is based on a joint geological and geophysical study performed in the South Central Andes region. We acquired and processed terrestrial and satellite gravity data, as well as terrestrial and aeromagnetic data. Balanced geological cross-sections were constrained by physical properties of rocks (densities and magnetic susceptibilities obtained from field samples and well log). This study was performed in order to interpret a complex region that is still under debate: the location of Famatinian magmatic arc and its boundary with the Cuyania terrain. By means of gravity anomaly we developed direct and inverse models constrained by field data. The existence of a major high-density geological structure was evidenced from these models, located below the Vinchina basin and to the east of Cerro Rajado respectively. The existence of such gravity high could be linked to the boundary between the Famatinian magmatic arc and the accreted Cuyania wedge.

  18. Quantum-chemical approach to cohesive properties of metals: Anomalous behaviour of Be

    International Nuclear Information System (INIS)

    Calculations based upon the incremental scheme, i.e. an expansion of the total correlation energy in terms of one-body, two-body and higher-order contributions, have been performed on a variety of solids with band gaps. Metals require a special treatment. Via an embedding scheme, we can force localization in metallic-like model systems and can mimic the metallic band structure within finite fragments of the solid. This allows for a gradual delocalization towards the infinite crystal within the incremental scheme. Up to now we successfully applied the method to magnesium and group 12 elements where in all cases the ground-state properties agree very well with experiment.The beryllium crystal has the same hcp structure as Mg; the atoms are characterized by closed ns2 shells. At the same time Mg is almost free-electron-like whereas Be, although in general metallic, shows a lower density of states of almost entirely p character at the Fermi energy; that is the reason for the anomalous behavior of Be compared with other group 2 and 12 metals

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

    Energy Technology Data Exchange (ETDEWEB)

    Duong, Le Quy; Das, Tanmoy; Feng, Y. P.; Lin, Hsin, E-mail: nilnish@gmail.com [Graphene Research Centre and Department of Physics, National University of Singapore, Singapore 117546 (Singapore)

    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.

  20. Experimental Demonstration of Anomalous Field Enhancement in All-Dielectric Transition Magnetic Metamaterials

    OpenAIRE

    Jingbo Sun; Xiaoming Liu; Ji Zhou; Zhaxylyk Kudyshev; Litchinitser, Natalia M.

    2015-01-01

    Anomalous field enhancement accompanied by resonant absorption phenomenon was originally discussed in the context of plasma physics and in applications related to radio-communications between the ground and spacecraft returning to Earth. Indeed, there is a critical period of time when all communications are lost due to the reflection/absorption of electromagnetic waves by the sheath of plasma created by a high speed vehicle re-entering the atmosphere. While detailed experimental studies of th...

  1. Saturation properties of nuclear matter in the presence of strong magnetic field

    CERN Document Server

    Rezaei, Z

    2016-01-01

    Different saturation properties of cold symmetric nuclear matter in the strong magnetic field have been considered. We have seen that for magnetic fields about $B> 3 \\times 10 ^ {17}\\ G$, {for both cases with and without nucleon anomalous magnetic moments}, the saturation density and saturation energy grow by increasing the magnetic field. It is indicated that the magnetic susceptibility of symmetric nuclear matter becomes negative showing the diamagnetic response especially at $B 3 \\times 10 ^ {17}\\ G$, {the softening of equation of state caused by Landau quantization is overwhelmed by stiffening due to the magnetization of nuclear matter.} We have shown that the effects of strong magnetic field on nuclear matter may affect the constraints on the equation of state of symmetric nuclear matter obtained applying the experimental observable.

  2. Aging and memory phenomena in magnetic and transport properties of vortex matter: a brief review

    OpenAIRE

    Nicodemi, Mario; Jensen, Henrik Jeldtoft

    2001-01-01

    There is mounting experimental evidence that strong off-equilibrium phenomena, such as ``memory'' or ``aging'' effects, play a crucial role in the physics of vortices in type II superconductors. We give a short review, based on a recently introduced schematic vortex model, of current progresses in understanding out of equilibrium vortex behaviours. We develop a unified description of ``memory'' phenomena in magnetic and transport properties, such as magnetisation loops and their ``anomalous''...

  3. Magnetically Responsive Nanostructures with Tunable Optical Properties.

    Science.gov (United States)

    Wang, Mingsheng; Yin, Yadong

    2016-05-25

    Stimuli-responsive materials can sense specific environmental changes and adjust their physical properties in a predictable manner, making them highly desired components for designing novel sensors, intelligent systems, and adaptive structures. Magnetically responsive structures have unique advantages in applications, as external magnetic stimuli can be applied in a contactless manner and cause rapid and reversible responses. In this Perspective, we discuss our recent progress in the design and fabrication of nanostructured materials with various optical responses to externally applied magnetic fields. We demonstrate tuning of the optical properties by taking advantage of the magnetic fields' abilities to induce magnetic dipole-dipole interactions or control the orientation of the colloidal magnetic nanostructures. The design strategies are expected to be extendable to the fabrication of novel responsive materials with new optical effects and many other physical properties. PMID:27115174

  4. Obtaining Magnetic Properties of Meteorites Using Magnetic Scanner

    Czech Academy of Sciences Publication Activity Database

    Nábělek, Ladislav; Mazanec, M.; Simon, K.; Kletetschka, G.; Hrubá, J.

    San Francisco: American Geophysical Union, 2015. s. 83947-83947. [AGU Fall Meeting 2015. 14.12.2015-18.12.2015, San Francisco] Institutional support: RVO:67985831 Keywords : meteorites * magnetic properties * Chelyabinsk meteorite Subject RIV: DE - Earth Magnetism, Geodesy, Geography https ://agu.confex.com/agu/fm15/meetingapp.cgi/Paper/83947

  5. Anomalous magnetization dynamics close to the temperature of spin-reorientation transition in ε-In0.24Fe1.76O3 nanowire arrays

    International Nuclear Information System (INIS)

    An anomalous direction of the shift of the temperature maximum of magnetic susceptibility with increasing magnetic field frequency was observed in ε-In0.24Fe1.76O3 nanowires arrays in spite of the prediction of the theory of thermoactivated processes. The unusual effect can be explained by the redistribution of the contributions from low- and high-temperature phases to the temperature dependence of magnetic susceptibility. The magnetic state of each of the phases is described by the model of cluster magnetic glass. Separated electron spin resonance responses of these phases were distinguished.

  6. MAGNETIC NANOFLUID WITH ANTITUMORAL PROPERTIES

    Directory of Open Access Journals (Sweden)

    Alexandru Mihai Grumezescu

    2012-09-01

    Full Text Available The present study deals with the synthesis and characterization of magnetic nanofluid and it’s in vitro anti-cancer activity against HEp2 cells. The magnetic nanofluid with an average size of 10 nm was synthesized via a modified precipitation technique and characterized by FT-IR, XRD, DTA-TG and TEM. After 24 h incubation of HEp2 with the magnetic nanofluid, significant changes in the cell morphology were discernible in fluorescent microscopy. Cytotoxicity assay shows that the magnetic nanofluid exhibits significant cytotoxicity against HEp2, 50% of thee cells being killed after 24 hours incubation with magnetic nanofluid without any external alternating magnetic field.

  7. Metastable magnetic phases and anomalous virgin magnetization in (Sm1-yNdy)0.98MnO3

    International Nuclear Information System (INIS)

    Metastable magnetic behavior across the field induced first-order transition from Anti-ferromagnetic to ferromagnetic phase is studied on a single crystal (Sm0.95Nd0.05)0.98MnO3. The generic feature of virgin magnetization curve lying outside the envelope magnetization curve is explained by analyzing the field dependent magnetic relaxation behavior under different magnetic histories. (author)

  8. The strange and charm quark contributions to the anomalous magnetic moment of the muon from lattice QCD

    CERN Document Server

    Koponen, Jonna; Davies, Christine T H; Donald, Gordon; Dowdall, Rachel; de Oliveira, Pedro Goncalves; Lepage, G Peter; Teubner, Thomas

    2014-01-01

    We describe a new technique (published in Phys. Rev. D89 114501) to determine the contribution to the anomalous magnetic moment of the muon coming from the hadronic vacuum polarisation using lattice QCD. Our method uses Pad\\'e approximants to reconstruct the Adler function from its derivatives at $q^2=0$. These are obtained simply and accurately from time-moments of the vector current-current correlator at zero spatial momentum. We test the method using strange quark correlators calculated on MILC Collaboration's $n_f = 2+1+1$ HISQ ensembles at multiple values of the lattice spacing, multiple volumes and multiple light sea quark masses (including physical pion mass configurations). We find the (connected) contribution to the anomalous moment from the strange quark vacuum polarisation to be $a^s_\\mu=53.41(59)\\times 10^{-10}$, and the contribution from charm quarks to be $a^c_\\mu=14.42(39)\\times 10^{-10}$ - 1% accuracy is achieved for the strange quark contribution. The extension of our method to the light quar...

  9. Characterization of the anomalous luminescence properties from self-ordered porous anodic alumina with oxalic acid electrolytes

    International Nuclear Information System (INIS)

    The pore height and diameter of the nanoscale structure of porous anodic alumina (PAA) film produced by the anodization technique are controllable. The structures can be applied for the fabrication of visible spectral range optical devices. In this study we characterized the luminescence properties of self-ordered PAA films evaporated onto silicon substrates. Anomalous luminescence properties produced by carrier confinement were observed in PAA films fabricated with the introduction of oxalic acid electrolytes during the anodization process. The recombination mechanisms were characterized by measuring the temperature-dependent photoluminescence (PL) spectra. The PL spectra of PAA films show an asymmetrical luminescence profile in the blue emission region. The Gaussian function divides these into two subbands. The subbands originate from two different kinds of oxygen-deficient defect centers, namely, F+ (oxygen vacancy with only one electron) and F (oxygen vacancy with two electrons) centers. The F centers are densest at the surface but show a gradual decrease with an increase in the pore wall depth and electrolyte concentration. However, the reverse trend is observed for the F+ centers. In strong contrast to the commonly expected trend of a uniform reduction in non-radiative recombination with decreasing lattice temperature, we observed an anomalous low-temperature PL growth and decline between the F and F+ centers. Theoretical models corroborate the anomalous temperature behavior. All the calculations are in agreement with the experimental observations.

  10. Scattering of a Spin-Polarized Neutral Fermion with the Anomalous Magnetic Moment in AN Aharonov-Casher Configuration

    Science.gov (United States)

    Khalilov, V. R.

    The scattering of a nonrelativistic neutral massive fermion having the anomalous magnetic moment (AMM) in an electric field of a uniformly charged long conducting thread aligned perpendicularly to the fermion motion is considered to study the so-called Aharonov-Casher (AC) effect by taking into account the particle spin. For this solution, the nonrelativistic Dirac-Pauli equation for a neutral massive fermion with AMM in (3+1) dimensions is found, which takes into account explicitly the particle spin and interaction between AMM of moving fermion and the electric field. Expressions for the scattering amplitude and the cross-section are obtained for spin-polarized massive neutral fermion scattered off the above conducting thread. We conclude that the scattering amplitude and cross-section of spin-polarized massive neutral fermions are influenced by the interaction of AMM of moving neutral fermions with the electric field as well as by the polarization of fermion beam in the initial state.

  11. Hadron production in e+e- annihilation at BaBar, and implication for the muon anomalous magnetic moment

    CERN Document Server

    Porter, Frank C

    2013-01-01

    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- to K+K-, pi+pi-, and e+e- to 4 hadrons.

  12. Can the two-Higgs-doublet model survive the constraint from the muon anomalous magnetic moment, as suggested?

    International Nuclear Information System (INIS)

    Requiring the two-Higgs-doublet model II to accommodate the 3σ deviation in the muon anomalous magnetic moment imposes specific constraints on the Higgs spectrum. We analyze the combination of all the relevant available constraints on the model parameter space. The use of constraints from b→sγ, the precision electroweak measurements of Rb, and the ρ parameter, together with exclusions from direct searches at CERN LEP, gives extremely severe restrictions on the model parameters. That is 'almost enough' to destroy the model altogether. The exclusion would be even stronger if the direct searches could be optimized to complement the other constraints, as will be discussed in detail in this work

  13. Hadron production in e+e- annihilation at BABAR, and implication for the muon anomalous magnetic moment

    International Nuclear Information System (INIS)

    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

  14. Magnetic properties of ground-state mesons

    CERN Document Server

    Simonis, Vytautas

    2016-01-01

    Starting with the bag model a method for the study of the magnetic properties (magnetic moments, magnetic dipole transition widths) of ground-state mesons is developed. We calculate the M1 transition moments and use them subsequently to estimate the corresponding decay widths. These are compared with experimental data, where available, and with the results obtained in other approaches. Finally, we give the predictions for the static magnetic moments of all ground-state vector mesons including those containing heavy quarks. We have a good agreement with experimental data for the M1 decay rates of light as well as heavy mesons. Therefore, we expect our predictions for the static magnetic properties (usual magnetic moments) to be of sufficiently high quality, too.

  15. The Characterization of the Magnetic Properties of Soft Magnetic Materials

    DEFF Research Database (Denmark)

    Larsen, Raino Michael

    1996-01-01

    The hysteresis curve and magnetic properties such as permeability, saturation induction, residual induction, coercive force and hysteresis losses are presented. The design and construction of equipment making it possible to measure true DC-values as well as AC-properties of toroid rings and...

  16. Depolarization of high-energy neutral particles in crystals and the possibility to measure anomalous magnetic moments of short-lived hyperons

    CERN Document Server

    Baryshevsky, V G

    2016-01-01

    The degree of depolarization of neutral particles in crystals can reach tens of percents over the crystal length of several centimeters, which can be the basis for possible experimental application of the depolarization effect for measuring anomalous magnetic moments of short-lived neutral hyperons.

  17. f-f Magnetic polaron Wigner glass and anomalous superconductivity in U sub 1 sub - sub x Th sub x Be sub 1 sub 3

    CERN Document Server

    Kasuya, T

    2000-01-01

    Mechanisms of the anomalous properties in the heavy fermion superconductor UBe sub 1 sub 3 and its alloys, in particular for the Th dopings, are studied in detail based on the fundamental electronic states to be consistent with all the crucial experimental results. As the reference systems for the magnetic polaron formation, Ce monopnictides, as well as USb and UTe, are mentioned. From detailed systematic studies of the dilute alloy systems, it is postulated that the 5f states in UBe sub 1 sub 3 split into the well-localized core 5f GAMMA sup 2 sub 7 singlet state and other delocalized 5f states situated around the Fermi energy forming the f-f magnetic polarons through the strong intra-atomic ferromagnetic f-f exchange interaction. The accompanied lattice polarons are also shown to play important roles. In the p-d band states, the f-f exchange interaction and the intersite p-f mixing interactions for the p-f Kondo state are of nearly equal strengths causing a rich variety of delicately balanced states. For th...

  18. Anomalous-plasmoid-ejection-induced secondary magnetic reconnection: modeling solar flares and coronal mass ejections by laser–plasma experiments

    Institute of Scientific and Technical Information of China (English)

    Quanli; Dong; Dawei; Yuan; Shoujun; Wang; Xun; Liu; Yutong; Li; Xiaoxuan; Lin; Huigang; Wei; Jiayong; Zhong; Shaoen; Jiang; Yongkun; Ding; Bobin; Jiang; Kai; Du; Yongjian; Tang; Mingyang; Yu; Xiantu; He; Neng; Hua; Zhanfeng; Qiao; Kuixi; Huang; Ming; Chen; Jianqiang; Zhu; Gang; Zhao; Zhengming; Sheng; Jie; Zhang

    2013-01-01

    The driving mechanism of solar flares and coronal mass ejections is a topic of ongoing debate, apart from the consensus that magnetic reconnection plays a key role during the impulsive process. While present solar research mostly depends on observations and theoretical models, laboratory experiments based on high-energy density facilities provide the third method for quantitatively comparing astrophysical observations and models with data achieved in experimental settings.In this article, we show laboratory modeling of solar flares and coronal mass ejections by constructing the magnetic reconnection system with two mutually approaching laser-produced plasmas circumfused of self-generated megagauss magnetic fields. Due to the Euler similarity between the laboratory and solar plasma systems, the present experiments demonstrate the morphological reproduction of flares and coronal mass ejections in solar observations in a scaled sense,and confirm the theory and model predictions about the current-sheet-born anomalous plasmoid as the initial stage of coronal mass ejections, and the behavior of moving-away plasmoid stretching the primary reconnected field lines into a secondary current sheet conjoined with two bright ridges identified as solar flares.

  19. Magnetic and Electrical Properties of Leachate

    Directory of Open Access Journals (Sweden)

    Kartika Kirana

    2011-11-01

    Full Text Available Heavy metals content as well as magnetic and electrical properties of leachate from Sarimukti, West Java were studied in an attempt to seek correlation between heavy metals content and magnetic/electrical properties. Such correlation is expected to open the way for the use of magnetic/electrical properties as proxy indicators for the concentration of heavy metals in the leachate. The number of leachate samples studied is 21; 15 were taken spatially at depth of 1 m while the remaining 6 samples were taken vertically at a particular point. Measurement results showed that the heavy metals content in the leachate has a smaller concentration, except for Fe. The correlation between magnetic susceptibility and heavy metals content was found to be not so significant. The best correlation coefficient between magnetic susceptibility with heavy metals in leachate was found in Zn. Correlation between electrical conductivity and heavy metal is also not so significant, except for Zn and Cd. The use of magnetic properties as proxy indicator for heavy metals content in leachate is plausible provided that the magnetic susceptibility exceeds certain threshold value. Correlation between magnetic susceptibility, electrical conductivity and heavy metal content would be good if each quantity has a large value.

  20. Anomalous thickness-dependent strain states and strain-tunable magnetization in Zn-doped ferrite epitaxial films

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Y. J.; Bao, J.; Gao, C., E-mail: zlluo@ustc.edu.cn, E-mail: cgao@ustc.edu.cn [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230026 (China); CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Yang, M. M.; Luo, Z. L., E-mail: zlluo@ustc.edu.cn, E-mail: cgao@ustc.edu.cn; Hu, C. S.; Chen, X. C.; Pan, G. Q. [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230026 (China); Huang, H. L. [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, S.; Wang, J. W.; Li, P. S.; Liu, Y.; Zhao, Y. G. [Department of Physics and State Key Laboratory of New Ceramics, Fine Processing, Tsinghua University, Beijing 100084 (China); Jiang, T.; Liu, Y. K.; Li, X. G. [Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science, Technology of China, Hefei, Anhui 230026 (China)

    2014-05-07

    A series of Zn{sub x}Fe{sub 3−x}O{sub 4} (ZFO, x = 0.4) thin films were epitaxially deposited on single-crystal (001)-SrTiO{sub 3} (STO) substrates by radio frequency magnetron sputtering. The anomalous thickness-dependent strain states of ZFO films were found, i.e., a tensile in-plane strain exists in the thinner ZFO film and which monotonously turns into compressive in the thicker films. Considering the lattice constant of bulk ZFO is bigger than that of STO, this strain state cannot be explained in the conventional framework of lattice-mismatch-induced strain in the hetero-epitaxial system. This unusual phenomenon is proposed to be closely related to the Volmer-Weber film growth mode in the thinner films and incorporation of the interstitial atoms into the island's boundaries during subsequent epitaxial growth of the thicker films. The ZFO/STO epitaxial film is found in the nature of magnetic semiconductor by transport measurements. The in-plane magnetization of the ZFO/STO films is found to increase as the in-plane compressive strain develops, which is further proved in the (001)-ZFO/PMN-PT film where the film strain state can be in situ controlled with applied electric field. This compressive-strain-enhanced magnetization can be attributed to the strain-mediated electric-field-induced in-plane magnetic anisotropy field enhancement. The above results indicate that strain engineering on magnetic oxide semiconductor ZFO films is promising for novel oxide-electronic devices.

  1. Anomalous thickness-dependent strain states and strain-tunable magnetization in Zn-doped ferrite epitaxial films

    Science.gov (United States)

    Yang, Y. J.; Yang, M. M.; Luo, Z. L.; Hu, C. S.; Bao, J.; Huang, H. L.; Zhang, S.; Wang, J. W.; Li, P. S.; Liu, Y.; Zhao, Y. G.; Chen, X. C.; Pan, G. Q.; Jiang, T.; Liu, Y. K.; Li, X. G.; Gao, C.

    2014-05-01

    A series of ZnxFe3-xO4 (ZFO, x = 0.4) thin films were epitaxially deposited on single-crystal (001)-SrTiO3 (STO) substrates by radio frequency magnetron sputtering. The anomalous thickness-dependent strain states of ZFO films were found, i.e., a tensile in-plane strain exists in the thinner ZFO film and which monotonously turns into compressive in the thicker films. Considering the lattice constant of bulk ZFO is bigger than that of STO, this strain state cannot be explained in the conventional framework of lattice-mismatch-induced strain in the hetero-epitaxial system. This unusual phenomenon is proposed to be closely related to the Volmer-Weber film growth mode in the thinner films and incorporation of the interstitial atoms into the island's boundaries during subsequent epitaxial growth of the thicker films. The ZFO/STO epitaxial film is found in the nature of magnetic semiconductor by transport measurements. The in-plane magnetization of the ZFO/STO films is found to increase as the in-plane compressive strain develops, which is further proved in the (001)-ZFO/PMN-PT film where the film strain state can be in situ controlled with applied electric field. This compressive-strain-enhanced magnetization can be attributed to the strain-mediated electric-field-induced in-plane magnetic anisotropy field enhancement. The above results indicate that strain engineering on magnetic oxide semiconductor ZFO films is promising for novel oxide-electronic devices.

  2. Magnetic properties of singlet ground state systems

    International Nuclear Information System (INIS)

    Experiments are described determining the properties of a magnetic system consisting of a singlet ground state. Cu(NO3)2.2 1/2H2O has been studied which is a system of S = 1/2 alternating antiferromagnetic Heisenberg chains. The static properties, spin lattice relaxation time and field-induced antiferromagnetically ordered state measurements are presented. Susceptibility and magnetic cooling measurements of other compounds are summarised. (Auth.)

  3. Suppressing the neoclassical tearing modes in tokamaks during anomalous transverse transport owing to predomination of the magnetic well effect over the bootstrap drive

    International Nuclear Information System (INIS)

    Suppression of neoclassical tearing modes in tokamaks under anomalous transverse transport conditions when the magnetic well effect predominates over the bootstrap drive is studied. Reduced equations of transfer are used in the description. Geodetic effects are considered during the magnetic well calculation. A criterion for the stabilization of neoclassical tearing modes by the compound effect at an arbitrary level of the transverse heat transport by electrons and ions is derived

  4. Anomalous magnetic moments in Fe-Pt and Fe-Pd Invar alloys under high pressure

    International Nuclear Information System (INIS)

    Magnetization measurements have been carried out for disordered Fe72Pt28, Fe66Pd34, and Fe68Pd32 Invar alloys under high pressure using a technique combining a pressure-clamp-type Drickamer cell and a pulse magnet. In Fe72Pt28 at room temperature, the magnetization decreased rapidly with increasing pressure up to 2.5 GPa, but above 2.5 GPa the rate of decrease became small and remained at a small value up to 5.6 GPa. In Fe-Pd Invar alloys at room temperature, the magnetization decreased linearly with increasing pressure. But, at 4.2 K, the change of magnetization with pressure was small in Fe66Pd34, which means that Fe66Pd34 behaves as a strong ferromagnet

  5. Anomalous properties of flavonoids in reversed phase high performance liquid chromatography

    Science.gov (United States)

    Zenkevich, I. G.; Gushchina, S. V.

    2011-09-01

    It is shown through reversed phase high performance liquid chromatography that a characteristic feature of such abundant natural flavonoids as flavon-3-ols is an anomalously strong antibate dependence of their retention indices ( RI) on the organic solvent concentration ( C) in the eluent, dRI/ dC flavonoids in aqueous solutions.

  6. Efficiency enhancement of anomalous-Doppler electron cyclotron masers with tapered magnetic field

    International Nuclear Information System (INIS)

    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

  7. Dynamical properties of unconventional magnetic systems

    International Nuclear Information System (INIS)

    The Advanced Study Institute addressed the current experimental and theoretical knowledge of the dynamical properties of unconventional magnetic systems including low-dimensional and mesoscopic magnetism, unconventional ground state, quantum magnets and soft matter. The main approach in this Advanced Study Institute was to obtain basic understanding of co-operative phenomena, fluctuations and excitations in the wide range unconventional magnetic systems now being fabricated or envisioned. The report contains abstracts for lectures, invited seminars and posters, together with a list of the 95 participants from 24 countries with e-mail addresses

  8. Dynamical properties of unconventional magnetic systems

    Energy Technology Data Exchange (ETDEWEB)

    Helgesen, G. [ed.

    1997-05-01

    The Advanced Study Institute addressed the current experimental and theoretical knowledge of the dynamical properties of unconventional magnetic systems including low-dimensional and mesoscopic magnetism, unconventional ground state, quantum magnets and soft matter. The main approach in this Advanced Study Institute was to obtain basic understanding of co-operative phenomena, fluctuations and excitations in the wide range unconventional magnetic systems now being fabricated or envisioned. The report contains abstracts for lectures, invited seminars and posters, together with a list of the 95 participants from 24 countries with e-mail addresses

  9. Ultrathin magnetic structures II measurement techniques and novel magnetic properties

    CERN Document Server

    Heinrich, Bretislav

    2006-01-01

    The ability to understand and control the unique properties of interfaces has created an entirely new field of magnetism, with profound impact in technology and serving as the basis for a revolution in electronics. Our understanding of the physics of magnetic nanostructures has also advanced significantly. This rapid development has generated a need for a comprehensive treatment that can serve as an introduction to the field for those entering it from diverse fields, but which will also serve as a timely overview for those already working in this area. The four-volume work Ultra-Thin Magnetic

  10. Anomalous depression of Tc by non magnetic impurities in antiferromagnetic superconductor with Tc N

    International Nuclear Information System (INIS)

    Coexistence of superconductivity (SC) and magnetism has been one or the fundamental problems in condensed matter physics. Of particular interest has been the case of magnetic superconductors in which SC occurs in an already magnetically ordered lattice (superconducting transition temperature, Tc N). In a conventional superconductor, non magnetic impurities are expected to have very little effect on Tc. In the case of magnetic superconductor with Tc N, nonmagnetic impurities were theoretically conjectured to suppress Tc due to destruction of translational symmetry of antiferromagnetic lattice. However, this aspect has not been verified experimentally, as only two such systems, that too with rather low Tc 2B2C (R= Tm, Er, Ho, Dy) (Tc 11 K; 10.5 K, 8 K, 6 K; TN = 1.5 K, 7 K, 8 K, 11 K, respectively). Of these, DyNi2B2C has Tc N with both the transition temperatures above 5 K which gives an ideal opportunity to test the above mentioned conjecture. Here a summary of the studies of effect of substitution of the non magnetic Y on Tc or DyNi2B2C (Tc N) and ErNi2B2C (Tc > TN) is presented

  11. Transport and magnetic properties of Pb1-xMnxTe(Cr) Pb1-xMnxTe(Mo)

    International Nuclear Information System (INIS)

    We have investigated transport and magnetic properties of the Pb1-xMnxTe alloys doped with Cr and Mo. Anomalous behavior of the pinned Fermi level position with manganese concentration was observed. It was shown that in Pb1-xMnxTe(Mo) the Fermi level could be pinned within the valence band as well as within the gap. In the latter case considerable persistent photoconductivity was observed at low temperatures. The studies of the magnetic susceptibility showed that magnetic properties of Pb1-xMnxTe doped with Cr, Mo are defined by weak antiferromagnetic interaction between manganese ions. (authors)

  12. New insight into the origin of anomalous magnetism of titanohematite lamellae in rhombohedral oxide assemblages -consequence for Mars magnetism

    Czech Academy of Sciences Publication Activity Database

    Kletetschka, Günther; Zbořil, R.; Adachi, T.; Mikula, V.; Heřmánek, M.; Wasilewski, P. J.

    2007-01-01

    Roč. 88, č. 23 (2007), GP33A-07. ISSN 0096-3941. [American Geophysical Union ; Joint Assembly. 22.05.2007-25.05.2007, Acapulco] Institutional research plan: CEZ:AV0Z30130516 Keywords : titanohematite * magnetization * magnetic anomalies Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  13. On magnetic monopoles, the anomalous g-factor of the electron and the spin-orbit coupling in the Dirac theory

    CERN Document Server

    Coddens, Gerrit

    2016-01-01

    We discuss the algebra and the interpretation of the anomalous Zeeman effect and the spin-orbit coupling within the Dirac theory. Whereas the algebra for the anomalous Zeeman effect is impeccable and therefore in excellent agreement with experiment, the physical interpretation of that algebra uses images that are based on macroscopic intuition but do not correspond to the meaning of this algebra. The interpretation violates the Lorentz symmetry. We give an alternative intuitive description of the meaning of this effect, which respects the symmetry and is exact. It can be summarized by stating that a magnetic field makes any charged particle spin. We show also that the traditional discussion about magnetic monopoles confuses two issues, viz. the symmetry of the Maxwell equations and the quantization of charge. These two issues define each a different concept of magnetic monopole. They cannot be merged together into a unique all-encompassing issue. We also generalize the minimal substitution for a charged parti...

  14. Anomalous origin of the left circumflex coronary artery from the pulmonary artery. A very rare congenital anomaly in an adult patient diagnosed by cardiovascular magnetic resonance

    Directory of Open Access Journals (Sweden)

    Giannitsis Evangelos

    2008-01-01

    Full Text Available Abstract Here we report for the first time on the diagnostic potential of cardiovascular magnetic resonance (CMR to delineate the proximal course of an anomalous left circumflex coronary artery (LCX originating from the right pulmonary artery in an adult patient with no other form of congenital heart disease. The patient was referred to our institution due to exertional chest discomfort. X-Ray coronary angiography showed a normal left anterior descending coronary artery (LAD and right coronary artery (RCA, while the LCX was filled retrograde by collateral flow through the LAD and the RCA. The origin of the LCX was postulated to be the pulmonary artery, but the exact origin of the anomalous artery could not be depicted on conventional angiograms. CMR provided the unambiguous depiction of the origin of the anomalous LCX from the right pulmonary artery and the delineation of its proximal course in this case of a very rare coronary anomaly in adults.

  15. Anomalous magnetic behavior of superconducting Tl2Ba2CaCu2O8 thin films in small magnetic fields close to the transition temperature

    International Nuclear Information System (INIS)

    Using a specially designed SQUID magnetometer we measured the temperature dependence of the critical current density in a ring patterned Tl2Ba2CaCu2O8 thin film for magnetic fields 0.03Oe≤Hc is determined. The jc(T) data show a field-dependent anomalous kink close to Tc pointing to reduced dissipation with increasing temperature allowing to construct a corresponding H-T borderline. A similar behavior is observed for the normalized relaxation rate S(T) as extracted from the temporal behavior of the remanent state, which, at low temperatures, exhibits the expected increase for increasing T-values, while an anomalous decrease of S(T) is found for temperatures above 85 K. While the low-T regime is attributed to creep of 2D pinned single vortex lines, the high-T behavior is suggested to be dominated by collective motion with a more sluggish dynamics. This change in dynamics is also reflected by the activation barriers for flux creep U(j), which show a corresponding crossover in μ from 0.06 to 0.99. An additional scaling analysis of the E-j characteristics for T≥85 K according to vortex glass theory reveals quasi-2D collective creep behavior with Tg=96 K. (orig.)

  16. Magnetic properties of sulfur-doped graphene

    Science.gov (United States)

    Zhu, J.; Park, H.; Podila, R.; Wadehra, A.; Ayala, P.; Oliveira, L.; He, J.; Zakhidov, A. A.; Howard, A.; Wilkins, J.; Rao, A. M.

    2016-03-01

    While studying magnetism of d- and f-electron systems has been consistently an active research area in physics, chemistry, and biology, there is an increasing interest in the novel magnetism of p-electron systems, especially in graphene and graphene-derived nanostructures. Bulk graphite is diamagnetic in nature, however, graphene is known to exhibit either a paramagnetic response or weak ferromagnetic ordering. Although many groups have attributed this magnetism in graphene to defects or unintentional magnetic impurities, there is a lack of compelling evidence to pinpoint its origin. To resolve this issue, we systematically studied the influence of entropically necessary intrinsic defects (e.g., vacancies, edges) and extrinsic dopants (e.g., S-dopants) on the magnetic properties of graphene. We found that the saturation magnetization of graphene decreased upon sulfur doping suggesting that S-dopants demagnetize vacancies and edges. Our density functional theory calculations provide evidence for: (i) intrinsic defect demagnetization by the formation of covalent bonds between S-dopant and edges/vacancies concurring with the experimental results, and (ii) a net magnetization from only zig-zag edges, suggesting that the possible contradictory results on graphene magnetism in the literature could stem from different defect-types. Interestingly, we observed peculiar local maxima in the temperature dependent magnetizations that suggest the coexistence of different magnetic phases within the same graphene samples.

  17. Numerical study of effective optical nonlinear properties in composites with anomalous distribution

    International Nuclear Information System (INIS)

    We investigate the nonlinear optical response of random composites consisting of nonlinear conductors and linear conductors with an anomalous distribution. Random resistor-capacitor networks are used to simulate our model, in which the nonlinear component with the fraction p is taken as i=g1ν+χ1 vertical ν vertical bar2v and the linear component with the fraction 1-p obeys an anomalous distribution h(g2)∼g2-α, where 02<1. We find that the distribution exponent α plays an important role in the effective linear and nonlinear optical response. As α decreases, the enhancement of optical nonlinear χe can be achieved. Moreover, the effective nonlinear optical response exhibits a sharp peak at a moderate volume fraction, dependent on α. The effective medium approximation is found to be in good agreement with linear response of numerical simulation, and describes nonlinear response of our numerical results qualitatively

  18. Anomalous magnetic moments in Fe-Pt and Fe-Pd Invar alloys under high pressure

    CERN Document Server

    Matsushita, M; Endo, S; Ishizuka, M; Kindo, K; Ono, F

    2002-01-01

    Magnetization measurements have been carried out for disordered Fe sub 7 sub 2 Pt sub 2 sub 8 , Fe sub 6 sub 6 Pd sub 3 sub 4 , and Fe sub 6 sub 8 Pd sub 3 sub 2 Invar alloys under high pressure using a technique combining a pressure-clamp-type Drickamer cell and a pulse magnet. In Fe sub 7 sub 2 Pt sub 2 sub 8 at room temperature, the magnetization decreased rapidly with increasing pressure up to 2.5 GPa, but above 2.5 GPa the rate of decrease became small and remained at a small value up to 5.6 GPa. In Fe-Pd Invar alloys at room temperature, the magnetization decreased linearly with increasing pressure. But, at 4.2 K, the change of magnetization with pressure was small in Fe sub 6 sub 6 Pd sub 3 sub 4 , which means that Fe sub 6 sub 6 Pd sub 3 sub 4 behaves as a strong ferromagnet.

  19. Structure and magnetic properties of powder soft magnetic materials

    Directory of Open Access Journals (Sweden)

    J. Konieczny

    2007-01-01

    Full Text Available Purpose: The paper presents influence of high-energy mechanical milling process, isothermal annealing and toa combination of these two technologies of cobalt base metallic glasses Co77Si11.5B11.5 on magnetic propertiesand their structure.Design/methodology/approach: The powder test piece obtained from the input amorphous ribbon in highenergyball milling. The diffraction examinations and examinations of thin foils were made on the JEOL JEM200CX transmission electron microscope. Observations of the structure of powders were made on the OptonDSM-940 scanning electron microscope. The X-ray tests were realized with the use of the XRD 7 SEIFERTFPMdiffractometer.Findings: analysis of the magnetic properties test results of the of the Co77Si11.5B11.5 powders obtained inthe high-energy ball of milling process proved that the process causes significant decrease in the magneticproperties. The structure and magnetic properties of this material may be improved by means of a proper choiceof parameters of this process as well as the final thermal treatment.Research limitations/implications: For the powders, further magnetical, structure and composition examinationsare planed.Practical implications: The amorphous and nanocrystalline metal powders obtained by high-energy ballmilling of metallic glasses feature an alternative to solid alloys and make it possible to obtain the ferromagneticnanocomposites, whose shape and dimensions can be freely formed.Originality/value: The paper presents influence of parameters of the high-energy ball milling process onstructure and magnetic properties of soft magnetic powder materials obtained in this technique. Results and adiscussion of the influence of high energy mechanical milling process on particle size and their distribution aswell as structure and magnetic properties of investigated samples is presented.

  20. Anomalous low field magnetization in fine filament NbTi conductors

    International Nuclear Information System (INIS)

    The first cable conductors for SSC were made with NbTi filaments whose diameters were in the 18 to 23 micron range. In an effort to reduce the magnetization effects in accelerator dipoles resulting from these large filaments, second generation conductors are now being manufactured with much smaller filaments. As part of this development a series of NbTi conductors were made with filament diameters ranging from 8.0 to 2.8 μm and having an average interfilament spacing of approximately 12% of filament diameter. Measurements at 4.3 K show that as the filament spacing decreases below a certain critical value the low field magnetization increases rapidly. This increase is seen to be strong function of interfilament distance, magnetic field and temperature. Details of these measurements and its implication for practical high current SSC wire design are discussed

  1. Anomalous magnetism of superconducting Mg-doped InN film

    Directory of Open Access Journals (Sweden)

    P. H. Chang

    2016-02-01

    Full Text Available We report on the Meissner effect of Mg-doped InN film with superconducting transition onset temperature Tc,onset of 5 K. Mg-doped InN is magnetically ordered and exhibits a simultaneous first-order magnetic and electric transition near 50 K. Its behavior is similar to that of iron-based superconductors. A strong correlation is proposed to exist between structural distortion and superconductivity when Mg is doped into InN. The suppression of magnetic ordering close to Tc by doping is further demonstrated by anisotropic magnetoresistance and M-H measurements. The findings suggest that the superconducting mechanism in the system may not be conventional BCS.

  2. Chiral magnetic effect and anomalous transport from real-time lattice simulations

    CERN Document Server

    Mueller, Niklas; Sharma, Sayantan

    2016-01-01

    We present a first-principle study of anomaly induced transport phenomena by performing real-time lattice simulations with dynamical fermions coupled simultaneously to non-Abelian $SU(N_c)$ and Abelian $U(1)$ gauge fields. Investigating the behavior of vector and axial currents during a sphaleron transition in the presence of an external magnetic field, we demonstrate how the interplay of the Chiral magnetic (CME) and Chiral separation effect (CSE) lead to the formation of a propagating wave. We further analyze the dependence of the magnitude of the induced vector current and the propagation of the wave on the amount of explicit chiral symmetry breaking due to finite quark mass.

  3. Magnetic properties of sheet silicates

    International Nuclear Information System (INIS)

    Susceptibility, magnetisation and Moessbauer measurements are reported for a representative selection of 2:1 layer phyllosilicates. Eight samples from the mica, vermiculite and smectite groups include examples diluted in iron which are paramagnetic at all temperatures, as well as iron-rich silicates which order magnetically below 10 K. Anisotropic susceptibility of crystals of muscovite, biotite and vermiculite is quantitatively explained with a model where the Fe2+ ions lie in sites of effective trigonal symmetry, the trigonal axis lying normal to the sheets. The ferrous ground state is an orbital singlet. Ferric iron gives an isotropic contribution to the susceptibility. Fe2+-Fe2+ exchange interactions are ferromagnetic with Gapprox. equal to2 K, whereas Fe3+-Fe3+ coupling is antiferromagnetic in the purely ferric minerals. A positive paramagnetic Curie temperature for glauconite may be attributable to Fe2+ → Fe3+ charge transfer. Magnetic order was found to set in inhomogeneously for glauconite at 1-7 K. One biotite sample showed an antiferromagnetic transition at Tsub(N) = 7 K marked by a well-defined susceptibility maximum. Its magnetic structure, consisting of ferromagnetic sheets with moments in their planes coupled antiferromagnetically by other, weak interactions, resembles that found earlier for the 1:1 mineral greenalite. (orig.)

  4. Anomalous diffusion of field lines and charged particles in Arnold-Beltrami-Childress force-free magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Ram, Abhay K. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Dasgupta, Brahmananda [Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, Alabama 35805 (United States); Krishnamurthy, V. [Center for Ocean-Land-Atmosphere Studies, George Mason University, Fairfax, Virginia 22030 (United States); Mitra, Dhrubaditya [Nordita, KTH Royal Institute of Technology and Stockholm University, 10691 Stockholm (Sweden)

    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

  5. Soft magnetic thin films: influence of annealing on magnetic properties

    International Nuclear Information System (INIS)

    Soft magnetic materials are currently used in a variety of applications in electrical machines, sensors and elements of devices. If prepared in thin film form, they can be applied to micro- and nano-patterned devices. However, with respect to ribbons and bulk materials, thin films of the same composition usually display worse soft magnetic properties, thus requiring suitable solutions to restore high permeability and low coercivity. In this review, the magnetic properties of thin films prepared by sputtering are presented. Several compositions of soft magnetic materials are investigated, including Co-Fe-Si-B, Fe-Cu-Nb-Si-B, Fe-Si-B, Fe-Co-Nb-Si-P-B, Fe-Zr-Nb-Cu-B. Their amorphous-to-crystallization processes are studied by means of furnace annealing and Joule heating. Hysteresis loops and magnetic domain imaging, together with structural techniques, are used to follow the effects of annealing, which include stress relaxation and crystallization. The effects of magnetic field annealing are investigated and discussed.

  6. Electrodeposition of nanostructured CoNi thin films and their anomalous infrared properties

    International Nuclear Information System (INIS)

    Different composition, thickness and structure of CoNi thin films supported on glassy carbon were prepared by electrochemical codeposition. Potential step method was applied to prepare CoNi thin films with different composition which was controlled by varying the concentration ratio of Co2+/Ni2+ (x:y) in the deposition solution, thus this type of CoNi thin film was defined as CoNi(x:y). Nevertheless, CoNi thin films with different thickness and structure (denoted as CoNi(n)) were synthesized in a fixed Co2+/Ni2+ solution under cyclic voltammetric conditions by varying the cyclic numbers (n) within a defined potential range. AES and EDS analysis revealed that the atomic ratio of Co/Ni in the film (including both outer and inner layer) was in good accordance with the initial Co2+/Ni2+ ratio. XRD investigation indicated that the CoNi(20:0) and CoNi(15:5) thin films were hexagonal closed-packed (hcp) structure, however, the CoNi(10:10), CoNi(5:15) and CoNi(0:20) thin films were face centered cubic (fcc) structure. SEM studies demonstrated that the CoNi(x:y) thin films were uniformly composed of irregular nanoparticles. In the case of CoNi(n), with n increasing, the structure of nanoparticles inside the CoNi thin films underwent a transition from imperfectly spherical particles to multiform particles, and finally to irregular polyhedral particles, accompany with an increase of average size. In situ FTIR reflection spectroscopic studies demonstrated that the mainly chemisorbed CO species (COad) on CoNi(x:y) surfaces were transferred from linearly bonded CO (COL) to bridge bonded CO (COB) as a function of the content of Ni and the crystal phase structure of CoNi thin films. CoNi(x:y) and CoNi(n) thin films all exhibited anomalous IR properties, corresponding respectively to abnormal IR effects (AIREs), Fano-like IR effects and surface-enhanced IR absorption effects. AIREs characterized mostly with inversion of IR band was found on CoNi(x:y), CoNi(4), CoNi(8) thin films

  7. Magnetism of uranium/iron multilayers: II. Magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Beesley, A M [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Zochowski, S W [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom); Thomas, M F [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Herring, A D F [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Langridge, S [ISIS, Rutherford Appleton Laboratory, Chilton, Oxfordshire OX11 0QX (United Kingdom); Brown, S D [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Ward, R C C [Clarendon Laboratory, University of Oxford, Oxford OX1 3PU (United Kingdom); Wells, M R [Clarendon Laboratory, University of Oxford, Oxford OX1 3PU (United Kingdom); Springell, R [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom); Stirling, W G [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Lander, G H [European Commission, JRC, Institute for Transuranium Elements, Postfach 2340, Karlsruhe, D-76125 (Germany)

    2004-12-01

    Well-defined U/Fe multilayers of varying layer thicknesses and bilayer repeat numbers were prepared by a dc magnetron sputtering method. Polarized neutron reflectometry, off-specular neutron diffraction and magnetic moment measurements were used to determine the physical properties of the multilayers leading to an evaluation of the magnetic moments associated with the U and Fe atoms. The multilayers exhibit ferromagnetic behaviour with the easy axis in the plane of the multilayer. The saturation magnetization was found to increase with increasing Fe-layer thickness and the magnetic moment averaged over the structured iron layers was below the bulk value of 2.2 {mu}{sub B}/Fe atom. No anomalies were observed in the magnetization from 4.2 to 375 K in temperature-dependent scans at 0.005 and 0.1 T or in magnetic field scans from 0 to 7 T at 4.2 and 295 K. The hysteresis curves exhibited a small degree of perpendicular magnetic anisotropy. The Curie temperatures for the multilayers were determined from ac susceptibility measurements and were found to be less than the bulk Fe value of 1043 K.

  8. Magnetic properties of poly(3-hexylthiophene)

    Energy Technology Data Exchange (ETDEWEB)

    Paula, F.R. de [Departamento de Fisica, Universidade Federal de Sao Carlos, C.P. 676, 13565-905 Sao Carlos, SP (Brazil)], E-mail: depaula@df.ufscar.br; Walmsley, L. [Departamento de Fisica, Instituto de Geociencias Exatas, Universidade Estadual Paulista, C.P. 178, 13500-970 Rio Claro, SP (Brazil); Pereira, E.C. [Departamento de Quimica, Laboratorio Interdisciplinar de Eletroquimica and Ceramica, Universidade Federal de Sao Carlos, C.P. 676, 13565-905 Sao Carlos, SP (Brazil); Oliveira, A.J.A. de [Departamento de Fisica, Universidade Federal de Sao Carlos, C.P. 676, 13565-905 Sao Carlos, SP (Brazil)

    2008-07-15

    A room temperature ferromagnetic phase is observed in samples of poly(3-hexylthiophene) partially doped with ClO{sub 4}{sup -}. The magnetic behavior presents a strong dependence on the sample preparation conditions, in particular, a dependence with the final potential of the sample after reduction. The origin of the ferromagnetism is proposed to be associated with interactions between spin 1/2 polarons formed in the polymeric chain upon doping. The dependence of saturation and spontaneous magnetization as the function of the final potential after reduction shows a way to control the magnetic properties of this polymer.

  9. Magnetic properties of poly(3-hexylthiophene)

    International Nuclear Information System (INIS)

    A room temperature ferromagnetic phase is observed in samples of poly(3-hexylthiophene) partially doped with ClO4-. The magnetic behavior presents a strong dependence on the sample preparation conditions, in particular, a dependence with the final potential of the sample after reduction. The origin of the ferromagnetism is proposed to be associated with interactions between spin 1/2 polarons formed in the polymeric chain upon doping. The dependence of saturation and spontaneous magnetization as the function of the final potential after reduction shows a way to control the magnetic properties of this polymer

  10. Temperature dependence of the perpendicular magnetic anisotropy in Ta/Co2FeAl/MgO structures probed by Anomalous Hall Effect

    Science.gov (United States)

    Gabor, M. S.; Petrisor, T.; Pop, O.; Colis, S.; Tiusan, C.

    2015-10-01

    We report a detailed study of the temperature dependence of the magnetic anisotropy in Ta/Co2FeAl/MgO structures by means of Anomalous Hall Effect measurements. The volume magnetic anisotropy, although negligible at room temperature, shows a non-negligible value at low temperatures and favors an in-plane easy magnetization axis. The surface magnetic anisotropy, which promotes the perpendicular magnetic easy axis, shows an increase from 0.76 ± 0.05 erg /cm2 at 300 K, up to 1.08 ± 0.04 erg /cm2 at 5 K, attributed to the evolution of the Co2FeAl layer saturation magnetization with temperature.

  11. Anomalous magnetic hyperfine structure of the 229Th ground-state doublet in muonic atoms

    Science.gov (United States)

    Tkalya, E. V.

    2016-07-01

    The magnetic hyperfine (MHF) splitting of the ground and low-energy 3 /2+(7.8 ±0.5 eV) levels in the 229Th nucleus in the muonic atom (μ1S1 /2 -229Th) * is calculated considering the distribution of the nuclear magnetization in the framework of the collective nuclear model with wave functions of the Nilsson model for the unpaired neutron. It is shown that (a) deviation of the MHF structure of the isomeric state exceeds 100% from its value for a pointlike nuclear magnetic dipole (the order of sublevels is reversed); (b) partial inversion of levels of the 229Th ground-state doublet and spontaneous decay of the ground state to the isomeric state occur; (c) the E 0 transition, which is sensitive to differences in the mean-square charge radii of the doublet states, is possible between mixed sublevels with F =2 ; and (d) MHF splitting of the 3 /2+ isomeric state may be in the optical range for certain values of the intrinsic gK factor and a reduced probability of a nuclear transition between the isomeric and the ground states.

  12. Magnetic properties of confined electron gas

    International Nuclear Information System (INIS)

    The effects of confinement by a two or three-dimensional harmonic potential on the magnetic properties of a free electron gas are investigated using the grand-canonical ensemble framework. At high temperatures an extension of Darwin's, Felderhof and Raval's works is made taking into account spin effects at low temperature. A comprehensive description of the magnetic properties of a free electron gas is given. The system is regarded as finite, but the boundary condition psi=0 is not introduced. The limits of weak and strong confinement are also analysed

  13. Electronic structure and magnetic properties of actinides

    International Nuclear Information System (INIS)

    The study of the actinide series shows the change between transition metal behavior and lanthanide behavior, between constant weak paramagnetism for thorium and strong Curie-Weiss paramagnetism for curium. Curium is shown to be the first metal of the actinide series to be magnetically ordered, its Neel temperature being 52K. The magnetic properties of the actinides depending on all the peripheral electrons, their electronic structure was studied and an attempt was made to determine it by means of a phenomenological model. Attempts were also made to interrelate the different physical properties which depend on the outer electronic structure

  14. Anomalous bootstrap current due to drift waves

    International Nuclear Information System (INIS)

    An anomalous parallel current driven by radial flux in tokamak is discussed. Drift waves, which cause an anomalous cross field diffusion, can generate a parallel current in a sheared magnetic field, if the fluctuation level has radial dependence. (author)

  15. Magnetic properties of polymerized diphenyloctatetrayne

    International Nuclear Information System (INIS)

    A new type of metal-free ferromagnetic carbon material was obtained by thermal polymerization and electron beam irradiation of diphenyloctatetrayne (DPOT). The isothermal magnetic measurements showed hysteresis loops indicating weak but intrinsic ferromagnetism with Curie temperatures of around 600 K. Electron spin resonance spectroscopy showed that the material contained stable free radicals in the range of 1017–1020 radicals g−1 depending on the polymerization process. The ferromagnetism should be due to high radical concentration although no correlation was observed between them. It was shown that an amorphous ferromagnetic carbon could be obtained from a simple crystalline solid by heating at moderate temperatures. Highlights: ► Diphenyloctatetrayne as a precursor for carbon with high radical concentration. ► The carbon material consists of sp2 configuration. ► A weak intrinsic metal-free ferromagnetism was observed for the carbon products.

  16. Magnetic properties of polymerized diphenyloctatetrayne

    Energy Technology Data Exchange (ETDEWEB)

    Beristain, Miriam F.; Jimenez-Solomon, Maria F.; Ortega, Alejandra; Escudero, Roberto [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-360, Ciudad Universitaria, Mexico DF 04510 (Mexico); Munoz, Eduardo [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apartado Postal 20-364, Ciudad Universitaria, Mexico DF 01000 (Mexico); Maekawa, Yasunari; Koshikawa, Hiroshi [High Performance Polymer Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Ogawa, Takeshi, E-mail: ogawa@unam.mx [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-360, Ciudad Universitaria, Mexico DF 04510 (Mexico)

    2012-10-15

    A new type of metal-free ferromagnetic carbon material was obtained by thermal polymerization and electron beam irradiation of diphenyloctatetrayne (DPOT). The isothermal magnetic measurements showed hysteresis loops indicating weak but intrinsic ferromagnetism with Curie temperatures of around 600 K. Electron spin resonance spectroscopy showed that the material contained stable free radicals in the range of 10{sup 17}-10{sup 20} radicals g{sup -1} depending on the polymerization process. The ferromagnetism should be due to high radical concentration although no correlation was observed between them. It was shown that an amorphous ferromagnetic carbon could be obtained from a simple crystalline solid by heating at moderate temperatures. Highlights: Black-Right-Pointing-Pointer Diphenyloctatetrayne as a precursor for carbon with high radical concentration. Black-Right-Pointing-Pointer The carbon material consists of sp{sup 2} configuration. Black-Right-Pointing-Pointer A weak intrinsic metal-free ferromagnetism was observed for the carbon products.

  17. Linear and nonlinear magnetic properties of ferrofluids

    Science.gov (United States)

    Szalai, I.; Nagy, S.; Dietrich, S.

    2015-10-01

    Within a high-magnetic-field approximation, employing Ruelle's algebraic perturbation theory, a field-dependent free-energy expression is proposed which allows one to determine the magnetic properties of ferrofluids modeled as dipolar hard-sphere systems. We compare the ensuing magnetization curves, following from this free energy, with those obtained by Ivanov and Kuznetsova [Phys. Rev. E 64, 041405 (2001), 10.1103/PhysRevE.64.041405] as well as with new corresponding Monte Carlo simulation data. Based on the power-series expansion of the magnetization, a closed expression for the magnetization is also proposed, which is a high-density extension of the corresponding equation of Ivanov and Kuznetsova. From both magnetization equations the zero-field susceptibility expression due to Tani et al. [Mol. Phys. 48, 863 (1983), 10.1080/00268978300100621] can be obtained, which is in good agreement with our MC simulation results. From the closed expression for the magnetization the second-order nonlinear magnetic susceptibility is also derived, which shows fair agreement with the corresponding MC simulation data.

  18. Magnetic properties and heating effect in bacterial magnetic nanoparticles

    International Nuclear Information System (INIS)

    A suspension of bacterial magnetosomes was investigated with respect to structural and magnetic properties and hyperthermic measurements. The mean particle diameter of about 35 nm was confirmed by transmission electron microscopy (TEM), X-ray and magnetic analysis. The X-ray powder diffraction peaks of magnetosomes fit very well with standard Fe3O4 reflections. The found value for specific absorption rate (SAR) of 171 W/g at 5 kA/m and 750 kHz means that magnetosomes may be considered as good materials for the biomedical applications in hyperthermia treatments. Moreover, they have biocompatible phospholipid membrane.

  19. Anomalous cross-field current and fluctuating equilibrium of magnetized plasmas

    DEFF Research Database (Denmark)

    Rypdal, K.; Garcia, O.E.; Paulsen, J.V.

    1997-01-01

    It is shown by simple physical arguments and fluid simulations that electrostatic flute-mode fluctuations can sustain a substantial cross-field current in addition to mass and energy transport. The simulations show that this current determines essential features of the fluctuating plasma equilibr......It is shown by simple physical arguments and fluid simulations that electrostatic flute-mode fluctuations can sustain a substantial cross-field current in addition to mass and energy transport. The simulations show that this current determines essential features of the fluctuating plasma...... equilibrium, and explain qualitatively the experimental equilibria and the coherent flute-mode structures observed in a simple magnetized torus....

  20. Pair Production and Vacuum Polarization of Vector Particles with Electric Dipole Moments and Anomalous Magnetic Moments

    CERN Document Server

    Kruglov, S I

    2001-01-01

    The matrix, 8-component Dirac-like form of P-odd equations for boson fields of spins 1 and 0 are obtained and the GL(2,c) symmetry group of equations is derived. We found exact solutions of the field equation for vector particles with arbitrary electric and magnetic moments in external constant and uniform electromagnetic fields. The differential probability of pair production of vector particles with the EDM and AMM by an external constant and uniform electromagnetic field has been found using the exact solutions. We have calculated the imaginary and real parts of the electromagnetic field Lagrangian that takes into account the vacuum polarization of vector particles.

  1. Pair Production and Vacuum Polarization of Vector Particles with Electric Dipole Moments and Anomalous Magnetic Moments

    OpenAIRE

    Kruglov, S. I.

    2001-01-01

    The matrix, 8-component Dirac-like form of P-odd equations for boson fields of spins 1 and 0 are obtained and the GL(2,c) symmetry group of equations is derived. We found exact solutions of the field equation for vector particles with arbitrary electric and magnetic moments in external constant and uniform electromagnetic fields. The differential probability of pair production of vector particles with the EDM and AMM by an external constant and uniform electromagnetic field has been found usi...

  2. Weakened magnetic braking as the origin of anomalously rapid rotation in old field stars

    Science.gov (United States)

    van Saders, Jennifer L.; Ceillier, Tugdual; Metcalfe, Travis S.; Silva Aguirre, Victor; Pinsonneault, Marc H.; García, Rafael A.; Mathur, Savita; Davies, Guy R.

    2016-01-01

    A knowledge of stellar ages is crucial for our understanding of many astrophysical phenomena, and yet ages can be difficult to determine. As they become older, stars lose mass and angular momentum, resulting in an observed slowdown in surface rotation. The technique of ‘gyrochronology’ uses the rotation period of a star to calculate its age. However, stars of known age must be used for calibration, and, until recently, the approach was untested for old stars (older than 1 gigayear, Gyr). Rotation periods are now known for stars in an open cluster of intermediate age (NGC 6819; 2.5 Gyr old), and for old field stars whose ages have been determined with asteroseismology. The data for the cluster agree with previous period-age relations, but these relations fail to describe the asteroseismic sample. Here we report stellar evolutionary modelling, and confirm the presence of unexpectedly rapid rotation in stars that are more evolved than the Sun. We demonstrate that models that incorporate dramatically weakened magnetic braking for old stars can—unlike existing models—reproduce both the asteroseismic and the cluster data. Our findings might suggest a fundamental change in the nature of ageing stellar dynamos, with the Sun being close to the critical transition to much weaker magnetized winds. This weakened braking limits the diagnostic power of gyrochronology for those stars that are more than halfway through their main-sequence lifetimes.

  3. Anomalous origin of the left circumflex coronary artery from the pulmonary artery. A very rare congenital anomaly in an adult patient diagnosed by cardiovascular magnetic resonance

    OpenAIRE

    Giannitsis Evangelos; Ringwald Gerd; Korosoglou Grigorios; Katus Hugo A

    2008-01-01

    Abstract Here we report for the first time on the diagnostic potential of cardiovascular magnetic resonance (CMR) to delineate the proximal course of an anomalous left circumflex coronary artery (LCX) originating from the right pulmonary artery in an adult patient with no other form of congenital heart disease. The patient was referred to our institution due to exertional chest discomfort. X-Ray coronary angiography showed a normal left anterior descending coronary artery (LAD) and right coro...

  4. The Reaction e+e− → π+ π− And Its Relation To The Anomalous Magnetic Moment Of The Muon

    International Nuclear Information System (INIS)

    The hadronic contribution to the vacuum polarization in the nonperturbative regime of QCD is a crucial issue for the interpretation of the recent measurements of the anomalous magnetic moment of positive and negative muons in Brookhaven to allow for a precision test of the standard model. The present status of the hadronic contribution is reviewed with particular emphasis on recent results with the general purpose detector KLOE at the electron positron collider DAΦNE in Frascati. (author)

  5. Magnetic Properties of 3D Printed Toroids

    Science.gov (United States)

    Bollig, Lindsey; Otto, Austin; Hilpisch, Peter; Mowry, Greg; Nelson-Cheeseman, Brittany; Renewable Energy; Alternatives Lab (REAL) Team

    Transformers are ubiquitous in electronics today. Although toroidal geometries perform most efficiently, transformers are traditionally made with rectangular cross-sections due to the lower manufacturing costs. Additive manufacturing techniques (3D printing) can easily achieve toroidal geometries by building up a part through a series of 2D layers. To get strong magnetic properties in a 3D printed transformer, a composite filament is used containing Fe dispersed in a polymer matrix. How the resulting 3D printed toroid responds to a magnetic field depends on two structural factors of the printed 2D layers: fill factor (planar density) and fill pattern. In this work, we investigate how the fill factor and fill pattern affect the magnetic properties of 3D printed toroids. The magnetic properties of the printed toroids are measured by a custom circuit that produces a hysteresis loop for each toroid. Toroids with various fill factors and fill patterns are compared to determine how these two factors can affect the magnetic field the toroid can produce. These 3D printed toroids can be used for numerous applications in order to increase the efficiency of transformers by making it possible for manufacturers to make a toroidal geometry.

  6. The quantum anomalous Hall effect

    OpenAIRE

    LIU, CHAO-XING; Zhang, Shou-Cheng; Qi, Xiao-Liang

    2015-01-01

    The quantum anomalous Hall effect is defined as a quantized Hall effect realized in a system without external magnetic field. Quantum anomalous Hall effect is a novel manifestation of topological structure in many-electron systems, and may have potential applications in future electronic devices. In recent years, quantum anomalous Hall effect has been proposed theoretically and realized experimentally. In this review article, we provide a systematic overview of the theoretical and experimenta...

  7. Properties of magnetic nano-particles

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker

    1997-01-01

    The intrinsic thermodynamic magnetic properties of clusters are discussed using spin wave theory for a Heisenberg model, with a fixed magnitude of the spins S-i = S and site independent nearest neighbor exchange interaction. The consequences of the more realistic Hubbard model is considered in wh...

  8. Magnetic properties of polymer bonded nanocrystalline powder

    Directory of Open Access Journals (Sweden)

    P. Sakiewicz

    2007-01-01

    Full Text Available Purpose: The aim of this paper was to develop a dielectromagnetic based on nanocrystalline Fe73.5Cu1Nb3Si13.5B9powder bonded with organo-silicon polymer and to investigate the powder particle size and content of polymerresponse of the magnetic properties.Design/methodology/approach: The dynamic magnetic properties at the frequency range from 50 Hz up to100 kHz of nanocrystalline iron based powder cores were measured using computerized hysteresis loop tracerRemacomp C-100 and Ferrometr device.Findings: It was found from the experimental studies, that nanocrystalline powder cores proved to be suitablefor high frequency applications. Their frequency dependences are comparable to that of carbonyl iron powdercores but shows smaller power losses.Research limitations/implications: Further studies should be undertaken in order to produce high densitycomposites with good soft magnetic properties and to find a good compromise between mechanical andmagnetic properties for power electronics applications.Practical implications: Developed nanocrystalline powder cores with permeability’s below 100 are potentialcandidates for a variety of industrial applications, such as electromagnetic interference filters, radio frequencycoupling devices, filter inductors and radio frequency tuning cores.Originality/value: Soft magnetic materials have recently regained interest as inductive component whichis a result of better raw materials, more developed technologies and a need for the materials from electricalmicromotors and low power motors for automation, robotics and other equipments. The present studycomplements and extends earlier investigations of polymer bonded powders.

  9. Magnetic properties of group VIB hexacarbonyls

    International Nuclear Information System (INIS)

    Careful measurements of the magnetic susceptibilities of group VIB metal hexacarbonyls show an ideal diamagnetic behaviour. The properties of W(CO)6, together with the relatively low price, lead to the suggestion of W(CO)6 as a new calibration standard for the diamagnetic region. (Author)

  10. Magnetic Properties of Nanoparticles of Antiferromagnetic Materials

    DEFF Research Database (Denmark)

    Mørup, Steen; Frandsen, Cathrine; Bødker, Franz;

    2003-01-01

    The magnetic properties of antiferromagnetic nanoparticles have been studied by Mossbauer spectroscopy and neutron scattering. Temperature series of Mossbauer spectra of non-interacting, superparamagnetic hematite nanoparticles were fitted by use of the Blume-Tjon relaxation model. It has been fo...

  11. Magnetic susceptibility properties of polluted soils

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An investigation of magnetic properties using magnetic susceptibility (X) and frequency-dependent susceptibility (Xfd) was conducted on representative modern pollutants, which include smelted slag dust, automobile exhaust dust and coal ash. Their magnetic susceptibility values are more than 500×10-8 m3/kg, and frequency-dependent susceptibility values less than 3%, indicating that ample ferrimagnetic and scanty superparamagnetic grains occurred in the studied pollutants. Similar to the artificially synthetic polluted soils, the industrially-polluted soils display a negative relationship between magnetic susceptibility and frequency-dependent susceptibility. However, the unpolluted soils, e.g. the Quaternary loess in the Chinese Loess Plateau, show a positive relationship between them. In this note, we propose a convenient and effective approach for identifying the polluted soils.

  12. Magnetic properties of the iron laminations for CBA magnets

    International Nuclear Information System (INIS)

    The required magnetic properties of the iron for CBA dipoles are for the most part the same as those for conventional accelerators, namely: low coercive force, high permeability at both low and high inductions, and high saturation induction. There are two main differences in the CBA application, (1) the iron is at 3.80K, and (2) the magnetic field in the iron can go as high as 6 Tesla, which is well above saturation. Measurements of the magnetization curves for CBA iron laminations at 3000K and 4.20K are presented. The data are analyzed in terms of a simple model in which the variation in saturation induction can be separated from the low field permeability variation. Tolerances on coercive force, permeability, and saturation induction are discussed

  13. Preacceleration in collapsing magnetic neutral sheets and anomalous abundances of solar flare particles

    International Nuclear Information System (INIS)

    Levine showed that a collapsing magnetic neutral sheet can accelerate ambient protons to several times the mean thermal speed provided that the collapse time scale, t/sub B/, is shorter than the proton Coulomb loss time, t/sub p/. Levine proposed that this process may be relevant for solar coronal heating. Here we apply this concept to heavier elements in order to investigate the composition of the particles which can be accelerated by such a sheet. The ambient medium is taken to be a closed magnetic loop. We assume that, in such a structure, the temperature reaches a maximum value T/sub m/ such that the externally imposed collapse time scale t/sub B/ is only marginally smaller than t/sub p/ in the loop. In this marginal condition, the neutral sheet also accelerates an element of atomic weight A in all of its stages of ionization up to a maximum charge Z/sub m/, where Z/sub m/< or =A/sup 1/2/. Tables of ionization equilibrium have been combined with the thermal structure of a constant pressure loop in order to calculate the fractions phi/sub x/ of 18 heavy elements (from carbon to nickel) which satisfy this criterion. Normalizing phi/sub x/ to oxygen, we find that, relative to the composition of the ambient materials, C and N can be depleted by factors of up to 2--10, while the other heavy elements are enhanced (hydrogen is also enhanced). The enhancement (Q) show peaks in the ranges Mg--P and Cr--Fe, and a dip in the range S--Ar. The Q values converge on unity as T/sub m/ decreases, and decreasing T/sub m/ also increases phi/sub x/ for all elements

  14. Magnetic properties of samples of the system GaxFe1-x[NiCr]O4 with frustrated magnetic structure

    International Nuclear Information System (INIS)

    Magnetic properties of samples of the system GaxFe1-x[NiCr]O4 (x 0.0, 0.2, 0.4, 0.6, 0.8) are investigated. The assumption is made that two magnetic phase transitions take place for the ferrites with x ≥ 0.2: at TC the transition from the paramagnetic state to a spin-glass state; and at Tt a second transition from a spin-glass state to a frustrated magnetic phase. This assumption is in good agreement with theoretical models. It is established that long-range magnetic ordering occurs at the temperature Tt. It is suggested that a frustrated magnetic structure in one sublattice is necessary for the occurrence of anomalous dependences of the spontaneous magnetization on temperature σs(T) of N, P or L type. It is established that if the frustrated magnetic structure is present in both sublattices of the ferrite, an anomalous σs(T) curve of another type is formed. Our conclusion is that the reason for the frustration of the magnetic connections in the samples of the system GaxFe1-x[NiCr]O4 with x≤0.2 is the presence of strong indirect interlattice interaction FeA3+ - O2- -Cr B3+ of positive sign. (author)

  15. Anomalous magnetic reordering in magnetodielectric terbium iron garnet at low temperatures

    International Nuclear Information System (INIS)

    The paper deals with five topics: i) the single three-dimensional irreductible representation (Γ4g=T1g) of the paramagnetic space group Ia3¯d No. 230 is chosen according to the representation analysis of Bertaut for the interpretation of the neutron powder diffraction experiments performed on terbium iron garnet (Tb3Fe5O12); ii) the use of the method of the “symmetry lowering device” of Bertaut in order to select the appropriate rhombohedral subgroup of Ia3¯d which allows to deal with the case where the cubic description provides an incomplete answer to the changes observed below 160 K in the ferrimagnetic structure around the [1 1 1] axis from the Néel model toward the “double umbrella” observed at 13 K; iii) the magnetic modes belonging to the one-dimensional irreductible representation A2g of the highest rhombohedral subgroup R3¯c No. 167 are able to describe the occurrence of its anisotropic character which steeply increases below 160 K due to the concomitant anisotropic effects; iv) the broad anomaly observed near 54 K in the temperature dependences of the components of both sublattices of the Tb3+ ions in the Wyckoff positions (6e) and (6e′) is explained partially on the basis of the concept of Belov of the strong paraprocess which has been termed “exchange-enhanced paramagnetism” at the so-called “low-temperature point” (TB); v) the results are related to the magnetodielectric effect in low magnetic field and to the significant coupling between exchange magnons and ligand-field excitations reported recently in this compound. - Highlights: • We examine the changes of the “double umbrella” in TbIG using neutron diffraction. • Symmetry arguments of Bertaut clarify suitable rhombohedral space group at 13 K. • Its opening leads to an increasing of anisotropy of the Tb components below 160 K. • The “low-temperature point” of Belov explains partly its intricate behavior near 54 K. • A relationship with the magnetodielectric

  16. A study of magnetic fluctuations and their anomalous scaling in the solar wind: the Ulysses fast-latitude scan

    Directory of Open Access Journals (Sweden)

    c. Pagel

    2001-01-01

    Full Text Available The solar wind is a highly turbulent and intermittent medium at frequencies between 10-4 and 10-1 Hz. Power spectra are used to look at fluctuations in the components of the magnetic field at high frequencies over a wide range of latitudes. Results show steady turbulence in the polar regions of the Sun and a more varied environment in the equatorial region. The magnetic field fluctuations exhibit anomalous scaling at high frequencies. Various models have been proposed in an attempt to better understand the scaling nature of such fluctuations in neutral fluid turbulence. We have used the Ulysses fast latitude scan data to perform a wide ranging comparison of three such models on the solar wind magnetic field data: the well-known P model, in both its Kolmogorov and Kraichnan forms, the lognormal cascade model and a model adapted from atmospheric physics, the G infinity model. They were tested by using fits to graphs of the structure function exponents g(q, by making a comparison with a non-linear measure of the deviation of g(q from the non-intermittent straight line, and by using extended self similarity technique, over a large range of helio-latitudes. Tests of all three models indicated a high level of intermittency in the fast solar wind, and showed a varied structure in the slow wind, with regions of apparently little intermittency next to regions of high intermittency, implying that the slow wind has no uniform origin. All but one of the models performed well, with the lognormal and Kolmogorov P model performing the best over all the tests, indicating that inhomogeneous energy transfer in the cascade is a good description. The Kraichnan model performed relatively poorly, and the overall results show that the Kraichnan model of turbulence is not well supported over the frequency and distance ranges of our data set. The G infinity model fitted the results surprisingly well and showed that there may very well be important universal geometrical

  17. Soft magnetic moldable composites: Properties and applications

    International Nuclear Information System (INIS)

    A new type of electromagnetic soft magnetic material (SMM) is introduced, based on spherical iron powder particles and a suitable polymer binder. A key feature of this material is that it can be cast or molded into almost any 3D shape, hence the denotation soft magnetic moldable composite (SM2C). The SM2C is compared with a set of reference materials, such as ferrites, laminated steels, and soft magnetic composites, in terms of primary properties such as permeability and loss, and other properties, such as thermal conductivity and manufacturability. The SM2C has the obvious disadvantage of relatively low permeability, but offers benefits such as relatively low losses and high potential for close integration into electromagnetic circuits. Some recent SM2C applications are illustrated, and design and manufacturing aspects are discussed. - Highlights: ► A new type of soft magnetic composite is introduced. ► Properties are compared to other flux core materials. ► The new material has low losses but also low permeability. ► Potential benefits in freedom of design and manufacturing issues.

  18. Magnetic properties of pelagic marine carbonates

    Science.gov (United States)

    Roberts, Andrew P.; Florindo, Fabio; Chang, Liao; Heslop, David; Jovane, Luigi; Larrasoaña, Juan C.

    2013-12-01

    Pelagic carbonates are deposited far from continents, usually at water depths of 3000-6000 m, at rates below 10 cm/kyr, and are a globally important sediment type. Recent advances, with recognition of widespread preservation of biogenic magnetite (the inorganic remains of magnetotactic bacteria), have fundamentally changed our understanding of the magnetic properties of pelagic carbonates. We review evidence for the magnetic minerals typically preserved in pelagic carbonates, the effects of magnetic mineral diagenesis on paleomagnetic and environmental magnetic records of pelagic carbonates, and what magnetic properties can tell us about the open-ocean environments in which pelagic carbonates are deposited. We also discuss briefly late diagenetic remagnetisations recorded by some carbonates. Despite recent advances in our knowledge of these phenomena, much remains undiscovered. We are only at early stages of understanding how biogenic magnetite gives rise to paleomagnetic signals in sediments and whether it carries a poorly understood biogeochemical remanent magnetisation. Recently developed techniques have potential for testing how different magnetotactic bacterial species, which produce different magnetite morphologies, respond to changing nutrient and oxygenation conditions. Future work needs to test whether it is possible to develop proxies for ancient nutrient conditions from well-calibrated modern magnetotactic bacterial occurrences. A tantalizing link between giant magnetofossils and Paleogene hyperthermal events needs to be tested; much remains to be learned about the relationship between climate and the organisms that biomineralised these large and novel magnetite morphologies. Rather than being a well-worn subject that has been studied for over 60 years, the magnetic properties of pelagic carbonates hold many secrets that await discovery.

  19. Tenth-Order Lepton Anomalous Magnetic Moment--Sixth-Order Vertices Containing Vacuum-Polarization Subdiagrams

    International Nuclear Information System (INIS)

    This paper reports the values of contributions to the electron g-2 from 300 Feynman diagrams of the gauge-invariant Set III(a) and 450 Feynman diagrams of the gauge-invariant Set III(b). The evaluation is carried out in two versions. Version A is to start from the sixth-order magnetic anomaly M6 obtained in the previous work. The mass-independent contributions of Set III(a) and Set III(b) are 2.1275(2) and 3.3271(6) in units of (α/π)5, respectively. Version B is based on the recently developed automatic code generation scheme. This method yields 2.1271(3) and 3.3271(8) in units of (α/π)5, respectively. They are in excellent agreement with the results of the first method within the uncertainties of numerical integration. Combining these results as statistically independent we obtain the best values, 2.1273(2), and 3.3271(5) times (α/π)5, for the mass-independent contributions of the Set III(a) and Set III(b), respectively. We have also evaluated mass-dependent contributions of diagrams containing muon and/or tau-particle loop. Including them the total contribution of Set III(a) is 2.1349(2) and that of Set III(b) is 3.3299(5) in units of (α/π)5. The total contributions to the muon g-2 of various leptonic vacuum-polarization loops of Set III(a) and Set III(b) are 112.418(32) and 15.407(5) in units of (α/π)5, respectively.

  20. Microwave absorbing properties and magnetic properties of different carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The microwave absorbing properties and magnetic properties of as-grown Fe-filled carbon nanotubes (CNTs), annealed Fe-filled CNTs, and multi-walled CNTs were studied. Vibrating sample magnetometer results showed that the annealed Fe-filled CNTs have the weakest coercivity and strongest saturation magnetization among the three types CNTs, due to the presence of more ferromagnetic α-Fe nanowires. After annealing, the values increased to 291.0 Oe and 28.0 emu/g and the samples showed excellent microwave absorbing properties. The reflection loss was over 5 dB between 11.6 GHz and 18 GHz with a maximum value of 10.8 dB for annealed Fe-filled CNTs (1.1 wt%)/epoxy composite.

  1. Microwave absorbing properties and magnetic properties of different carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    GUI XuChun; WANG KunLin; WEI JinQuan; L(U) RuiTao; SHU QinKe; JIA Yi; WANG Chen; ZHU HongWei; WU DeHai

    2009-01-01

    The microwave absorbing properties and magnetic properties of as-grown Fe-filled carbon nanotubes (CNTs), annealed Fe-filled CNTs, and multi-walled CNTs were studied. Vibrating sample magnetometer results showed that the annealed Fe-filled CNTs have the weakest coercivity and strongest saturation magnetization among the three types CNTs, due to the presence of more ferromagnetic α-Fe nanowires.After annealing, the values increased to 291.00e and 28.0 emu/g and the samples showed excellent microwave absorbing properties. The reflection loss was over 5 dB between 11.6 GHz and 18 GHz with a maximum value of 10.8 dB for annealed Fe-filled CNTs (1.1 wt%)/epoxy composite.

  2. Electronic structure, cohesive, and magnetic properties of the actinide-iridium Laves phases

    International Nuclear Information System (INIS)

    The electronic structure of the isostructural AIr2 systems (A = Th, Pa, U, Np, Pu, and Am) has been obtained by means of the scalar relativistic and fully relativistic linear muffin-tin orbital techniques. Ground-state properties such as lattice constants and onset of magnetic order have been calculated and compared with measured data. The hybridization between the actinide 5f and the ligand 5d states and the direct 5f wave-function overlap are found to be of comparable importance for the bandwidth of the itinerant 5f states. The anomalous paramagnetism of PuIr2 can be explained only by a fully relativistic treatment

  3. Anomalous Hall effect

    Czech Academy of Sciences Publication Activity Database

    Nagaosa, N.; Sinova, Jairo; Onoda, S.; MacDonald, A. H.; Ong, N. P.

    2010-01-01

    Roč. 82, č. 2 (2010), s. 1539-1592. ISSN 0034-6861 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * spintronics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 51.695, year: 2010

  4. Properties of GRB Lightcurves from Magnetic Reconnection

    CERN Document Server

    Beniamini, Paz

    2015-01-01

    The energy dissipation mechanism within Gamma ray bursts' (GRBs) ultra-relativistic outflows that drive the prompt $\\gamma$-ray emission remains uncertain. Two leading candidates are internal shocks and magnetic reconnection. While the emission from internal shocks has been extensively studied, that from reconnection still has few quantitative predictions. We study the prompt GRB emission from magnetic reconnection and compare its expected temporal and spectral properties to observations. The main difference from internal shocks is that for magnetic reconnection one expects relativistic bulk motions with a Lorentz factor of $\\Gamma'\\gtrsim$a few in the mean rest frame of the outflow - the comoving frame. We consider a thin spherical shell (or reconnection layer) expanding at a bulk Lorentz factor $\\Gamma\\gg 1$ in which the emitting material moves with $\\Gamma'$ in the comoving frame along this layer in two anti-parallel directions (e.g. of the reconnecting field lines). The resulting relativistic beaming of t...

  5. Synthesis and Properties of Magnetic Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Sixin LI; Jiancheng ZHANG; Yue SHEN; Bo NI; Jingang ZHANG

    2006-01-01

    The uniform mesoporous SBA-15 consisting of SiO2 with long-range channels offers an excellent host material to synthesize or assemble the magnetic nanocomposites, such as Fe, Ni.In this paper, highly dispersed and uniform iron nanoparticles were incorporated into the pore channels of SBA-15 through a newly developed strategy in which some kinds of coupling agents were used to entrap the nanoparticles into the silica framework.The X-ray diffraction(XRD), fourier transmission infrared spectroscopy(FTIR), high-resolution transmission electronic microscopy(HRTEM)and energy dispersive X-ray spectroscopy(EDX)were performed to further identify the successful incorporation and grafting of iron. Compared with other ordinary non-assembled magnetic nanoparticles, the assembled Fe nanoparticles with the diameter even in the size range of 5~6 nm still have better magnetic properties.

  6. Thermoelectric properties and ferromagnetism of diluted magnetic semiconductors Sb2-xCrxTe3

    International Nuclear Information System (INIS)

    Thermoelectric properties of single crystals of a new dilute magnetic semiconductor p-Sb2-xCrxTe3 are studied in the temperature interval 7-300 K. The temperature dependences of the thermal conductivity are measured. The Seebeck coefficient S is found to increase upon doping with Cr. At low temperatures, a ferromagnetic phase with Curie temperature TC ∼ 5.8 K exists for a Cr concentration x = 0.0215, its easy magnetization axis being parallel to the crystallographic axis C3. At T = 4.2 K, a negative magnetoresistance and anomalous Hall effect are observed; in strong magnetic fields, the Shubnikov-de Haas effect is manifested

  7. The critical properties of magnetic films

    International Nuclear Information System (INIS)

    Within the framework of the transverse spin-1/2 Ising model and by using the effective field theory with a probability distribution technique that accounts for the self spin correlations, we have studied the critical properties of an L-layer film of simple cubic symmetry in which the exchanges strength are assumed to be different from the bulk values in NS surface layers. We derive and illustrate the expressions for the phase diagrams, order parameter profiles and susceptibility. In such films, the critical temperature can shift to either lower or higher temperature compared with the corresponding bulk value. We calculate also some magnetic properties of the film, such as the layer magnetizations, their averages and their profiles and the longitudinal susceptibility of the film. The film longitudinal susceptibility still diverges at the film critical temperature as does the bulk longitudinal susceptibility.

  8. Optical properties of metals: Infrared emissivity in the anomalous skin effect spectral region

    Energy Technology Data Exchange (ETDEWEB)

    Echániz, T. [Departamento de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, UPV/EHU, Sarriena s/n, Leioa 48940 (Spain); Pérez-Sáez, R. B., E-mail: raul.perez@ehu.es; Tello, M. J. [Departamento de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, UPV/EHU, Sarriena s/n, Leioa 48940 (Spain); Instituto de Síntesis y Estudio de Materiales, Universidad del País Vasco, Apdo. 644, Bilbao 48080 (Spain)

    2014-09-07

    When the penetration depth of an electromagnetic wave in a metal is similar to the mean free path of the conduction electrons, the Drude classical theory is no longer satisfied and the skin effect becomes anomalous. Physical parameters of this theory for twelve metals were calculated and analyzed. The theory predicts an emissivity peak ε{sub peak} at room temperature in the mid-infrared for smooth surface metals that moves towards larger wavelengths as temperature decreases. Furthermore, the theory states that ε{sub peak} increases with the emission angle but its position, λ{sub peak}, is constant. Copper directional emissivity measurements as well as emissivity obtained using optical constants data confirm the predictions of the theory. Considering the relationship between the specularity parameter p and the sample roughness, it is concluded that p is not the simple parameter it is usually assumed to be. Quantitative comparison between experimental data and theoretical predictions shows that the specularity parameter can be equal to one for roughness values larger than those predicted. An exhaustive analysis of the experimental optical parameters shows signs of a reflectance broad peak in Cu, Al, Au, and Mo around the wavelength predicted by the theory for p = 1.

  9. Optical properties of metals: Infrared emissivity in the anomalous skin effect spectral region

    International Nuclear Information System (INIS)

    When the penetration depth of an electromagnetic wave in a metal is similar to the mean free path of the conduction electrons, the Drude classical theory is no longer satisfied and the skin effect becomes anomalous. Physical parameters of this theory for twelve metals were calculated and analyzed. The theory predicts an emissivity peak εpeak at room temperature in the mid-infrared for smooth surface metals that moves towards larger wavelengths as temperature decreases. Furthermore, the theory states that εpeak increases with the emission angle but its position, λpeak, is constant. Copper directional emissivity measurements as well as emissivity obtained using optical constants data confirm the predictions of the theory. Considering the relationship between the specularity parameter p and the sample roughness, it is concluded that p is not the simple parameter it is usually assumed to be. Quantitative comparison between experimental data and theoretical predictions shows that the specularity parameter can be equal to one for roughness values larger than those predicted. An exhaustive analysis of the experimental optical parameters shows signs of a reflectance broad peak in Cu, Al, Au, and Mo around the wavelength predicted by the theory for p = 1

  10. Magnetic Properties of Friction Stir Processed Composite

    Science.gov (United States)

    Das, Shamiparna; Martinez, Nelson Y.; Das, Santanu; Mishra, Rajiv S.; Grant, Glenn J.; Jana, Saumyadeep; Polikarpov, Evgueni

    2016-07-01

    Of the many existing inspection or monitoring systems, each has its own advantages and drawbacks. These systems are usually comprised of semi-remote sensors that frequently cause difficulty in reaching complex areas of a component. This study proposes to overcome that difficulty by developing embedded functional composites, so that embedding can be achieved in virtually any component part and periodically can be interrogated by a reading device. The "reinforcement rich" processed areas can then be used to record properties such as strain, temperature, and stress state, to name a few, depending on the reinforcement material. Friction stir processing was used to fabricate a magnetostrictive composite by embedding galfenol particles into a nonmagnetic aluminum matrix. The aim was to develop a composite that produces strain in response to a varying magnetic field. Reinforcements were distributed uniformly in the matrix. Magnetization curves were studied using a vibrating sample magnetometer. A simple and cost-effective setup was developed to measure the magnetostrictive strain of the composites. Important factors affecting the magnetic properties were identified and the processing route was modified to improve the magnetic response.

  11. Metal nanorod arrays and their magnetic properties

    International Nuclear Information System (INIS)

    Large-area, highly uniform metal nanorod arrays (iron, cobalt, nickel) with variable diameters have been successfully synthesized by electrochemical deposition method using polycarbonate (PC) membrane template. By means of X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) at room temperature, their microstructures and magnetic properties were investigated. The mechanism of crystals nucleated and grown theories in metal nanorod arrays were also discussed

  12. Magnetic properties of Tb12Co7

    International Nuclear Information System (INIS)

    The magnetic properties of the compound Tb12Co7 with the Ho12Co7-type monoclinic structure were investigated from 5 to 300 K in applied magnetic fields up to 5 T. The field-cooled and zero-field-cooled magnetization curves of Tb12Co7 measured at low field and at low temperatures exhibit different behavior, which is due to the temperature-dependent coercivity. The ferromagnetic-paramagnetic transition temperature in a field of 0.01 T is about 100 K. At 5 K, the saturation magnetization and the coercivity are 165 A m2 kg-1 and 0.18 T, respectively. The maximum magnetic-entropy change, vertical bar ΔS M vertical bar, of Tb12Co7 is 3.08 J kg-1 K-1 at 100 K for a field change of 2 T, which is comparable to that of rare-earth perovskite manganites series La1-x M x MnO3

  13. Monte Carlo study of nanowire magnetic properties

    Institute of Scientific and Technical Information of China (English)

    R.Masrour; L.Bahmad; A.Benyoussef

    2013-01-01

    In this work,we use Monte Carlo simulations to study the magnetic properties of a nanowire system based on a honeycomb lattice,in the absence as well as in the presence of both an external magnetic field and crystal field.The system is formed with NL layers having spins that can take the values σ =+1/2 and S =+1,0.The blocking temperature is deduced,for each spin configuration,depending on the crystal field A.The effect of the exchange interaction coupling Jp between the spin configurations σ and S is studied for different values of temperature at fixed crystal field.The established ground-state phase diagram,in the plane (Jp,A),shows that the only stable configurations are:(1/2,0),(1/2,+1),and (1/2,-1).The thermal magnetization and susceptibility are investigated for the two spin configurations,in the absence as well as in the presence of a crystal field.Finally,we establish the hysteresis cycle for different temperature values,showing that there is almost no remaining magnetization in the absence of the external magnetic field,and that the studied system exhibits a super-paramagnetic behavior.

  14. Magnetic properties of icosahedral MRu12 clusters

    International Nuclear Information System (INIS)

    The magnetic properties of icosahedral MRu12 clusters are studied using the discrete-variational local-spin-density-functional method, where M = V, Cr, Mn, Fe, Co, and Ni. The results show that all of the Ih MRu12 clusters, just like the case for the Ih Ru13 cluster, have double magnetic solutions. In contrast to the moment of 4 μB for the Ih Ru13 cluster, the total magnetic moments of the Ih MRu12 clusters, ranging from 1 μB to 20 μB, have been changed greatly by the substitution of the central Ru atom with M. Among them, the NiRu12 cluster has a giant moment of 20 μB. Furthermore, the NiRu12 cluster has nondegenerate ground state and could be expected to be remarkably stable. Therefore, for the purpose of enhancing the magnetic moment of the Ih Ru13 cluster, Ni is a promising candidate as a dopant. Finally, we predict that all the Ih MRu12 clusters except NiRu12 might belong to the class in which the magnetization of the cluster increases with temperature. (author)

  15. Magnetic properties and microstructure of bulk Nd-Fe-B magnets solidified in magnetic field

    International Nuclear Information System (INIS)

    The Nd-Fe-B bulk magnets with a slab shape of 0.9 x 4 x 15 mm3 were prepared by injection casting into a copper mold. The effects of applying a magnetic field during the casting process on the magnetic properties and microstructure of Nd9.5Fe71.5Ti2.5Zr0.5Cr1B14.5C0.5 alloy have been studied. The results show that the sample cast with magnetic field has a stronger (00L) texture of Nd2Fe14B phase with the c-axis perpendicular to the slab plane than the sample cast without magnetic field. The intensity of the texture weakens from surface to inner region of the bulk magnets. Applying a magnetic field during the casting process is helpful to refine the grain size effectively. As a result, the magnetic properties are improved from Br = 5.8 kG, iHc = 6.5 kOe, and (BH)max = 5.9 MGOe for thesample cast without magnetic field to Br = 6.1 kG, iHc = 10.3 kOe, and (BH)max = 7.3 MGOe for the sample cast with a 3.7 kOe magnetic field.

  16. Suppression of the Neoclassical Tearing Modes in Tokamaks under Anomalous Transverse Transport Conditions when the Magnetic Well Effect Predominates over the Bootstrap Drive

    International Nuclear Information System (INIS)

    A study is made of the suppression of neoclassical tearing modes in tokamaks under anomalous transverse transport conditions when the magnetic well effect predominates over the bootstrap drive. It is stressed that the corresponding effect, which is called the compound suppression effect, depends strongly on the profiles of the electron and ion temperature perturbations. Account is taken of the fact that the temperature profile can be established as a result of the competition between anomalous transverse heat transport, on the one hand, and longitudinal collisional heat transport, longitudinal heat convection, longitudinal inertial transport, and transport due to the rotation of magnetic islands, on the other hand. The role of geodesic effects is discussed. The cases of competition just mentioned are described by the model sets of reduced transport equations, which are called, respectively, collisional, convective, inertial, and rotational plasmophysical models. The magnetic well is calculated with allowance for geodesic effects. It is shown that, for strong anomalous heat transport conditions, the contribution of the magnetic well to the generalized Rutherford equation for the island width W is independent of W not only in the collisional model (which has been investigated earlier) but also in the convective and inertial models and depends very weakly (logarithmically) on W in the rotational model. It is this weak dependence that gives rise to the compound effect, which is the subject of the present study. A criterion for the stabilization of neoclassical tearing modes by the compound effect at an arbitrary level of the transverse heat transport by electrons and ions is derived and is analyzed for two cases: when the electron heat transport and ion heat transport are both strong, and when the electron heat transport is strong and the ion heat transport is weak

  17. Anomalous magnetism and electron paramagnetic resonance spectroscopy of the ZrNi1-xCrxSn solid solution

    International Nuclear Information System (INIS)

    The static magnetic properties and electron paramagnetic resonance (EPR) spectra of ZrNi1-xCrxSn solid solution (0pp=(120±5)G type and g=1.980±0.001, peak-to-peak width ΔHpp=(10±1)G, respectively. They have been attributed to Cr3+ ions in Ni-sites of the lattice coupled by magnetic dipolar interaction (type I) and to exchange coupled Cr3+ pairs or clusters of more than two Cr3+ ions (type II). The third line detected in the samples with x=0.3,0.4 characterised by geff=2.0003±0.0001 and ΔHpp=(3.0±0.5)G has been interpreted as conduction electron spin resonance (CESR). (orig.)

  18. Anomalous-viscosity current drive

    Science.gov (United States)

    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.

  19. Anomalous transport from holography: Part I

    CERN Document Server

    Bu, Yanyan; Sharon, Amir

    2016-01-01

    We revisit the transport properties induced by the chiral anomaly in a charged plasma holographically dual to anomalous $U(1)_V\\times U(1)_A$ Maxwell theory in Schwarzschild-$AdS_5$. Off-shell constitutive relations for vector and axial currents are derived using various approximations generalising most of known in the literature anomaly-induced phenomena and revealing some new ones. In a weak external field approximation, the constitutive relations have all-order derivatives resummed into six momenta-dependent transport coefficient functions: the diffusion, the electric/magnetic conductivity, and three anomaly induced functions. The latter generalise the chiral magnetic and chiral separation effects. Nonlinear transport is studied assuming presence of constant background external fields. The chiral magnetic effect, including all order nonlinearity in magnetic field, is proven to be exact when the magnetic field is the only external field that is turned on. Non-linear corrections to the constitutive relations...

  20. Superconducting properties of a stoichiometric FeSe compound and two anomalous features in the normal state

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yoo Jang; Hong, Jong Beom; Min, Byeong Hun; Kwon, Yong Seung [Sungkyunkwan University, Suwon (Korea, Republic of); Lee, Kyu Jun; Jung, Myung Hwa [Sogang University, Seoul (Korea, Republic of); Rhyee, Jong Soo [Kyunghee University, Seoul (Korea, Republic of)

    2011-08-15

    This paper reports the superconducting behavior of the tetragonal iron-chalcogenide superconductor FeSe. The electrical resistivity and the magnetic moment measurements confirmed its superconductivity with T{sup zero}{sub c} and T{sup mag}{sub c} of 9.4 K under ambient pressure. Electron probe macro analysis indicated that the sample had a stoichiometric Fe:Se ratio of 1:1. The Seebeck coefficient, which was 12.3 {mu}V/K at room temperature, changed to a negative value near 200 K, indicating it to be a two-carrier material. Above T{sub c}, the {rho}(T) curve revealed an 'S' shape, and d{rho}(T)/dT and d{sup 2}{rho}(T)/dT{sup 2} showed two anomalous features, one near T{sub an} = 30 K and the other near T{sup *} = 110 K. The Seebeck coefficient, S(T), also displays peculiar behavior near the T{sub an} and T{sup *}. We also report a rather smaller critical current density, J{sub c} = 10{sup 2} {approx} 10{sup 4} A/cm{sup 2}, compared to those observed for the other pnictides and doped chalcogenides.

  1. Superconducting properties of a stoichiometric FeSe compound and two anomalous features in the normal state

    International Nuclear Information System (INIS)

    This paper reports the superconducting behavior of the tetragonal iron-chalcogenide superconductor FeSe. The electrical resistivity and the magnetic moment measurements confirmed its superconductivity with Tzeroc and Tmagc of 9.4 K under ambient pressure. Electron probe macro analysis indicated that the sample had a stoichiometric Fe:Se ratio of 1:1. The Seebeck coefficient, which was 12.3 μV/K at room temperature, changed to a negative value near 200 K, indicating it to be a two-carrier material. Above Tc, the ρ(T) curve revealed an 'S' shape, and dρ(T)/dT and d2ρ(T)/dT2 showed two anomalous features, one near Tan = 30 K and the other near T* = 110 K. The Seebeck coefficient, S(T), also displays peculiar behavior near the Tan and T*. We also report a rather smaller critical current density, Jc = 102 ∼ 104 A/cm2, compared to those observed for the other pnictides and doped chalcogenides.

  2. The New (g-2) Experiment: A proposal to measure the muon anomalous magnetic moment to +-0.14 ppm precision

    Energy Technology Data Exchange (ETDEWEB)

    Carey, R.M.; Lynch, K.R.; Miller, J.P.; Roberts, B.L.; Morse, W.M.; Semertzides, Y.K.; Druzhinin, V.P.; Khazin, B.I.; Koop, I.A.; Logashenko, I.; Redin, S.I.; /Boston U. /Brookhaven /Novosibirsk, IYF /Cornell U., CIHEP /Fermilab /Frascati /Illinois U., Urbana /James Madison U. /Groningen, KVI /KEK, Tsukuba /Kentucky U.

    2009-02-01

    We propose to measure the muon anomalous magnetic moment, a{sub {mu}}, to 0.14 ppm-a fourfold improvement over the 0.54 ppm precision obtained in the BNL experiment E821. The muon anomaly is a fundamental quantity and its precise determination will have lasting value. The current measurement was statistics limited, suggesting that greater precision can be obtained in a higher-rate, next-generation experiment. We outline a plan to use the unique FNAL complex of proton accelerators and rings to produce high-intensity bunches of muons, which will be directed into the relocated BNL muon storage ring. The physics goal of our experiment is a precision on the muon anomaly of 16 x 10{sup -11}, which will require 21 times the statistics of the BNL measurement, as well a factor of 3 reduction in the overall systematic error. Our goal is well matched to anticipated advances in the worldwide effort to determine the standard model (SM) value of the anomaly. The present comparison, {Delta}a{sub {mu}} (Expt: -SM) = (295 {+-} 81) x 10{sup -11}, is already suggestive of possible new physics contributions to the muon anomaly. Assuming that the current theory error of 51 x 10{sup -11} is reduced to 30 x 10{sup -11} on the time scale of the completion of our experiment, a future {Delta}a{sub {mu}} comparison would have a combined uncertainty of {approx} 34 x 10{sup -11}, which will be a sensitive and complementary benchmark for proposed standard model extensions. The experimental data will also be used to improve the muon EDM limit by up to a factor of 100 and make a higher-precision test of Lorentz and CPT violation. We describe in this Proposal why the FNAL complex provides a uniquely ideal facility for a next-generation (g-2) experiment. The experiment is compatible with the fixed-target neutrino program; indeed, it requires only the unused Booster batch cycles and can acquire the desired statistics in less than two years of running. The proton beam preparations are largely aligned

  3. Tensile Properties of Pla And Phbv Blends: Anomalous Elongation and Aging

    OpenAIRE

    Gérard, Thibaut; Noto, Tiffany; Budtova, Tatiana

    2012-01-01

    International audience Polylactide (PLA) and polyhydroxyalkanoates (PHA) are polymers made from renewable resources. Despite their growing competitiveness with conventional petrol-based polymers, they still have some disadvantages such as poor (fragile) mechanical properties. Blending is a potentially prospective way of obtaining new materials with improved properties, which can overcome the drawbacks of the pure components. In this work, PLA and poly(hydroxybutyrate-co-hydroxyvalerate) (P...

  4. Comment on ``Unified explanation of the anomalous dynamic properties of highly asymmetric polymer blends'' [J. Chem. Phys. 138, 054903 (2013)

    Science.gov (United States)

    Colmenero, J.

    2013-05-01

    In a recent paper by Ngai and Capaccioli ["Unified explanation of the anomalous dynamic properties of highly asymmetric polymer blends," J. Chem. Phys. 138, 054903 (2013), 10.1063/1.4789585] the authors claimed that the so-called coupling model (CM) provides a unified explanation of all dynamical anomalies that have been reported for dynamically asymmetric blends over last ten years. Approximately half of the paper is devoted to chain-dynamic properties involving un-entangled polymers. According to the authors, the application of the CM to these results is based on the existence of a crossover at a time tc ≈ 1-2 ns of the magnitudes describing chain-dynamics. Ngai and Capaccioli claimed that the existence of such a crossover is supported by the neutron scattering and MD-simulation results, corresponding to the blend poly(methyl methacrylate)/poly(ethylene oxide), by Niedzwiedz et al. [Phys. Rev. Lett. 98, 168301 (2007), 10.1103/PhysRevLett.98.168301] and Brodeck et al. [Macromolecules 43, 3036 (2010), 10.1021/ma902820a], respectively. Being one of the authors of these two papers, I will demonstrate here that there is no evidence supporting such a crossover in the data reported in these papers.

  5. Leading-order hadronic contribution to the anomalous magnetic moment of the muon from N_f=2+1+1 twisted mass fermions

    CERN Document Server

    Burger, Florian; Hotzel, Grit; Jansen, Karl; Petschlies, Marcus; Renner, Dru B

    2013-01-01

    We present results for the leading order QCD correction to the anomalous magnetic moment of the muon including the first two generations of quarks as dynamical degrees of freedom. Several light quark masses are examined in order to yield a controlled extrapolation to the physical pion mass. We analyse ensembles for three different lattice spacings and several volumes in order to investigate lattice artefacts and finite-size effects, respectively. We also provide preliminary results for this quantity for two flavours of mass-degenerate quarks at the physical value of the pion mass.

  6. Subtraction Procedure for Calculation of Anomalous Magnetic Moment of Electron in QED and its Application to Numerical Computation at 3-loop Level

    CERN Document Server

    Volkov, S A

    2015-01-01

    A new subtraction procedure for removal both ultraviolet and infrared divergences in Feynman integrals is proposed. This method is developed for computation of QED corrections to the electron anomalous magnetic moment. The procedure is formulated in the form of a forest formula with linear operators that are applied to Feynman amplitudes of UV-divergent subgraphs. The contribution of each Feynman graph that contains propagators of electrons and photons is represented as a finite Feynman-parametric integral. Application of the developed method to the calculation of 2-loop and 3-loop contributions is described.

  7. Leading-order hadronic contribution to the anomalous magnetic moment of the muon from N_f=2+1+1 twisted mass fermions

    Energy Technology Data Exchange (ETDEWEB)

    Burger, Florian [Humboldt U. Berlin; Feng, Xu [KEK; Hotzel, Grit [Humboldt U. Berlin; Jansen, Karl [DESY; Petschlies, Marcus [The Cyprus Institute; Renner, Dru B. [JLAB

    2013-11-01

    We present results for the leading order QCD correction to the anomalous magnetic moment of the muon including the first two generations of quarks as dynamical degrees of freedom. Several light quark masses are examined in order to yield a controlled extrapolation to the physical pion mass. We analyse ensembles for three different lattice spacings and several volumes in order to investigate lattice artefacts and finite-size effects, respectively. We also provide preliminary results for this quantity for two flavours of mass-degenerate quarks at the physical value of the pion mass.

  8. Leading-order hadronic contribution to the anomalous magnetic moment of the muon from N{sub f}=2+1+1 twisted mass fermions

    Energy Technology Data Exchange (ETDEWEB)

    Burger, Florian; Hotzel, Grit [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Feng, Xu [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan); Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Petschlies, Marcus [The Cyprus Institute, Nicosia (Cyprus); Renner, Dru B. [Jefferson Lab, Newport News, VA (United States)

    2013-12-15

    We present results for the leading order QCD correction to the anomalous magnetic moment of the muon including the first two generations of quarks as dynamical degrees of freedom. Several light quark masses are examined in order to yield a controlled extrapolation to the physical pion mass. We analyse ensembles for three different lattice spacings and several volumes in order to investigate lattice artefacts and finite-size effects, respectively. We also provide preliminary results for this quantity for two flavours of mass-degenerate quarks at the physical value of the pion mass.

  9. Contribution of the π0γ and ηγ intermediate states to the vacuum polarization and the muon anomalous magnetic moment

    International Nuclear Information System (INIS)

    Using new experimental data, the contribution to the anomalous magnetic moment of the muon from the π0γ and ηγ intermediate states in the vacuum polarization is calculated with high precision taking into account the correction for using the trapezoidal rule: αμ(π0γ) + αμ(ηγ) = (53.1 ± 1.5) x 10-11. It is found the small contribution from e+e-π0, e+e-η and μ+μ-π0 intermediate states equal to 0.5 x 10-11

  10. Magnetic properties of Ni2N

    International Nuclear Information System (INIS)

    A powder sample of body-centered tetragonal Ni2N in a single phase was prepared by a high rate-type triode dc reactive sputtering and the magnetic properties have been reinvestigated. It is confirmed that Ni2N is not a ferromagnet. However, the material is not a simple paramagnet either and shows a weak spin-glass-like behavior at low temperatures with a freezing temperature of about 8 K. Posible origins of the behavior are discussed. Band-structure calculations are reported to see the stability of the nonmagnetic ground state of bct Ni2N against lattice expansion and appearance of nitrogen vacancies

  11. The anomalous physical and chemical properties of gold nano-particles

    International Nuclear Information System (INIS)

    Full text: Although gold is the most inert of all metallic elements, it has been discovered during the last two decades that it has interesting properties as a nano-particle. Some of the properties of interest include its activity as a heterogeneous catalyst, particularly at low temperatures, its optical properties, and the tendency of its nano-particles to adopt non-crystallographic structures. There are a number of curious aspects to catalysis by gold that are attracting academic and industrial investigation and much is still not understood about the mechanism by which they work. For example, apparently similar preparation techniques result in activities of hugely varying magnitude. In the present talk I assess the what is known about gold nano-particles, with particular reference to their physical, electronic, crystallographic and catalytic properties. It is shown that there is much evidence in favour of the belief that it is the unique electronic structure of these particles that imbues them with catalytic activity. If this is true then tighter control of the electronic structure would allow for the design of more specific and more active catalysts

  12. Structural, Electronic, Magnetic, and Vibrational Properties of Graphene and Silicene: A First-Principles Perspective

    KAUST Repository

    Kaloni, Thaneshwor P.

    2013-11-01

    This thesis covers the structural, electronic, magnetic, and vibrational properties of graphene and silicene. In Chapter I, we will start with an introduction to graphene and silicene. In Chapter II, we will briefly discuss about the methodology (i. e. density functional theory)In Chapter III, we will introduce band gap opening in graphene either by introducing defects/doping or by creating superlattices with h-BN substrate. In Chapter IV, we will focus on the structural and electronic properties of K and Ge-intercalated graphene on SiC(0001). In addition, the enhancement of the superconducting transition temperature in Li-decorated graphene supported by h-BN substrate will be discussed. In Chapter V, we will discuss the vibrational properties of free-standing silicene. In addition, superlattices of silicene with h-BN as well as the phase transition in silicene by applying an external electric field will be discussed. The electronic and magnetic properties transition metal decorated silicene will be discussed, in particular the realization of the quantum anomalous Hall effect will be addressed. Furthermore, the structural, electronic, and magnetic properties of Mn decorated silicene supported by h-BN substrate will be discussed. The conclusion is included in Chapters VI. Finally, we will end with references and a list of publications for this thesis.

  13. Magnetic properties of Martian olivine basalts studied by terrestrial analogues

    International Nuclear Information System (INIS)

    Here we present a comparison study of terrestrial olivine basalt and relatively un-weathered basalt studied by the Mars Exploration Rover Spirit on Mars. The Moessbauer spectra of terrestrial olivine basalt exhibit some characteristics that can also be seen in the Mars spectra. The results from Moessbauer spectroscopy on Mars indicate that the olivine in the rocks has undergone alteration at high temperatures (600-1,000 deg. C), a process known to give rise to anomalously magnetic rocks on Earth. This suggests that if the rocks at Gusev crater had solidified in an external magnetic field of terrestrial magnitude, these would have become highly magnetic enough to explain the presence of magnetic anomalies on Mars.

  14. Anomalous electrostatic potential properties in carbon nanotube thin films under a weak external electric field

    OpenAIRE

    Ishiyama, U; Cuong, Nguyen Thanh; Okada, Susumu

    2016-01-01

    Using density functional theory, we studied the electronic properties of carbon nanotube (CNT) thin films under an electric field. The carrier accumulation due to the electric field depends strongly on the CNT species forming the thin films. Under a low electron concentration, the injected electrons are distributed throughout the CNTs, leading to an unusual electric field between CNTs, the direction of which is opposite to that of the applied field. This unusual field response of CNT thin fil...

  15. Properties of GRB Lightcurves from Magnetic Reconnection

    Science.gov (United States)

    Beniamini, Paz; Granot, Jonathan

    2016-04-01

    The energy dissipation mechanism within Gamma-Ray Burst (GRB) outflows, driving their extremely luminous prompt γ-ray emission is still uncertain. The leading candidates are internal shocks and magnetic reconnection. While the emission from internal shocks has been extensively studied, that from reconnection still has few quantitative predictions. We study the expected prompt-GRB emission from magnetic reconnection and compare its temporal and spectral properties to observations. The main difference from internal shocks is that for reconnection one expects relativistic bulk motions with Lorentz factors Γ' ≳ a few in the jet's bulk frame. We consider such motions of the emitting material in two anti-parallel directions (e.g. of the reconnecting magnetic-field lines) within an ultra-relativistic (with Γ ≫ 1) thin spherical reconnection layer. The emission's relativistic beaming in the jet's frame greatly affects the light-curves. For emission at radii R0 tracking (for Γ' > 2). However, only the relativistic turbulence mode can naturally account also for the following correlations: luminosity-variability, peak luminosity - peak frequency and pulse width energy dependence / spectral lags.

  16. Nanoscale magnetism and novel electronic properties of a bilayer bismuth(111) film with vacancies and chemical doping.

    Science.gov (United States)

    Sahoo, M P K; Zhang, Yajun; Wang, Jie

    2016-07-27

    Magnetically doped topological insulators (TIs) exhibit several exotic phenomena including the magnetoelectric effect and quantum anomalous Hall effect. However, from an experimental perspective, incorporation of spin moment into 3D TIs is still challenging. Thus, instead of 3D TIs, the 2D form of TIs may open up new opportunities to induce magnetism. Based on first principles calculations, we demonstrate a novel strategy to realize robust magnetism and exotic electronic properties in a 2D TI [bilayer Bi(111) film: abbreviated as Bi(111)]. We examine the magnetic and electronic properties of Bi(111) with defects such as bismuth monovacancies (MVs) and divacancies (DVs), and these defects decorated with 3d transition metals (TMs). It has been observed that the MV in Bi(111) can induce novel half metallicity with a net magnetic moment of 1 μB. The origin of half metallicity and magnetism in MV/Bi(111) is further explained by the passivation of the σ-dangling bonds near the defect site. Furthermore, in spite of the nonmagnetic nature of DVs, the TMs (V, Cr, Mn, and Fe) trapped at the 5/8/5 defect structure of DVs can not only yield a much higher spin moment than those trapped at the MVs but also display intriguing electronic properties such as metallic, semiconducting and spin gapless semiconducting properties. The predicted magnetic and electronic properties of TM/DV/Bi(111) systems are explained through density of states, spin density distribution and Bader charge analysis. PMID:27406933

  17. Anomalous properties of heavy fermion materials%重费米子材料中的反常物性

    Institute of Scientific and Technical Information of China (English)

    杨义峰

    2014-01-01

    Heavy fermion research is of great importance for exploring the organization of exotic quantum phenomena in strongly correlated electron systems. Our recent studies on the anom-alous normal state properties of heavy fermion materials reveal a universal temperature evolution governing the emergence of heavy electrons and the presence of the Fano interference effect. Our work provides a new avenue for understanding heavy fermion physics as well as the underlying mechanism of unconventional superconductivity.%重费米子研究对探索强关联电子体系新奇量子现象的组织原则具有重要的意义。文章介绍了作者近年来对重费米子材料正常态反常性质的研究进展,揭示了重电子的普适温度演化行为和Fano干涉效应,为理解重费米子物理和探索非常规超导机理提供了新的思路。

  18. Anomalous magnetic response of a quasi-periodic mesoscopic ring in presence of Rashba and Dresselhaus spin-orbit interactions

    Science.gov (United States)

    Patra, Moumita; Maiti, Santanu K.

    2016-04-01

    We investigate the properties of persistent charge current driven by magnetic flux in a quasi-periodic mesoscopic Fibonacci ring with Rashba and Dresselhaus spin-orbit interactions. Within a tight-binding framework we work out individual state currents together with net current based on second-quantized approach. A significant enhancement of current is observed in presence of spin-orbit coupling and sometimes it becomes orders of magnitude higher compared to the spin-orbit interaction free Fibonacci ring. We also establish a scaling relation of persistent current with ring size, associated with the Fibonacci generation, from which one can directly estimate current for any arbitrary flux, even in presence of spin-orbit interaction, without doing numerical simulation. The present analysis indeed gives a unique opportunity of determining persistent current and has not been discussed so far.

  19. Magnetic Properties of Magnetic Nanoparticles for Efficient Hyperthermia

    OpenAIRE

    Obaidat, Ihab M.; Bashar Issa; Yousef Haik

    2015-01-01

    Localized magnetic hyperthermia using magnetic nanoparticles (MNPs) under the application of small magnetic fields is a promising tool for treating small or deep-seated tumors. For this method to be applicable, the amount of MNPs used should be minimized. Hence, it is essential to enhance the power dissipation or heating efficiency of MNPs. Several factors influence the heating efficiency of MNPs, such as the amplitude and frequency of the applied magnetic field and the structural and magnet...

  20. Negative thermal expansion and associated anomalous physical properties: review of the lattice dynamics theoretical foundation

    Science.gov (United States)

    Dove, Martin T.; Fang, Hong

    2016-06-01

    Negative thermal expansion (NTE) is the phenomenon in which materials shrink rather than expand on heating. Although NTE had been previously observed in a few simple materials at low temperature, it was the realisation in 1996 that some materials have NTE over very wide ranges of temperature that kick-started current interest in this phenomenon. Now, nearly two decades later, a number of families of ceramic NTE materials have been identified. Increasingly quantitative studies focus on the mechanism of NTE, through techniques such as high-pressure diffraction, local structure probes, inelastic neutron scattering and atomistic simulation. In this paper we review our understanding of vibrational mechanisms of NTE for a range of materials. We identify a number of different cases, some of which involve a small number of phonons that can be described as involving rotations of rigid polyhedral groups of atoms, others where there are large bands of phonons involved, and some where the transverse acoustic modes provide the main contribution to NTE. In a few cases the elasticity of NTE materials has been studied under pressure, identifying an elastic softening under pressure. We propose that this property, called pressure-induced softening, is closely linked to NTE, which we can demonstrate using a simple model to describe NTE materials. There has also been recent interest in the role of intrinsic anharmonic interactions on NTE, particularly guided by calculations of the potential energy wells for relevant phonons. We review these effects, and show how anhamonicity affects the response of the properties of NTE materials to pressure.

  1. Fundamental magnetic properties of Greigite (Fe3S4)

    OpenAIRE

    Chang, Liao

    2009-01-01

    Over the last twenty years, greigite (Fe3S4), an authigenic magnetic iron sulphide mineral, has been increasingly identified in sulphate-reducing marine and lacustrine sedimentary systems. Its presence can significantly affect palaeomagnetic and environmental magnetic records. Understanding the recording characteristics of any magnetic mineral requires that its fundamental magnetic properties are known. However, unlike magnetite (Fe3O4) and other common terrestrial magnetic minerals, the fund...

  2. Magnetic properties of high-Tc superconductors

    International Nuclear Information System (INIS)

    Magnetic properties of high-Tc superconductors have been studied in order to determine the free-energy surface, the characteristic critical fields, order parameters structure, and the grain size effect on magnetization. Studies of the thermodynamic reversibility for YBa2Cu3O(7-delta) show the rounding in magnetization vs. temperature curves is a reflection of the thermodynamic fluctuations near Tc. Specific heat jump C(0)-C(H) values that have been calculated from the free-energy surfaces show good agreement with the direct calorimetric measurements. Comparative studies of the free-energy surfaces, flux creep and critical currents for both melt-textured and grain-aligned YBa2Cu3O(7-delta) samples have been undertaken in order to evaluate the difference caused by different micro structures in these samples. The free energy per unit length of a vortex is found to be essentially the same in the melt-textured sample as for the single crystals in the grain-aligned sample, suggesting that the line energy is the same for these rather different samples. The specific heat jump values calculated from the free-energy surfaces also show close agreement between the two samples. Magnetic field and temperature dependence of the average Ginzburg-Landau order parameter (f) is evaluated by fitting the magnetization data of grain-aligned YBa2Cu3O(7-delta) to the Hao-Clem model in the region of thermodynamic reversibility. H(sub C)(T) and H(sub c2)(T) were also determined from the fitting along with the kappa(sub c)(T) values. The study reveals the kappa(sub c) is a slowly decreasing function of temperature near T(sub c). Fittings of the same model to Bi2Sr2Ca2Cu3O10 have been carried out. The 2-D nature of bismuth family superconductors introduces some difficulties in applying Hao-Clem model and it is discussed in comparison with YBa2Cu3O(7-delta) results

  3. Efimov effect and anomalous transport properties of a quantum Lorentz gas

    International Nuclear Information System (INIS)

    The Lorentz gas is one of the simplest many-body systems which admits a detailed theoretical analysis still having a meaningful physical interpretation. The author studies a complication for the description of the equilibrium state of a gas due to the so called Efimov effect, being an anomaly of the quantum mechanical three-body system. In statistical mechanical studies concerning the thermodynamic properties of gases it is usually assumed that the constituents interact via short-range potentials, which excludes for instance the Coulomb gas. The author investigates the consequences of the effective long-range behaviour due to the Efimov effect in the three-body sub-systems for a binary gas mixture. In particular problems arise in the cluster expansion of the quantum mechanical partition function where it can readily be shown that the bound-state part of the three-particle contribution diverges logarithmically at the Efimov point. The question is whether this implies the divergence of the complete three particle contribution or not. Some aspects of the non-equilibrium behaviour of the quantum Lorentz gas are studied. (Auth.)

  4. Anomalous surface states modify the size-dependent mechanical properties and fracture of silica nanowires

    International Nuclear Information System (INIS)

    Molecular dynamics simulations of amorphous silica nanowires under tension were analyzed for size and surface stress effects on mechanical properties and for structural modifications via bond angle distributions. Their fracture behavior was also investigated beyond the elastic limit. The Young’s moduli of silica nanowires were predicted to be about 75–100 GPa, depending on the nanowire size. The ultimate strength was calculated to be ∼10 GPa, depending on the diameter, which is in excellent agreement with the experiments. The dependence of the Young’s modulus on nanowire diameter is explained in terms of surface compressive stress effects. The fracture behavior of nanowires was also found to be influenced by surface compressive stresses. Bond angle distribution analysis of various nanowires reveals significant compressive surface states, as evidenced by the appearance of a secondary peak in the Si-O-Si bond angle distribution at ∼97°, which is absent in bulk silica. The strain rate was found to have a negligible effect on the Young’s modulus of the silica nanowires, but it has a critical role in determining their fracture mode. (paper)

  5. Anomalous dielectric and thermal properties of Ba-doped PbZrO3 ceramics

    Science.gov (United States)

    Pirc, R.; Rožič, B.; Koruza, J.; Cordoyiannis, G.; Malič, B.; Kutnjak, Z.

    2015-11-01

    The dielectric and thermal properties of an antiferroelectric (AFE) material characterised by an intermediate ferroelectric (FE) phase between the AFE and paraelectric phase in zero field are studied by means of a generalised Landau-Kittel model of AFEs. A temperature-dependent coupling of the two sublattices is introduced in accordance with the Rae-Dove (RD) model of re-entrant phase transitions. The sublattice polarisation components are calculated as functions of temperature and the applied electric field by minimising numerically the free energy. The calculated dielectric susceptibility shows anomalies at the boundaries of the intermediate FE phase, characteristic for first-order phase transitions. It is shown that this behaviour is in qualitative agreement with the measured dielectric constant in Ba-doped PbZrO3 ceramics. The model also predicts a negative adiabatic electrocaloric temperature change Δ T in a broad temperature range in the AFE phase, in qualitative agreement with experiments. The dipolar heat capacity is also predicted to be negative in the intermediate phase in zero field, in analogy with the results of the RD model.

  6. Magnetic properties and specific heat of KV1-xCrxP2S7

    International Nuclear Information System (INIS)

    Magnetic properties and the specific heat of a series of new compounds, KV1-xCrxP2S7 have been investigated. They are antiferromagnets with the Neel temperatures TN, determined from a specific heat, 19, 15 and 17 K for x=0, 0.75 and 1.0, respectively. The magnetic susceptibility shows a broad peak at Tp above TN, 26, 18 and 20 K for x=0, 0.75 and 1.0, respectively. The easy magnetization axis is parallel to the c*-axis for x=0 and 0.75, while it is perpendicular to the c*-axis for x=1.0. The effective magnetic moment μeff is about 1.8 μB for KVP2S7, which is smaller than the spin only value of V3+ ion and cannot be explained by the simple crystalline electric field effects. On the other hand, μeff is about 4.0 μB, which almost corresponds to the spin only value of Cr3+ ion for KCrP2S7. The magnetization curve at 2 K is not linear below 7 T for three compounds and a curious hysteresis is observed for KVP2S7. The another marked magnetic behavior of the present system is a very large diamagnetism χdia∼-10-3 (emu/mol) for three compounds. Anomalous magnetic properties of the present system are considered to originate in the covalency of S-S and S-(V,Cr) bonds, the network of which may produce the large diamagnetism. The overlapping of the 3d orbitals of V and Cr ions with surrounding S 3p orbitals may affect the magnetic moment of these ions

  7. Magnetic nanoparticles and concentrated magnetic nanofluids: Synthesis, properties and some applications

    Institute of Scientific and Technical Information of China (English)

    Ladislau; Vékás; Doina; Bica; Mikhail; V.; Avdeev

    2007-01-01

    This paper reviews some recent results concerning chemical synthesis of magnetic nanoparticles and preparation of various types of magnetic nanofluids. Structural properties and behaviour in external magnetic field of magnetic nanofluids will be emphasized with relation to their use in leakage-free rotating seals and in biomedical applications.

  8. Magnetically modified TiO2 powders – microstructure and magnetic properties

    Czech Academy of Sciences Publication Activity Database

    Žitovský, O.; Seidlerová, J.; Šafařík, Ivo; Luňáček, J.; Šafaříková, Miroslava; Kutláková Mamulová, K.; Jirásková, Yvonna

    Vol.75. Amsterdam: Elsevier, 2015, s. 1450-1457. ISSN 1875-3892. [International Conference on Magnetism /20./. Barcelona (ES), 05.07.2015-10.07.2015] Institutional support: RVO:68081723 ; RVO:67179843 Keywords : Magnetically modified TiO2 * X-ray powder diffraction * microstructure * magnetic properties * vibrating sample magnetometer Subject RIV: BM - Solid Matter Physics ; Magnetism; EI - Biotechnology ; Bionics (UEK-B)

  9. Magnetic properties of YBCO-PST composites

    International Nuclear Information System (INIS)

    The magnetic properties of granular superconductor-insulator composites were investigated. The composites were random composition of the YBa2Cu3O7-δ (YBCO) high-temperature superconductor and Pb(Sc0.5Ta0.5)O3 (PTS) ferroelectric insulator. The composites exhibited lower superconducting volume ratio than the YBCO content. For samples with YBCO content low enough no global (the whole sample) and local (separated grains) superconductivity was observed. The observed decay of the superconductivity, lowering of the critical temperature, and the increase in number of paramagnetic centers as PST content increases are explained assuming reaction among YBCO and PST phases and possible formation of an additional ones, which did not exist in the initial powders. (author)

  10. Magnetic properties of rare earth iron compounds

    International Nuclear Information System (INIS)

    In this thesis, a study is made of hyperfine interactions in the intermetallic compounds Rsub(x)Fesub(y) (R = rare earth, Y or Th) by using the Moessbauer effect in the 57Fe nucleus. The hyperfine interactions in two series of Rsub(x)Fesub(y) compounds, for which Ysub(x)Fesub(y) and Ersub(x)Fesub(y) were chosen, are studied. Thus a comparison can be made between the magnetic properties of compounds with diamagnetic yttrium and ferromagnetic erbium, respectively. In addition, the magnetic anisotropy of these compounds Ysub(x)Fesub(y) and Ersub(x)Fesub(y) has been investigated. The major part of this thesis concerns a study of the R2Fe17 intermetallic compounds. Since Co or Ni substitution for Fe in R2Fe17 compounds results in a fast increase of the Curie temperature, some pseudobinary R2Fesub(17-x)Msub(x) compounds with R = Tm and Er and M = Co and Ni, have been investigated. ThFe5 has been studied, since it is the only known existing RFe5 compound with a crystal structure which is closely related to that of Th2Fe17

  11. Observation of Anomalous Properties associated with the Low Temperature Structural Distortion in β-FeSe and Related Superconductorsa

    Directory of Open Access Journals (Sweden)

    Wu M. K.

    2012-03-01

    Full Text Available The discovery of Superconductivity in the tetragonal phase FeSe provides a unique platform for the detailed investigation of the correlation between the physical properties and crystal structure to better understand the possible origin of superconductivity in the new iron-based superconductors. We have carried out a series of properties characterizations by measuring magnetic susceptibility, Raman, NMR and femtosecond spectroscopy on single crystals and epitaxial thin films of the FeSe and Te-doped Fe(SeTe samples. Our results show clearly the presence of anomalies in all the characterized properties at the temperature where a structural distortion from tetragonal to orthorhombic (or monoclinic appears for all superconducting samples, but not in the non-superconducting ones. This structural distortion was observed not accompanied by a magnetic ordering as commonly occurs in the parent compounds of FeAs-based superconductors. All the observations suggest that the low temperature structural distortion is essential for the occurrence of superconductivity in the FeSe and related compounds. Details of the experimental results will be presented and discussed.

  12. Numerical calculations of magnetic properties of nanostructures

    CERN Document Server

    Kapitan, Vitalii; Nefedev, Konstantin

    2015-01-01

    Magnetic force microscopy and scanning tunneling microscopy data could be used to test computer numerical models of magnetism. The elaborated numerical model of a face-centered lattice Ising spins is based on pixel distribution in the image of magnetic nanostructures obtained by using scanning microscope. Monte Carlo simulation of the magnetic structure model allowed defining the temperature dependence of magnetization; calculating magnetic hysteresis curves and distribution of magnetization on the surface of submonolayer and monolayer nanofilms of cobalt, depending on the experimental conditions. Our developed package of supercomputer parallel software destined for a numerical simulation of the magnetic-force experiments and allows obtaining the distribution of magnetization in one-dimensional arrays of nanodots and on their basis. There has been determined interpretation of magneto-force microscopy images of magnetic nanodots states. The results of supercomputer simulations and numerical calculations are in...

  13. Structural Origin of the Anomalous Temperature Dependence of the Local Magnetic Moments in the CaFe2As2 Family of Materials

    Science.gov (United States)

    Ortenzi, L.; Gretarsson, H.; Kasahara, S.; Matsuda, Y.; Shibauchi, T.; Finkelstein, K. D.; Wu, W.; Julian, S. R.; Kim, Young-June; Mazin, I. I.; Boeri, L.

    2015-01-01

    We report a combination of Fe K β x-ray emission spectroscopy and density functional reduced Stoner theory calculations to investigate the correlation between structural and magnetic degrees of freedom in CaFe2(As1-xPx) 2 . The puzzling temperature behavior of the local moment found in rare earth-doped CaFe2As2 [H. Gretarsson et al., Phys. Rev. Lett. 110, 047003 (2013)] is also observed in CaFe2(As1-xPx) 2 . We explain this phenomenon based on first-principles calculations with scaled magnetic interaction. One scaling parameter is sufficient to describe quantitatively the magnetic moments in both CaFe2(As1-xPx) 2 (x =0.055 ) and Ca0.78La0.22Fe2As2 at all temperatures. The anomalous growth of the local moments with increasing temperature can be understood from the observed large thermal expansion of the c -axis lattice parameter combined with strong magnetoelastic coupling. These effects originate from the strong tendency to form As-As dimers across the Ca layer in the CaFe2As2 family of materials. Our results emphasize the dual local-itinerant character of magnetism in Fe pnictides.

  14. Magnetic Properties of AIIBIVCV2 Compounds Doped with Mn

    Directory of Open Access Journals (Sweden)

    A.V. Kochura

    2013-12-01

    Full Text Available Mn-doped AIIBIVCV2 semiconductors bulk crystals were grown by direct melting of base components with fast cooling. Structural and magnetic properties of samples were investigated. Analysis of the temperature dependence of the magnetization reveals three types of magnetic species: the substitutional Mn ions making Mn complexes (especially dimers, the MnAs micro- and nanosize precepitates.

  15. Anomalous cosmic rays in the distant heliosphere and the reversal of the Sun's magnetic polarity in Cycle 23

    OpenAIRE

    McDonald, F. B.; Stone, E. C.; Cummings, A. C.; Webber, W. R.; Heikkila, B. C.; Lal, N.

    2007-01-01

    Beginning in early June 2001 and extending over a ∼3 month period the Cosmic Ray Subsystem (CRS) experiment on Voyager 1 (80.3 AU, 34°N) observed a rapid transition in the energy of the peak intensity of anomalous cosmic ray (ACR) He from ∼11 MeV/n to ∼25 MeV/n. One month later there began a similar spectral shift at Voyager 2 (64.7 AU, 24°S). When these ACR transition times are extrapolated back from the estimated location of the heliospheric termination shock (TS) to the Sun (∼1 year) there...

  16. A Measurement Of The Anomalous Magnetic Moment Of The Positive Muon With A Precision Of 0.7 Parts Per Million

    CERN Document Server

    Gray, F E

    2003-01-01

    The anomalous magnetic moment of the positive muon has been measured to a precision of 0.7 parts per million in an experiment at Brookhaven National Laboratory. The standard model prediction for this quantity can be calculated with a similar uncertainty, although there are currently inconsistent results for one crucial part of this evaluation. Comparison of the theoretical and experimental values tests the standard model and probes for physics beyond it, including supersymmetry, for which a large signal is expected from many models. This thesis describes the principle of the experiment and the status of the theoretical evaluations. It concentrates on the details of an energy-binned method of determining the anomalous precession frequency from the recorded data. The result that is obtained, after combination with previous measurements, is aexp;avgm=11659203 8×10- 10, to be compared with the present standard model predictions aSM;e+e- m =11659168.87.7×10 -10and aSM;tm=11659193.2 6.8&...

  17. Magnetic properties and quantum entanglement on decorated zigzag ladder

    International Nuclear Information System (INIS)

    Magnetic properties and quantum entanglement of Heisenberg model with two-, three- and four- site exchange interactions on zigzag ladder are studied. Magnetic properties and concurrence (measure of quantum entanglement) are analyzed by means of variational mean-field-like treatment based on the Gibbs-Bogoliubov inequality. The magnetization plateau and second-order phase transition were obtained. A comparison of the entanglement and magnetic behavior for zigzag ladder is made. We have found that in the antiferromagnetic region the behavior of the concurrence coincides with the magnetization one

  18. A study of the hard magnetic properties in different hard magnetic materials

    International Nuclear Information System (INIS)

    The magnetic properties of several hard magnetic materials have been investigated to determine any trends in their magnetic characteristics. The materials studied were Nd15Fe77B8, SmCo5, Sm2 (Co,Fe,Cu,Zr)17, strontium ferrite magnets and single domain particles of Ba-ferrite and Cu-Mn-Al. The initial magnetization curves, field dependence of coercivity and remanence curves were measured

  19. Anomalous magnetic behavior in holmium doped La0.7Sr0.3MnO3 film

    International Nuclear Information System (INIS)

    Low field magnetization measurements are reported in a highly oriented La0.55Ho0.15Sr0.3MnO3 film on LaAlO3 substrate in the temperature range of 2-300 K and in fields up to 50 mT. Interesting magnetic history effects are observed at low temperatures which are not seen in high magnetic fields. It appears that the inhomogeneous magnetic state at low temperatures evolves due to competing magnetic interactions leading to the observed irreversibility behavior in these materials

  20. The effects of magnetic nanoparticle properties on magnetic fluid hyperthermia

    OpenAIRE

    Kappiyoor, Ravi; Liangruksa, Monrudee; Ganguly, Ranjan; Puri, Ishwar K.

    2010-01-01

    Magnetic fluid hyperthermia (MFH) is a noninvasive treatment that destroys cancer cells by heating a ferrofluid-impregnated malignant tissue with an ac magnetic field while causing minimal damage to the surrounding healthy tissue. The strength of the magnetic field must be sufficient to induce hyperthermia but it is also limited by the human ability to safely withstand it. The ferrofluid material used for hyperthermia should be one that is readily produced and is nontoxic while providing suff...

  1. Magnetic properties of biomineral particles produced by bacteria Klebsiella oxytoca

    Science.gov (United States)

    Raĭkher, Yu. L.; Stepanov, V. I.; Stolyar, S. V.; Ladygina, V. P.; Balaev, D. A.; Ishchenko, L. A.; Balasoiu, M.

    2010-02-01

    Ferrihydrite nanoparticles (2-5 nm in size) produced by bacteria Klebsiella oxytoca in the course of biomineralization of iron salt solutions from a natural medium exhibit unique magnetic properties: they are characterized by both the antiferromagnetic order inherent in a bulk ferrihydrite and the spontaneous magnetic moment due to the decompensation of spins in sublattices of a nanoparticle. The magnetic susceptibility enhanced by the superantiferromagnetism effect and the magnetic moment independent of the magnetic field provide the possibility of magnetically controlling these natural objects. This has opened up the possibilities for their use in nanomedicine and bioengineering. The results obtained from measurements of the magnetic properties of the ferrihydrite produced by Klebsiella oxytoca in its two main crystalline modifications are reported, and the data obtained are analyzed theoretically. This has made it possible to determine numerical values of the magnetic parameters of real biomineral nanoparticles.

  2. Laser-Induced Magnetic Nanostructures with Tunable Topological Properties

    OpenAIRE

    Finazzi, M.; Savoini, M.; Khorsand, A. R.; Tsukamoto, A.; Itoh, A.; L. Duo; Kirilyuk, A.; Rasing, T.H.M.; Ezawa, M.

    2013-01-01

    We report the creation and real-space observation of magnetic structures with well-defined topological properties and a lateral size as low as about 150 nm. They are generated in a thin ferrimagnetic film by ultrashort single optical laser pulses. Thanks to their topological properties, such structures can be classified as Skyrmions of a particular type that does not require an externally applied magnetic field for stabilization. Besides Skyrmions, we are able to generate magnetic features wi...

  3. The magnetic properties of potassium holmium double tungstate

    International Nuclear Information System (INIS)

    The magnetic investigations of potassium holmium double tungstate KHo(WO4)2 have been performed. The results of measurements of magnetic susceptibility and magnetization as a function of temperature (T from 0.3 K up to 100 K) and magnetic field (up to 1.5 T) are presented. A strong anisotropy of magnetic properties was found. The magnetic measurements data were used to calculate the interaction energy. It was shown that the interactions between nearest neighbors Ho3+ ions have antiferromagnetic character.

  4. Magnetic Properties of Heisenberg Thin Films in an External Field

    Institute of Scientific and Technical Information of China (English)

    CHEN Hong; ZHANG Jing

    2004-01-01

    The magnetic properties of Heisenberg ferromagnetic films in an external magnetic field are investigated by means of the variational cumulant expansion (VCE). The magnetization can be in principle calculated analytically as the function of the temperature and the number of atomic layers in the film to an arbitrary order of accuracy in the VCE. We calculate the spontaneous magnetization and coercivity to the third order for spin-1/2 Heisenberg films with simple cubic lattices by using a graphic technique.

  5. Hadron production in e+e- annihilation at BABAR, and implication for the muon anomalous magnetic moment

    Energy Technology Data Exchange (ETDEWEB)

    Porter, Frank C. [Caltech, Pasadena, CA (United States). Physics Dept.

    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

  6. $W^{+-}$-production in $e^{-}$ p-collisions at CERN LEP/LHC energies with a non-standard $W^{+-}$ anomalous magnetic moment

    CERN Document Server

    Gutiérrez-Rodríguez, A

    2000-01-01

    We discuss the production of charged bosons in deep inelastic e-p- scattering, in the context of an electroweak model, in which the vector boson self interactions may be different from those prescribed by the electroweak standard model. We present results which show the strong dependence of the cross section on the anomalous magnetic dipole moment kappa of the W/sup +or-/. We show that even small deviations from the standard model value of kappa ( kappa =1) implies an observable deviation in the W/sup +or-/-production rates at CERN LEP/LHC energies. We also show that for the analysis of the charged boson production via e/sup -/p collisions at LEP/LHC energies will be very important to include the contribution from heavy boson exchange diagrams to the cross section rates. (25 refs).

  7. The strange and charm quark contributions to the anomalous magnetic moment (g -2) of the muon from current-current correlators

    CERN Document Server

    Chakraborty, Bipasha; Donald, Gordon; Dowdall, Rachel; de Oliveira, Pedro Gonçalves; Koponen, Jonna; Lepage, G Peter; Teubner, T

    2014-01-01

    We describe a new technique (presented in arXiv:1403.1778) to determine the contribution to the anomalous magnetic moment (g-2) of the muon coming from the hadronic vacuum polarisation using lattice QCD. Our method uses Pad\\'{e} approximants to reconstruct the Adler function from its derivatives at $q^2=0$. These are obtained simply and accurately from time-moments of the vector current-current correlator at zero spatial momentum. We test the method using strange quark correlators calculated on MILC Collaboration's $n_f$ = 2+1+1 HISQ ensembles at multiple values of the lattice spacing, multiple volumes and multiple light sea quark masses (including physical pion mass configurations).

  8. Magnetic properties of cobalt-carbon nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, Denys; Prylutskyy, Yuriy; Matzui, Ludmila; Zakharenko, Mykola [National Shevchenko University, Department of Physics, Volodymyrska Str., 64, Kyiv 01680 (Ukraine); Le Normand, Francois; Derory, Alain [Groupe Surfaces-Interfaces, Institut de Physique et Chimie des Materiaux, 23 rue du Loess, BP 43, 67037 Strasbourg (France)

    2010-04-15

    The paper presents the results of experimental study of the structure and magnetic characteristics of Co-graphite compounds, which were obtained by metal reduction of metal chlorides in graphite intercalated compound (GIC) by C{sub 8}K. The obtained materials were shown to have heterogeneous structure consisting of nanographite matrix in which nanoclusters of Co-GIC are distributed. Magnetic field was applied either along or perpendicularly to the C-axis. It was shown that magnetism of this compound is determined mainly by nanoclusters of Co-GIC for which high anisotropy of magnetic characteristic were observed. ZFC and FC temperature dependences of magnetic susceptibility indicate the formation spin glass state below {proportional_to}20 K. It was also shown that experimental dependences of magnetization contain the contribution due to antiferromagnetic sublattice and magnetization due to uncompensated magnetic moments (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Injection-Molded Soft Magnets Prepared from Fe-Based Metallic Glass: Mechanical and Magnetic Properties

    Science.gov (United States)

    Zhong, Tian; Huang, Ran; Huang, Jia; Ouyang, Wei

    2015-10-01

    The injection-molded metallic glass soft magnet is prepared from the powder of melt-spun ribbon of Fe36Co36B20Si4Nb4 glassy alloy and Nylon 6,6 of wt.% from 5 to 20 via the polymer injection molding technology. The product is characterized by the SEM, mechanical, and magnetic test. The results indicate that this type of materials has comparable mechanical properties and morphological feature with the conventional injection-molded NdFeB magnet and exhibits excellent soft magnetic behaviors. The magnetic properties of the injected magnets are compared with the raw metallic glass, solvent-casted resin bonding magnets, and thermal-treated magnets to confirm that the processing temperature of Nylon injection does not affect the magnetism. The injection technology is a practical processing method to be applied on the metallic glass for potential usage.

  10. Electronic properties of magnetically doped nanotubes

    Indian Academy of Sciences (India)

    Keivan Esfarjani; Z Chen; Y Kawazoe

    2003-01-01

    Effect of doping of carbon nanotubes by magnetic transition metal atoms has been considered in this paper. In the case of semiconducting tubes, it was found that the system has zero magnetization, whereas in metallic tubes the valence electrons of the tube screen the magnetization of the dopants: the coupling to the tube is usually antiferromagnetic (except for Cr).

  11. Magnetic structures and properties of vanadium diiodide.

    NARCIS (Netherlands)

    Kuindersma, S. R.; Haas, C.; Sanchez, J. P.; Al, R.

    1979-01-01

    Single-crystal measurements of the magnetic susceptibilities of VI2 show an anomaly at a crit. temp. of ∼14 K. This anomaly can be ascribed to a magnetic phase transition from a 120° structure to a collinear arrangement of the spins with a magnetic unit cell amagn = a√3, bmagn = 2 a and cmagn = 2 c.

  12. Viking magnetic properties investigation: preliminary results.

    Science.gov (United States)

    Hargraves, R B; Collinson, D W; Spitzer, C R

    1976-10-01

    Three permanent magnet arrays are aboard the Viking lander. By sol 35, one array, fixed on a photometric reference test chart on top of the lander, has clearly attracted magnetic particles from airborne dust; two other magnet arrays, one strong and one weak, incorporated in the backhoe of the surface sampler, have both extracted considerable magnetic mineral from the surface as a result of nine insertions associated with sample acquisition. The loose martian surface material around the landing site is judged to contain 3 to 7 percent highly magnetic mineral which, pending spectrophotometric study, is thought to be mainly magnetite. PMID:17793086

  13. Viking magnetic properties investigation - Preliminary results

    Science.gov (United States)

    Hargraves, R. B.; Collinson, D. W.; Spitzer, C. R.

    1976-01-01

    Three permanent-magnet arrays are aboard the Viking lander. By sol 35, one array, fixed on a photometric reference test chart on top of the lander, has clearly attracted magnetic particles from airborne dust; two other magnet arrays, one strong and one weak, incorporated in the backhoe of the surface sampler, have both extracted considerable magnetic mineral from the surface as a result of nine insertions associated with sample acquisition. The loose Martian surface material around the landing site is judged to contain 3 to 7 per cent highly magnetic mineral which, pending spectrophotometric study, is thought to be mainly magnetite.

  14. Magnetism in nanoparticles: tuning properties with coatings.

    Science.gov (United States)

    Crespo, Patricia; de la Presa, Patricia; Marín, Pilar; Multigner, Marta; Alonso, José María; Rivero, Guillermo; Yndurain, Félix; González-Calbet, José María; Hernando, Antonio

    2013-12-01

    This paper reviews the effect of organic and inorganic coatings on magnetic nanoparticles. The ferromagnetic-like behaviour observed in nanoparticles constituted by materials which are non-magnetic in bulk is analysed for two cases: (a) Pd and Pt nanoparticles, formed by substances close to the onset of ferromagnetism, and (b) Au and ZnO nanoparticles, which were found to be surprisingly magnetic at the nanoscale when coated by organic surfactants. An overview of theories accounting for this unexpected magnetism, induced by the nanosize influence, is presented. In addition, the effect of coating magnetic nanoparticles with biocompatible metals, oxides or organic molecules is also reviewed, focusing on their applications. PMID:24201075

  15. Barium hexaferrite nanoparticles: Synthesis and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Martirosyan, K.S., E-mail: karen.martirosyan@utb.edu [Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204 (United States); Texas Center for Superconductivity, University of Houston, Houston, TX 77204 (United States); Department of Electrical and Computer Engineering, University of Houston, Houston, TX 77204 (United States); Galstyan, E. [Texas Center for Superconductivity, University of Houston, Houston, TX 77204 (United States); Hossain, S.M.; Wang Yiju [Department of Electrical and Computer Engineering, University of Houston, Houston, TX 77204 (United States); Litvinov, D. [Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204 (United States); Texas Center for Superconductivity, University of Houston, Houston, TX 77204 (United States); Department of Electrical and Computer Engineering, University of Houston, Houston, TX 77204 (United States)

    2011-01-15

    Carbon combustion synthesis is applied to rapid and energy efficient fabrication of crystalline barium hexaferrite nanoparticles with the average particle size of 50-100 nm. In this method, the exothermic oxidation of carbon nanoparticles with an average size of 5 nm with a surface area of 80 m{sup 2}/g generates a self-propagating thermal wave with maximum temperatures of up to 1000 deg. C. The thermal front rapidly propagates through the mixture of solid reactants converting it to the hexagonal barium ferrite. Carbon is not incorporated in the product and is emitted from the reaction zone as a gaseous CO{sub 2}. The activation energy for carbon combustion synthesis of BaFe{sub 12}O{sub 19} was estimated to be 98 kJ/mol. A complete conversion to hexagonal barium ferrite is obtained for carbon concentration exceeding 11 wt.%. The magnetic properties H{sub c}{approx}3000 Oe and M{sub s}{approx}50.3 emu/g of the compact sintered ferrites compare well with those produced by other synthesis methods.

  16. Barium hexaferrite nanoparticles: Synthesis and magnetic properties

    International Nuclear Information System (INIS)

    Carbon combustion synthesis is applied to rapid and energy efficient fabrication of crystalline barium hexaferrite nanoparticles with the average particle size of 50-100 nm. In this method, the exothermic oxidation of carbon nanoparticles with an average size of 5 nm with a surface area of 80 m2/g generates a self-propagating thermal wave with maximum temperatures of up to 1000 deg. C. The thermal front rapidly propagates through the mixture of solid reactants converting it to the hexagonal barium ferrite. Carbon is not incorporated in the product and is emitted from the reaction zone as a gaseous CO2. The activation energy for carbon combustion synthesis of BaFe12O19 was estimated to be 98 kJ/mol. A complete conversion to hexagonal barium ferrite is obtained for carbon concentration exceeding 11 wt.%. The magnetic properties Hc∼3000 Oe and Ms∼50.3 emu/g of the compact sintered ferrites compare well with those produced by other synthesis methods.

  17. Enhancement of the magnetic properties of iron nanoparticles upon incorporation of samarium

    International Nuclear Information System (INIS)

    Ion implantation of a rare-earth element is shown to dramatically enhance the magnetic properties of Fe nanostructures. Low energy 7 keV Sm+ ion implantation was used to modify the properties of superparamagnetic Fe nanoparticles on the surface of a SiO2 film on Si. The Fe nanoparticles were prepared through low energy ion implantation followed by electron-beam annealing. Ion beam analysis and transmission electron microscopy measurements showed that Sm implantation resulted in the formation of a Sm xFe1 − xO y layer on top of the Fe nanoparticles and sputtering of Fe in the Fe nanoparticles. There is an enhancement of the saturation magnetization when there is a Sm xFe1 − xO y layer on top of the Fe nanoparticles. This enhancement is most noticeable for an implanted Sm concentration of 3 × 1015 cm−2 and there is also an enhancement of the susceptibility and hence the permeability by a factor greater than 14. An anomalously large moment per implanted atom is found and which is above the values expected for Fe or any known Sm xFe1 − xO y compound. High Sm fluences result in complete ablation of the Fe nanoparticles and the magnetic order disappears. (papers)

  18. Magnetic properties of ball-milled TbFe2 and TbFe2B

    Indian Academy of Sciences (India)

    J Arout Chelvane; S Kasiviswanathan; M V Rao; G Markandeyulu

    2004-04-01

    The magnetic properties of ball-milled TbFe2 and TbFe2B were studied by magnetization measurements. X-ray diffraction studies on TbFe2B showed that boron occupied interstitial position in the crystal structure, just as hydrogen did. The value of the saturation magnetization of TbFe2B was found to be smaller than that of TbFe2. This is explained on the basis of a charge transfer between the boron atoms and the 3d band of Fe. The anisotropy of TbFe2B was found to be large compared to that of TbFe2. X-ray diffractograms for the ball milled samples showed that after 80 h of milling, a predominantly amorphous phase was obtained. TbFe2B was found to undergo easy amorphization compared to TbFe2. Magnetization of TbFe2 was found to decrease rapidly with initial milling hours and was found to be constant with further hours of milling. TbFe2B exhibited an anomalous behaviour with an increase in moment with milling hours and this may be due to the segregation of -Fe.

  19. Control over magnetic properties in bulk hybrid materials

    Science.gov (United States)

    Urban, Christian; Quesada, Adrian; Saerbeck, Thomas; Rubia, Miguel Angel De La; Garcia, Miguel Angel; Fernandez, Jose Francisco; Schuller, Ivan K.; UCSD Collaboration; Instituto de Ceramica, Madrid Collaboration; Institut Laue-Langevin, Grenoble Collaboration

    We present control of coercivity and remanent magnetization of a bulk ferromagnetic material embedded in bulk vanadium sesquioxide (V2O3) by using a standard bulk synthesis procedure. The method generalizes the use of structural phase transitions of one material to control structural and magnetic properties of another. A structural phase transition (SPT) in the V2O3 host material causes magnetic properties of Ni to change as function of temperature. The remanent magnetization and the coercivity are reversibly controlled by the SPT without additional external magnetic fields. The reversible tuning shown here opens the pathway for controlling the properties of a vast variety of magnetic hybrid bulk systems. This Work is supported by the Office of Basic Energy Science, U.S. Department of Energy, BES-DMS funded by the Department of Energy's Office of Basic Energy Science, DMR under grant DE FG02 87ER-45332.

  20. Magnetic Properties of Strontium Hexaferrite Nanostructures Measured with Magnetic Force Microscopy.

    Science.gov (United States)

    Li, Qiang; Song, Jie; Saura-Múzquiz, Matilde; Besenbacher, Flemming; Christensen, Mogens; Dong, Mingdong

    2016-01-01

    Magnetic property is one of the important properties of nanomaterials. Direct investigation of the magnetic property on the nanoscale is however challenging. Herein we present a quantitative measurement of the magnetic properties including the magnitude and the orientation of the magnetic moment of strontium hexaferrite (SrFe12O19) nanostructures using magnetic force microscopy (MFM) with nanoscale spatial resolution. The measured magnetic moments of the as-synthesized individual SrFe12O19 nanoplatelets are on the order of ~10(-16) emu. The MFM measurements further confirm that the magnetic moment of SrFe12O19 nanoplatelets increases with increasing thickness of the nanoplatelet. In addition, the magnetization directions of nanoplatelets can be identified by the contrast of MFM frequency shift. Moreover, MFM frequency imaging clearly reveals the tiny magnetic structures of a compacted SrFe12O19 pellet. This work demonstrates the mesoscopic investigation of the intrinsic magnetic properties of materials has a potential in development of new magnetic nanomaterials in electrical and medical applications. PMID:27174466

  1. Photothermal investigation of local and depth dependent magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Pelzl, J; Meckenstock, R, E-mail: pelzl@fks.rub.d [Institute of Experimental Physics, Solid State Spectroscopy, Ruhr-University, D-44780 Bochum (Germany)

    2010-03-01

    To achieve a spatially resolved measurement of magnetic properties two different photothermal approaches are used which rely on heat dissipated by magnetic resonance absorption or thermal modulation of the magnetic properties, respectively. The heat produced by modulated microwave absorption is detected by the classical photothermal methods such as photoacoustic effect and mirage effect. Examples comprise depth resolution of the magnetization of layered tapes and visualisation of magnetic excitations in ferrites. The second photothermal technique relies on the local modulation of magnetic properties by a thermal wave generated with an intensity modulated laser beam incident on the sample. This technique has a higher spatial resolution and sensitivity and has been used to characterize lateral magnetic properties of multilayers and spintronic media. To extend the lateral resolution of the ferromagnetic resonance detection into the nm-range techniques have been developed which are based on the detection of the modulated thermal microwave response by the thermal probe of an atomic force microscope (AFM) or by detection the thermal expansion of the magnetic sample in the course of the resonant microwave absorption with an AFM or tunnelling microscope. These thermal near field based techniques in ferromagnetic resonance have been successfully applied to image magnetic inhomogeneities around nano-structures and to measure the ferromagnetic resonance from magnetic nano-dots.

  2. Photothermal investigation of local and depth dependent magnetic properties

    International Nuclear Information System (INIS)

    To achieve a spatially resolved measurement of magnetic properties two different photothermal approaches are used which rely on heat dissipated by magnetic resonance absorption or thermal modulation of the magnetic properties, respectively. The heat produced by modulated microwave absorption is detected by the classical photothermal methods such as photoacoustic effect and mirage effect. Examples comprise depth resolution of the magnetization of layered tapes and visualisation of magnetic excitations in ferrites. The second photothermal technique relies on the local modulation of magnetic properties by a thermal wave generated with an intensity modulated laser beam incident on the sample. This technique has a higher spatial resolution and sensitivity and has been used to characterize lateral magnetic properties of multilayers and spintronic media. To extend the lateral resolution of the ferromagnetic resonance detection into the nm-range techniques have been developed which are based on the detection of the modulated thermal microwave response by the thermal probe of an atomic force microscope (AFM) or by detection the thermal expansion of the magnetic sample in the course of the resonant microwave absorption with an AFM or tunnelling microscope. These thermal near field based techniques in ferromagnetic resonance have been successfully applied to image magnetic inhomogeneities around nano-structures and to measure the ferromagnetic resonance from magnetic nano-dots.

  3. Magnetic properties of stainless steels at room and cryogenic temperatures

    International Nuclear Information System (INIS)

    The magnetic properties of ten types of ferritic and martensitic stainless steels have been measured at room temperature and at 77 K. The steel samples studied were in the annealed state as received from the manufacturer. Our room temperature measurements indicate significantly harder magnetic properties than those quoted in the ASM International Handbook, which studied fully annealed stainless steel samples. Despite having harder magnetic properties than fully annealed steels some of the as-received steels still display soft magnetic properties adequate for magnetic applications. The carbon content of the steels was found to affect the permeability and coercive force, with lower-carbon steels displaying significantly higher permeability and lower coercive force. The decrease in coercive force with reduced carbon content is attributed to fewer carbide inclusions which inhibit domain wall motion. Cooling to 77 K resulted in harder magnetic properties. Averaged over the ten steels tested the maximum permeability decreased by 8%, the coercive force increased by 14%, and the residual and saturation flux densities increased by 4% and 3%, respectively. The change in coercive force when cooled is comparable to the theoretical prediction for iron, based on a model of domain wall motion inhibited by inclusions. The modest changes of the magnetic properties indicate that the stainless steels can still be used in magnetic applications at very low temperatures.

  4. Process and magnetic properties of cold pressed Ne Fe B bonded magnets

    International Nuclear Information System (INIS)

    Bonded magnets are polymer composites based on a mixture of a hard magnetic powder and a polymer. This mixture is processed as a traditional powder metallurgy material, cold pressed, or like a thermoplastic material, by injection molding. The polymeric phase to a large extent determines the mechanical properties of the composite, while magnetic powder determines its magnetic properties. They are less expensive and easier to produce, specially in the case of high complexity parts. This paper presents the relationship between process variables and magnetic properties of cold pressed Nd Fe B bonded magnets produced from melt spun flakes mixed with thermosetting resins. The experiments were done using Statistical Design of Experiments. The variables investigates were: uniaxial compaction pressure, binder type; binder content; size of Nd Fe B particles; addition of lubricant; and addition of small quantities of magnetic additives, particles of ferrites, iron, or alnico. (author)

  5. Hydrothermal synthesis and magnetic properties of CuO hollow microspheres

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • CuO hollow microspheres were synthesized through hydrothermal route. • The possible growth mechanism was proposed according to the experimental results. • CuO hollow microspheres show an anomalous ferromagnetic behavior at 5 K and 300 K. - Abstract: In the present work, CuO hollow microspheres with the diameter about 2 μm were successfully synthesized through a facile hydrothermal method. The phase purity, morphologies and structure features of the as obtained products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy, respectively. It was found that reaction temperature, reaction time and different volume ratios of ethanol and distilled water played important roles on the morphologies of the obtained CuO hollow microspheres. The possible formation mechanism was also proposed according to the corresponding experimental results. The magnetic properties were investigated by superconducting quantum interference device, revealing that the CuO hollow microspheres exhibited an anomalous ferromagnetic behavior at 5 K and 300 K. At the same time, the origin of the ferromagnetism in CuO hollow microspheres was also discussed

  6. Viking magnetic properties investigation - Further results

    Science.gov (United States)

    Hargraves, R. B.; Collinson, D. W.; Arvidson, R. E.; Spitzer, C. R.

    1976-01-01

    The amounts of magnetic particles held on the reference test chart and backhoe magnets on lander 2 and lander 1 are comparable, indicating the presence of an estimated 3 to 7 percent by weight of relatively pure, strongly magnetic particles in the soil at the lander 2 sampling site. Preliminary spectrophotometric analysis of the material held on the backhoe magnets on lander 1 indicates that its reflectance characteristics are indistinguishable from material within a sampling trench with which it has been compared. The material on the RTC magnet shows a different spectrum, but it is suspected that the difference is the result of a reflectance contribution from the magnesium metal covering on the magnet. It is argued that the results indicate the presence, now or originally, of magnetite, which may be titaniferous.

  7. Viking magnetic properties investigation: further results.

    Science.gov (United States)

    Hargraves, R B; Collinson, D W; Arvidson, R E; Spitzer, C R

    1976-12-11

    The amounts of magnetic particles held on the reference test chart and backhoe magnets on lander 2 and lander 1 are comparable, indicating the presence of an estimated 3 to 7 percent by weight of relatively pure, strongly magnetic particles in the soil at the lander 2 sampling site. Preliminary spectrophotometric analysis of the material held on the backhoe magnets on lander 1 indicates that its reflectance characteristics are indistinguishable from material within a sampling trench with which it has been compared. The material on the RTC magnet shows a different spectrum, but it is suspected that the difference is the result of a reflectance contribution from the magnesium metal covering on the magnet. It is argued that the results indicate the presence, now or originally, of magnetite, which may be titaniferous. PMID:17797090

  8. Magnetic and Magneto-Optical Properties in Paramagnetic NdF3 Under High Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; LIU Gong-Qiang

    2005-01-01

    In this paper, we first theoretically report the magnetic and magneto-optical properties in paramagnetic media under high external magnetic field. Considering the action of the external magnetic field He and indirect exchange interaction Hv, the characteristic of the magnetic saturation and the property of the Faraday rotation to be nonlinear with external magnetic field are presented in paramagnetic NdF3. In terms of our theory, the indirect exchange interaction plays an important role in the magnetization M and the Faraday rotation θ in NdF3 under high external magnetic field. The theory is in good agreement with experimental results. On the other hand, a reasonable explanation for the temperature dependence of the ratio of the Verdet constant to the magnetic susceptibility V/x is obtained.

  9. Magnetic and magnetotransport properties of ultrathin La{}_{0.7}Ba{}_{0.3}MnO3 epitaxial films embedded in SrRuO3

    Science.gov (United States)

    Bern, F.; Ziese, M.; Vrejoiu, I.; Li, X.; van Aken, P. A.

    2016-05-01

    The structural, magnetic and magnetotransport properties of La{}0.7Ba{}0.3MnO3 layers interfaced with SrRuO3 layers were studied. High quality trilayers with coherent interfaces were fabricated by pulsed laser deposition. The thickness of the embedded La{}0.7Ba{}0.3MnO3 layer was varied between one and five unit cells, whereas the embedding SrRuO3 layers were kept at a constant thickness of three unit cells. In this embedded geometry La{}0.7Ba{}0.3MnO3 layers are ferromagnetic, even if only one unit cell thick. Magnetization and anomalous Hall effect curves show an antiferromagnetic coupling of the layers that leads to an intricate magnetic field dependence. When this is disentangled, it can be shown that the magnetic and transport properties are mainly dominated by the corresponding properties of the constituent materials.

  10. CeRh3B2: A ferromagnet with anomalously large Ce 5d spin and orbital magnetic moments

    International Nuclear Information System (INIS)

    We report a high-energy magnetic-Compton-scattering study performed on the ferromagnet CeRh3B2. This technique solely measures the electron spin magnetic moments. In contrast to a number of Ce intermetallics with nonmagnetic elements, the Ce 5d spin moment is found to be large and parallel to the Ce 4f spin moment. Therefore the Kondo effect does not play a key role for CeRh3B2. The inferred large Ce 5d orbital magnetic moment is a signature of the strong spin-orbit interaction for the Ce 5d band. copyright 1998 The American Physical Society

  11. Theory of the electronic and magnetic structure and transport properties of single molecule magnets

    OpenAIRE

    Rostamzadeh Renani, Fatemeh

    2013-01-01

    Developing electronic components at the molecular scale is the ultimate goal in molecular electronics. Because of their large magnetic anisotropy barriers and associated stable magnetic moments, single molecule magnets (SMMs) bring a new dimension to this field and also raise the possibility of molecular magnetic information storage and quantum computation. Therefore the transport properties of transistors based on individual SMMs are attracting considerable experimental and theoretical inter...

  12. Magnetic properties of Fe doped SiC crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kuryliszyn-Kudelska, I.; Dobrowolski, W. [Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, 02-668 Warsaw (Poland); Diduszko, R.; Tymicki, E. [Institute of Electronic Materials Technology, ul. Wolczynska 133, 01-919 Warsaw (Poland); Grasza, K. [Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, 02-668 Warsaw (Poland); Institute of Electronic Materials Technology, ul. Wolczynska 133, 01-919 Warsaw (Poland)

    2007-05-15

    In this paper we report on the crystal growth and magnetic as well as structural studies of SiC:Fe. SiC crystals were grown by Physical Vapor Transport method. We used Fe enriched source material to dope crystals. The magnetic properties were examined by AC/DC magnetometry. AC magnetic susceptibility as well as DC magnetization measurements revealed ferromagnetic type of magnetic ordering. The structural measurements using powder X-ray diffraction were performed. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Intrinsic and extrinsic magnetic properties of the naturally layered manganites

    International Nuclear Information System (INIS)

    Structural and magnetic properties of the two-layered Ruddlesden-Popper phase SrO(La1-xSrxMnO3)2 with x = 0.3--0.5 are highlighted. Intrinsic properties of these naturally layered manganites include a colossal magnetoresistance, a composition-dependent magnetic anisotropy, and almost no remanence. Above the Curie temperature there is a non-vanishing extrinsic magnetization attributed to intergrowths (stacking faults in the layered structure). These lattice imperfections consist of additional or missing manganite layers, as observed in transmission electron microscopy. Their role in influencing the properties of the host material is highlighted

  14. Magnetic and magnetothermal properties and the magnetic phase diagram of high purity single crystalline terbium along the easy magnetization direction

    International Nuclear Information System (INIS)

    The magnetic and magnetothermal properties of a high purity terbium single crystal have been re-investigated from 1.5 to 350 K in magnetic fields ranging from 0 to 75 kOe using magnetization, ac magnetic susceptibility and heat capacity measurements. The magnetic phase diagram has been refined by establishing a region of the fan-like phase broader than reported in the past, by locating a tricritical point at 226 K, and by a more accurate definition of the critical fields and temperatures associated with the magnetic phases observed in Tb. (paper)

  15. Magnetoresistive properties of nanostructured magnetic metals, manganites, and magnetic semiconductors

    Science.gov (United States)

    Solin, N. I.; Romashev, L. N.; Naumov, S. V.; Saranin, A. A.; Zotov, A. V.; Olyanich, D. A.; Kotlyar, V. G.; Utas, O. A.

    2016-02-01

    We consider methods for controlling magnetoresistive parameters of magnetic metal superlattices, manganites, and magnetic semiconductors. By reducing the thickness of ferromagnetic layers in superlattices (e.g., Fe layers in Fe/Cr superlattices), it is possible to form superparamagnetic clustered-layered nanostructures with a magnetoresistance weakly depending on the direction of the external magnetic field, which is very important for applications of such type of materials. Producing Mn vacancies and additionally annealing lanthanum manganites in the oxygen atmosphere, it is possible to increase their magnetoresistance by more than four orders of magnitude. By changing the thickness of p- n junction in the structure of ferromagnetic semiconductors, their magnetoresistance can be increased by 2-3 orders of magnitude.

  16. Synthesis and magnetic properties of Co-Zn magnetic fluid

    Energy Technology Data Exchange (ETDEWEB)

    Vaidyanathan, G. [Department of Physics, Pondicherry Engineering College, Pondicherry 605014 (India)], E-mail: gvn_pec@yahoo.com; Sendhilnathan, S. [Department of Physics, Sri Manakula Vinayagar Engineering College, Pondicherry 605107 (India)], E-mail: sendhil29@yahoo.co.in

    2008-03-15

    Co{sub 1-x}Zn{sub x}Fe{sub 2}O{sub 4} (with x varying from 0 to 0.7) nanoparticles to be used for ferrofluid preparation were prepared by chemical co-precipitation method. The fine particles were suitably dispersed in transformer oil using oleic acid as the surfactant. The magnetization (M{sub s}) and the size of the particles were measured at room temperature. The magnetization (M{sub s}) was found to decrease with the increase in zinc substitution. The magnetic particle size (D{sub m}) of the fluid was found to vary from 11.19 to 4.25 nm decreasing with the increase in zinc substitution.

  17. Hysteretic properties of magnetic composite microwires

    Czech Academy of Sciences Publication Activity Database

    Chizhik, A.; Stupakiewicz, A.; Zablotskyy, Vitaliy A.; Zhukov, A.; Maziewski, A.; Gonzalez, J.

    New York: Nova Science Publishers, 2014 - (Dias, J.), s. 43-57 ISBN 978-1-63321-336-4 Institutional support: RVO:68378271 Keywords : hysteresis * magnetic domains * microwires * magneto -optical Kerr effect * domain nucleation Subject RIV: BM - Solid Matter Physics ; Magnetism

  18. Viking magnetic properties experiment - Extended mission results

    Science.gov (United States)

    Hargraves, R. B.; Collinson, D. W.; Arvidson, R. E.; Cates, P. M.

    1979-01-01

    The backhoe magnets on Viking Lander (VL) 2 were successfully cleaned, followed by a test involving successive insertions of the cleaned backhoe into the surface. Rapid saturation of the magnets confirmed evidence from primary mission results that the magnetic mineral in the Martian surface is widely distributed, most probably in the form of composite particles of magnetic and nonmagnetic minerals. An image of the VL 2 backhoe taken via the X4 magnifying mirror demonstrates the fine-grained nature of the attracted magnetic material. The presence of maghemite and its occurrence as a pigment in, or a thin coating on, all mineral particles or as discrete, finely divided and widely distributed crystallites, are consistent with data from the inorganic analysis experiments and with laboratory simulations of results of the biology experiments on Mars.

  19. Magnetic properties of dense holographic QCD

    International Nuclear Information System (INIS)

    We investigate the Sakai-Sugimoto model at nonzero baryon chemical potential in a background magnetic field both in the confined phase and in the deconfined phase with restored chiral symmetry. In this case the 8-brane Chern-Simons term becomes important. In the confined phase it generates a gradient of the pseudoscalar 'pion', which carries a nonvanishing baryon charge. Above a critical value of the chemical potential there is a second-order phase transition to a mixed phase which includes also ordinary baryonic matter. However, at fixed baryon charge density the matter is purely pion-gradient above a critical magnetic field. In the deconfined chiral-symmetric phase at nonzero chemical potential the magnetic field induces an axial current. We also compute the magnetization of the baryonic matter and find that it is paramagnetic in all three phases but with nonlinear behavior at a large magnetic field.

  20. Magnetoresistance and Anomalous Hall Effect of InSb Doped with Mn

    Directory of Open Access Journals (Sweden)

    A.V. Kochura

    2013-12-01

    Full Text Available Transport properties of polycrystalline (In, MnSb samples are investigated. Behavior of the temperature and magnetic field dependencies of the resistivity, anomalous Hall coefficient and magnetoresistivity at low temperatures points out the influence of Mn complexes, Mn ions and nano- and microsizes MnSb precipitates on charge transport.

  1. Dielectric and Magnetic Properties in Relaxor Magnet LuFeCoO4

    Science.gov (United States)

    Soda, Minoru; Masuda, Takatsugu

    2016-03-01

    Dielectric and magnetic properties in the relaxor magnet LuFeCoO4 having a triangular lattice are studied by permittivity, magnetization, and neutron diffraction measurements. We found that LuFeCoO4 has the nuclear diffuse scattering induced by Polar Nanoregions (PNRs) where local polarizations in nanoregions are randomly oriented. Synchronized changes in PNRs and magnetic short-range order with decreasing temperature are observed, which reveal the existence of the strong coupling between dielectricity and magnetism. The coincidence of the correlation lengths of the nuclear atoms and spins in the crystallographic a-b plane at the onset temperature of two-dimensional magnetic order is confirmed, suggesting that the magnetic order develops inside the PNRs. With further decreasing temperature, the magnetic correlation extends beyond the domain wall of the crystal cluster in contrast with another relaxor magnet BiFeO3-1/3BaTiO3.

  2. Stress dependent vector magnetic properties in electrical steel

    International Nuclear Information System (INIS)

    The dependence of macroscopic magnetic properties on applied and residual stresses is promising for development of new magnetic non-destructive evaluation techniques in ferrous materials. The reliability of AC magnetometry, in determining the effect of strain on magnetic macroscopic parameters, is evaluated against scalar and vector Vibrating Sample Magnetometer measurements on strained electrical steel samples after unloading. Hysteresis loops have been measured at 0°, 30°, 45°, 60° and 90° to the direction of the applied stress. Vector magnetic properties reveal a stress-related anisotropy component, which increases with strain and deteriorates after fracture. The effect of residual stress on the saturation and remanent magnetization, as well as the differential susceptibility, is discussed with respect to data from AC magnetometry at 0.1 Hz. The results of the latter are representative of the magnetic configuration of the material under test and make it a promising candidate for NDE applications in steels

  3. Neutrino Mass, Dark Matter and Anomalous Magnetic Moment of Muon in a $U(1)_{L_{\\mu}-L_{\\tau}}$ Model

    CERN Document Server

    Biswas, Anirban; Khan, Sarif

    2016-01-01

    The observation of neutrino masses, mixing and the existence of dark matter are amongst the most important signatures of physics beyond the Standard Model (SM). In this paper, we propose to extend the SM by a local $L_\\mu - L_\\tau$ gauge symmetry, two additional complex scalars and three right-handed neutrinos. The $L_\\mu - L_\\tau$ gauge symmetry is broken spontaneously when one of the scalars acquires a vacuum expectation value. The $L_\\mu - L_\\tau$ gauge symmetry is known to be anomaly free and can explain the beyond SM measurement of the anomalous muon $({\\rm g-2})$ through additional contribution arising from the extra $Z_{\\mu\\tau}$ mediated diagram. Small neutrino masses are explained naturally through the Type-I seesaw mechanism, while the mixing angles are predicted to be in their observed ranges due to the broken $L_\\mu-L_\\tau$ symmetry. The second complex scalar is shown to be stable and becomes the dark matter candidate in our model. We show that while the $Z_{\\mu\\tau}$ portal is ineffective for the...

  4. Magnetic properties of a spin-3 Chromium condensate

    OpenAIRE

    He, Liang; Yi, Su

    2009-01-01

    We study the ground state properties of a spin-3 Cr condensate subject to an external magnetic field by numerically solving the Gross-Piteavskii equations. We show that the widely adopted single-mode approximation is invalid under a finite magnetic field. In particular, a phase separation like behavior may be induced by the magnetic field. We also point out the possible origin of the phase separation phenomenon.

  5. Measurement of magnetic properties of confined compact toroid plasma (spheromak)

    International Nuclear Information System (INIS)

    The theoretical aspect of the spheromak is described in this paper. The MS machine hardware will be explored along with the formation scheme and diagnostic systems. The magnetic pickup probes, their calibration procedures and the data analysis methods will be discussed. Observations from the probe measurements and magnetic properties of the MS spheromak are considered. The axisymmetric Grad-Shafranov equilibrium code calculations are presented and compared with the measurements. Magnetic helicity and its correlation with the experimental observations is described

  6. Processing, properties and some novel applications of magnetic nanoparticles

    Indian Academy of Sciences (India)

    D Bahadur; J Giri; Bibhuti B Nayak; T Sriharsha; P Pradhan; N K Prasad; K C Barick; R D Ambashta

    2005-10-01

    Magnetic nanoparticles have been prepared by various soft chemical methods including self-assembly. The bare or surface-modified particles find applications in areas such as hyperthermia treatment of cancer and magnetic field-assisted radioactive chemical separation. We present here some of the salient features of processing of nanostructured magnetic materials of different sizes and shapes, their properties and some possible applications. The materials studied included metals, metal-ceramic composites, and ferrites.

  7. Magnetic properties of plutonium and Pu compounds

    Czech Academy of Sciences Publication Activity Database

    Havela, L.; Shick, Alexander; Gouder, T.

    2009-01-01

    Roč. 105, č. 7 (2009), 07E130/1-07E130/3. ISSN 0021-8979. [Annual Conference on Magnetism and Magnetic Materials /53./. Austin, 11.11.2008-14.11. 2008] R&D Projects: GA ČR GA202/07/0644; GA ČR GA202/06/0178 Institutional research plan: CEZ:AV0Z10100520 Keywords : electronic structure * electron correlations * photoemission Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.072, year: 2009

  8. Enhanced magnetic-field-induced optical properties of nanostructured magnetic fluids by doping nematic liquid crystals

    Science.gov (United States)

    Wang, Xiang; Pu, Shengli; Ji, Hongzhu; Yu, Guojun

    2012-05-01

    Ferronematic materials composed of 4-cyano-4'-pentylbiphenyl nematic liquid crystal and oil-based Fe3O4 magnetic fluid were prepared using ultrasonic agitation. The birefringence (Δ n) and figure of merit of optical properties ( Q = Δ n/α, where α is the extinction coefficient) of pure magnetic fluids and the as-prepared ferronematic materials were examined and compared. The figure of merit of optical properties weighs the birefringence and extinction of the materials and is more appropriate to evaluate their optical properties. Similar magnetic-field- and magnetic-particle-concentration-dependent properties of birefringence and figure of merit of optical properties were obtained for the pure magnetic fluids and the ferronematic materials. For the ferronematic materials, the values of Q increase with the volume fractions of nematic liquid crystal under certain fixed field strength and are larger than those of their corresponding pure magnetic fluids at high field region. In addition, the enhancement of Q value increases monotonously with the magnetic field and becomes remarkable when the applied magnetic field is beyond 50 mT. The maximum relative enhanced value of Q R exceeds 6.8% in our experiments. The results of this work may conduce to extend the pragmatic applications of nanostructured magnetic fluids in optical field.

  9. Enhanced magnetic-field-induced optical properties of nanostructured magnetic fluids by doping nematic liquid crystals.

    Science.gov (United States)

    Wang, Xiang; Pu, Shengli; Ji, Hongzhu; Yu, Guojun

    2012-01-01

    Ferronematic materials composed of 4-cyano-4'-pentylbiphenyl nematic liquid crystal and oil-based Fe3O4 magnetic fluid were prepared using ultrasonic agitation. The birefringence (Δn) and figure of merit of optical properties (Q = Δn/α, where α is the extinction coefficient) of pure magnetic fluids and the as-prepared ferronematic materials were examined and compared. The figure of merit of optical properties weighs the birefringence and extinction of the materials and is more appropriate to evaluate their optical properties. Similar magnetic-field- and magnetic-particle-concentration-dependent properties of birefringence and figure of merit of optical properties were obtained for the pure magnetic fluids and the ferronematic materials. For the ferronematic materials, the values of Q increase with the volume fractions of nematic liquid crystal under certain fixed field strength and are larger than those of their corresponding pure magnetic fluids at high field region. In addition, the enhancement of Q value increases monotonously with the magnetic field and becomes remarkable when the applied magnetic field is beyond 50 mT. The maximum relative enhanced value of QR exceeds 6.8% in our experiments. The results of this work may conduce to extend the pragmatic applications of nanostructured magnetic fluids in optical field. PMID:22587542

  10. Magnetic properties of Pr-Fe-Co-B bonded HDDR magnets with alloying additions

    Directory of Open Access Journals (Sweden)

    Eguiberto Galego

    2007-09-01

    Full Text Available Microstructures and magnetic properties of Pr-Fe-Co-B bonded magnets were investigated. The magnets can be represented by the formulae, Pr14Fe63.9Co16B6M 0.1 (M = Ti, V, Cr, Ni, Zr, Nb or Mo, Pr14Fe63.8Co16B6Nb 0.1T0.1 (T/= Al, Si, P, Cu or Ga and Pr14Fe63.6Co16B6Nb 0.1R0.3 (R = Gd, Tb or Dy. The effects of additions on the magnetic properties of PrFeCoB-based magnets have been studied. Magnetically hard powders have been produced from homogenised alloys using the hydrogenation, disproportionation, desorption and recombination (HDDR process. The HDDR powders were isostatically pressed and bonded with cyanoacrylate adhesive to form permanent magnets.

  11. Magnetic and structural properties of Co-Pt perpendicular recording media with large magnetic anisotropy

    International Nuclear Information System (INIS)

    A Co-Pt film with large magnetic anisotropy at room temperature deposition was studied in terms of magnetic and structural properties. A high Ar gas pressure deposition of the Co-Pt film with a high crystal orientation could realize excellent magnetic properties such as a high perpendicular coercivity and a large magnetic anisotropy. This deposition technique of the Co-Pt film could form physically isolated and magnetically weak coupled grains. Magnetization reversal mechanism of the Co-Pt film deposited at a high Ar gas pressure was revealed to be a rotational mode, while the Co-Pt film deposited at low gas pressure seemed to be a magnetic domain wall motion

  12. About chiral models of dense matter and its magnetic properties

    International Nuclear Information System (INIS)

    The chiral models of dense nucleon matter are discussed. The quark matter with broken chiral symmetry is described. The magnetic properties of dense matter are presented and conclusions are given. 37 refs. (A.S.)

  13. Microstructure characterization and magnetic properties of nano structured materials

    Energy Technology Data Exchange (ETDEWEB)

    Sun, X.C

    2000-07-01

    The present thesis deals with the unique microstructural properties and their novel magnetic properties of core-shell Ni-Ce nano composite particles, carbon encapsulated Fe, Co, and Ni nanoparticles and the nano crystallization behavior of typical ferromagnetic Fe{sub 78}Si{sub 9}B{sub 13} ribbons. These properties have intensively been investigated by high resolution transmission electron microscopy (HREM), X-ray diffraction (XRD), scanning electron microscopy (Sem), X-ray energy dispersive spectroscopy [eds.]; selected area electron diffraction pattern (SAED), Ft-IR, differential scanning calorimeter (DSC). In addition, magnetic moments measurements at different temperatures and applied fields have been performed by transmission Moessbauer spectroscopy, superconducting quantum interference device magnetometer (SQUID), and vibrating sample magnetometer (VSM). The present studies may provide the insights for the better understanding of the correlation between the unique microstructure and novel magnetic properties for several magnetic nano structured materials. (Author)

  14. Evaluating the effect of magnetocaloric properties on magnetic refrigeration performance

    DEFF Research Database (Denmark)

    Engelbrecht, Kurt; Bahl, Christian Robert Haffenden

    2010-01-01

    Active magnetic regenerator (AMR) refrigerators represent an alternative to vapor compression technology that relies on the magnetocaloric effect in a solid refrigerant. Magnetocaloric materials are in development and properties are reported regularly. Recently, there has been an emphasis on...

  15. Microstructure characterization and magnetic properties of nano structured materials

    International Nuclear Information System (INIS)

    The present thesis deals with the unique microstructural properties and their novel magnetic properties of core-shell Ni-Ce nano composite particles, carbon encapsulated Fe, Co, and Ni nanoparticles and the nano crystallization behavior of typical ferromagnetic Fe78Si9B13 ribbons. These properties have intensively been investigated by high resolution transmission electron microscopy (HREM), X-ray diffraction (XRD), scanning electron microscopy (Sem), X-ray energy dispersive spectroscopy (Eds.); selected area electron diffraction pattern (SAED), Ft-IR, differential scanning calorimeter (DSC). In addition, magnetic moments measurements at different temperatures and applied fields have been performed by transmission Moessbauer spectroscopy, superconducting quantum interference device magnetometer (SQUID), and vibrating sample magnetometer (VSM). The present studies may provide the insights for the better understanding of the correlation between the unique microstructure and novel magnetic properties for several magnetic nano structured materials. (Author)

  16. Transport properties and anomalous fatigue effect of Ag/Bi0.9La0.1FeO3/La0.7Sr0.3MnO3 heterostructures

    International Nuclear Information System (INIS)

    The transport properties and fatigue effect of Ag/Bi0.9La0.1FeO3/La0.7Sr0.3MnO3 heterostructures are described. By examining the I—V curves, an anomalous fatigue effect was found and its influences on resistive states were studied. I—V curves combined with C—f spectra were used to directly analyze the transport properties and fatigue effect. Compared to the first I—V cycle state, this structure shows more than one order increase of resistance after 100 cycles of “I—V curve training”. The redistribution of oxygen vacancies in the depletion layer of Ag/Bi0.9La0.1FeO3 is believed to be responsible for the different resistance mechanisms and tenfold magnitude drop in resistance. The resistive switching is understood to be caused by electric field—induced carrier trapping and detrapping, which changes the depletion layer thickness at the Ag/Bi0.9La0.1FeO3 interface. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  17. Magnetic properties of Fe1-xMnx/Fe nanocomposites

    DEFF Research Database (Denmark)

    Anhøj, Thomas Aarøe; Jacobsen, Claus Schelde; Mørup, Steen

    2004-01-01

    We have prepared nanocomposites of mixtures of ferromagnetic alpha-Fe and antiferromagnetic gamma-Fe50Mn50 nanoparticles, and studied their magnetic and structural properties by magnetization measurements, Mössbauer spectroscopy, and x-ray diffraction. A sample consisting of a 1:1 mixture of the...

  18. Magnetic properties and spin kinetics in Kondo lattices

    Directory of Open Access Journals (Sweden)

    S.I. Belov, A.S. Kutuzov

    2015-12-01

    Full Text Available We present a theoretical model to describe unusual properties of Kondo lattices. The influence of the Kondo effect on the static magnetic susceptibility and electron spin resonance (ESR parameters is studied in a simple molecular field approximation together with a scaling perturbative approach. Theoretical expressions well agree with the ESR and static magnetic susceptibility experimental data.

  19. Magnetic Properties of Nanometer-sized Crystalline and Amorphous Particles

    DEFF Research Database (Denmark)

    Mørup, Steen; Bødker, Franz; Hansen, Mikkel Fougt; Jiang, Jianzhong

    Amorphous transition metal-metalloid alloy particles can be prepared by chemical preparation techniques. We discuss the preparation of transition metal-boron and iron-carbon particles and their magnetic properties. Nanometer-sized particles of both crystalline and amorphous magnetic materials are...

  20. Electronic and magnetic properties of Am and Cm

    Energy Technology Data Exchange (ETDEWEB)

    Edelstein, N.

    1985-02-01

    A review of the present status of the analyses of the optical spectra of Am and Cm in various oxidation states is given. From these analyses, the magnetic properties of the ground states of these ions can be determined. These predicted values are compared with the various magnetic measurements available.

  1. Magnetic properties of biomineral nanoparticles produced by Klebsiella oxytoca bacteria

    International Nuclear Information System (INIS)

    Ferrihydrite nanoparticles of the size 2-5 nm produced by environmental Klebsiella oxytoca bacteria through biomineralization of iron salt solutions possess unique magnetic properties. Namely, in these grains there co-exist the antiferromagnetic order inherent to bulk ferrihydrite and the permanent magnetic moment caused by the decompensation of the nanoparticle spin sublattices. The magnetic susceptibility of the particles enhanced by the superantiferromagnetism effect, together with the presence of magnetic moment independent of the external field, provides the possibility of magnetic manipulation of these natural objects. Thereby a way to their use in nanomedicine and biotechnologies opens. In the present work measurement results on magnetization of the two main crystallization phases of ferrihydrite produced by Klebsiella oxytoca are reported and theoretical analysis of these data is performed. This enables us to evaluate the magnetic parameters of real biomineral nanoparticles

  2. Size dependent magnetic properties of iron oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, Jhunu; Haik, Yousef. E-mail: haik@eng.fsu.edu; Chen, C.-J.Ching-Jen

    2003-02-01

    {gamma}Fe{sub 2}O{sub 3} nanoparticles has been synthesized by a combination of chemical and ultrasonication procedure and further stabilized with surfactant. Their magnetic properties are compared with the different fractions (10-12, 20-30, 100-150 nm) of commercially available iron oxide. The sizes obtained from the scanning transmission electron micrographs are correlated with the magnetic properties of the particles.

  3. Electronic and magnetic properties of ruthenocuprates

    International Nuclear Information System (INIS)

    We report on X-ray photoemission of core levels, valence band studies using angle-integrated photoemission, and magnetization measurements of ruthenocuprate and SrRuO3 polycrystalline samples. The data indicate that the RuO2 planes are the source of the energetics of the magnetic ordering. We also find that adding hydrogen leads to changes in the many-body response on both the CuO2 and EuO planes. (orig.)

  4. Magnetic properties of FeSe superconductor

    OpenAIRE

    Grechnev, G. E.; Panfilov, A.S.; Desnenko, V. A.; Fedorchenko, A. V.; Gnatchenko, S. L.; Chareev, D. A.; Volkova, O. S.; A.N. Vasiliev

    2012-01-01

    A detailed magnetization study for the novel FeSe superconductor is carried out to investigate the behavior of the intrinsic magnetic susceptibility $\\chi$ in the normal state with temperature and under hydrostatic pressure. The temperature dependencies of $\\chi$ and its anisotropy $\\Delta \\chi=\\chi_{|}-\\chi_{\\bot}$ are measured for FeSe single crystals in the temperature range 4.2-300 K, and a substantial growth of susceptibility with temperature is revealed. The observed anisotropy $\\Delta ...

  5. Magnetic-Coupling Properties in Polycrystals

    OpenAIRE

    Fuentes, L. (Lidia)

    1998-01-01

    Quantitative Texture Analysis procedures for characterisation of polycrystal pyromagnetic, magnetoelectric and piezomagnetic effects are proposed. The considered phenomena link the thermic, electric and elastic subsystems of a given body with its magnetic subsystem. Brief resumes of required thermodynamic, tensor and texture methods are given. Peculiar behaviour of magnetic (axial-tensor) quantities under colour symmetry operations is described. The use of Neumann's Principle in the investiga...

  6. Magnetic properties of bimetallic nanoislands deposited on Pt(111)

    Energy Technology Data Exchange (ETDEWEB)

    Bornemann, Sven; Minar, Jan; Mankovsky, Sergey; Ebert, Hubert [Department Chemie und Biochemie, LMU Muenchen, 81377 Muenchen (Germany); Ouazi, Safia; Rusponi, Stefano; Brune, Harald [Institute of Condensed Matter Physics, EPF Lausanne (Switzerland); Staunton, Julie B. [Department of Physics, University of Warwick (United Kingdom)

    2010-07-01

    In recent years, magnetic nanostructures on surfaces have been the subject of intense research activities which are driven by fundamental as well as practical interests. One of the central questions for future applications is how the magnetic properties like the magnetic anisotropy evolve in-between single magnetic adatoms and submonolayer magnetic particle arrays. Experimentalists have succeeded in assembling surface supported single domain particles where the magnetic moments of all atoms form a so-called macrospin and it is commonly believed that the special magnetic characteristics of such structures are mainly due to their exposed low-coordinated edge atoms. For some of these novel systems, however, unexpected low anisotropies or reduced magnetic moments are observed which makes it difficult to find promising candidates for real life technical applications. To support these experimental efforts the fully relativistic spin-polarized KKR method has been applied to investigate the influence of spin-orbit coupling on the magnetic properties of various FeCo nanostructures deposited on Pt(111). The discussion focuses on interface and alloy contributions to the magnetic anisotropy in these systems.

  7. Magnetic properties of the magnetic hybrid membranes based on various polymer matrices and inorganic fillers

    Energy Technology Data Exchange (ETDEWEB)

    Rybak, Aleksandra, E-mail: Aleksandra.Rybak@polsl.pl [Department of Physical Chemistry and Technology of Polymers, Faculty of Chemistry, Silesian University of Technology, Strzody 9, 44-100 Gliwice (Poland); Kaszuwara, Waldemar [Faculty of Materials Science and Engineering, Warsaw University of Technology, Woloska 141, 02-507 Warszawa (Poland)

    2015-11-05

    Magnetic hybrid membranes based on ethylcellulose (EC), poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and various magnetic praseodymium and neodymium powder microparticles as fillers were obtained. Permeability, diffusion and sorption coefficients of O{sub 2}, N{sub 2} and synthetic air components were estimated for homogeneous and heterogeneous membranes using the Time Lag method based on constant pressure permeation technique. The microstructure studies and the phase analysis of magnetic membranes were also performed using SEM and XRD. The influence of magnetic parameters, like coercivity, remanence and saturation magnetization of created membranes on the gas transport properties was studied. The results showed that their coercivity depended on composition and microstructure of the magnetic powder. On the other hand, remanence and saturation magnetization increased with the increase of the powder addition in the membrane. It was found that the magnetic membrane's gas transport properties were improved with the increase of membrane's remanence, saturation magnetization and magnetic particle filling. The decrease in powder particle size and associated increase of the membrane's coercivity also positively influenced the gas transport and separation properties of investigated membranes. It was observed that the magnetic ethylcellulose and poly(2,6-dimethyl-1,4-phenylene oxide) membranes had higher gas permeability, while their permselectivity and solubility coefficient values were rather maintained or slightly increased. The results also showed that the magnetic powder content enhanced significantly gas diffusivity in EC and PPO membranes. It was also analyzed the dependence of the drift coefficient w on the magnetic parameters of investigated membranes. The correlation between the membrane selectivity, permeability and magnetic properties with their XRD characteristics was stated. - Highlights: • Membrane's production consisting of EC or PPO

  8. Magnetic properties of the magnetic hybrid membranes based on various polymer matrices and inorganic fillers

    International Nuclear Information System (INIS)

    Magnetic hybrid membranes based on ethylcellulose (EC), poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and various magnetic praseodymium and neodymium powder microparticles as fillers were obtained. Permeability, diffusion and sorption coefficients of O2, N2 and synthetic air components were estimated for homogeneous and heterogeneous membranes using the Time Lag method based on constant pressure permeation technique. The microstructure studies and the phase analysis of magnetic membranes were also performed using SEM and XRD. The influence of magnetic parameters, like coercivity, remanence and saturation magnetization of created membranes on the gas transport properties was studied. The results showed that their coercivity depended on composition and microstructure of the magnetic powder. On the other hand, remanence and saturation magnetization increased with the increase of the powder addition in the membrane. It was found that the magnetic membrane's gas transport properties were improved with the increase of membrane's remanence, saturation magnetization and magnetic particle filling. The decrease in powder particle size and associated increase of the membrane's coercivity also positively influenced the gas transport and separation properties of investigated membranes. It was observed that the magnetic ethylcellulose and poly(2,6-dimethyl-1,4-phenylene oxide) membranes had higher gas permeability, while their permselectivity and solubility coefficient values were rather maintained or slightly increased. The results also showed that the magnetic powder content enhanced significantly gas diffusivity in EC and PPO membranes. It was also analyzed the dependence of the drift coefficient w on the magnetic parameters of investigated membranes. The correlation between the membrane selectivity, permeability and magnetic properties with their XRD characteristics was stated. - Highlights: • Membrane's production consisting of EC or PPO polymers and

  9. The effects of magnetic nanoparticle properties on magnetic fluid hyperthermia

    Science.gov (United States)

    Kappiyoor, Ravi; Liangruksa, Monrudee; Ganguly, Ranjan; Puri, Ishwar K.

    2010-11-01

    Magnetic fluid hyperthermia (MFH) is a noninvasive treatment that destroys cancer cells by heating a ferrofluid-impregnated malignant tissue with an ac magnetic field while causing minimal damage to the surrounding healthy tissue. The strength of the magnetic field must be sufficient to induce hyperthermia but it is also limited by the human ability to safely withstand it. The ferrofluid material used for hyperthermia should be one that is readily produced and is nontoxic while providing sufficient heating. We examine six materials that have been considered as candidates for MFH use. Examining the heating produced by nanoparticles of these materials, barium-ferrite and cobalt-ferrite are unable to produce sufficient MFH heating, that from iron-cobalt occurs at a far too rapid rate to be safe, while fcc iron-platinum, magnetite, and maghemite are all capable of producing stable controlled heating. We simulate the heating of ferrofluid-loaded tumors containing nanoparticles of the latter three materials to determine their effects on tumor tissue. These materials are viable MFH candidates since they can produce significant heating at the tumor center yet maintain the surrounding healthy tissue interface at a relatively safe temperature.

  10. Large batch recycling of waste Nd–Fe–B magnets to manufacture sintered magnets with improved magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.T. [College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China); Yue, M., E-mail: yueming@bjut.edu.cn [College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China); Liu, W.Q. [College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China); Li, X.L.; Yi, X.F.; Huang, X.L. [Anhui Province Key Laboratories of Rare Earth Permanent Magnet Materials, Anhui, 231500 (China); Anhui Earth-panda Advance Magnetic Material Co., Ltd., Anhui, 231500 (China); Zhang, D.T. [College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China); Chen, J.W. [Anhui Province Key Laboratories of Rare Earth Permanent Magnet Materials, Anhui, 231500 (China); Anhui Earth-panda Advance Magnetic Material Co., Ltd., Anhui, 231500 (China)

    2015-11-15

    The waste Nd–Fe–B sintered magnets up to 500 kg per batch were recycled to manufacture anisotropic sintered magnets by combination of hydrogen decrepitation (HD) and alloying technique. Magnetic properties and thermal stability of both the waste magnets and recycled magnets were investigated. The recycled magnet exhibits magnetic properties with remanence (B{sub r}) of 12.38 kGs, coercivity (H{sub ci}) of 24.89 kOe, and maximum energy product [(BH){sub max}] of 36.51 MGOe, respectively, which restores 99.20% of B{sub r}, 105.65% of H{sub ci}, and 98.65% of (BH){sub max} of the waste magnets, respectively. The volume fraction of Nd-rich phase in the recycled magnets is about 10.1 vol.%, which is bigger than that of the waste magnets due to the additive of Nd{sub 3}PrFe{sub 14}B alloy containing more rare earth. The remanence temperature coefficient (α) and coercivity temperature coefficient (β) of the recycled magnets are −0.1155%/K and −0.5099%/K in the range of 288–423 K, respectively, which are comparative to those of the waste magnets. - Highlights: • Large batch recycling of waste Nd–Fe–B sintered magnets were performed. • The recycled magnet restores 99.20% of B{sub r}, 105.65% of H{sub ci} and 98.65% of (BH){sub max} of the magnet. • The recycled magnets bears bigger volume fraction and better distribution of Nd-rich phase. • The recycled magnets exhibit similar temperature coefficients and maximum working temperature.

  11. Large batch recycling of waste Nd–Fe–B magnets to manufacture sintered magnets with improved magnetic properties

    International Nuclear Information System (INIS)

    The waste Nd–Fe–B sintered magnets up to 500 kg per batch were recycled to manufacture anisotropic sintered magnets by combination of hydrogen decrepitation (HD) and alloying technique. Magnetic properties and thermal stability of both the waste magnets and recycled magnets were investigated. The recycled magnet exhibits magnetic properties with remanence (Br) of 12.38 kGs, coercivity (Hci) of 24.89 kOe, and maximum energy product [(BH)max] of 36.51 MGOe, respectively, which restores 99.20% of Br, 105.65% of Hci, and 98.65% of (BH)max of the waste magnets, respectively. The volume fraction of Nd-rich phase in the recycled magnets is about 10.1 vol.%, which is bigger than that of the waste magnets due to the additive of Nd3PrFe14B alloy containing more rare earth. The remanence temperature coefficient (α) and coercivity temperature coefficient (β) of the recycled magnets are −0.1155%/K and −0.5099%/K in the range of 288–423 K, respectively, which are comparative to those of the waste magnets. - Highlights: • Large batch recycling of waste Nd–Fe–B sintered magnets were performed. • The recycled magnet restores 99.20% of Br, 105.65% of Hci and 98.65% of (BH)max of the magnet. • The recycled magnets bears bigger volume fraction and better distribution of Nd-rich phase. • The recycled magnets exhibit similar temperature coefficients and maximum working temperature

  12. Optical/near-infrared polarization survey of Sh 2-29: Magnetic fields, dense cloud fragmentations, and anomalous dust grain sizes

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Fábio P.; Franco, Gabriel A. P.; Reis, Wilson [Departamento de Física, ICEx, UFMG, Caixa Postal 702, 30.123-970 Belo Horizote, MG (Brazil); Roman-Lopes, Alexandre [Departamento de Fisica-Universidad de La Serena, Cisternas 1200, La Serena (Chile); Román-Zúñiga, Carlos G., E-mail: fabiops@fisica.ufmg.br, E-mail: franco@fisica.ufmg.br, E-mail: wilsonr@fisica.ufmg.br, E-mail: roman@dfuls.cl, E-mail: croman@astrosen.unam.mx [Instituto de Astronomía-Universidad Nacional Autónoma de México, Unidad Académica en Ensenada, Ensenada BC 22860 (Mexico)

    2014-03-01

    Sh 2-29 is a conspicuous star-forming region marked by the presence of massive embedded stars as well as several notable interstellar structures. In this research, our goals were to determine the role of magnetic fields and to study the size distribution of interstellar dust particles within this turbulent environment. We have used a set of optical and near-infrared polarimetric data obtained at OPD/LNA (Brazil) and CTIO (Chile), correlated with extinction maps, Two Micron All Sky Survey data, and images from the Digitized Sky Survey and Spitzer. The region's most striking feature is a swept out interstellar cavity whose polarimetric maps indicate that magnetic field lines were dragged outward, piling up along its borders. This led to a higher magnetic strength value (≈400 μG) and an abrupt increase in polarization degree, probably due to an enhancement in alignment efficiency. Furthermore, dense cloud fragmentations with peak A{sub V} between 20 and 37 mag were probably triggered by its expansion. The presence of 24 μm point-like sources indicates possible newborn stars inside this dense environment. A statistical analysis of the angular dispersion function revealed areas where field lines are aligned in a well-ordered pattern, seemingly due to compression effects from the H II region expansion. Finally, Serkowski function fits were used to study the ratio of the total-to-selective extinction, revealing a dual population of anomalous grain particle sizes. This trend suggests that both effects of coagulation and fragmentation of interstellar grains are present in the region.

  13. Optical/near-infrared polarization survey of Sh 2-29: Magnetic fields, dense cloud fragmentations, and anomalous dust grain sizes

    International Nuclear Information System (INIS)

    Sh 2-29 is a conspicuous star-forming region marked by the presence of massive embedded stars as well as several notable interstellar structures. In this research, our goals were to determine the role of magnetic fields and to study the size distribution of interstellar dust particles within this turbulent environment. We have used a set of optical and near-infrared polarimetric data obtained at OPD/LNA (Brazil) and CTIO (Chile), correlated with extinction maps, Two Micron All Sky Survey data, and images from the Digitized Sky Survey and Spitzer. The region's most striking feature is a swept out interstellar cavity whose polarimetric maps indicate that magnetic field lines were dragged outward, piling up along its borders. This led to a higher magnetic strength value (≈400 μG) and an abrupt increase in polarization degree, probably due to an enhancement in alignment efficiency. Furthermore, dense cloud fragmentations with peak AV between 20 and 37 mag were probably triggered by its expansion. The presence of 24 μm point-like sources indicates possible newborn stars inside this dense environment. A statistical analysis of the angular dispersion function revealed areas where field lines are aligned in a well-ordered pattern, seemingly due to compression effects from the H II region expansion. Finally, Serkowski function fits were used to study the ratio of the total-to-selective extinction, revealing a dual population of anomalous grain particle sizes. This trend suggests that both effects of coagulation and fragmentation of interstellar grains are present in the region.

  14. Electrical Properties of Nanostructured Magnetic Colloid and Influence of Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    PU Sheng-Li; CHEN Xian-Feng; DI Zi-Yun; GENG Tao; XIA Yu-Xing

    2007-01-01

    We investigate the electrical properties of the nanostructured magnetic colloid without and with magnetic Held. The competition between the directional motion of the charged magnetic nanoparticles and other minor nonmagnetic impurities (also small amount of ions) under applied voltage and their random orientation due to thermal activation is implemented to elaborate the electrically conduction mechanism under zero magnetic Geld. Two equivalent electric circuits are employed for explaining the charging and discharging processes. The tunnelling conduction mechanism upon application of externally magnetic field may exist in the nanostructured magnetic colloid. The alternation of the two conduction mechanisms accounts for the current spikes when the magnetic field is switched on or off. This work presents the peculiar electrical phenomena of the magnetically colloidal system.

  15. Influence Of Nanoparticles Diameter On Structural Properties Of Magnetic Fluid In Magnetic Field

    Science.gov (United States)

    Kúdelčík, Jozef; Bury, Peter; Hardoň, Štefan; Kopčanský, Peter; Timko, Milan

    2015-07-01

    The properties of magnetic fluids depend on the nanoparticle diameter, their concentration and the carrier liquid. The structural changes in magnetic fluids with different nanoparticle diameter based on transformer oils TECHNOL and MOGUL under the effect of a magnetic field and temperature were studied by acoustic spectroscopy. At a linear and jump changes of the magnetic field at various temperatures a continuous change was observed of acoustic attenuation caused by aggregation of the magnetic nanoparticles to structures. From the anisotropy of acoustic attenuation and using the Taketomi theory the basic parameters of the structures are calculated and the impact of nanoparticle diameters on the size of structures is confirmed.

  16. Magnetic Properties of Iron Clusters in Silver

    Energy Technology Data Exchange (ETDEWEB)

    Elzain, M., E-mail: elzain@squ.edu.om; Al Rawas, A.; Yousif, A.; Gismelseed, A.; Rais, A.; Al-Omari, I.; Bouziane, K. [College of Science, Department of Physics (Oman); Widatallah, H. [Khartoum University, Department of Physics, Faculty of Science (Sudan)

    2004-12-15

    The discrete variational method is used to study the effect of interactions of iron impurities on the magnetic moments, hyperfine fields and isomer shifts at iron sites in silver. We study small clusters of iron atoms as they grow to form FCC phase that is coherent with the silver lattice. The effects of the lattice relaxation and the ferromagnetic and antiferromagnetic couplings are also considered. When Fe atoms congregate around a central Fe atom in an FCC arrangement under ferromagnetic coupling, the local magnetic moment and the contact charge density at the central atom hardly change as the cluster builds up, whereas the hyperfine field increases asymptotically as the number of Fe nearest neighbors increases. Introduction of antiferromagnetic coupling has minor effect on the local magnetic moments and isomer shifts, however it produces large reduction in the hyperfine field. The lattice relaxation of the surrounding Fe atoms towards a BCC phase around a central Fe atom leads to reduction in the magnetic moment accompanied by increase in the magnetic hyperfine field.

  17. Magnetic properties of nanostructured CuFe2O4

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Goya, G.F.; Rechenberg, H.R.

    1999-01-01

    The structural evolution and magnetic properties of nanostructured copper ferrite, CuFe2O4, have been investigated by X-ray diffraction, Mossbauer spectroscopy, and magnetization measurements. Nanometre-sized CuFe2O4 particles with a partially inverted spinel structure were synthesized by high...... size while the coercive force, shift of the hysteresis loop, magnetic hardness, and saturation magnetization at 4.2 K increase with decreasing average grain size. At 295 K the coercive-field dependence on the average grain size is described, with particles showing superparamagnetic relaxation effects...

  18. Thermal to electricity conversion using thermal magnetic properties

    Science.gov (United States)

    West, Phillip B [Idaho Falls, ID; Svoboda, John [Idaho Falls, ID

    2010-04-27

    A system for the generation of Electricity from Thermal Energy using the thermal magnetic properties of a Ferromagnetic, Electrically Conductive Material (FECM) in one or more Magnetic Fields. A FECM is exposed to one or more Magnetic Fields. Thermal Energy is applied to a portion of the FECM heating the FECM above its Curie Point. The FECM, now partially paramagnetic, moves under the force of the one or more Magnetic Fields. The movement of the FECM induces an electrical current through the FECM, generating Electricity.

  19. Integrated On-line Instrumentation System of Magnetic Properties Measurement

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A portable microcomputer-controlled inspection system has been developed for detection of mag netic properties of soft magnetic materials. It incorporates custom designed software for control of the magnetic field during operation such as demagnetization, field sweeping, and for data logging and analysis. Results are recorded using a 12-bit analog to digital converter and are then stored on disk. The magnetic hysteresis loop and Barkhausen noise data can be converted into important magnetic parameters:, coecivity, remanence, and hysteresis loss, Barkhausen ampli tude, and Barkhausen noise energy. This system incorporated with the magnetostriction, and magnetoacoustic emission, is then related with the nondestructive detection of material degra dation.

  20. Theoretical description of anomalous properties of novel room temperature multiferroics Pb(Fe1/2Ta1/2)x(Zr0.53Ti0.47)1-xO3 and Pb(Fe1/2Nb1/2)x(Zr0.53Ti0.47)1-xO3

    OpenAIRE

    Glinchuk, Maya D.; Eliseev, Eugene A.; Morozovska, Anna N.

    2015-01-01

    The theoretical description of the anomalous ferroelectric, ferromagnetic and magnetoelectric properties of Pb(Fe1/2Ta1/2)x(Zr0.53Ti0.47)1-xO3 and Pb(Fe1/2Nb1/2)x(Zr0.53Ti0.47)1-xO3 micro-ceramics is given. We performed calculations of temperature, composition and external field dependence of ferroelectric, ferromagnetic and antiferromagnetic phases transition temperatures, remanent polarization, magnetization, hysteresis loops, coercive fields, dielectric permittivity and magnetoelectric cou...

  1. Magnetoresistance and magnetic properties of the double perovskites

    International Nuclear Information System (INIS)

    The magnetic double perovskite materials of composition A2BB'O6 with A an alkaline earth ion and B and B' a magnetic and non-magnetic transition metal or lanthanide ions, respectively, have attracted considerable attention due to their interesting magnetic properties ranging from antiferromagnetism to geometrically frustrated spin systems and ferromagnetism. With respect to application in spin electronics, the ferromagnetic double perovskites with BB' = CrW, CrRe, FeMo or FeRe and A = Ca, Ba, Sr are highly interesting due to their in most cases high Curie temperatures well above room temperature and their half-magnetic behaviour. Here, we summarize the structural, magnetotransport, magnetic and optical properties of the ferromagnetic double perovskites and discuss the underlying physics. In particular, we discuss the impact of the steric effects resulting in a distorted perovskite structure, doping effects obtained by a partial replacing of the divalent alkaline earth ions on the A site by a trivalent lanthanide as well as B/B' cationic disorder on the Curie temperature TC, the saturation magnetization and the magnetotransport properties. Our results support the presence of a kinetic energy driven mechanism in the ferromagnetic double perovskites, where ferromagnetism is stabilised by a hybridization of states of the non-magnetic B'- site positioned in between the high spin B-sites. (author)

  2. Magnetic properties and thermodynamics in a metallic nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Wei, E-mail: weijiang.sut.edu@gmail.com; Li, Xiao-Xi; Guo, An-Bang; Guan, Hong-Yu; Wang, Zan; Wang, Kai

    2014-04-15

    A metallic nanotube composed of the ferromagnetic spin-3/2 inner shell and spin-1 outer shell with a ferrimagnetic interlayer coupling has been studied by using the effective-field theory with correlations (EFT). With both existence of the magnetic anisotropy and transverse field, we have studied effects of them on the magnetic properties and the thermodynamics. Some interesting phenomena have been found in the phase diagrams. At low temperature, the magnetization curves present different behaviors. Two compensation points have been found for the certain values of the system parameters in the system. The research results of metallic nanotubes may have potential applications in the fields of biomedicine and molecular devices. - Highlights: • A hexagonal metallic nanotube is composed of spin-3/2 inner layer and spin-1 outer layer. • Various types of magnetization curves depend on physical parameters and temperature. • We study the effects of physical parameters on the magnetic properties and thermodynamics.

  3. Magnetic properties of epitaxial CrN films

    International Nuclear Information System (INIS)

    The authors have investigated the structural and magnetic properties of CrN films grown on MgO(001) and sapphire(0001) by rf-plasma-assisted molecular beam epitaxy. CrN/MgO(001) exhibits a better epitaxial quality than CrN/sapphire(0001). The CrN/MgO film shows clear paramagnetic behavior at low temperatures, whereas CrN/sapphire exhibits a ferromagneticlike response with an order temperature above room temperature which resembles the magnetic behavior found in Cr-doped dilute magnetic semiconductors. Keeping in mind that bulk CrN exhibits antiferromagnetic behavior, the dramatically different magnetic behaviors found in epitaxial CrN films grown on MgO and sapphire demonstrate the importance of epitaxial constraints in determining their magnetic properties

  4. Observational properties of magnetic white dwarfs

    CERN Document Server

    Ferrario, Lilia

    2016-01-01

    There are no known examples of magnetic white dwarfs with fields larger than about 3MG paired with a non-degenerate companion in detached binary systems. The suggestion is that highly magnetic, isolated white dwarfs may originate from stars that coalesce during common envelope evolution while those stars that emerge from a common envelope on a close orbit may evolve into double degenerate systems consisting of two white dwarfs, one or both magnetic. The presence of planets or planetary debris around white dwarfs is also a new and exciting area of research that may give us important clues on the formation of first and second generation planetary systems, since these place unique signatures in the spectra of white dwarfs.

  5. Enhancement of exchange coupling and hard magnetic properties in nanocomposites by magnetic annealing

    International Nuclear Information System (INIS)

    An enhancement of the exchange coupling and hard magnetic properties of melt-spun Nd2Fe14B/α-Fe-type nanocomposites was achieved by optimization of their nanostructured morphology via magnetic annealing. Compared with the Nd2.4Pr5.6Dy1Fe84Mo1B6 sample annealed without a magnetic field, the magnetic annealing results in a noticeable improvement in the coercivity i H c, the remanence 4πMr, and energy product (BH)max. (BH)max at 50 K was enhanced by 43.7% after magnetic annealing in a field of 19 T. The kink in the demagnetization curve disappeared and, additionally, a much better squareness of the demagnetization curves was observed in the magnetically annealed samples. The intergrain exchange coupling was evaluated by Henkel plots. Evidence for stronger intergrain exchange coupling was found in the magnetically annealed sample, which is due to nanostructure refinement promoted by the magnetic annealing. The nanostructure refinement was confirmed by X-ray diffraction, transmission electron microscope, low-temperature demagnetization curves and a modified Brown's equation analysis. The improvement of hard magnetic properties of the magnetically annealed sample results mainly from the magnetic-field-induced exchange-coupling enhancement

  6. Superconductivity and magnetism: Materials properties and developments

    International Nuclear Information System (INIS)

    The 24th Risoe International Symposium on Materials Science focuses on development of new materials, devices and applications, as well as experimental and theoretical studies of novel and unexplained phenomena in superconductivity and magnetism, e.g. within high.Tc superconductivity, magnetic superconductors, MgB2, CMR materials, nanomagnetism and spin-tronics. The aim is to stimulate exchange of ideas and establish new collaborations between leading Danish and international scientists. The topics are addressed by presentations from 24 invited speakers and by 41 contributed papers. (ln)

  7. Magnetic properties of confined holographic QCD

    International Nuclear Information System (INIS)

    We investigate the Sakai-Sugimoto model at nonzero baryon chemical potential in a background magnetic field in the confined phase where chiral symmetry is broken. The D8-brane Chern-Simons term holographically encodes the axial anomaly and generates a gradient of the η' meson, which carries a non-vanishing baryon charge. Above a critical value of the chemical potential, there is a second-order phase transition to a mixed phase which includes also ordinary baryonic matter. However, at fixed baryon charge density, the matter is purely η'-gradient above a critical magnetic field

  8. Superconductivity and magnetism: Materials properties and developments

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, N.H.; Bay, N.; Grivel, J.C. (eds.) [and others

    2003-07-01

    The 24th Risoe International Symposium on Materials Science focuses on development of new materials, devices and applications, as well as experimental and theoretical studies of novel and unexplained phenomena in superconductivity and magnetism, e.g. within high.T{sub c} superconductivity, magnetic superconductors, MgB{sub 2}, CMR materials, nanomagnetism and spin-tronics. The aim is to stimulate exchange of ideas and establish new collaborations between leading Danish and international scientists. The topics are addressed by presentations from 24 invited speakers and by 41 contributed papers. (ln)

  9. Relationship between Magnetic and Mechanical Properties of Cermet Tools

    International Nuclear Information System (INIS)

    The commercial cermet cutting tools consist of multi-carbide and a binder metal of iron group, such as cobalt and nickel which are ferromagnetic. In this paper, a new approach to evaluate the mechanical properties of TiCN based cermet by magnetic properties were studied in relation to binder content and sintering conditions. The experimental cermet was prepared using commercial composition with the other binder contents by PM process. It was found that the magnetic properties of the sintered cermets remarkably depended on the microstructure and the total carbon content. The magnetic saturation was proportional to increment of coercive force. At high carbon content in sintered cermet, the magnetic saturation was increased by decreasing the concentration of solutes such as W, Mo, Ti in Co-Ni binder. As the coercive force increases, the hardness usually increases. The strength and toughness of the cermet also increased with increasing the magnetic saturation. The measurement of magnetic properties made it possible to evaluate the mechanical properties in the cermet cutting tools

  10. Spectral Properties of the Martian Crustal Magnetic Field

    Science.gov (United States)

    Lewis, K. W.; Simons, F. J.

    2010-12-01

    Although the planet Mars no longer possesses an internal dynamo, its crustal rocks retain strong remanent magnetization thought to have been induced by an ancient core-sourced field. The strength and distribution of the crustal field is extremely heterogeneous, and particularly strong in the Terra Cimmeria region of the southern hemisphere. The field as a whole is inconsistent with induction from a single dipolar source, although previous studies have attempted to isolate individual magnetic anomalies to deduce paleopolar orientations. While several areas of the planet appear to have been demagnetized, including large impact basins and the Tharsis volcanic province, the distribution of the field is generally poorly correlated with surface geologic structures. However, beyond the spatial pattern of crustal magnetization, the magnetic power spectrum can provide information about the nature of the source and formation processes. Previous studies have used the power spectrum of the Martian field to estimate the approximate depth of the magnetic anomalies. We extend this approach by applying the spatiospectral localization technique of Wieczorek and Simons (2005) and Dahlen and Simons (2008) to isolate the magnetic power spectra of several areas of the Martian surface. This method allows us to look beyond the strongly magnetized Terra Cimmeria region, which dominates the global power spectrum. Localized spectral estimates, along with their appropriate errors, allow us to examine the significance of observed variations between distinct regions of the planet, and to evaluate the validity of analyses which operate on the whole sphere. Significant differences are observed between spectra of the Terra Cimmeria region and the remainder of the planet, a result of the concentration of power at certain spherical harmonic degrees in this anomalous region. Approximate depths to the magnetic sources are calculated for tiled windows on the planet using the stochastic magnetized

  11. The structural and magnetic properties of holmium/scandium superlattices

    DEFF Research Database (Denmark)

    Bryn-Jacobsen, C.; Cowley, R.A.; McMorrow, D.F.;

    1997-01-01

    The properties of Ho/Sc superlattices grown by molecular beam epitaxy (MBE) have been investigated using X-ray and neutron diffraction techniques. Structural studies reveal the novel existence of more than one a lattice parameter. Examining the magnetic properties, it is found that the Ho 4f...

  12. Development of soft magnetic materials with special properties

    International Nuclear Information System (INIS)

    New steps in the development of soft magnetic alloys are based on a better understanding of the magnetizing processes in close connection with the development of magnetic forms and components for different applications. New result on the influence of crystal grains, inclusions, and mechanical stresses on the soft magnetic properties of Ni-Fe-alloys with ca. 50 to 75% Nickel-contents are given. Special soft magnetic alloys were developed and improved for low temperature applications, for small temperature coefficients, for different shapes of hysteresis loops, or for high wear resistance - and moreover forms, components, and basic designs of chokes for RFI suppression, of transformers for electronic power supplies, of transformers for ground-fault interrupters, and for magnetic shielding equipments. (orig.) 891 GSC/orig. 892 AV

  13. Remanence Properties and Magnetization Reversal Mechanism of Fe Nanowire Arrays

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-Bo; LIU Qing-Fang; XUE De-Sheng; LI Fa-Shen

    2004-01-01

    @@ Remanence properties and magnetization reversal mechanism of Fe nanowire arrays with diameters 16 nm and130nm are studied. Isothermal remanent magnetization curves show that the contribution of irreversible magnetization decreases when the diameter changes from 16nm to 130nm. The remanence coercivities of these nanowires obtained in dc-demagnetization curve are about 2400 Oe and 800 Oe, respectively. The magnetization reversal mechanism is different in these two samples. For the nanowire array with diameter 16nm, both the nucleation and the pinning have effects on magnetization reversal mechanism, and the pinning field (about 2500Oe) is larger than the nucleation field (about 2200 Oe). However, for the nanowire array with diameter 130nm,the magnetization reversal mechanism is dominated by the pinning effect of domain walls.

  14. Magnetic Properties of Quantum Ferrimagnetic Spin Chains

    OpenAIRE

    Yamamoto, Shoji

    1998-01-01

    Magnetic susceptibilities of spin-$(S,s)$ ferrimagnetic Heisenberg chains are numerically investigated. It is argued how the ferromagnetic and antiferromagnetic features of quantum ferrimagnets are exhibited as functions of $(S,s)$. Spin-$(S,s)$ ferrimagnetic chains behave like combinations of spin-$(S-s)$ ferromagnetic and spin-$(2s)$ antiferromagnetic chains provided $S=2s$.

  15. Magnetic properties of thin Ni films measured by a dc SQUID-based magnetic microscope

    DEFF Research Database (Denmark)

    Snigirev, O.V.; Andreev, K.E.; Tishin, A.M.; Gudoshnikov, S.A.; Bohr, Jakob

    1997-01-01

    We have applied a scanning HTS (high-temperature superconductor) de SQUID (superconducting quantum interference device) -based magnetic microscope to study the magnetic properties of Au/Ni/Si(100) films in the thickness range from 8 to 200 Angstrom at T = 77 K. A one-domain structure with in...

  16. Tenth-order QED contribution to lepton anomalous magnetic moment: Fourth-order vertices containing sixth-order vacuum-polarization subdiagrams

    International Nuclear Information System (INIS)

    This paper reports the tenth-order contributions to the g-2 of the electron ae and those of the muon aμ from the gauge-invariant Set II(c), which consists of 36 Feynman diagrams, and Set II(d), which consists of 180 Feynman diagrams. Both sets are obtained by insertion of sixth-order vacuum-polarization diagrams in the fourth-order anomalous magnetic moment. The mass-independent contributions from Set II(c) and Set II(d) are -0.116 489 (32)(α/π)5 and -0.243 00 (29)(α/π)5, respectively. The leading contributions to aμ, which involve electron loops only, are -3.888 27 (90)(α/π)5 and 0.4972 (65)(α/π)5 for Set II(c) and Set II(d), respectively. The total contributions of the electron, muon, and tau-lepton loops to ae are -0.116 874 (32)(α/π)5 for the Set II(c), and -0.243 10 (29)(α/π)5 for the Set II(d), respectively. The contributions of the electron, muon, and tau-lepton loop to aμ are -5.5594 (11)(α/π)5 for the Set II(c) and 0.2465 (65)(α/π)5 for the Set II(d), respectively.

  17. Kaluza—Klein Corrections to the μ Anomalous Magnetic Moment in the Appelquist—Cheng—Dobrescu Model

    International Nuclear Information System (INIS)

    Applying the effective Lagrangian method, we analyze the radiative contributions of the Kaluza—Klein (KK) modes to the muon magnetic dipole moments in the Appelquist—Cheng—Dobrescu model. Summing over the infinite series composed by the KK towers, we verify the final results satisfying the decoupling theorem in the limit R−1 → ∞. For the compactification scale R−1 = 300 GeV, we obtain the electroweak radiative corrections from the KK modes to the muon MDM amount to 6.72 × 10−12 at one loop level

  18. The role of electrolyte pH on phase evolution and magnetic properties of CoFeW codeposited films

    Science.gov (United States)

    Ghaferi, Z.; Sharafi, S.; Bahrololoom, M. E.

    2016-07-01

    In this research, nanocrystalline Co-Fe-W alloy coatings were electrodeposited from a citrate-borate bath. The influence of electrolyte pH on the morphology, microstructure and magnetic properties of these films was also studied. By increasing pH value, the amount of iron content increased from 30 to 55 wt.% which indicates anomalous fashion at higher pH electrolytes. X-ray diffraction patterns showed that the structure of these films depend on electrolyte pH effectively. However, two-phase structure coatings showed smaller average grain size compared with one- phase solid solutions. Vibrating sample magnetometer measurements indicated that the coercivity of the coatings was in the range of 21-76 Oe. However, the highest pH value produced coating with superior magnetic behaviour. Microhardness of the coatings reached its maximum value at about 260HV which is referred to the highest tungsten content.

  19. Magnetic properties of ultrasmall iron-oxide nanoparticles

    International Nuclear Information System (INIS)

    Highlights: • The ultrasmall iron oxide nanoparticles in organic fluid were synthesized with diameter d ∼ 3 nm. • Very low blocking temperature, TB = 10 K, is determined in accordance with size. • Nanoparticles in fluid are noninteracting, drying brings interaction between nanoparticles. • High influence of surface on the magnetic properties. • High magnetic anisotropy due to surface anisotropy, ∼ 106 erg/cm3, 100 times higher than in bulk. - Abstract: The work presents structural and magnetic properties of ultrasmall magnetic nanoparticles consisting of inorganic iron oxide core and organic ester shell, dispersed in an organic fluid, synthesized via polyol route. The structure analysis shows that nanoparticles are crystalline, less than 3 nm in size, mutually clearly separated. The magnetic properties are in accordance with the size of the nanoparticles and do not indicate interparticle interactions. The particles show pure superparamagnetic behavior with very low blocking temperature. ZFCFC bifurcation and ac susceptibility peaks are at temperatures TB < 12 K. The properties of fluid were compared with dried powder sample. Drying of fluid brings about interactions between the magnetic nanoparticles that considerably affect spin dynamics of the particles. The surface of nanoparticles has a significant influence on their behavior. The Mössbauer parameters indicate existence of γ-Fe2O3 core and non-stoichiometric surface layer. Magnetic field dependent magnetization analysis suggests smaller apparent size of the particles d0 = 0.56 nm. High magnetic anisotropy due to surface layer anisotropy was measured to be of the order 106 erg/cm3 that is two orders of magnitude higher than that in bulk material

  20. Magnetic properties of electroplated wires coated by ferrofluid

    International Nuclear Information System (INIS)

    Low-frequency magnetic properties of ferromagnetic composite wires were studied with and without coating by ferrofluid. Non-magnetic CuBe wires of 0.1 mm diameter were electroplated with FeCoNi layer of 1 μm thickness. Magnetization curves were measured in the frequency range of 10 Hz-3 kHz. The composite CuBe/FeCoNi/ferrofluid material shows a hysteretic behaviour in a small field. The hysteresis loop of ferrofluid covered electroplated wire is not a simple sum of the ferrofluid 'wire' plus non-covered wire signals. It indicates an interaction between magnetic wire and ferrofluid which can be revealed by low-frequency measurements. The combination 'electroplated wire/ferrofluid' can be considered as a new type of composite magnetic material consisting of solid magnetic core coated by complementary liquid magnetic material. Low-frequency measurements in presence of ferrofluid can be a useful method to study magnetic properties of ferromagnets

  1. Magnetic properties of dipolar chains in ferrofluids

    Energy Technology Data Exchange (ETDEWEB)

    Avgin, I., E-mail: ihavgin@gmail.com [Department of Electrical Engineering, Ege University, Izmir (Turkey); Huber, D.L. [Physics Department, University of Wisconsin-Madison, Madison, WI (United States)

    2014-07-01

    We have investigated the dipole interaction energies per particle and the local dipole field distributions in a frozen magnetization model of a ferrofluid chain in a saturating magnetic field. A lognormal distribution of particle diameters was assumed. The interaction energies were calculated for one dimensional arrays of dipoles with moments parallel to the chain. We have computed the energies by various approximations related to the hard sphere particle diameter distribution. A similar approach was followed for the local field distributions. It was found that the energy per particle and mean local field were largely determined by the mean particle diameter, but the distribution of local fields was sensitive to both the mean diameter and the assumptions about spatial correlations between particles of different size. Detailed results are presented for water-soluble Fe{sub 3}O{sub 4}/PAA (polyacrylic acid). (author)

  2. Magnetic properties of Nd5 Fe17

    International Nuclear Information System (INIS)

    A new stable compound in the Nd-Fe system has been identified as Nd5 Fe17. The crystal structure belongs to the hexagonal space group P63 mcm, with a = 2.0214(8) nm and c = 1.2329(8) nm, and with 12 formula units per unit cell. This compound is a ferromagnetic with Tc = 503 K and magnetization 162 emu/g at 4.2 K. Moessbauer spectra have been measured at different temperatures and fitted with five Fe sites, yielding an average Beff = 30.7 tesla at T = 10 K, from which an average Fe moment of 2.12 Bohr magnetons is deduced. X-ray powder diagrams from magnetically aligned samples suggest basal anisotropy. (author)

  3. Magnetic properties of rare earth superlattices

    CERN Document Server

    Wilkins, C J T

    2001-01-01

    Single-crystal Tm/Y and Tm/Lu superlattices have been grown using molecular beam epitaxy and their chemical structures have been determined using X-ray diffraction. Magnetisation measurements have revealed a more complicated phase diagram than that of pure Tm. Application of a field along the c-direction gave rise to an extra transition, and transitions were detected for the superlattices when the field was applied along the b-axis. In neutron diffraction studies, c-axis longitudinally modulated magnetic structures were found for both Tm/Y and Tm/Lu, which propagate coherently through the non-magnetic layers. In the case of Tm/Lu superlattices, there is evidence for ordering of the basal plane components.

  4. Magnetic properties of RCo5-based systems

    International Nuclear Information System (INIS)

    Highlights: → The GdxY1-xCo4Si compounds with x ≥ 0.2 are ferrimagnetic. → The saturation Co moments are linearly dependent on exchange field. → A linear relation of exchange splittings ΔE and Co moments was shown. → The effective cobalt moments are little influenced by composition. - Abstract: Band structure calculations and magnetic measurements were performed on (GdxY1-x)Co4Si as well as on YCo4M compounds, where M = Ga, Al, and Co. The substitutions both at rare-earth and cobalt sites influence strongly the cobalt moments as well as the Curie temperatures. When Y is replaced by Gd, in GdxY1-xCo4Si system, the mean cobalt moments increase from 0.73μB/atom to 1.25μB/atom. The computed magnetic moments per formula unit agree rather well with experimental data. The reciprocal susceptibilities for ferrimagnetic compounds show non-linear temperature dependences. The effective cobalt moments are little dependent on composition. The ratio r between the mean number of cobalt spins determined from effective and saturation cobalt moments, respectively follows a dependence on Curie temperature of the form r∝Tc-2/3. The magnetic behaviour of cobalt is analysed in spin fluctuations model.

  5. Defect energetics and magnetic properties of 3 d-transition-metal-doped topological crystalline insulator SnTe

    Science.gov (United States)

    Wang, Na; Wang, JianFeng; Si, Chen; Gu, Bing-Lin; Duan, WenHui

    2016-08-01

    The introduction of magnetism in SnTe-class topological crystalline insulators is a challenging subject with great importance in the quantum device applications. Based on the first-principles calculations, we have studied the defect energetics and magnetic properties of 3 d transition-metal (TM)-doped SnTe. We find that the doped TM atoms prefer to stay in the neutral states and have comparatively high formation energies, suggesting that the uniform TMdoping in SnTe with a higher concentration will be difficult unless clustering. In the dilute doping regime, all the magnetic TMatoms are in the high-spin states, indicating that the spin splitting energy of 3 d TM is stronger than the crystal splitting energy of the SnTe ligand. Importantly, Mn-doped SnTe has relatively low defect formation energy, largest local magnetic moment, and no defect levels in the bulk gap, suggesting that Mn is a promising magnetic dopant to realize the magnetic order for the theoretically-proposed large-Chern-number quantum anomalous Hall effect (QAHE) in SnTe.

  6. Magnetic properties of Cr telluride-selenide alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mankovsky, Sergey; Polesya, Svetlana; Ebert, Hubert [Dept. Chemie und Biochemie, Universitaet Muenchen, Butenandtstr. 5-13, D-81377 Muenchen (Germany); Huang, Zhong-Le; Bensch, Wolfgang [Institute for Anorganic Chemistry, Olshausenstr. 40, D-24098, Kiel (Germany)

    2007-07-01

    Results of a theoretical study of the magnetic properties of Cr telluride-selenide alloys having trigonal crystal structure are presented in comparison with experimental results. Both ground state and temperature-dependent magnetic properties of Cr{sub 1-{delta}}Te and Cr{sub x}(Te{sub {alpha}}Se{sub {beta}}){sub 2} (with ratio {alpha}:{beta}=7:1,6:2,5:3) have been investigated in a wide region of chromium content. For the alloys Cr{sub x}(Te{sub {alpha}}Se{sub {beta}}){sub 2} a transition to the state with antiferromagnetic order in a fully occupied sub-lattice and with no order in a partially occupied sub-lattice was obtained. For the alloys Li{sub x}Cr{sub 0.5}Ti{sub 0.75}Se{sub 2}, a non-monotonic dependence of structural and magnetic properties have been found upon increase of Li concentration x, that is in agreement with experimental results. The ground state properties have been studied on the basis of electronic structure calculations using the Korringa-Kohn-Rostoker (KKR) band structure method combined with the CPA alloy theory. Using Monte Carlo simulations we obtained the magnetic configuration at T=0 K and studied the magnetic properties at T>0 K as well. The required exchange coupling parameters were obtained from our ab-initio electronic structure calculations.

  7. Origin of the anomalous temperature dependence of coercivity in soft ferromagnets

    International Nuclear Information System (INIS)

    We report on the origin of the anomalous temperature dependence of coercivity observed in some soft ferromagnets by studying the magnetic and electronic properties of FeZr films doped using ion implantation by H, He, B, C, and N. The anomalous increase of the coercivity with temperature was observed only in the C- and B-doped samples. Using x-ray photoelectron spectroscopy, we show that the anomalous behavior of the coercivity coincides with the occurrence of an electron charge transfer for those implanted samples. The origin of the anomaly is discussed in terms of (i) magnetic softness, (ii) nature of the Fe-C and -B covalent bonds, and (iii) large charge transfer

  8. The Highest Magnetic Fields in the Universe: Anomalous X-Ray Pulsars and Soft Gamma-ray Repeaters

    CERN Document Server

    Mereghetti, S

    2005-01-01

    In the last few years it has been recognized that two apparently distinct classes of peculiar high-energy sources are actually related and can be explained as young neutron stars with magnetic fields as high as 10e14 - 10e15 Gauss. One of these ''magnetars'', SGR 1806-20, has recently emitted the most powerful giant flare ever recorded. The high-energy observations of SGR 1806-20 carried out with XMM-Newton and INTEGRAL in the past two years showed a long term trend of increasing activity preceding the 2004 December 27 event. INTEGRAL data of this giant flare provided unique evidence for hard X-ray emission lasting about one hour after the burst onset, possibly due to the interaction of mildly relativistic ejecta with the circumstellar medium.

  9. Non-Anomalous Semigroups and Real Numbers

    OpenAIRE

    Binder, Damon

    2016-01-01

    Motivated by intuitive properties of physical quantities, the notion of a non-anomalous semigroup is formulated. These are totally ordered semigroups where there are no `infinitesimally close' elements. The real numbers are then defined as the terminal object in a closely related category. From this definition a field structure on $\\mathbb R$ is derived, relating multiplication to morphisms between non-anomalous semigroups.

  10. Effect of poly (ethylene glycol) coating on the magnetic and thermal properties of biocompatible magnetic liquids

    International Nuclear Information System (INIS)

    The aim of this study was to investigate the influence of poly(ethylene glycol) surface-active coating on the magnetic and thermal properties of biocompatible magnetic liquids. The data were analyzed using the high-temperature approximation model taking into account polydispersity of a system. Heating ability of the PEG-stabilized magnetic fluids was determined by the calorimetric measurement of specific absorption rate (SAR) at a frequency of 750 kHz and a magnetic field of 0-2 kA/m. MF-Oleate/PEG heating properties were found to be comparable to the ones of MF-Oleate. The PEG shell thus does not seem to effect the thermal characteristics and SAR values and might make the magnetic fluid useful for application in hyperthermia treatment.

  11. Magnetically textured ferrofluid in a non-magnetic matrix: Magnetic properties

    Indian Academy of Sciences (India)

    Mrudul Gadhvi; R V Upadhyay; Kinnari Parekh; R V Mehta

    2004-04-01

    Texturing of two different magnetic fluids were carried out in paraffin wax under the influence of an external magnetic field. The textured samples were characterized using magnetization measurement and a.c. susceptibility techniques. The results are discussed in the light of ratio of anisotropic energy to magnetic and thermal energies.

  12. Magnetic Properties of Bismuth Ferrite Nanopowder Obtained by Mechanochemical Synthesis

    OpenAIRE

    Szafraniak-Wiza, I.; Andrzejewski, B.; Hilczer, B.

    2014-01-01

    Multiferroic bismuth ferrite (BiFeO3) nanopowders have been obtained in room temperature by mechanical synthesis. Depending on the post-synthesis processing the nanopowders have exhibited differences in the mean sizes, presence of amorphous layer and/or secondary phases. Extended magnetic study performed for fresh, annealed and hot-pressed nanopowders have revealed substantial improvement of the magnetic properties in the as-prepared powder.

  13. Synthesis and magnetic properties of Zn Spinel ceramics

    Czech Academy of Sciences Publication Activity Database

    Huber, Š.; Sofer, Z.; Nádherný, L.; Jankovský, O.; Šimek, P.; Sedmidubský, D.; Maryško, Miroslav

    2013-01-01

    Roč. 57, č. 2 (2013), s. 162-166. ISSN 0862-5468 R&D Projects: GA ČR GA13-17538S; GA MŠk(CZ) 7AMB12FR019 Institutional support: RVO:68378271 Keywords : Zn spinel * synthesis * magnetic properties * antiferromagnet * bulk ZnO Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.434, year: 2013

  14. Nonlinear optical properties of the magnetized QED Vacuum

    CERN Document Server

    Mendonça, J T

    2007-01-01

    New processes associated with the nonlinear optical properties of the electromagnetic vacuum, as predicted by quantum electrodynamics are described. We consider the presence of a static and a rotating magnetic field. The cases of harmonic generation and two different types of sideband cascades are considered. First order and second order effects with respect to the external magnetic field are discussed in detail. Possible experimental configurations using ultra-intense lasers are compared with the alternative use of cw lasers in stable optical cavities.

  15. Evaluating the effect of magnetocaloric properties on magnetic refrigeration performance

    OpenAIRE

    Engelbrecht, Kurt; Bahl, Christian Robert Haffenden

    2010-01-01

    Active magnetic regenerator (AMR) refrigerators represent an alternative to vapor compression technology that relies on the magnetocaloric effect in a solid refrigerant. Magnetocaloric materials are in development and properties are reported regularly. Recently, there has been an emphasis on developing materials with a high entropy change with magnetization while placing lower emphasis on the adiabatic temperature change. This work uses model magnetocaloric materials and a numerical AMR model...

  16. GEMAS: unmixing magnetic properties of European agricultural soil

    OpenAIRE

    Fabian, Karl; Reimann, Clemens; Kuzina, Dilyara; Kosareva, Lina; Fattakhova, Leysan; Nurgaliev, Danis; Flight, Dee; Johnson, Christopher; Scheib, Andreas

    2016-01-01

    High resolution magnetic measurements provide new methods for world-wide characterization and monitoring of agricultural soil which is essential for quantifying geologic and human impact on the critical zone environment and consequences of climatic change, for planning economic and ecological land use, and for forensic applications. Hysteresis measurements of all Ap samples from the GEMAS survey yield a comprehensive overview of mineral magnetic properties in European agricultural soil on a c...

  17. Magnetic Nanoparticles: Surface Effects and Properties Related to Biomedicine Applications

    OpenAIRE

    Bashar Issa; Obaidat, Ihab M.; Albiss, Borhan A.; Yousef Haik

    2013-01-01

    Due to finite size effects, such as the high surface-to-volume ratio and different crystal structures, magnetic nanoparticles are found to exhibit interesting and considerably different magnetic properties than those found in their corresponding bulk materials. These nanoparticles can be synthesized in several ways (e.g., chemical and physical) with controllable sizes enabling their comparison to biological organisms from cells (10–100 μm), viruses, genes, down to proteins (3–50 nm). The opti...

  18. Magnetic properties of spark plasma sintering magnets using fine powders prepared by mechanical compounding method

    International Nuclear Information System (INIS)

    Sr-La-Co M-type ferrite fine particles were prepared by mechanical compounding (MC) method using the planetary ball-mill and subsequent heat treatment. This experiment was carried out to investigate the magnetic properties of Sr-La-Co M-type ferrite magnets prepared by spark plasma sintering (SPS) method using powders made by the MC method. The optimum condition of making SPS magnet, and some properties of a typical specimen are as follows: chemical composition, SrO·6.0Fe2O3; additives, 1.0 wt% La2O3 and 0.1 wt% Co3O4; pressing pressure, 50 MPa; sintering condition: 1100 deg. Cx5 min. Magnetic and physical properties are Br=0.323 T, HcJ=325 kA/m, (BH)max=18.3 kJ/m3, and density=5.15 Mg/m3

  19. GEMAS: Unmixing magnetic properties of European agricultural soil

    Science.gov (United States)

    Fabian, Karl; Reimann, Clemens; Kuzina, Dilyara; Kosareva, Lina; Fattakhova, Leysan; Nurgaliev, Danis

    2016-04-01

    High resolution magnetic measurements provide new methods for world-wide characterization and monitoring of agricultural soil which is essential for quantifying geologic and human impact on the critical zone environment and consequences of climatic change, for planning economic and ecological land use, and for forensic applications. Hysteresis measurements of all Ap samples from the GEMAS survey yield a comprehensive overview of mineral magnetic properties in European agricultural soil on a continental scale. Low (460 Hz), and high frequency (4600 Hz) magnetic susceptibility k were measured using a Bartington MS2B sensor. Hysteresis properties were determined by a J-coercivity spectrometer, built at the paleomagnetic laboratory of Kazan University, providing for each sample a modified hysteresis loop, backfield curve, acquisition curve of isothermal remanent magnetization, and a viscous IRM decay spectrum. Each measurement set is obtained in a single run from zero field up to 1.5 T and back to -1.5 T. The resulting data are used to create the first continental-scale maps of magnetic soil parameters. Because the GEMAS geochemical atlas contains a comprehensive set of geochemical data for the same soil samples, the new data can be used to map magnetic parameters in relation to chemical and geological parameters. The data set also provides a unique opportunity to analyze the magnetic mineral fraction of the soil samples by unmixing their IRM acquisition curves. The endmember coefficients are interpreted by linear inversion for other magnetic, physical and chemical properties which results in an unprecedented and detailed view of the mineral magnetic composition of European agricultural soils.

  20. Do micromagnetic simulations correctly predict hard magnetic hysteresis properties?

    Science.gov (United States)

    Toson, P.; Zickler, G. A.; Fidler, J.

    2016-04-01

    Micromagnetic calculations using the finite element technique describe semi-quantitatively the coercivity of novel rare earth permanent magnets in dependence on grain size, grain shape, grain alignment and composition of grain boundaries and grain boundary junctions and allow the quantitative prediction of magnetic hysteretic properties of rare earth free magnets based on densely packed elongated Fe and Co nanoparticles, which depend on crystal anisotropy, aspect ratio and packing density. The nucleation of reversed domains preferentially takes place at grain boundary junctions in granular sintered and melt-spun magnets independently on the grain size. The microstructure and the nanocompostion of the intergranular regions are inhomogeneous and too complex in order to make an exact model for micromagnetic simulations and to allow a quantitative prediction. The incoherent magnetization reversal processes near the end surfaces reduce and determine the coercive field values of Co- and Fe-based nanoparticles.

  1. Magnetic properties of nanostructured CuFe2O4

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Goya, G.F.; Rechenberg, H.R.

    1999-01-01

    The structural evolution and magnetic properties of nanostructured copper ferrite, CuFe2O4, have been investigated by X-ray diffraction, Mossbauer spectroscopy, and magnetization measurements. Nanometre-sized CuFe2O4 particles with a partially inverted spinel structure were synthesized by high......-energy ball milling in an open container with grain sizes ranging from 9 to 61 nm. Superparamagnetic relaxation effects have been observed in milled samples at room temperature by Mossbauer and magnetization measurements. At 15 K, the average hyperfine field of CuFe2O4 decreases with decreasing average grain...... size while the coercive force, shift of the hysteresis loop, magnetic hardness, and saturation magnetization at 4.2 K increase with decreasing average grain size. At 295 K the coercive-field dependence on the average grain size is described, with particles showing superparamagnetic relaxation effects...

  2. Structural and magnetic properties of granular CoPd multilayers

    Science.gov (United States)

    Vivas, L. G.; Figueroa, A. I.; Bartolomé, F.; Rubín, J.; García, L. M.; Deranlot, C.; Petroff, F.; Ruiz, L.; González-Calbet, J. M.; Brookes, N. B.; Wilhelm, F.; Rogalev, A.; Bartolomé, J.

    2016-02-01

    Multilayers of bimetallic CoPd alloyed and assembled nanoparticles, prepared by room temperature sequential sputtering deposition on amorphous alumina, were studied by means of high-resolution transmission electron microscopy, x-ray diffraction, SQUID-based magnetometry and x-ray magnetic circular dichroism. Alloying between Co and Pd in these nanoparticles gives rise to a high perpendicular magnetic anisotropy. Their magnetic properties are temperature dependent: at low temperature, the multilayers are ferromagnetic with a high coercive field; at intermediate temperature the behavior is of a soft-ferromagnet, and at higher temperature, the perpendicular magnetic anisotropy in the nanoparticles disappears. The magnetic orbital moment to spin moment ratio is enhanced compared with Co bare nanoparticles and Co fcc bulk.

  3. Structure, synthetic methods, magnetic properties and biomedical applications of ferrofluids.

    Science.gov (United States)

    Shokrollahi, H

    2013-07-01

    This paper is aimed at conducting a survey of the synthetic methods and magnetic properties of nanoparticles as ferrofluids used in biomedicine. As compared with other works in the field, the distinctive feature of the current work is the systematic study of recent advances in ferrofluids utilized in hyperthermia and magnetic resonance imaging (MRI). The most important feature for application of ferrofluids is super-paramagnetic behavior of magnetic cores with relatively high saturation magnetization. Although Fe3O4 nanoparticles have traditionally been used in medicine; the modified Mn-ferrite has recently received special attention due to its higher saturation magnetization and r2-relaxivity as a contrast agent in MRI. Co-ferrite nanoparticles are also good candidates for hyperthermia treatment because of their high coercivity and magnetocrystalline anisotropy. The thermal decomposition and hydrothermal methods are good candidates for obtaining appropriate super-paramagnetic particles. PMID:23623058

  4. Magnetic property of a single crystal UCu2Ge2

    International Nuclear Information System (INIS)

    We have succeeded in growing a single crystal of UCu2Ge2 with the tetragonal structure by the Sn-flux method and measured the electrical resistivity, magnetic susceptibility, magnetization and specific heat. This is the first single crystal growth of UCu2Ge2. The magnetic properties are highly anisotropic, reflecting the crystal structure. An easy-axis of magnetization is found to be the [001] direction (c-axis) with a saturation moment 1.75 μB/U, while the [100] direction (a-axis) is the hard-axis in magnetization, indicating an Ising-type ferromagnetism. The electronic specific heat coefficient is determined as 30mJ/(K2·mol). (author)

  5. Single crystal Processing and magnetic properties of gadolinium nickel

    Energy Technology Data Exchange (ETDEWEB)

    Shreve, Andrew John [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    GdNi is a rare earth intermetallic material that exhibits very interesting magnetic properties. Spontaneous magnetostriction occurs in GdNi at T{sub C}, on the order of 8000ppm strain along the c-axis and only until very recently the mechanism causing this giant magnetostriction was not understood. In order to learn more about the electronic and magnetic structure of GdNi, single crystals are required for anisotropic magnetic property measurements. Single crystal processing is quite challenging for GdNi though since the rare-earth transition-metal composition yields a very reactive intermetallic compound. Many crystal growth methods are pursued in this study including crucible free methods, precipitation growths, and specially developed Bridgman crucibles. A plasma-sprayed Gd2O3 W-backed Bridgman crucible was found to be the best means of GdNi single crystal processing. With a source of high-quality single crystals, many magnetization measurements were collected to reveal the magnetic structure of GdNi. Heat capacity and the magnetocaloric effect are also measured on a single crystal sample. The result is a thorough report on high quality single crystal processing and the magnetic properties of GdNi.

  6. Particle size dependent rheological property in magnetic fluid

    Science.gov (United States)

    Wu, Jie; Pei, Lei; Xuan, Shouhu; Yan, Qifan; Gong, Xinglong

    2016-06-01

    The influence of the particle size on the rheological property of magnetic fluid was studied both by the experimental and computer simulation methods. Firstly, the magnetic fluids were prepared by dispersing Fe3O4 nanospheres with size varied from 40 nm to 100 nm and 200 nm in the solution. Then, the rheological properties were investigated and it was found that the relative magnetorheological effects increased with increasing the particle size. Finally, the molecular dynamic simulation was used to analyze the mechanical characteristics of the magnetic fluid and the chain-like model agreed well with the experimental result. The authentic chain-like structure observed by a microscope agreed with the simulation results. The three particles composed of the similar cluster nanostructure, thus they exhibited similar magnetic property. To this end, the unique assembling microstructures was the origination of the mechanical difference. And it was found that the higher MR (magnetorheological) effects of the large particle based magnetic fluid was originated from the stronger assembling microstructure under the applying magnetic field.

  7. Magnetic Nanoparticles: Surface Effects and Properties Related to Biomedicine Applications

    Science.gov (United States)

    Issa, Bashar; Obaidat, Ihab M.; Albiss, Borhan A.; Haik, Yousef

    2013-01-01

    Due to finite size effects, such as the high surface-to-volume ratio and different crystal structures, magnetic nanoparticles are found to exhibit interesting and considerably different magnetic properties than those found in their corresponding bulk materials. These nanoparticles can be synthesized in several ways (e.g., chemical and physical) with controllable sizes enabling their comparison to biological organisms from cells (10–100 μm), viruses, genes, down to proteins (3–50 nm). The optimization of the nanoparticles’ size, size distribution, agglomeration, coating, and shapes along with their unique magnetic properties prompted the application of nanoparticles of this type in diverse fields. Biomedicine is one of these fields where intensive research is currently being conducted. In this review, we will discuss the magnetic properties of nanoparticles which are directly related to their applications in biomedicine. We will focus mainly on surface effects and ferrite nanoparticles, and on one diagnostic application of magnetic nanoparticles as magnetic resonance imaging contrast agents. PMID:24232575

  8. Magnetic Nanoparticles: Surface Effects and Properties Related to Biomedicine Applications

    Directory of Open Access Journals (Sweden)

    Bashar Issa

    2013-10-01

    Full Text Available Due to finite size effects, such as the high surface-to-volume ratio and different crystal structures, magnetic nanoparticles are found to exhibit interesting and considerably different magnetic properties than those found in their corresponding bulk materials. These nanoparticles can be synthesized in several ways (e.g., chemical and physical with controllable sizes enabling their comparison to biological organisms from cells (10–100 μm, viruses, genes, down to proteins (3–50 nm. The optimization of the nanoparticles’ size, size distribution, agglomeration, coating, and shapes along with their unique magnetic properties prompted the application of nanoparticles of this type in diverse fields. Biomedicine is one of these fields where intensive research is currently being conducted. In this review, we will discuss the magnetic properties of nanoparticles which are directly related to their applications in biomedicine. We will focus mainly on surface effects and ferrite nanoparticles, and on one diagnostic application of magnetic nanoparticles as magnetic resonance imaging contrast agents.

  9. Structure and magnetic properties of powder HITPERM material

    Directory of Open Access Journals (Sweden)

    J.E. Frąckowiak

    2007-03-01

    Full Text Available Purpose: The aim of the work is to investigate the structure and magnetic properties of the cobalt based HITPERM amorphous alloy Co68Fe4Mo1Si13.5B13.5 subjected high-energy ball milling and to the isothermal annealing to a combination of these two technologies.Design/methodology/approach: The nanocrystalline ferromagnetic powders were manufactured by high-energy ball milling of metallic glasses ribbons in as state. Using the HFQS program the distributions of the magnetic hyperfine P(H fields were determined for spectra smoothed in this way, employing the Hesse-Rübartsch method. Observations of the structure of powders were made on the OPTON DSM-940 scanning electron microscope. The diffraction examinations and examinations of thin foils were made on the JEOL JEM 200CX transmission electron microscope equipped in equipped with the EDS LINK ISIS X- ray energy dispersive spectrometer made by Oxford. Graphical analyses of the obtained X-ray diffraction patterns, as well as of the HC=f(TA relationship were made using the MICROCAL ORIGIN 6.0 program.Findings: The analysis of the structure and magnetic properties test results of the HITPERM powders alloy Co68Fe4Mo1Si13.5B13.5 obtained in the high-energy ball of milling process proved that the process causes significant decrease in the magnetic properties. The magnetic properties of this material and structure and may be improved by means of a proper choice of parameters of this process as well as the final thermal treatment.Research limitations/implications: For the soft magnetic powder material, further magnetical, composition examinations and structure are planed.Practical implications: Feature an alternative to solid alloys are the amorphous and nanocrystalline metal powders obtained by milling of metallic glasses and make it possible to obtain the ferromagnetic nanocomposites, whose dimensions and shape can be freely formed.Originality/value: The paper presents results of influence of parameters

  10. Artificial metamaterials for reprogrammable magnetic and microwave properties

    Science.gov (United States)

    Haldar, Arabinda; Adeyeye, Adekunle Olusola

    2016-01-01

    We demonstrate a reliable method for realizing various antiferromagnetic states in lithographically defined, dipolar coupled rhomboid nanomagnets. We directly probe the remanent state using magnetic force microscopy and measured the microwave absorptions using broadband ferromagnetic resonance spectroscopy technique. Reprogrammable microwave absorption properties are shown by switching between ferromagnetic and antiferromagnetic remanent states using a simple field initialization. There is a direct correlation between the magnetic remanent states and the microwave responses. Experimental results were supported by micromagnetic simulations which show a good agreement. The results may find applications in low power magnonic devices based on reprogrammable magnetic metamaterials.

  11. Optical and magnetic properties of PbTe(Ni)

    OpenAIRE

    Romčević, Nebojša; Trajić, J.; Romčević, M.; Stojanović, D.; T. A. Kuznetsova; Khokhlov, D.; Dobrowolski, W.; Rudolf, Rebeka; Anžel, Ivan

    2012-01-01

    Far-infrared and magnetic properties of Ni doped PbTe (ZNi = 1 £ 1019 at./cm3)single crystal are investigated in a broad range of temperature and magnetic elds. Far-infrared re°ection spectra were analyzed using a tting procedure based on the modi ed plasmon{two phonon interaction model. Together with the strong plasmon{two longitudinal optical phonon coupling we obtained a local mode of Ni at about 180 cm¡1. This mode intensity depends on temperature. Magnetic measurements shows that PbTe al...

  12. Magnetoactive elastomeric composites: Cure, tensile, electrical and magnetic properties

    Indian Academy of Sciences (India)

    K Sasikumar; G Suresh; K A Thomas; Reji John; V Natarajan; T Mukundan; R M R Vishnubhatla

    2006-11-01

    Magnetically active elastomer materials were prepared by incorporating nickel powder in synthetic elastomeric matrices, polychloroprene and nitrile rubber. Cure characteristics, mechanical, electrical and magnetic properties were experimentally determined for different volume fractions of magnetoactive filler. The cure time decreases sharply for initial filler loading and the decrease is marginal for additional loading of filler. The tensile strength and modulus at 100% strain was found to increase with increase in the volume fraction of nickel due to reinforcement action. The magnetic impedance and a.c. conductivity are found to increase with increase in volume fraction of nickel as well as frequency.

  13. Electronic and Magnetic Properties of Small Iridium Clusters

    Institute of Scientific and Technical Information of China (English)

    KUANG Xiang-jun

    2004-01-01

    The electronic and magnetic properties of small IrN clusters (N=5, 6, 9, 13, and 19 ) are studied by using the discrete-variational local-spin-density-functional method. The equilibrium bond length in the chosen geometry for IrN clusters are determined and show bond contraction compared with the bulk interatomic spacing. The clusters with magnetic ground state have ferromagnetic interaction and their average magnetic moment per atom has a complex size dependence. At last, the reactivity of IrN clusters toward H2, N2 and CO molecules is predicted.

  14. Effects of temperature and Nickel content on magnetic properties of Ni-doped ZnO

    Institute of Scientific and Technical Information of China (English)

    REN Lingling; JEUNG Won Young

    2006-01-01

    Magnetic properties of diluted magnetic semiconductors (DMSs), Ni-doped ZnO materials, prepared by sol-gel method were investigated by measuring magnetization as functions of magnetic field.The Ni content affects the magnetic properties at low sintered temperature but it has few effects on the magnetic properties at high sintered temperature.The sintered temperature has great effects on the magnetic properties of Ni/ZnO at high original mole ratio of Ni/Zn while it has slight effects on the magnetic properties of Ni/ZnO at low original mole ratio of Ni/Zn whatever low or high sintered temperature.

  15. Pressure vessel steel embrittlement monitoring by magnetic properties measurements

    International Nuclear Information System (INIS)

    The magnetic properties of specimens of one heat of A533B nuclear pressure vessel grade steel have been examined in the as-received condition and after neutron irradiation to various fluence levels up to 4 x 1018 cm-2 (E > 0.1 MeV) in the University of Illinois advanced TRIGA reactor core at two temperatures, approximately 120 and 260 C. The effect of certain heat treatments was also investigated. The magnetic properties were measured by an automated hysteresis curve-tracing method using a miniature transformer which incorporated the specimens in its core. Changes in magnetic hysteresis energy loss were correlated with neutron fluence in the case of certain irradiated specimens and with microhardness measurements in the case of heat-treated specimens. At the higher irradiation temperatures, no significant changes in either the magnetic hysteresis properties or the microhardness were noted for the present fluences. The relationship between the observed magnetic properties response and irradiation-induced embrittlement is discussed

  16. Surface properties and fatigue limit of metal. Comminication 3. Model of fatigue for metal failure with regard for anomalous properties of surface layer. Scale effect. Residual stresses

    International Nuclear Information System (INIS)

    The obtained data on the anomalous decrease of the yield point near the material surface with regard for characteristics of cyclic crack resistance are used to formulate a model of fatigue material failure. The model permits calculating a fatigue limit either of a specimen or of a construction according to a noncritical nonpropagating crack under bending, tension-compression for objects of different thickness and shape with notches of different depth with the presence of residual stresses and loading cycle asymmetry

  17. Composite Materials with Magnetically Aligned Carbon Nanoparticles Having Enhanced Electrical Properties and Methods of Preparation

    Science.gov (United States)

    Hong, Haiping (Inventor); Peterson, G.P. (Bud) (Inventor); Salem, David R. (Inventor)

    2016-01-01

    Magnetically aligned carbon nanoparticle composites have enhanced electrical properties. The composites comprise carbon nanoparticles, a host material, magnetically sensitive nanoparticles and a surfactant. In addition to enhanced electrical properties, the composites can have enhanced mechanical and thermal properties.

  18. The Mott localization and magnetic properties in condensed fermions systems

    International Nuclear Information System (INIS)

    In the present thesis the Mott localization and magnetic properties in condensed fermions system are considered. The Hubbard model has been used to strongly correlated electron systems and the Skyrme potential to a dense neutron matter with small concentration of protons. A variational approach to the metal-insulator transition is proposed which combines the Mott and Gutzwiller-Brinkman-Rice aspects of the localization. Magnetic properties of strongly correlated electrons are analyzed within the modified spin-rotation-invariant approach in the slow-boson representation. The theoretical prediction for considered systems are presented. 112 refs, 39 figs

  19. Estimation of hydrothermal deposits location from magnetization distribution and magnetic properties in the North Fiji Basin

    Science.gov (United States)

    Choi, S.; Kim, C.; Park, C.; Kim, H.

    2013-12-01

    The North Fiji Basin is belong to one of the youngest basins of back-arc basins in the southwest Pacific (from 12 Ma ago). We performed the marine magnetic and the bathymetry survey in the North Fiji Basin for finding the submarine hydrothermal deposits in April 2012. We acquired magnetic and bathymetry datasets by using Multi-Beam Echo Sounder EM120 (Kongsberg Co.) and Overhouser Proton Magnetometer SeaSPY (Marine Magnetics Co.). We conducted the data processing to obtain detailed seabed topography, magnetic anomaly, reduce to the pole(RTP), analytic signal and magnetization. The study areas composed of the two areas(KF-1(longitude : 173.5 ~ 173.7 and latitude : -16.2 ~ -16.5) and KF-3(longitude : 173.4 ~ 173.6 and latitude : -18.7 ~ -19.1)) in Central Spreading Ridge(CSR) and one area(KF-2(longitude : 173.7 ~ 174 and latitude : -16.8 ~ -17.2)) in Triple Junction(TJ). The seabed topography of KF-1 existed thin horst in two grabens that trends NW-SE direction. The magnetic properties of KF-1 showed high magnetic anomalies in center part and magnetic lineament structure of trending E-W direction. In the magnetization distribution of KF-1, the low magnetization zone matches well with a strong analytic signal in the northeastern part. KF-2 area has TJ. The seabed topography formed like Y-shape and showed a high feature in the center of TJ. The magnetic properties of KF-2 displayed high magnetic anomalies in N-S spreading ridge center and northwestern part. In the magnetization distribution of KF-2, the low magnetization zone matches well with a strong analytic signal in the northeastern part. The seabed topography of KF-3 presented a flat and high topography like dome structure at center axis and some seamounts scattered around the axis. The magnetic properties of KF-3 showed high magnetic anomalies in N-S spreading ridge center part. In the magnetization of KF-2, the low magnetization zone mismatches to strong analytic signal in this area. The difference of KF-3

  20. Magnetic properties of multisegmented cylindrical nanoparticles with alternating magnetic wire and tube segments

    Energy Technology Data Exchange (ETDEWEB)

    Salazar-Aravena, D.; Corona, R.M. [Departamento de Física, Universidad de Santiago de Chile (USACH), Avda. Ecuador 3493, 917-0124 Santiago (Chile); Goerlitz, D.; Nielsch, K. [Institute of Applied Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg (Germany); Escrig, J., E-mail: jescrigm@gmail.com [Departamento de Física, Universidad de Santiago de Chile (USACH), Avda. Ecuador 3493, 917-0124 Santiago (Chile); Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Avda. Ecuador 3493, 917-0124 Santiago (Chile)

    2013-11-15

    The magnetic properties in multisegmented cylindrical nanostructures comprised of nanowire and nanotube segments are investigated numerically as a function of their geometry. In this work we report systematic changes in the coercivity and remanence in these systems. Besides, we have found the ideal conditions for a magnetic configuration with two antiparallel domains that could be used to help to stabilize magnetic nanoparticles inside ferromagnetic multisegmented cylindrical nanoparticles. This magnetic behavior is due to the fact that the tube segment reverses its magnetization before the wire segment, allowing the control of the magnetic domain walls motion between two segments. In this way, these magnetic nanoobjects can be an alternative to store information or even perform logic functions. - Highlights: • Magnetic states of wire/tube were investigated as a function of their geometry. • Multisegmented systems present two well-defined jumps in the hysteresis curve. • It is possible to prepare an antiparallel magnetic configuration. • The step width for the optimum condition reaches 60 mT. • The tube segments reverse their magnetization first than the wire segments.

  1. Preparation, magnetic and electromagnetic properties of organic magnetic prepolymer containing copper phthalocyanine ring

    International Nuclear Information System (INIS)

    A novel kind of organic magnetic prepolymer containing copper phthalocyanine ring was prepared via the polymerization of ferrocenyl organic metal magnetic resin (FOMR) with cuprous chloride. The process of prepolymerization was monitored by Fourier transform infrared spectroscopy and ultraviolet–visible spectrophotometry. Magnetic behavior of the samples was studied by a vibrating sample magnetometer. The experimental results indicated that the organic magnetic prepolymer containing copper phthalocyanine ring showed ferromagnetic property and the magnetism of the samples can be finely tuned by controlling the condition of the reaction. The maximum saturation magnetization of the organic magnetic prepolymer containing copper phthalocyanine ring increased from 3.69 to 8.38 emu/g by increasing the reaction time. Meanwhile, the remnant magnetization increased from 1.06 to 2.36 emu/g. Measurement of electromagnetic parameters of the samples showed that complex permittivity and complex permeability also increased with increase in the reaction time. Among these, the imaginary part of permittivity increased from 0.22 to 0.38 at the frequency of 10.0 GHz. - Highlights: ► A novel organic magnetic prepolymer was successfully prepared. ►The saturation magnetization of samples increased with increase in the reaction time. ► The complex permittivity of samples increased with increase in the reaction time. ► The complex permeability of samples increased with increase in the reaction time. ► The material is believed to be useful in electronic and biomedical fields.

  2. Measurement of magnetic properties at cryogenic temperatures

    CERN Multimedia

    1977-01-01

    This picture shows part of the low-mu permeameter to measure permeability of stainless steels and other low-mu materials used in superconducting magnets. The sample, a 5 mm diam., 45 mm long rod, is suspended to long leads before being inserted in the test cryostat. For the measurement the sample is surrounded by a flux- measuring coil and placed in the field of a superconducting solenoid. At a given field the sample is removed.During the removal, the voltage induced in the flux-measuring coil is time integrated giving the flux variation. This equipment was developed to select stainless steels and other low-mu materials used in the ISR Prototype Superconducting Qaudrupole. The person is W.Ansorge.

  3. Magnetic properties of heat treated bacterial ferrihydrite nanoparticles

    Science.gov (United States)

    Balaev, D. A.; Krasikov, A. A.; Dubrovskiy, A. A.; Popkov, S. I.; Stolyar, S. V.; Bayukov, O. A.; Iskhakov, R. S.; Ladygina, V. P.; Yaroslavtsev, R. N.

    2016-07-01

    The magnetic properties of ferrihydrite nanoparticles, which are products of vital functions of Klebsiella oxitoca bacteria, have been studied. The initial powder containing the nanoparticles in an organic shell was subjected to low-temperature (T=160 °C) heat treatment for up to 240 h. The bacterial ferrihydrite particles exhibit a superparamagnetic behavior. Their characteristic blocking temperature increases from 26 to 80 K with the heat treatment. Analysis of the magnetization curves with regard to the magnetic moment distribution function and antiferromagnetic contribution shows that the low-temperature heat treatment enhances the average magnetic moment of a particle; i.e., the nanoparticles coarsen, probably due to their partial agglomeration during heat treatment. It was established that the blocking temperature nonlinearly depends on the particle volume. Therefore, a model was proposed that takes into account both the bulk and surface magnetic anisotropy. Using this model, the bulk and surface magnetic anisotropy constants KV≈1.7×105 erg/cm3 and KS≈0.055 erg/cm2 have been determined. The effect of the surface magnetic anisotropy of ferrihydrite nanoparticles on the observed magnetic hysteresis loops is discussed.

  4. Structural, electronic and magnetic properties of MnB2

    Indian Academy of Sciences (India)

    R Masrour; E K Hlil; M Hamedoun; A Benyoussef; O Mounkachi; H El Moussaoui

    2015-08-01

    The self-consistent ab-initio calculations, based on density functional theory approach and using the full potential linear augmented plane wave method, are performed to investigate both electronic and magnetic properties of the MnB2 compounds. Polarized spin and spin–orbit coupling are included in calculations within the framework of the ferromagnetic state between two adjacent Mn atoms. Magnetic moment considered to lie along the (001) axes are computed. The antiferromagnetic and ferromagnetic energies of MnB2 systems are obtained. Obtained data from ab-initio calculations are used as input for the high-temperature series expansions (HTSEs) calculations to compute other magnetic parameters. The exchange interactions between the magnetic atoms Mn–Mn in MnB2 are established by using the mean field theory. The HTSEs of the magnetic susceptibility with the magnetic moments in MnB2 (Mn) through Ising model is given. The critical temperature C (K) is obtained by HTSEs applied to the magnetic susceptibility series combined with the Padé approximant method. The critical exponent associated with the magnetic susceptibility is deduced as well.

  5. Improved Electrical Insulation of Rare Earth Permanent Magnetic Materials With High Magnetic Properties

    Institute of Scientific and Technical Information of China (English)

    CHANG Ying; WANG Da-peng; LI Wei; PAN Wei; YU Xiao-jun; QI Min

    2009-01-01

    Rare earth permanent magnetic materials are typical electrical conductor, and their magnetic properties will decrease because of the eddy current effect, so it is difficult to keep them stable for a long enough time under a high frequency AC field. In the present study, as far as rare earth permanent magnets are concerned, for the first time, rare earth permanent magnets with strong electrical insulation and high magnetic performance have been obtained through experiments, and their properties are as follows:(1) Sm2TM17: Br=0.62 T, jHc=803.7 kA/m, (BH)m= The magnetic properties of Sm2TM17 and NdFeB are obviously higher than those of ferrite permanent magnet, and the electric insulating characteristics of Sm2TM17 and NdFeB applied have in fact been approximately the same as those of ferrite. Therefore, Sm2TM17 and NdFeB will possess the ability to take the place of ferrite under a certain high frequency AC electric field.

  6. Dynamic magnetic properties of ZnO nanocrystals incorporating Fe

    Energy Technology Data Exchange (ETDEWEB)

    Kuryliszyn-Kudelska, I., E-mail: kuryl@ifpan.edu.pl [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Hadzic, B. [Institute of Physics, Belgrade University, Pregrevica 118, 11080 Belgrade (Serbia); Sibera, D. [West Pomeranian University of Technology, Institute of Chemical and Environment Engineering, Pulaskiego 10, 70-322 Szczecin (Poland); Romcevic, M.; Romcevic, N. [Institute of Physics, Belgrade University, Pregrevica 118, 11080 Belgrade (Serbia); Narkiewicz, U. [West Pomeranian University of Technology, Institute of Chemical and Environment Engineering, Pulaskiego 10, 70-322 Szczecin (Poland); Dobrowolski, W. [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland)

    2011-03-03

    Research highlights: > We have studied the magnetic properties of ZnO(Fe) nanocrystalline samples. > The aim of this paper was to compare the dynamic magnetic properties of ZnO(Fe) nanocrystals for two methods of synthesis. > We observed different type of dynamic magnetic behavior for two types of magnetic nanocrystals synthesized by hydrothermal and coprecipitation-calcination methods. > For nanocrystals synthesized by hydrothermal process the results of low-field AC susceptibility are satisfactorily explained by superparamagnetic model including inter-particle interactions. > For samples synthesized by calcinations process we observed the spin-glasslike behavior. - Abstract: The aim of the present work is to study the magnetic properties of ZnO(Fe) nanocrystalline samples prepared by two methods of synthesis. We have used the microwave assisted hydrothermal synthesis and traditional wet chemistry method followed by calcination. The detailed structural characterization was performed by means of X-ray diffraction and micro-Raman spectroscopy measurements. The dynamic magnetic properties were studied by means of AC susceptibility {chi}. The measurements were performed at small AC magnetic field with amplitude not exceeding 5 Oe and different frequency values (from 7 Hz to 9970 Hz). The AC susceptibility maxima have been found for in-phase susceptibility Re({chi}) and for out of phase susceptibility Im({chi}). We analyzed the observed frequency dependence of the peak temperature in the AC susceptibility curve using the empirical parameter {Phi} that is a quantitative measure of the frequency shift and is given by the relative shift of the peak temperature per decade shift in frequency, as well as Vogel-Fulcher law.

  7. Magnetic properties and scale-up of nanostructured cobalt carbide permanent magnetic powders

    Energy Technology Data Exchange (ETDEWEB)

    Zamanpour, Mehdi, E-mail: zamanpour.m@husky.neu.edu; Bennett, Steven; Taheri, Parisa; Chen, Yajie [Center for Microwave Magnetic Materials and Integrated Circuits, Northeastern University, Boston, Massachusetts 02115 (United States); Harris, Vincent G. [Center for Microwave Magnetic Materials and Integrated Circuits, Northeastern University, Boston, Massachusetts 02115 (United States); Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts 02115 (United States)

    2014-05-07

    Co{sub x}C magnetic nanoparticles were successfully synthesized via a modified polyol process without using a rare-earth catalyst during the synthesis process. The present results show admixtures of Co{sub 2}C and Co{sub 3}C phases possessing magnetization values exceeding 45 emu/g and coercivity values exceeding 2.3 kOe at room temperature. Moreover, these experiments have illuminated the important role of surfactants, reaction temperature, and reaction duration on the crystallographic structure and magnetic properties of Co{sub x}C, while tetraethylene glycol was employed as a reducing agent. The role of the ratios of Co{sub 2}C and Co{sub 3}C phases in the admixture magnetic properties is discussed. The crystallographic structure and particle size of the Co{sub x}C nanoparticles were characterized by X-ray diffractometry and scanning electron microscopy. Vibrating sample magnetometry was used to determine magnetic properties. Scale-up of synthesis to more than 5 g per batch was demonstrated with no significant degradation of magnetic properties.

  8. Magnetic properties and magnetic phase diagrams of intermetallic compound GdMn2Ge2

    Institute of Scientific and Technical Information of China (English)

    Guo Guang-Hua(郭光华); Zhang Hai-Bei(张海贝); R.Z.Levitin

    2003-01-01

    A modified Yafet-Kittle model is applied to investigate the magnetic properties and magnetic phase transition of the intermetallic compound GdMn2Ge2.Theoretical analysis and calculation show that there are five possible magnetic structures in GdMn2Ge2.Variations of external magnetic field and temperature give rise to the first-order or secondorder magnetic transitions from one phase to another.Based on this model,the magnetic curves of GdMn2Ge2 single crystals at different temperatures are calculated and a good agreement with experimental data has obtained.Based on the calculation,the H-T magnetic phase diagrams of GdMn2Ge2 are depicted.The Gd-Gd,Gd-Mn,intralayer Mn-Mn and interlayer Mn-Mn exchange coupling parameters are estimated.It is shown that,in order to describe the magnetic properties of GdMn2Ge2,the lattice constant and temperature dependence of interlayer Mn-Mn exchange interaction must be taken into account.

  9. Spectrum of anomalous magnetohydrodynamics

    Science.gov (United States)

    Giovannini, Massimo

    2016-05-01

    The equations of anomalous magnetohydrodynamics describe an Abelian plasma where conduction and chiral currents are simultaneously present and constrained by the second law of thermodynamics. At high frequencies the magnetic currents play the leading role, and the spectrum is dominated by two-fluid effects. The system behaves instead as a single fluid in the low-frequency regime where the vortical currents induce potentially large hypermagnetic fields. After deriving the physical solutions of the generalized Appleton-Hartree equation, the corresponding dispersion relations are scrutinized and compared with the results valid for cold plasmas. Hypermagnetic knots and fluid vortices can be concurrently present at very low frequencies and suggest a qualitatively different dynamics of the hydromagnetic nonlinearities.

  10. Drug delivery property, bactericidal property and cytocompatibility of magnetic mesoporous bioactive glass

    International Nuclear Information System (INIS)

    A multifunctional magnetic mesoporous bioactive glass (MMBG) has been widely used for a drug delivery system, but its biological properties have been rarely reported. Herein, the effects of mesopores and Fe3O4 nanoparticles on drug loading–release property, bactericidal property and biocompatibility have been investigated by using mesoporous bioactive glass (MBG) and non-mesoporous bioactive glass (NBG) as control samples. Both MMBG and MBG have better drug loading efficiency than NBG because they possess ordered mesoporous channels, big specific surface areas and high pore volumes. As compared with MBG, the Fe3O4 nanoparticles in MMBG not only provide magnetic property, but also improve sustained drug release property. For gentamicin-loaded MMBG (Gent-MMBG), the sustained release of gentamicin and the Fe3O4 nanoparticles minimize bacterial adhesion significantly and prevent biofilm formation against Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis). Moreover, the magnetic Fe3O4 nanoparticles in MMBG can promote crucial cell functions such as cell adhesion, spreading and proliferation. The excellent biocompatibility and drug delivery property of MMBG suggest that Gent-MMBG has great potentials for treatment of implant-associated infections. - Highlights: • Multifunctional magnetic mesoporous bioactive glass is fabricated. • The bioactive glass has great biocompatibility. • The bioactive glass exhibits high drug loading–release properties. • The drug delivery system has bactericidal property. • Magnetic particles improve cell adhesion, spreading and proliferation

  11. Magnetic properties of xenoliths from Yakut kimberlite pipes

    Science.gov (United States)

    Tselebrovskiy, Alexey; Maksimochkin, Valeriy

    2014-05-01

    Lower continental crust is poorly known due to its limited availability. One source of information about the formation of the lower crust is the study of xenoliths found in kimberlites, mainly peridotites, eclogites and other rocks made by the kimberlite magma to the surface from great depths. Magnetic methods can solve problems related on the one hand, the definition of the phase composition of natural ferrimagnetics responsible for the magnetic properties of rocks, and on the other - with the establishment of the thermodynamic conditions in which they were formed - their genesis. For example, in [1, 2], there were differences in the magnetic properties of kimberlites taken from tubes with different diamond productivity. In this work, studies have been conducted of the magnetic properties and mineralogy of xenoliths from 10 Yakut kimberlit pipes, courtesy of Doctor of Geological and Mineralogical Sciences V. K. Garanin. Found that the natural remanent magnetization (NRM) and magnetic susceptibility (k0) of the investigated samples varies widely: NRM = (0.002-12.59) A/m, k0 = (0.23-59.9)*10-3 SI. Magnetic properties vary by species: average NRM peridotites (0.002-0.32) A/m order of magnitude smaller eclogitic rocks (0.58-12.59) A/m. Thermomagnetic analysis (TMA) of the test samples showed the presence of xenoliths of the ferromagnetic phase with a Curie point close to Tc magnetite. Because of the high correlation between the values of NRM, k0 and ferrimagnetic saturation magnetization (SM) can be inferred that the magnetic properties of the rocks studied at temperatures above ambient is basically determined by the concentration of magnetite in them. Besides magnetite TMA were also identified ferrimagnetic phase with Curie temperatures from -50°C to -125°C. Mineralogical analysis performed on three samples of peridotite tubes Udachnaya, Yubileynaya and Mir and two samples of eclogite tubes Udachnaya and Komsomolskaya, showed that at temperatures below room

  12. Electromagnetic fields and anomalous transports in heavy-ion collisions—a pedagogical review

    Science.gov (United States)

    Huang, Xu-Guang

    2016-07-01

    The hot and dense matter generated in heavy-ion collisions may contain domains which are not invariant under P and CP transformations. Moreover, heavy-ion collisions can generate extremely strong magnetic fields as well as electric fields. The interplay between the electromagnetic field and triangle anomaly leads to a number of macroscopic quantum phenomena in these P- and CP-odd domains known as anomalous transports. The purpose of this article is to give a pedagogical review of various properties of the electromagnetic fields, the anomalous transport phenomena, and their experimental signatures in heavy-ion collisions.

  13. Electromagnetic fields and anomalous transports in heavy-ion collisions --- A pedagogical review

    CERN Document Server

    Huang, Xu-Guang

    2015-01-01

    The hot and dense matter generated in heavy-ion collisions may contain domains in which the P and CP symmetries of QCD are violated. Moreover, heavy-ion collisions can generate extremely strong magnetic fields as well as electric fields. The interplay among the electromagnetic field, triangle anomaly, and the P and CP violation of QCD leads to a number of macroscopic quantum phenomena known as the anomalous transports. The purpose of the article is to give a pedagogical review of various properties of the electromagnetic fields, the anomalous transports phenomena, and their experimental signatures in heavy-ion collisions.

  14. Magnetic Properties of Young Stars in the TW Hydrae Association

    CERN Document Server

    Yang, Hao; Valenti, Jeff A

    2008-01-01

    We present an analysis of infrared (IR) echelle spectra of five stars in the TW Hydrae Association (TWA). We model the Zeeman broadening in four magnetic-sensitive \\ion{Ti}{1} lines near $2.2 \\mu$m and measure the value of the photospheric magnetic field averaged over the surface of each star. To ensure that other broadening mechanisms are properly taken into account, we also inspect several magnetically insensitive CO lines near $2.3 \\mu$m and find no excess broadening above that produced by stellar rotation and instrumental broadening, providing confidence in the magnetic interpretation of the width of the \\ion{Ti}{1} lines. We then utilize our results to test the relationship between stellar magnetic flux and X-ray properties and compare the measured fields with equipartition field values. Finally, we use our results and recent results on a large sample of stars in Taurus to discuss the potential evolution of magnetic field properties between the age of Taurus ($\\sim$2 Myrs) and the age of TWA ($\\sim$10 My...

  15. Anomalous x-ray scattering

    International Nuclear Information System (INIS)

    The availability of tunable synchrotron radiation has made it possible systematically to perform x-ray diffraction studies in regions of anomalous scattering near absorption edges, e.g. in order to derive phase information for crystal structure determination. An overview is given of recent experimental and theoretical work and discuss the properties of the anomalous atomic scattering factor, with emphasis on threshold resonances and damping effects. The results are applied to a discussion of the very strong anomalous dispersion recently observed near the L3 edge in a cesium complex. Also given is an overview of elements and levels where similar behavior can be expected. Finally, the influence of solid state and chemical effects on the absorption edge structure is discussed. 64 references

  16. Thermodynamic properties of Heisenberg magnetic systems

    International Nuclear Information System (INIS)

    In this paper, we present a comprehensive investigation of the effects of the transverse correlation function (TCF) on the thermodynamic properties of Heisenberg antiferromagnetic (AFM) and ferromagnetic (FM) systems with cubic lattices. The TCF of an FM system is positive and increases with temperature, while that of an AFM system is negative and decreases with temperature. The TCF lowers internal energy, entropy and specific heat. It always raises the free energy of an FM system but raises that of an AFM system only above a specific temperature when the spin quantum number is S ≥ 1. Comparisons between the effects of the TCFs on the FM and AFM systems are made where possible

  17. Synthesis and properties of magnetic ceramic nanoparticles

    Science.gov (United States)

    Sorescu, Monica

    2012-02-01

    Magnetic ceramic nanoparticles of the type xIn2O3-(1-x)alpha-Fe2O3, xV2O5-(1-x)alpha-Fe2O3 and xZnO-(1-x)alpha-Fe2O3 (x=0.1-0.7) were synthesized from the mixed oxides using mechanochemical activation for 0-12 hours. X-ray diffraction was used to derive the phase content, lattice constants and particle size information as function of ball milling time. Mossbauer spectroscopy results correlated with In3+, V5+ and Zn2+ substitution of Fe3+ in the hematite lattice. SEM/EDS measurements revealed that the mechanochemical activation by ball milling produced systems with a wide range of particle size distribution, from nanometer particles to micrometer agglomerates, but with a uniform distribution of the elements. Simultaneous DSC-TGA investigations up to 800 degrees C provided information on the heat flow, weight loss and the enthalpy of transformation in the systems under investigation. This study demonstrates the formation of a nanostructured solid solution for the indium oxide, an iron vanadate (FeVO4) for the vanadium oxide, and of the zinc ferrite (ZnFe2O4) for the zinc oxide. The transformation pathway for each case can be related to the oxidation state of the metallic specie of the oxide used in connection with hematite.

  18. Preparation and Properties of Various Magnetic Nanoparticles

    Directory of Open Access Journals (Sweden)

    Jaromir Hubalek

    2009-03-01

    Full Text Available The fabrications of iron oxides nanoparticles using co-precipitation and gadolinium nanoparticles using water in oil microemulsion method are reported in this paper. Results of detailed phase analysis by XRD and Mössbauer spectroscopy are discussed. XRD analysis revealed that the crystallite size (mean coherence length of iron oxides (mainly γ-Fe2O3 in the Fe2O3 sample was 30 nm, while in Fe2O3/SiO2 where the ε-Fe2O3 phase dominated it was only 14 nm. Gd/SiO2 nanoparticles were found to be completely amorphous, according to XRD. The samples showed various shapes of hysteresis loops and different coercivities. Differences in the saturation magnetization (MS correspond to the chemical and phase composition of the sample materials. However, we observed that MS was not reached in the case of Fe2O3/SiO2, while for Gd/SiO2 sample the MS value was extremely low. Therefore we conclude that only unmodified Fe2O3 nanoparticles are suitable for intended biosensing application in vitro (e.g. detection of viral nucleic acids and the phase purification of this sample for this purpose is not necessary.

  19. Magnetic Properties of Nd8Fe83Co3B6 Nanocomposite Magnets

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The influence of quenching technology, annealing temperature and time on the structures and magnetic properties of Nd8Fe83Co3B6 nanocomposite magnets was investigated. The results show that the α-Fe/Nd2Fe14B nanocomposite magnet containing a small amount of B is difficult to form amorphous state. The magnetic properties of 26 m/s quenched Nd8Fe83Co3B6 powders annealed at 640℃×480 s reach iHc=513 kA/m, Br=1.05 T and (BH)max=92.0 kJ/m3. The grain size is Dα-Fe=21.5 nm and DNd2Fe14B=30.2 nm.

  20. The charmonium dissociation in an "anomalous wind"

    CERN Document Server

    Sadofyev, Andrey V

    2016-01-01

    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 charmonium color screening length which are {\\it model-dependent} and those on the heavy quark drag force which are fixed by the second law of thermodynamics. We speculate on the possible charmonium dissociation induced by chiral anomaly in heavy ion collisions.