The Electronic Contribution to The Elastic Constants of Strained III-V Materials Under High Magnetic Fields

1995 ◽  
Vol 379 ◽  
Author(s):  
Kamakhya P Ghatak ◽  
B. Nag ◽  
G. Mazumder
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Experimental Method ◽  
Elastic Constants ◽  
Quantitative Agreement ◽  
High Magnetic Fields ◽  
Electronic Contribution ◽  
Theoretical Formulation ◽  
Wide Gap ◽  
Lattice Matched

ABSTRACTIn this paper an attempt is made to study the electronic contribution to the elastic constants of strained III-V materials under high magnetic fields on the basis of k.p theory. It is found taking strained Hgi - x CdxTe and Ini - xGaxAsyPi-y lattice matched InP as examples that they increase with increasing doping and oscillate with inverse magnetic field respectively. The strain enhances the numerical values of the elastic constants. The theoretical formulation is in quantitative agreement with the suggested experimental method of determining the above contributions for degenerate materials having arbitrary dispersion laws. In addition, the well-known results for strain free wide gap materials in the absence of magnetic field have been obtained from our generalized analysis under certain limiting conditions.

Effect of Stress on the Carrier Contribution to Elastic Constants in Thin Films of Small Gap Compounds

1993 ◽  
Vol 308 ◽  
Author(s):  
Kamakhya P. Ghatak ◽  
Sambhu Nath Biswas
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Experimental Method ◽  
Elastic Constants ◽  
Electron Concentration ◽  
Ultrathin Films ◽  
Theoretical Formulation ◽  
Lattice Matched

ABSTRACTIn this paper we have investigated the carrier contribution to elastic constants in very thin films of stressed small gap compounds within the domain of theory. It is found, taking stressed ultrathin films Hg1-xCdxTe and In1-xGaxAsyP1-y lattice matched to InP as examples, that the elastic constants increase with increasing electron concentration and decreasing film thickness respectively in oscillatory manners. Besides the stress enhances the numerical values of such contribution to the elastic constants. In addition, the theoretical formulation is in agreement with the suggested experimental method of determining such constants in materials having arbitary dispersion laws.

On The Electronic Contribution to Elastic Constants of Ultrathin Films of P-Type Si

1991 ◽  
Vol 226 ◽  
Author(s):  
Kamaxhya P Ghatak ◽  
Badal De
Keyword(s):  
Film Thickness ◽  
Experimental Method ◽  
Elastic Constants ◽  
Ultrathin Films ◽  
Hole Concentration ◽  
Electronic Contribution ◽  
Third Order ◽  
Theoretical Formulation ◽  
Third Order Elastic Constants ◽  
P Type

AbstractIn this paper we have formulated the electronic contribution to the elastic constants in ultrathin films of p-Si by considering the influences of heavy, light and split-off holes respectively. We have suggested an experimental method of determining the same in degenerate materials having arbitrary dispersion laws. The elastic constants increase with increasing hole concentration in an oscillatory way and decrease with increasing film thickness. The theoretical formulation is in agreement with the suggested experimental method of determining second and third order elastic constants.

scholarly journals Magnetocaloric Effect of Gadolinium at Adiabatic and Quasi-Isothermal Conditions in High Magnetic Fields

2015 ◽  
Vol 233-234 ◽  
pp. 216-219 ◽  
Author(s):  
Alexander P. Kamantsev ◽  
Victor V. Koledov ◽  
Alexey V. Mashirov ◽  
Elvina T. Dilmieva ◽  
Vladimir G. Shavrov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Experimental Method ◽  
Magnetocaloric Effect ◽  
Direct Measurement ◽  
Initial Temperature ◽  
Cooling Power ◽  
High Magnetic Fields ◽  
Isothermal Conditions ◽  
Simultaneous Measurements

High cooling power of magnetocaloric refrigeration can be achieved only at large amounts of heat, which can be transferred in one cycle from cold end to hot end at quasi-isothermal conditions. The simple experimental method for direct measurement of the transferred heat from material with magnetocaloric effect (MCE) to massive nonmagnetic block at quasi-isothermal conditions was proposed. The vacuum calorimeter was designed for the simultaneous measurements of MCE both at adiabatic conditions (∆T) and quasi-isothermal conditions (∆Q) in the magnetic fields of Bitter coil magnet. This calorimeter was tested on samples of pure polycrystalline Gd with direct MCE. The maximal obtained values were ∆T = 17.7 K and ∆Q = 5900 J/kg at initial temperature 20 °C in magnetic field 140 kOe.

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).

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?’.

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.

Far-infrared cyclotron resonance of wide-gap semiconductors using pulsed high magnetic fields

1996 ◽  
Vol 216 (3-4) ◽  
pp. 351-353 ◽  
Author(s):  
Mitsutake Oshikiri ◽  
Kanji Takehana ◽  
Toshihisa Asano ◽  
Giyuu Kido
Keyword(s):  
Magnetic Fields ◽  
Cyclotron Resonance ◽  
Far Infrared ◽  
High Magnetic Fields ◽  
Wide Gap

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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