scholarly journals Магнитные свойства сплавов Pb-=SUB=-1-y-=/SUB=-Sс-=SUB=-y-=/SUB=-Te

2021 ◽  
Vol 55 (12) ◽  
pp. 1167
Author(s):  
Е.П. Скипетров ◽  
Е.В. Богданов ◽  
Л.А. Скипетрова ◽  
А.А. Соловьев ◽  
А.В. Кнотько ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electronic Structure ◽  
Crystal Lattice ◽  
Magnetic Moment ◽  
Impurity Concentration ◽  
Unit Volume ◽  
Average Concentration ◽  
Free Electrons ◽  
Metal Sublattice ◽  
The Magnetic Field

The magnetic field dependences of the magnetization (B < 9 Т, T = 2.0 - 70 K) of the samples from a single crystal Pb1-yScyTe (y=0.01) ingot, synthesized by the Bridgman method, are studied. It is established that, in accordance with the generally accepted model of the rearrangement of the electronic structure of alloys during doping, there is no paramagnetic contribution of single scandium ions located in the nodes of the metal sublattice in the studied samples. The magnetization of the samples contains several contributions: superparamagnetism of scandium clusters, linear in field diamagnetism of the crystal lattice and the paramagnetism of free electrons, as well as the oscillating contribution of the de Haas – van Alphen effect. The field dependences of the main contribution of scandium clusters are successfully approximated using the Langevin function. The average concentration, magnetic moment and the total magnetic moment of the clusters per unit volume of the sample were determined with an increase in the impurity concentration along the ingot.

Doppler-Shifted Cyclotron Resonance in Thin Metal Films

1972 ◽  
Vol 50 (18) ◽  
pp. 2122-2137
Author(s):  
R. Turner ◽  
J. F. Cochran
Keyword(s):  
Magnetic Field ◽  
Metal Films ◽  
Thin Metal Film ◽  
Thin Metal ◽  
Free Electrons ◽  
Fermi Surfaces ◽  
First Order ◽  
Simple Quantum ◽  
The Magnetic Field ◽  
Good Agreement

According to Van Gelder the microwave absorption by a thin metal film in the presence of a static magnetic field normal to the film contains a series of peaks as the magnetic field is varied. In the present paper it is argued that these peaks correspond to Doppler-shifted cyclotron resonances of the carriers in the metal due to the quantization of electron momenta normal to the plane of the film. A simple quantum calculation is presented for the case of free electrons where the film is thin enough that to first order the microwave fields within are determined only by the boundary conditions and Maxwell's equations. The quantum expression is in good agreement with the absorption calculated using semiclassical arguments which can be readily extended to more complicated Fermi surfaces.

Effects of Ca2+-Doping on the Crystal Lattice of α-Fe2O3

2014 ◽  
Vol 975 ◽  
pp. 116-121
Author(s):  
Bruna da Costa Andrade ◽  
José Cleverton da Conceição Passos ◽  
Marcelo Andrade Macedo
Keyword(s):  
Magnetic Field ◽  
Electrical Resistivity ◽  
Crystal Lattice ◽  
Coercive Field ◽  
Calcium Concentration ◽  
Sol Gel ◽  
Impedance Analysis ◽  
Hematite Phase ◽  
Sol Gel Process ◽  
The Magnetic Field

Samples of CayFe12-yO19 (0 ≤ y ≤ 1.0) were prepared by a proteic sol–gel process with hematite phase and clusters of M-type calcium hexaferrite. Impedance analysis showed that the resistivity increased with calcium concentration in the 0.0 < y ≤ 0.2 range, but decreased for y > 0.2. The saturation of the electrical resistivity occurred at 7.5 × 106 Ω·cm for Ca0.9Fe11.1O19. The plot of magnetization as a function of the magnetic field showed high values of saturation magnetization (40 emu/g) with low remanence (6.7 emu/g) and coercive field (320 Oe).

scholarly journals Neutron anomalous magnetic moment in dense magnetized systems

2018 ◽  
Vol 27 (02) ◽  
pp. 1850011
Author(s):  
Zeinab Rezaei
Keyword(s):  
Magnetic Field ◽  
Equation Of State ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Nuclear Potential ◽  
Order Constraint ◽  
The Magnetic Field

In this work, we calculate the neutron anomalous magnetic moment (AMM) supposing that this value can depend on the density and magnetic field of the system. We employ the lowest-order constraint variation (LOCV) method and [Formula: see text] nuclear potential to calculate the medium dependency of the neutron AMM. It is confirmed that the neutron AMM increases by increasing the density, while it decreases as the magnetic field grows. The energy and equation of state for the system have also been investigated.

Quantum Hall effects

Quantum 20/20 ◽  
2019 ◽  
pp. 303-322
Author(s):  
Ian R. Kenyon
Keyword(s):  
Magnetic Field ◽  
Hall Effect ◽  
Energy Gap ◽  
Quantum Hall ◽  
Free Electrons ◽  
Electron Gases ◽  
Hall Conductance ◽  
Hall Effects ◽  
The Stability ◽  
The Magnetic Field

It is explained how plateaux are seen in the Hall conductance of two dimensional electron gases, at cryogenic temperatures, when the magnetic field is scanned from zero to ~10T. On a Hall plateau σ‎xy = ne 2/h, where n is integral, while the longitudinal conductance vanishes. This is the integral quantum Hall effect. Free electrons in such devices are shown to occupy quantized Landau levels, analogous to classical cyclotron orbits. The stability of the IQHE is shown to be associated with a mobility gap rather than an energy gap. The analysis showing the topological origin of the IQHE is reproduced. Next the fractional QHE is described: Laughlin’s explanation in terms of an IQHE of quasiparticles is presented. In the absence of any magnetic field, the quantum spin Hall effect is observed, and described here. Time reversal invariance and Kramer pairs are seen to be underlying requirements. It’s topological origin is outlined.

Conduction electron diamagnetism in alloys and magnetic-field-dependent dielectric constant of a Fermi gas

1964 ◽  
Vol 280 (1380) ◽  
pp. 85-96 ◽  
Keyword(s):  
Magnetic Field ◽  
Dielectric Constant ◽  
Free Electrons ◽  
Impurity Potential ◽  
First Order ◽  
Dilute Alloys ◽  
A Value ◽  
Field Dependent ◽  
Self Consistency ◽  
The Magnetic Field

The diamagnetism of free electrons in the presence of charged impurity centres which are sufficiently dilute to be non-interacting is calculated to first order in the strength of the potential of the impurity centre. This is done by combining the density-matrix treatment of Landau diamagnetism with the impurity-screening theory o f March & Murray. The susceptibility involves the integrated value of the impurity potential through the crystal, and its first derivative with respect to the magnetic field, B. If the impurity potential is assumed to have a value appropriate to B — 0, then the result for the change in diamagnetic susceptibility on alloying agrees with that of Kohn & Luming (1963). It is shown, however, that the impurity potential is modified in the presence of the magnetic field, and in particular it has angular dependence. The correction to the dia­magnetic susceptibility due to this self-consistency is shown to be significant (25% ). The relevance of the theory to experimental results on dilute alloys is briefly discussed. Finally, as a by-product of the investigation, we have obtained interesting results about the form of the field-dependent dielectric constant.

SOLAR NEUTRINO FLUX VARIATION AND NEUTRINO MAGNETIC MOMENT

1989 ◽  
Vol 04 (02) ◽  
pp. 111-114 ◽  
Author(s):  
PROBHAS RAYCHAUDHURI
Keyword(s):  
Magnetic Field ◽  
Sunspot Number ◽  
Magnetic Moment ◽  
Solar Neutrino ◽  
Convection Zone ◽  
Neutrino Flux ◽  
Flux Variation ◽  
Neutrino Magnetic Moment ◽  
Solar Neutrino Flux ◽  
The Magnetic Field

It is shown that neutrino flip through the magnetic field of the convection zone is not responsible for the anticorrelation between the solar neutrino flux and the sunspot number.

scholarly journals The theory of the galvomagnetic effects in bismuth

1936 ◽  
Vol 155 (886) ◽  
pp. 653-663 ◽  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Air Temperature ◽  
Solid Solutions ◽  
Hall Coefficient ◽  
Specific Resistance ◽  
Large Change ◽  
Free Electrons ◽  
The Magnetic Field ◽  
Positive Holes

The change in the specific resistance of bismuth when subject to a magnetic field is far greater than that of most metals, e . g ., a field of 10 kilo-gauss, at liquid air temperature, increases the resistance of bismuth eightfold, whilst the same field causes an increase of only 0·1% in the resistance of silver. Besides the large change of resistance it is found that the Hall coefficient of bismuth is also much greater than of most metals, and shows a curious dependence upon on the magnetic field strength, as well as a very striking temperature dependence. In this paper these effects are considered on the basis of a theory previously of bismuth, and the properties of the dilute solid solutions of other elements in bismuth.* It was shown that in bismuth the relation between the structure and the available number of valency electrons was such that these electrons formed an almost closed group, or in other words an almost completely filled Brillouin zone. In such a case an electric current is carried by a number (in bismuth a very small number) of electrons, and an equal number of positive holes. By positive holes we mean the few vacant places which are left when a zone or energy band is almost completely filled. These vacancies behave like positive charges; their effective mass is, in general, smaller than that of free electrons.

Electron Subband Levels of n-Type δ-Doped Quantum Wells under In-Plane Magnetic Fields

1997 ◽  
Vol 11 (09) ◽  
pp. 1195-1207
Author(s):  
E. K. Takahashi ◽  
A. T. Lino ◽  
L. M. R. Scolfaro
Keyword(s):  
Magnetic Field ◽  
Electronic Structure ◽  
Magnetic Fields ◽  
Quantum Well ◽  
Quantum Wells ◽  
Conduction Band ◽  
Electron Energy ◽  
Self Consistent ◽  
Plane Direction ◽  
The Magnetic Field

Self-consistent calculations of the electronic structure of center n-δ-doped GaAs/Al x Ga 1-x As quantum wells under in-plane magnetic fields are presented. The field B is varied up to 20 Tesla for different quantum well widths L w and sheet donor concentrations N D . The magnetic field produces noticeable changes in the energy dispersions along an in-plane direction perpendicular to B. The effects of B are more pronounced for higher electronic subbands. It is found that the diamagnetic shifts increase with increasing L w and/or N D . Contrarily to what has been observed in modulation-doped quantum wells, in these δ-doped systems the electron energy dispersions keep the single conduction band minimum at the center of the Brillouin zone even for intense magnetic fields.

Magnetostrictive Alloy Actuator for a Bone Transport Device

2008 ◽  
Author(s):  
Parsaoran Hutapea
Keyword(s):  
Magnetic Field ◽  
Experimental Work ◽  
Magnetic Moment ◽  
Longitudinal Direction ◽  
Bone Transport ◽  
Constitutive Behavior ◽  
Actuation System ◽  
Periosteal Surface ◽  
The Magnetic Field ◽  
Transport Device

The ultimate goal of our research is to develop a bone transport device using a magnetostrictive alloy actuation system. The device is designed to be subcutaneously mounted on the periosteal surface of the tibia. The magnetomechanical behavior of Terfenol-D smart magnetostrictive material has been well investigated in the literature when a magnetic field is applied along the longitudinal direction of the Terfenol-D material (perpendicular to the material’s magnetic moment). However, the requirement of our device is to have the magnetic field transversely applied on the Terfenol-D material (along the material’s magnetic moment). Therefore, the objective of this work was to study the magnetomechanical behavior of Terfenol-D under a transversely applied magnetic field. Experimental work was performed and a Terfenol-D material constitutive behavior was investigated.

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