Local Magnetic Fields in some Bismuth Compounds. A Survey of Experimental Evidences

1994 ◽  
Vol 49 (1-2) ◽  
pp. 418-424 ◽  
Author(s):  
E. A. Kravchenko ◽  
V. G. Orlov
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Magnetic Fields ◽  
Unpaired Electron ◽  
Internal Magnetic Field ◽  
Zero Magnetic Field ◽  
Typical Pattern ◽  
Bismuth Compounds ◽  
Local Magnetic Fields ◽  
Nuclear Quadrupole

Abstract The splittings observed in the 209Bi nuclear quadrupole resonances of α-Bi2O3, in zero magnetic field, follow the typical pattern of a Zeeman perturbed NQR spectrum. The lineshapes in Bi3O4Br also indicate a poorly resolved splitting that points to the presence of an internal magnetic field in the order of 200 G. This exceeds notably the dipole nuclear magnetic fields (about several G), but is orders of magnitude smaller than paramagnetic fields produced by unpaired electron spins. The results obtained using a SQUID and μSR-technique can also be interpreted as indicative of magnetic properties not conventionally expected in such compounds.

scholarly journals Medicean Moons Sailing Through Plasma Seas: Challenges in Establishing Magnetic Properties

2010 ◽  
Vol 6 (S269) ◽  
pp. 58-70
Author(s):  
Margaret G. Kivelson ◽  
Xianzhe Jia ◽  
Krishan K. Khurana
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Magnetic Fields ◽  
Boundary Conditions ◽  
Computer Simulations ◽  
Internal Field ◽  
Internal Magnetic Field ◽  
Complex Behavior ◽  
Flowing Plasma ◽  
Linear Interactions

AbstractJupiter's moons, embedded in the magnetized, flowing plasma of Jupiter's magnetosphere, the plasma seas of the title, are fluids whose highly non-linear interactions imply complex behavior. In a plasma, magnetic fields couple widely separated regions; consequently plasma interactions are exceptionally sensitive to boundary conditions (often ill-specified). Perturbation fields arising from plasma currents greatly limit our ability to establish more than the dominant internal magnetic field of a moon. With a focus on Ganymede and a nod to Io, this paper discusses the complexity of plasma-moon interactions, explains how computer simulations have helped characterize the system and presents improved fits to Ganymede's internal field.

scholarly journals Sensitivity of PS/CoPd Janus particles to an external magnetic field

RSC Advances ◽  
2021 ◽  
Vol 11 (28) ◽  
pp. 17051-17057
Author(s):  
Anna Eichler-Volf ◽  
Yara Alsaadawi ◽  
Fernando Vazquez Luna ◽  
Qaiser Ali Khan ◽  
Simon Stierle ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
External Magnetic Field ◽  
Magnetic Fields ◽  
Janus Particles ◽  
Weak Magnetic Fields

PS/CoPd Janus particles respond very sensitively to application of low external magnetic fields. Owing to the magnetic properties, the PS/CoPd particles may be used, for example, to sense the presence of weak magnetic fields as micro-magnetometers.

scholarly journals Controlled electrochemical growth and magnetic properties of CoFe2O4 nanowires with high internal magnetic field

2021 ◽  
pp. 159196
Author(s):  
Nabil Labchir ◽  
Abdelkrim Hannour ◽  
Abderrahim Ait Hssi ◽  
Didier Vincent ◽  
Patrick Ganster ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Internal Magnetic Field ◽  
Electrochemical Growth

scholarly journals The study of the magnetic properties of matter in strong magnetic fields. Part III.—Magnetostriction

1932 ◽  
Vol 135 (828) ◽  
pp. 537-554 ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Magnetic Fields ◽  
Crystal Lattice ◽  
The Body ◽  
Considerable Part ◽  
Strong Magnetic Fields ◽  
Theoretical Investigations ◽  
General Aspects

Magnetostriction may be defined in general as the change of shape of a substance when it is magnetised. The phenomenon may originate from various causes, but there is one which appears to us to be of major importance. From our present conceptions of the origin of cohesion between the atoms forming a crystal lattice it appears that a considerable part of this cohesion is due to forces of electrodynamical origin; we may therefore expect to influence these forces by means of a magnetic field, and thus produce a change of shape of the body. In ferromagnetic substances magnetostriction is easily observed in ordinary magnetic fields and a number of theoretical investigations have been carried out to explain the general aspects of the phenomenon. With para- and diamagnetic substances, however, no magnetostriction has been observed.

ELECTRON AND HOLE EFFECTIVE g FACTORS IN InAs/GaSb QUANTUM WELLS

2003 ◽  
Vol 02 (06) ◽  
pp. 437-444 ◽  
Author(s):  
A. ZAKHAROVA ◽  
S. T. YEN ◽  
K. A. CHAO
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Quantum Wells ◽  
Landau Level ◽  
Heavy Hole ◽  
Strong Dependence ◽  
Zero Magnetic Field ◽  
Electron Level ◽  
Hole Level ◽  
G Factors

We investigate the Landau level structures and the electron and hole effective g factors in InAs / GaSb quantum wells under electric and quantizing magnetic fields perpendicular to interfaces. In these structures, the lowest electron level in InAs can be below the highest heavy-hole level in GaSb at zero magnetic field B. Thus the electron and hole levels anticross with the increasing magnetic field and the strong dependence of the Landau level structures as well as g factors on B is obtained. We have found that the voltage across the structure and the lattice-mismatched strain also produce the essential changes in the Landau level structures as well as the electron and hole g factors.

scholarly journals Measurements of local magnetic fields in a solar flare by splitting of emissive peaks in cores of spectral lines

2018 ◽  
pp. 47-52 ◽  
Author(s):  
V. Lozitsky
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Solar Flare ◽  
Filling Factor ◽  
Spectral Lines ◽  
Local Fields ◽  
Strong Component ◽  
Component Structure ◽  
Local Magnetic Fields ◽  
The Magnetic Field

We present study of solar flare of 19 July 2000 which arose in active region NOAA 9087 and had M 5.6 / 3N importance. Observational material was obtained with the Echelle spectrograph of the horizontal solar telescope of the Astronomical Observatory of Taras Shevchenko National University of Kyiv. The local magnetic fields in this flare were measured by the splitting of emissive peaks of the FeI 5269.54, FeII 4923.93, Нα, Нβ, Нγand D3 HeI lines. The basic idea of the method is based on the fact that the flare emission in some spectral lines is clearly divided into two components: (1) wider and unpolarized, and (2) more narrow and polarized, with significant Zeeman splitting. This is indication to the two-component structure of the magnetic field, with substantially different magnetic fields and thermodynamical conditions in these two components. Due to the fact that the polarized emission is quite confidently separated from the unpolarized, it is possible to measure the local magnetic fields directly in the second (strong) component regardless of the filling factor. It was found that in the bright place of this flare, which was projected on the sunspot penumbra, the effective magnetic field Beff in the FeI 6301.5 i 6302.5 lines measured by splitting of the Fraunhofer profiles, was 900 G. However, the splitting of emissive peaks in Нα, Нβ, Нγ and D3 lines corresponds to 1000 G, 1400 G, 1450 G and about zero, respectively, with errors of 30-50 G for abovenamed FeI lines and about 100–150 G for other lines. This difference in the results is probably due to the fact that in the case of FeI 6301.5 i 6302.5 lines, the Beff value represents several parameters, including the value of the background field, the filling factor, and the intensity of the local fields in the strong component. In contrast, data on the Нα, Нβ, Нγ, and D3 lines mainly reflect local fields in the strong component and indicate the nonmonotonous distribution of the magnetic field with height in solar atmosphere, with its maximum at the chromospheric level. Earlier in this flare, when constructing its semi-empirical model, local amplification of the magnetic field at the photospheric level was discovered, and its value reached 1500 G. These data are confirmed by direct measurements of splitting of emissive peaks in FeI 5269.54 and FeII 4923.93 lines, according to which the magnetic field in the flare was 1250 ± 100 G. Thus, in this flare there were at least two regions (possibly two flat layers) of local amplification of the magnetic field.

Mössbauer study of the Ni–Zn ferrite system

1970 ◽  
Vol 48 (4) ◽  
pp. 381-396 ◽  
Author(s):  
J. M. Daniels ◽  
A. Rosencwaig
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Full Range ◽  
Zinc Content ◽  
Zero Magnetic Field ◽  
Nickel Zinc ◽  
Zn Ferrite ◽  
Superparamagnetic Clusters ◽  
Ferrite System ◽  
Nuclear Magnetic

Mössbauer spectra of 57Fe in the nickel–zinc ferrite system (ZnO)x(NiO)1−xFe2O3 have been obtained, at room temperature and at 77 °K, in zero magnetic field and also in a longitudinal magnetic field of 13.5 kG, covering the full range of zinc content. The dependence of the isomer shifts, line widths, quadrupole interactions, and nuclear magnetic fields of 57Fe3+ ions in both tetrahedral and octahedral sites has been determined. The principal results of this study are (a) the confirmation of the determination of the nuclear magnetic fields by Abe et al. using NMR, and the extension of these measurements to higher zinc concentrations, (b) an indication that the hypotheses of paramagnetic centers, proposed by Gilleo, and superparamagnetic clusters, proposed by Ishikawa, are not applicable to the nickel–zinc ferrites, (c) evidence of canted spin structures, first proposed by Yafet and Kittel, (d) various effects of chemical disorder in the nickel-zinc ferrites, and (e) an observation of the effect on the Mössbauer spectrum of relaxation in a magnetically ordered iron system.

Magnetic phenomena

2004 ◽  
Author(s):  
Robert E. Newnham
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Flux Density ◽  
Magnetic Dipole ◽  
Electric Charge ◽  
Dipole Moments ◽  
Magnetic Flux Density

In this chapter we deal with a number of magnetic properties and their directional dependence: pyromagnetism, magnetic susceptibility, magnetoelectricity, and piezomagnetism. In the course of dealing with these properties, two new ideas are introduced: magnetic symmetry and axial tensors. Moving electric charge generates magnetic fields and magnetization. Macroscopically, an electric current i flowing in a coil of n turns per meter produces a magnetic field H = ni amperes/meter [A/m]. On the atomic scale, magnetization arises from unpaired electron spins and unbalanced electronic orbital motion. The weber [Wb] is the basic unit of magnetic charge m. The force between two magnetic charges m1 and m2 is where r is the separation distance and μ0 (=4π×10−7 H/m) is the permeability of vacuum. In a magnetic field H, magnetic charge experiences a force F = mH [N]. North and south poles (magnetic charges) separated by a distance r create magnetic dipole moments mr [Wb m]. Magnetic dipole moments provide a convenient way of picturing the atomistic origins arising from moving electric charge. Magnetization (I) is the magnetic dipole moment per unit volume and is expressed in units of Wb m/m3 = Wb/m2. The magnetic flux density (B = I + μ0H) is also in Wb/m2 and is analogous to the electric displacement D. All materials respond to magnetic fields, producing a magnetization I = χH, and a magnetic flux density B = μH where χ is the magnetic susceptibility and μ is the magnetic permeability. Both χ and μ are in henries/m (H/m). The permeability μ = χ + μ0 and is analogous to electric permittivity. χ and μ are sometimes expressed as dimensionless quantities (x ̅ and μ ̅ and ) like the dielectric constant, where = x ̅/μ0 and = μ ̅/μ0. Other magnetic properties will be defined later in the chapter. A schematic view of the submicroscopic origins of magnetic phenomena is presented in Fig. 14.1. Most materials are diamagnetic with only a weak magnetic response induced by an applied magnetic field.

3. Spots and magnetic fields

2020 ◽  
pp. 65-99
Author(s):  
Philip Judge
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Magnetic Fields ◽  
Solar Interior ◽  
Solar Dynamo ◽  
The Sun ◽  
Electrically Conducting ◽  
New Science ◽  
The 1960S ◽  
Conducting Fluids

‘Spots and magnetic fields’ explores sunspot behaviour. We have known since 1908 that sunspots are magnetic, but why does the Sun form them at all? Is the Sun extraordinary in this, or is its behaviour in line with other stars? The Sun’s magnetic field is generated by a solar dynamo, which can be partly explained by magnetohydrodynamics (MHD)—the study of the magnetic properties and behaviour of electrically conducting fluids—however, there is no full consensus on the solar dynamo. In the 1960s the new science of helioseismology gave us insights into the Sun’s interior rotation, but we are unable to make truly critical observations in the solar interior.

scholarly journals Non-local terahertz photoconductivity in the topological phase of Hg1−xCdxTe

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. S. Kazakov ◽  
A. V. Galeeva ◽  
A. I. Artamkin ◽  
A. V. Ikonnikov ◽  
L. I. Ryabova ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Laser Pulses ◽  
Zero Magnetic Field ◽  
Zero Field ◽  
Topological Phase ◽  
Non Local ◽  
Dark Signal ◽  
The Magnetic Field

AbstractWe report on observation of strong non-local photoconducitivity induced by terahertz laser pulses in non-zero magnetic field in heterostructures based on Hg1−xCdxTe films being in the topological phase. While the zero-field non-local photoconductivity is negligible, it is strongly enhanced in magnetic fields ~ 0.05 T resulting in appearance of an edge photocurrent that exceeds the respective dark signal by orders of magnitude. This photocurrent is chiral, and the chirality changes every time the magnetic field or the electric bias is reversed. Appearance of the non-local terahertz photoconductivity is attributed to features of the interface between the topological film and the trivial buffer.

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