THE STUDY OF THE MAGNETIC BREAKDOWN EFFECT AS A FUNCTION OF ANGLE IN THE ORGANIC CONDUCTOR K- (BEDT-TTF)2Cu(NCS)2 IN HIGH MAGNETIC FIELDS

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3355-3359
Author(s):  
I. MIHUT ◽  
C. C. AGOSTA ◽  
C. H. MIELKE ◽  
M. TOKOMOTO
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Spin Splitting ◽  
High Magnetic Fields ◽  
Organic Conductor ◽  
Cross Sectional ◽  
Tank Circuit ◽  
Quantum Oscillations ◽  
Magnetic Breakdown ◽  
Splitting Factor

The magnetic breakdown effect can be seen by the growth of new frequencies in the quantum oscillations in clean metals as a function of magnetic field. We have studied the variation of the amplitudes in the quantum oscillations in the resistance (the Shubnikov-de Haas effect) as a function of angle in the quasi-two dimensional-organic conductor κ-(BEDT-TTF)2Cu(NCS)2. The measurements were made by means of a radio frequency (rf) tank circuit (~ 50 MHz) at very high magnetic fields(50T-60T) and low temperature(500 mK). The geometry of the rf excitation we used excited in-plane currents, and therefore we measured the in-plane resistivity. In contrast to conventional transport measurements that measure the inter-plane resistivity, the in-plane resistivity is dominated by the magnetic breakdown frequencies. As a result we measured much higher breakdown frequency amplitudes than conventional transport experiments. As is expected, the angular dependence of the Shubnikov-de Haas frequencies have a 1/cosθ behavior. This is due to the change of the cross sectional area of the tubular Fermi surface as the angle with respect to the magnetic field is changed. The amplitude of the oscillations changes due to the spin splitting factor which takes into account the ratio between the spin splitting and the energy spacing of the Landau levels which also has 1/cosθ behavior. We show that our data agree with the semi-classical theory (Lifshitz-Kosevich formula).

Conduction electron g-factor in tungsten from quantum oscillations in ultrasonic velocity

1977 ◽  
Vol 55 (4) ◽  
pp. 356-363 ◽  
Author(s):  
J. M. Perz
Keyword(s):  
Magnetic Field ◽  
Field Dependence ◽  
Second Harmonic ◽  
Ultrasonic Waves ◽  
Spin Splitting ◽  
Harmonic Oscillations ◽  
Minimum Area ◽  
Quantum Oscillations ◽  
Splitting Factor ◽  
Harmonic Content

From an analysis of the field dependence and harmonic content of quantum oscillations in the velocity of transverse ultrasonic waves associated with the ellipsoidal hole pockets at N in tungsten, the spin-splitting factor g = 1.73 ± 0.07 has been determined for central orbits near that of minimum area, i.e. with magnetic field H along a cubic axis [100]. This is consistent with the observed disappearance of the second harmonic oscillations for field nearly midway between two cubic axes, which implies g = 1.82 ± 0.07 for the relevant orbit.

scholarly journals Optical Imaging of Magnetic Particle Cluster Oscillation and Rotation in Glycerol

2021 ◽  
Vol 7 (5) ◽  
pp. 82
Author(s):  
River Gassen ◽  
Dennis Thompkins ◽  
Austin Routt ◽  
Philippe Jones ◽  
Meghan Smith ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Particles ◽  
Magnetic Particle ◽  
Barium Hexaferrite ◽  
Optical Microscope ◽  
Simplified Model ◽  
Particle Cluster ◽  
Average Deviation ◽  
Cross Sectional

Magnetic particles have been evaluated for their biomedical applications as a drug delivery system to treat asthma and other lung diseases. In this study, ferromagnetic barium hexaferrite (BaFe12O19) and iron oxide (Fe3O4) particles were suspended in water or glycerol, as glycerol can be 1000 times more viscous than water. The particle concentration was 2.50 mg/mL for BaFe12O19 particle clusters and 1.00 mg/mL for Fe3O4 particle clusters. The magnetic particle cluster cross-sectional area ranged from 15 to 1000 μμm2, and the particle cluster diameter ranged from 5 to 45 μμm. The magnetic particle clusters were exposed to oscillating or rotating magnetic fields and imaged with an optical microscope. The oscillation frequency of the applied magnetic fields, which was created by homemade wire spools inserted into an optical microscope, ranged from 10 to 180 Hz. The magnetic field magnitudes varied from 0.25 to 9 mT. The minimum magnetic field required for particle cluster rotation or oscillation in glycerol was experimentally measured at different frequencies. The results are in qualitative agreement with a simplified model for single-domain magnetic particles, with an average deviation from the model of 1.7 ± 1.3. The observed difference may be accounted for by the fact that our simplified model does not include effects on particle cluster motion caused by randomly oriented domains in multi-domain magnetic particle clusters, irregular particle cluster size, or magnetic anisotropy, among other effects.

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.

Magnetic Field Effect on Electrochemiluminescence of Carbazole

1971 ◽  
Vol 49 (21) ◽  
pp. 3577-3578 ◽  
Author(s):  
K. S. V. Santhanam
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Emission Intensity ◽  
Applied Field ◽  
Field Effect ◽  
Magnetic Field Effect ◽  
High Magnetic Fields ◽  
Annihilation Rate ◽  
Triplet Triplet Annihilation

Effect of magnetic field on electrochemiluminescence of carbazole has been studied in N,N dimethylformamide. The emission intensity increases with increasing applied field with a tendency to decrease at high magnetic fields. An explanation involving perturbation of triplet–triplet annihilation rate is proposed.

Large volume liquid state scalar Overhauser dynamic nuclear polarization at high magnetic field

2019 ◽  
Vol 21 (38) ◽  
pp. 21200-21204 ◽  
Author(s):  
Thierry Dubroca ◽  
Sungsool Wi ◽  
Johan van Tol ◽  
Lucio Frydman ◽  
Stephen Hill
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Fields ◽  
High Magnetic Field ◽  
Dynamic Nuclear Polarization ◽  
Large Volume ◽  
Liquid State ◽  
Nuclear Polarization ◽  
High Magnetic Fields

Dynamic Nuclear Polarization (DNP) can increase the sensitivity of Nuclear Magnetic Resonance (NMR), but it is challenging in the liquid state at high magnetic fields.

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?’.

Electronic properties ofUX3 (X=Ga,Al, and Sn) compounds in high magnetic fields: Transport, specific heat, magnetization, and quantum oscillations

1999 ◽  
Vol 59 (22) ◽  
pp. 14473-14483 ◽  
Author(s):  
A. L. Cornelius ◽  
A. J. Arko ◽  
J. L. Sarrao ◽  
J. D. Thompson ◽  
M. F. Hundley ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Specific Heat ◽  
Electronic Properties ◽  
High Magnetic Fields ◽  
Quantum Oscillations

scholarly journals Restoration of superconductivity in high magnetic fields in UTe2

2020 ◽  
Vol 34 (32) ◽  
pp. 2030007
Author(s):  
Andrei G. Lebed
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Superconducting State ◽  
Critical Magnetic Field ◽  
High Magnetic Fields ◽  
Two Dimensional ◽  
Upper Critical Magnetic Field ◽  
Reentrant Superconductivity ◽  
Theoretical Results ◽  
General Method

It was theoretically predicted more than 20 years ago [A. G. Lebed and K. Yamaji, Phys. Rev. Lett. 80, 2697 (1998)], that a triplet quasi-two-dimensional (Q2D) superconductor could restore its superconducting state in parallel magnetic fields, which are higher than its upper critical magnetic field, [Formula: see text]. It is very likely that, recently, such phenomenon has been experimentally discovered in the Q2D superconductor UTe2 by Nicholas Butch, Sheng Ran, and their colleagues and has been confirmed by Japanese–French team. We review our previous theoretical results using such a general method that it describes the reentrant superconductivity in the abovementioned compound and will hopefully describes the similar phenomena, which can be discovered in other Q2D superconductors.

scholarly journals INTERSUBBAND MAGNETOPHONON RESONANCES IN QUANTUM CASCADE STRUCTURES

2002 ◽  
Vol 16 (20n22) ◽  
pp. 2952-2955
Author(s):  
D. SMIRNOV ◽  
O. DRACHENKO ◽  
J. LEOTIN ◽  
H. PAGE ◽  
C. BECKER ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Tunneling Current ◽  
Applied Bias ◽  
Acoustic Phonons ◽  
Quantum Oscillations ◽  
Quantum Cascade ◽  
Electron Relaxation ◽  
Magnetophonon Resonance ◽  
Quantum Cascade Structures

We report on magnetotransport measurements of GaAs/GaAlAs quantum cascade structures in magnetic fields up to 62 T parallel to the current. We observe novel quantum oscillations series in tunneling current that are periodic in reciprocal magnetic field and have field positions independent of the applied bias. These oscillations are explained as intersubband magnetophonon resonance due to electron relaxation by emission of optical or acoustic phonons.

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