WEAK FIELD MAGNETIZATION AND SUSCEPTIBILITY FLUCTUATION IN Bi2Sr2CaCu2Oy SINGLE CRYSTALS

1989 ◽  
Vol 03 (14) ◽  
pp. 1045-1051 ◽  
Author(s):  
G. H. CHEN ◽  
G. YANG ◽  
Y. F. YAN ◽  
S. L. JIA ◽  
Y. M. NI ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Single Crystals ◽  
Temperature Increase ◽  
Weak Field ◽  
Experimental Measurements ◽  
Zero Field ◽  
Two Dimensional ◽  
Magnetization Curves ◽  
Field Limit ◽  
Low Magnetic Field

Some magnetization curves of single crystal of Bi 2 Sr 2 CaCu 2 O y in low magnetic field H ‖ c axis are given. The magnetization loop is getting smaller with the temperature increase and then disappears at temperature even higher than T c . The experimental measurements of the susceptibility in zero-field limit show that the results can be treated with two-dimensional thermo-fluctuation theory.

ISING MODEL IN THE MAGNETIC FIELD iπkT/2

1988 ◽  
Vol 02 (03n04) ◽  
pp. 471-481 ◽  
Author(s):  
K. Y. LIN ◽  
F. Y. WU
Keyword(s):  
Magnetic Field ◽  
Free Energy ◽  
Ising Model ◽  
Zero Field ◽  
Two Dimensional ◽  
Anisotropic Interactions ◽  
The Magnetic Field ◽  
Explicit Expressions

It is shown that the free energy and the magnetization of an Ising model in the magnetic field H = iπkT/2 can be obtained directly from corresponding expressions of these quantities in zero field, provided that the latter are known for sufficiently anisotropic interactions. Using this approach we derive explicit expressions of the free energy and the magnetization at H = iπkT/2 for a number of two-dimensional lattices.

THE ACCELERO-MAGNETIC FIELD, THOMAS PRECESSION AND AN EQUIVALENCE PRINCIPLE FOR SPIN

2001 ◽  
Vol 16 (07) ◽  
pp. 429-440 ◽  
Author(s):  
C. S. UNNIKRISHNAN
Keyword(s):  
Magnetic Field ◽  
Equivalence Principle ◽  
Weak Field ◽  
Physical Interaction ◽  
Precision Spectroscopy ◽  
Field Limit ◽  
Thomas Precession ◽  
Weak Field Limit ◽  
The Magnetic Field ◽  
Precision Test

In the weak field limit of Einstein gravity, there are gravitational analogues of the vector potential and the magnetic field. The equivalence principle guides us to a magnetic-like interaction arising from inertial acceleration. The spin precession due to this accelero-magnetic field is identified as the Thomas precession. Hence the torque that is responsible for the precession of the spin is identified as resulting from a physical interaction with a magnetic-like inertial-field. Once the equivalence principle is assumed to some accuracy, well supported by precision tests, this implies that the average effect of the accelero-magnetic field on a classical or quantum gyroscope is the same as that of the gravito-magnetic field on a gyroscope. Precision spectroscopy of spin-orbit doublets in atoms is hence an indirect high precision test of the existence and properties of the gravito-magnetic field. This also implies that the planned and current experiments will not see any deviations from the predictions of general relativity. This line of thought is extended to a brief discussion on the possibility of formulating an independent equivalence principle for the spin.

scholarly journals Влияние дисперсии магнитной анизотропии кластеров Ge-=SUB=-3-=/SUB=-Mn-=SUB=-5-=/SUB=- на температурные зависимости намагниченности тонких пленок Ge:Mn

2019 ◽  
Vol 45 (2) ◽  
pp. 36
Author(s):  
А.И. Дмитриев ◽  
М.С. Дмитриева ◽  
Г.Г. Зиборов
Keyword(s):  
Magnetic Field ◽  
Magnetic Anisotropy ◽  
Lognormal Distribution ◽  
Anisotropy Constant ◽  
Zero Field ◽  
Magnetization Curves ◽  
Magnetic Anisotropy Energy ◽  
Size Dependent ◽  
Magnetic Anisotropy Constant ◽  
Temperature Dependences

AbstractThe temperature dependences of magnetization M ( T ) of thin ion-implanted Ge:Mn (4 at % Mn) films containing Ge_3Mn_5 clusters were measured on samples cooled in the absence of magnetic field (zero field cooled, ZFC) and in a magnetic field of 10 kOe (field-cooled, FC). It has been established that the shape of ZFC–FC differential M ( T ) curves is determined by lognormal distribution of the size-dependent magnetic anisotropy energy of Ge_3Mn_5 clusters. Analysis of the observed ZFC–FC magnetization curves allowed the magnetic anisotropy dispersion (variance) and magnetic anisotropy constant to be estimated.

Continuous Two-Dimensional Melting of Vortex-Solid in High Temperature Superconductors

1989 ◽  
Vol 169 ◽  
Author(s):  
N.-C. Yeh
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
Defect Density ◽  
High Temperature Superconductors ◽  
Finite Size ◽  
Sample Thickness ◽  
Zero Field ◽  
Two Dimensional ◽  
Thermally Induced ◽  
Transport Studies

AbstractA model of continuous two-dimensional melting in the mixed state of high temperature superconductors is proposed. Two-dimensional melting sets in at a cross-over temperature Tx(H) below the three-dimensinal phase transition Tx(H) due to finite size effects, and Tx(H) is a function of the sample thickness (lc), applied magnetic field (H), and k(= λ/ξ) For a given zero-field transition temperature Tc0 and material properties, (such as defect density), the onset temperature of 2D-melting (Tx(H)) decreases with decreasing sample thickness and increasing magnetic field. In transport studies, thermally induced melting is further complicated by the depinning effect of high current densities.

Out-of-Plane and in-Plane Conduction in Insulating and Strongly Underdoped Cuprates

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3203-3206
Author(s):  
C. C. Almasan ◽  
G. A. Levin ◽  
E. Cimpoiasu ◽  
T. Stein ◽  
D. A. Gajewski ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Normal State ◽  
Low Temperatures ◽  
Elementary Step ◽  
Charge Carriers ◽  
Two Dimensional ◽  
Out Of Plane ◽  
Underdoped Cuprates

We report measurements of out-of-plane (ρ c ) and in-plane (ρab) normal-state resistivities of single crystals of insulating PrBa2Cu3O 7-δ and strongly underdoped oxygen deficient YBa2Cu3O 6.41 using a flux transformer method. In the superconducting specimens, the onset of superconductivity was suppressed by a magnetic field of 9 T. We have found that the anisotropy ρc/ρab of these samples increases monotonically at low temperatures with no signs of saturation. The temperature dependence of ρc/ρab for YBa2Cu3O6.41 is well described by ρc/ρab=a +bT-2/3, but over a smaller temperature range than for insulating PrBa2Cu3O 7-δ. Both the absence of saturation of ρc/ρab and its T-2/3 dependence indicate two-dimensional conduction. This means that the average in-plane hopping distance of the localized charge carriers increases with decreasing T according to Mott's [Formula: see text] law, while the elementary step in the c-direction remains T independent, equal to the spacing between the bilayers.

Influence of microwave photo-excitation on the transport properties of the high mobility GaAs/AlGaAs 2D electron system

MRS Advances ◽  
2019 ◽  
Vol 4 (61-62) ◽  
pp. 3347-3352
Author(s):  
T. R. Nanayakkara ◽  
R. L. Samaraweera ◽  
A. Kriisa ◽  
U. Kushan Wijewardena ◽  
S. Withanage ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Microwave Power ◽  
High Mobility ◽  
Electron System ◽  
Zero Field ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Field Limit ◽  
Theoretical Predictions ◽  
Dimensional Electron System

ABSTRACTWe examined the influence of the microwave power on the diagonal resistance in the GaAs/AlGaAs two dimensional electron system (2DES), in order to extract the electron temperature and determine microwave induced heating as a function of the microwave power. The study shows that microwaves produce a small discernable increase in the electron temperature both at null magnetic field and at finite magnetic fields in the GaAs/AlGaAs 2DES. The heating effect at null field appears greater in comparison to the examined finite field interval, although the increase in the electron temperature in the zero-field limit appears smaller than theoretical predictions.

Lattice statistics in a magnetic field. II. Order and correlations of a two-dimensional super-exchange antiferromagnet

1960 ◽  
Vol 256 (1287) ◽  
pp. 502-513 ◽  
Keyword(s):  
Magnetic Field ◽  
Long Range ◽  
Pair Correlation ◽  
Configurational Entropy ◽  
Square Lattice ◽  
Lattice Statistics ◽  
Zero Field ◽  
Two Dimensional ◽  
Ising Lattice ◽  
Pair Correlations

The long-range order and pair correlation functions of a two-dimensional super-exchange antiferromagnet in an arbitrary magnetic field are derived rigorously from properties of the standard square Ising lattice in zero field. (The model investigated was described in part I: it is a decorated square lattice with magnetic spins on the bonds coupled antiferromagnetically via non-magnetic spins on the vertices.) The behaviour near the transition temperature in a finite field is similar to that of the normal plane lattice, i. e. the long-range orders or spontaneous magnetizations of the sublattices vanish as ( T t – T ) ⅛ and the pair correlations behave as ω c + W ( T – T t ) ln | T – T t |. The configurational entropy is discussed and the anomalous entropy in the critical field at zero temperature is calculated exactly.

Sign in / Sign up

Export Citation Format

Share Document