scholarly journals Observation of Fractal Conductance Fluctuations over Three Orders of Magnitude

1999 ◽  
Vol 52 (5) ◽  
pp. 887 ◽  
Author(s):  
R. P. Taylor ◽  
A. P. Micolich ◽  
R. Newbury ◽  
T. M. Fromhold ◽  
C. R. Tench
Keyword(s):  
Magnetic Field ◽  
Transport Properties ◽  
Field Range ◽  
Magnetic Field Range ◽  
Physical Conditions ◽  
Fractal Behaviour ◽  
Conductance Fluctuations ◽  
Order Of Magnitude ◽  
The Magnetic Field

Fractal magneto-transport properties of mesoscopic semiconductor billiards are highly topical. In these studies, the magnetic field range over which fractal behaviour can be observed is crucial. Previous observations have been limited to approximately one order of magnitude. We present fractal conductance fluctuations observed over three orders of magnitude and discuss the physical conditions required to extend this range.

scholarly journals Магнитосопротивление и квантовые осцилляции в полуметалле WTe-=SUB=-2-=/SUB=-

2021 ◽  
Vol 63 (12) ◽  
pp. 2033
Author(s):  
А.Л. Пирозерский ◽  
Е.В. Чарная ◽  
M.K. Lee ◽  
L.-J. Chang ◽  
С.В. Наумов ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Single Crystal ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Field Range ◽  
Magnetic Field Range ◽  
Fundamental Frequencies ◽  
Shubnikov De Haas Oscillations ◽  
The Magnetic Field ◽  
Strong Spin

The discovery of extreme magnetoresistance (XMR) in non-magnetic materials attracted attention to the WTe2 semimetal. We have carried out studies of magnetoresistance in a tungsten ditelluride single crystal in the magnetic field range up to 14 T. Magnetoresistance increased with increasing field following a near quadratic law without saturation. The Shubnikov-de Haas oscillations were observed. Four fundamental frequencies were found in the oscillations spectrum, which correspond to two electron and two hole pockets caused by strong spin-orbit coupling.

SPECIFIC HEAT OF SPIN-1 AND SPIN-3/2 MIXED 3D ISING FERROMAGNETIC MODEL IN EXTERNAL MAGNETIC FIELD

2012 ◽  
Vol 26 (16) ◽  
pp. 1250101 ◽  
Author(s):  
XIYU SU ◽  
LINGLING ZHENG ◽  
QINYING HOU
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Specific Heat ◽  
Magnetic Order ◽  
Field Range ◽  
Magnetic Field Range ◽  
Disorder Phase Transition ◽  
Ferromagnetic System ◽  
The Magnetic Field ◽  
Transition Temperature Increase

The specific heat of spin-1 and spin-3/2 mixed 3D Ising ferromagnetic system in the external magnetic field is studied by Monte Carlo method. The obtained results show that the existence of the external magnetic field makes the order-disorder phase transition temperature increase; with the crystal field increasing, the critical external magnetic field for a new magnetic order phase occurring increases, and the magnetic field range for maintaining each order phase becomes larger.

MAGNETIC FIELD DEPENDENCE OF CRITICAL CURRENTS IN SUPERCONDUCTING POLYCRYSTALS

1992 ◽  
Vol 06 (03) ◽  
pp. 161-169 ◽  
Author(s):  
K.I. KUGEL ◽  
T. YU. LISOVSKAYA ◽  
R.G. MINTS
Keyword(s):  
Magnetic Field ◽  
Magnetic Field Dependence ◽  
Asymptotic Form ◽  
Critical Currents ◽  
Transport Current ◽  
Wide Field ◽  
London Penetration Depth ◽  
Field Range ◽  
Crystallographic Axes ◽  
The Magnetic Field

We study the dependence of critical current j c on magnetic field H in superconducting polycrystals which are considered as systems of superconducting crystallites (isotropic or anisotropic) with Josephson contacts between them. Isotropy or anisotropy of contacts depends on the orientation of their crystallographic axes relatively to edges of contact planes. It is shown that for a system of randomly oriented isotropic contacts, the dependence j c (H) in a relatively wide field range has the asymptotic form j c ~( ln H)/H2. This differs drastically from j c (H) for single contacts. Anisotropy effects due to large differences in London penetration depth λ values corresponding to external magnetic field directed along different axes are analyzed in detail. It is shown that for uniaxal crystals with λ1=λ2≪λ3, this anisotropy leads to the relation [Formula: see text] for chaotic orientation of crystallites. The form of j c (H) curves for two different orientations of the magnetic field relatively to the transport current through the sample is found.

INFLUENCE OF NEARBY QD LAYER ON 2DES IN QUANTUM HALL REGIME

2007 ◽  
Vol 21 (08n09) ◽  
pp. 1445-1449
Author(s):  
K. TAKEHANA ◽  
Y. IMANAKA ◽  
T. TAKAMASU ◽  
M. HENINI
Keyword(s):  
Magnetic Field ◽  
Transport Properties ◽  
Gate Voltage ◽  
Quantum Hall ◽  
Electron System ◽  
Hall Resistance ◽  
Field Range ◽  
Voltage Range ◽  
Quantum Hall Regime ◽  
Hall Regime

We have investigated transport properties in high magnetic field of a gated two-dimensional electron system (2DES) separated by a thin barrier from a layer of self-assembled InAs quantum dots (QDs) in the quantum Hall regime. The quality of 2DES was found to be high enough to observe both integer and fractional quantum Hall effect (QHE), despite the proximity of the QD layer to the 2DES. However, significant suppression of the magnetoresistance (ρ xx ) and Hall resistance (ρ xy ) were observed in higher magnetic field range of filling factor ν < 1 when a positive voltage was applied to the front gate. The gate voltage dependence of ρ xx and ρ xy shows a well-defined hysteresis loop at the narrow gate voltage range between -0.2 and +0.2 V at ν < 1, while no anomaly was observed at ν > 1. We deduce that charging and discharging of QDs occurs when the gate voltage is varied around Vg ~ 0 V, which indicates that the electron charge states of the QDs affect the transport properties of the nearby 2DES only at ν < 1. We infer that the spin-flip process induces a non-equilibrium state in the 2DEG, which causes the suppression of ρ xx and ρ xy .

Open orbits in ReO3

1979 ◽  
Vol 57 (6) ◽  
pp. 860-863 ◽  
Author(s):  
F. S. Razavi ◽  
W. R. Datars
Keyword(s):  
Magnetic Field ◽  
Plane Wave ◽  
Relative Number ◽  
Structure Calculation ◽  
Band Structure Calculation ◽  
Wave Band ◽  
Field Range ◽  
Augmented Plane Wave ◽  
Magnetic Field Range ◽  
The Third

Open orbits in the metal oxide ReO3 were studied by the induced torque method at a temperature of 1.4 K with magnetic fields up to 5.5 T.[Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] open orbits were detected. The results show that the third-band Fermi surface of ReO3 is connected along [Formula: see text] directions as predicted by Mattheiss' augmented-plane-wave band structure calculation. The angular magnetic field range for observation of open orbits and the relative number of primary and secondary open orbits are given.

scholarly journals Fiber optic magnetic field sensor using Co doped ZnO nanorods as cladding

RSC Advances ◽  
2018 ◽  
Vol 8 (33) ◽  
pp. 18243-18251 ◽  
Author(s):  
S. Narasimman ◽  
L. Balakrishnan ◽  
Z. C. Alex
Keyword(s):  
Magnetic Field ◽  
Fiber Optic ◽  
Zno Nanorods ◽  
Magnetic Field Sensor ◽  
Maximum Sensitivity ◽  
Field Range ◽  
Magnetic Field Range ◽  
Field Sensor ◽  
Doped Zno ◽  
Co Doped

A fiber optic magnetic field sensor based on Co doped ZnO nanorods is proposed and demonstrated. The sensor has an operating magnetic field range of 17 mT to 180 mT and shows a maximum sensitivity of ∼18% for 15 at% Co doped ZnO nanorods.

scholarly journals Effect of confinement potential shape on the electronic, thermodynamic, magnetic and transport properties of a GaAs quantum dot at finite temperature

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
K. Luhluh Jahan ◽  
Bahadir Boyacioglu ◽  
Ashok Chatterjee
Keyword(s):  
Magnetic Field ◽  
Heat Capacity ◽  
Quantum Dot ◽  
Transport Properties ◽  
Average Energy ◽  
Persistent Current ◽  
Confinement Potential ◽  
Potential Shape ◽  
Gaas Quantum Dot ◽  
The Magnetic Field

Abstract The effect of the shape of the confinement potential on the electronic, thermodynamic, magnetic and transport properties of a GaAs quantum dot is studied using the power-exponential potential model with steepness parameter p. The average energy, heat capacity, magnetic susceptibility and persistent current are calculated using the canonical ensemble approach at low temperature. It is shown that for soft confinement, the average energy depends strongly on p while it is almost independent of p for hard confinement. The heat capacity is found to be independent of the shape and depth of the confinement potential at low temperatures and for the magnetic field considered. It is shown that the system undergoes a paramagnetic-diamagnetic transition at a critical value of the magnetic field. It is furthermore shown that for low values of the potential depth, the system is always diamagnetic irrespective of the shape of the potential if the magnetic field exceeds a certain value. For a range of the magnetic field, there exists a window of p values in which a re-entrant behavior into the diamagnetic phase can occur. Finally, it is shown that the persistent current in the present quantum dot is diamagnetic in nature and its magnitude increases with the depth of the dot potential but is independent of p for the parameters considered.

scholarly journals He-Abnormal Stars

1993 ◽  
Vol 138 ◽  
pp. 394-404 ◽  
Author(s):  
Kurt Hunger ◽  
Detlev Groote
Keyword(s):  
Magnetic Field ◽  
Magnetic Dipole ◽  
Stellar Wind ◽  
Effective Magnetic Field ◽  
Physical Conditions ◽  
Phase Variations ◽  
Axes Of Symmetry ◽  
The Magnetic Field

AbstractThe He-rich variable HD 37479 has 2 axes of symmetry, one characterized by the depletion of metals, and one by the enrichment of He. The former is oriented along the axis of the magnetic dipole, while the latter is off set by some 45°. The 2 axes represent 2 different modes of diffusion, the first one being controlled solely by the magnetic field, irrespective of wind, the second one being due to stellar wind that is controlled by the magnetic field and intertial forces. It has been attempted to formulate simple physical conditions that allow to determine the diffusion regions on the surface. It is shown that the resulting surface map can well reproduce the observed phase variations of the equivalent widths of HeI 4471, of UV resonance lines of C IV and Si IV, and the effective magnetic field.

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