High Field Induced Torques and the Fermi Surface of Osmium

1974 ◽  
Vol 52 (14) ◽  
pp. 1295-1303 ◽  
Author(s):  
A. L. Plachy ◽  
A. E. Dixon
Keyword(s):  
Magnetic Field ◽  
Fermi Surface ◽  
Superconducting Magnet ◽  
High Magnetic Fields ◽  
Electron Model ◽  
Open Orbit ◽  
Closed Orbits ◽  
Free Electron Model ◽  
High Fields ◽  
The Magnetic Field

The Fermi surface of osmium has been investigated using the induced torque technique at high magnetic fields. This is believed to be the first report of an induced torque experiment performed on a low conductivity sample and in the high fields of a superconducting magnet. Open orbits were found for B along [Formula: see text]. These orbits continue to be seen as the magnetic field is tilted to at least 65° from the basal plane. The dependence of the open orbit torque on magnetic field strength, rotation rate, and tilt angle was studied. No open orbits were found for B along [Formula: see text]. Torques due to closed orbits were also studied, and comparison of the predictions of the free electron model is given for these torques. A maximum in the torque is seen for B along [0001], and an explanation is suggested for this behavior.

Tipping effects in Azbel-Kaner cyclotron resonance

1967 ◽  
Vol 297 (1449) ◽  
pp. 205-229 ◽  
Keyword(s):  
Magnetic Field ◽  
Fermi Surface ◽  
Cyclotron Resonance ◽  
Skin Depth ◽  
Electron Model ◽  
Line Shapes ◽  
Parallel Polarization ◽  
Free Electron Model ◽  
Set Up ◽  
The Magnetic Field

Calculations of Azbel-Kaner line shapes when the magnetic field is tipped out of the surface have been carried out in a number of cases for both the free electron model and an arbitrary Fermi surface with mass spread. For small angles of tip the results substantiate the Doppler shift theory advanced by Koch, Stradling & Kip and provide a consistent explanation of the observed peak shifts or splitting in all cases. Arguments are presented that at larger tip angles the overall absorption will decrease with increasing field, and the original resonance may become inverted, owing to the removal of non-stationary electrons from the skin depth. At large tip angles (5° or so) inverted and doubled resonances observed with parallel polarization are shown to arise from ‘field splashes’ set up by drifting electrons from the limiting points, regardless of the nature of the Fermi surface. Apparently normal resonances observed at very large tip angles are shown to arise from so-called ‘cylinder sections’ where d A /dk 2 H = 0 and v D = 0, A and v D being the area of the orbit in k space and the drift velocity respectively.

Induced Torque in Aluminum

1973 ◽  
Vol 51 (16) ◽  
pp. 1786-1793 ◽  
Author(s):  
F. W. Holroyd ◽  
R. J. Douglas ◽  
W. R. Datars
Keyword(s):  
Magnetic Field ◽  
Relaxation Time ◽  
Fermi Surface ◽  
Single Crystal ◽  
Path Integral ◽  
Rotating Magnetic Field ◽  
Closed Orbits ◽  
High Fields ◽  
Crystallographic Planes ◽  
The Magnetic Field

Torque on single-crystal spheres of aluminum induced by a rotating magnetic field was studied in fields up to 20 kOe at 4.2 K. The magnetic field was rotated in (112), (011), and (001) crystallographic planes. Anisotropy of the induced torque showed minima at [Formula: see text] and [Formula: see text] directions. It was reproducible in different samples and persisted in samples that had been strained by up to 8%. The torque anisotropy existed between 1.2 and 35 K. There was no evidence of open orbits. The induced torque tended towards saturation at high fields, and was attributed to closed orbits. The induced torque determined from a path-integral calculation of the magnetoconductivity, assuming the relaxation time to be isotropic and representing the Fermi surface by a modified single-OPW model which had no open orbits, is in excellent agreement with experiment.

A 3 T superconducting magnet for long-run magnetic Compton-scattering experiments

1998 ◽  
Vol 5 (3) ◽  
pp. 937-939 ◽  
Author(s):  
Nobuhiko Sakai ◽  
Hiroshi Ohkubo ◽  
Yasushi Nakamura
Keyword(s):  
Magnetic Field ◽  
Low Temperature ◽  
Compton Scattering ◽  
Superconducting Magnet ◽  
Field Direction ◽  
Compton Profile ◽  
Magnetic Field Direction ◽  
Long Run ◽  
Radiation Shields ◽  
The Magnetic Field

A 3 T superconducting magnet has been designed and constructed for magnetic Compton-profile (MCP) measurements with the new capabilities that the magnetic field direction can be altered quickly (within 5 s) and liquid-He refill is not required for more than one week. For the latter capability, two refrigerators have been directly attached to the cryostat to maintain the low temperature of the radiation shields and for the recondensation of liquid He. The system has been satisfactorily operated for over one week.

High magnetic field NMR investigation of the spin density wave phase of TMTSF2PF6

2002 ◽  
Vol 12 (9) ◽  
pp. 389-389
Author(s):  
W. G. Clark ◽  
F. Zamborsky ◽  
B. Alavi ◽  
P. Vonlanthen ◽  
W. Moulton ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Spin Density ◽  
Density Wave ◽  
Spin Density Wave ◽  
Proton Relaxation ◽  
High Magnetic Fields ◽  
Organic Conductor ◽  
First Order ◽  
The Magnetic Field ◽  
Very High

We report proton NMR measurements of the effect of very high magnetic fields up to 44.7 T (1.9 GHz) on the spin density wave (SDW) transition of the organic conductor TMTSF2PF6. Up to 1.8 GHz, no effect of critical slowing close to the transition is seen on the proton relaxation rate (1/T1), which is determined by the SDW fluctuations associated with the phase transition at the NMR frequency. Thus, the correlation time for such fluctuations is less than $1O^{-10}$s. A possible explanation for the absence of longer correlation times is that the transition is weakly first order, so that the full critical divergence is never achieved. The measurements also show a dependence of the transition temperature on the orientation of the magnetic field and a quadratic dependence on its magnitude that agrees with earlier transport measurements at lower fields. The UCLA part of this work was supported by NSF Grant DMR-0072524.

Small, modular and economically attractive fusion enabled by high temperature superconductors

2019 ◽  
Vol 377 (2141) ◽  
pp. 20180354 ◽  
Author(s):  
Dennis Whyte
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
Magnetic Fields ◽  
Current Density ◽  
High Temperature Superconductors ◽  
Fusion Energy ◽  
High Magnetic Fields ◽  
Operating Temperatures ◽  
The Magnetic Field ◽  
Game Changer

The advantages of high magnetic fields in tokamaks are reviewed, and why they are important in leading to more compact tokamaks. A brief explanation is given of what limits the magnetic field in a tokamak, and why high temperature superconductors (HTSs) are a game changer, not just because of their higher magnetic fields but also for reasons of higher current density and higher operating temperatures. An accelerated pathway to fusion energy is described, defined by the SPARC and ARC tokamak designs. This article is part of a discussion meeting issue ‘Fusion energy using tokamaks: can development be accelerated?’.

Finite Element Analysis of the Magnetic Field Simulation of High Temperature Superconducting Magnet

2014 ◽  
Vol 672-674 ◽  
pp. 562-566
Author(s):  
Ying Hong Luo ◽  
Jing Jing Wang
Keyword(s):  
Magnetic Field ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Field Distribution ◽  
Magnetic Energy ◽  
Superconducting Magnet ◽  
Magnetic Field Distribution ◽  
Magnetic Storage ◽  
Element Analysis ◽  
The Magnetic Field

Superconducting Magnetic Energy Storage (SMES) system use conductive coils made of superconductor wire to store energy, its application entirely depends on the design and development of superconducting magnet, as the magnetic storage element, during the operation of the superconducting magnet generates relatively strong magnetic field. In this paper, a 1MJ class single solenoidal SMES with Bi2223/Ag conductor is presented. On the basis of electromagnetic theory, subsequently infers mathematical model of magnetic field distribution by ANSYS finite element analysis software, modeling a two-dimensional electromagnetic analysis of 44 double pancakes to get the magnetic field distribution patterns. The results of the analysis provide a reference for the structural design, optimization of a superconducting magnet and shielding of stray magnetic field.

THE MILLIMETRE-WAVE MAGNETO-OPTICAL RESPONSE OF Sr2RuO4

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3238-3243
Author(s):  
A. ARDAVAN ◽  
E. RZEPNIEWSKI ◽  
R. S. EDWARDS ◽  
J. SINGLETON ◽  
Y. MAENO
Keyword(s):  
Magnetic Field ◽  
Fermi Surface ◽  
Effective Mass ◽  
Cyclotron Resonance ◽  
P Wave ◽  
Harmonic Series ◽  
Millimetre Wave ◽  
The Magnetic Field ◽  
Component Parallel ◽  
Absorption Mode

We report a study of the angle-dependent millimetre-wave magnetoconductivity of the p-wave triplet-paired perovskite superconductor Sr 2 RuO 4. We find two harmonic series. We assign the first to interlayer cyclotron resonance of the β-Fermi surface and its harmonics, yielding a cyclotron effective mass of [Formula: see text]. We assign the second series, which contains only odd harmonics, to cyclotron resonance of the γ-Fermi surface, yielding a cyclotron effective mass of [Formula: see text]. In addition, we find a very strong absorption mode in the presence of a magnetic field component parallel to the quasi-two-dimensional (Q2D) planes of the sample. Its dependence on the orientation of the magnetic field cannot be described in the context of conventional Q2D cyclotron resonance, and the origin of this mode is not yet clear.

Crystallographic orientation of primary and eutectic phases in a hypoeutectic Mn–Sb alloy induced by solidification in high magnetic fields

2019 ◽  
Vol 52 (5) ◽  
pp. 945-950 ◽  
Author(s):  
Shulin Dong ◽  
Tie Liu ◽  
Meng Dong ◽  
Shuang Wang ◽  
Wen Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Crystallographic Orientation ◽  
Field Direction ◽  
High Magnetic Fields ◽  
Magnetic Field Direction ◽  
Eutectic Alloys ◽  
Random Orientation ◽  
Binary Eutectic ◽  
The Magnetic Field

This paper investigates how applying high magnetic fields influences the crystallographic orientations of the primary and eutectic phases, and their relationship, in a binary eutectic alloy. At 0 T, the primary MnSb phase in hypoeutectic Mn–Sb showed a random orientation, but at 3, 6, 9 and 11.5 T, its c axis was perpendicular to the magnetic field direction. In all cases, the eutectic MnSb phases showed the same orientations as their neighboring primary MnSb phase, on which they nucleated and grew. With high magnetic fields, the c axes of the eutectic and primary MnSb phases were oriented perpendicular to the magnetic field direction. The results show that applying a high magnetic field during solidification is a way of controlling the crystallographic orientation of both the primary and the eutectic phases in eutectic alloys.

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