A temperature-dependent self-consistent calculation of localized-spin–fluctuation effects in AlMn

1976 ◽  
Vol 54 (7) ◽  
pp. 771-774 ◽  
Author(s):  
C.Y. Cheung
Keyword(s):  
Temperature Dependence ◽  
Spin Fluctuation ◽  
Fluctuation Theory ◽  
Effective Density ◽  
Temperature Dependent ◽  
Local Spin ◽  
Consistent Calculation ◽  
Quantitative Effect ◽  
Self Consistent ◽  
Fluctuation Effects

The renormalized local-spin–fluctuation theory of Paton and Zuckermann is extended in a temperature-dependent calculation. It is found that the temperature dependence of the renormalization parameters produce significant quantitative effect in the linear-T region of the effective density of d states.

TEMPERATURE-DEPENDENT MICROWAVE PERFORMANCE OF SB-HETEROSTRUCTURE BACKWARD DIODES FOR MILLIMETER-WAVE DETECTION

2007 ◽  
Vol 17 (01) ◽  
pp. 105-110
Author(s):  
N. SU ◽  
Z. ZHANG ◽  
P. FAY ◽  
H. P. MOYER ◽  
R. D. RAJAVEL ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Millimeter Wave ◽  
Variable Temperature ◽  
Device Performance ◽  
Material System ◽  
Temperature Dependent ◽  
Junction Resistance ◽  
Measured Voltage ◽  
Wave Detection ◽  
Self Consistent

The temperature dependence of heterostructure backward diodes based on the InAs/AlGaSb/GaSb material system for millimeter-wave detection has been investigated experimentally. Measured dc curvatures of 36 V-1 at 298 K and 74 V-1 at 4.2 K have been obtained. Variable-temperature on-wafer s-parameters to 110 GHz reveal that the junction capacitance of a typical 2×2 μ m 2 area device decreases from 18 fF at 298 K to 11 fF at 77 K, while the junction resistance decreases from 13.9 kΩ to 10.2 kΩ. Directly measured voltage sensitivities at 50 GHz of 3650 V/W and 7190 V/W were obtained at 298 K and 4.2 K, respectively, consistent with the expected value from measured dc curvature. A 1 dB compression point of 18.5 μW and 7.2 μW at 298 K and 77 K, respectively, was measured. A physical model based on self-consistent Poisson-Schrödinger equation solutions was obtained to explain the experimental observations, and suggests the ways to further improve the device performance.

Temperature Hysteresis in the Dynamic Spin-Fluctuation Theory for Strong Ferromagnets

2009 ◽  
Vol 152-153 ◽  
pp. 579-582 ◽  
Author(s):  
B.I. Reser ◽  
Vladimir I. Grebennikov ◽  
N.B. Melnikov
Keyword(s):  
Initial Data ◽  
Curie Temperature ◽  
Temperature Dependence ◽  
Catastrophe Theory ◽  
Spin Fluctuation ◽  
Fluctuation Theory ◽  
Magnetic Characteristics ◽  
Temperature Hysteresis ◽  
System Of Equations ◽  
Dynamic Spin

Temperature dependence of magnetic characteristics of Fe and Fe-Ni invar is considered in the dynamic nonlocal approximation of the spin-fluctuation theory. Numerical calculations show that the magnetic characteristics can have a discontinuous jump at high temperatures, well below the Curie temperature. Using methods of the catastrophe theory, we investigate the effect of small changes in the initial data on the results of the calculation. It is demonstrated that the discontinuous jump can only be smoothed but cannot be eliminated entirely without a significant change in the system of equations of the spin-fluctuation theory. Possible variants of such changes are discussed.

Effect of Pressure on the Spin Fluctuations and the Helical Ferromagnetism of MnSi

2016 ◽  
Vol 257 ◽  
pp. 30-33
Author(s):  
Aleksandr A. Povzner ◽  
Arkadij G. Volkov ◽  
Ivan A. Yasyulevich
Keyword(s):  
Magnetic Susceptibility ◽  
Local Minimum ◽  
Spin Fluctuation ◽  
Magnetic Moments ◽  
Paramagnetic State ◽  
Spin Fluctuations ◽  
Temperature Dependent ◽  
Effect Of Pressure ◽  
Fluctuation Effects ◽  
Moriya Interaction

The effect of pressure on the Neel temperature (TN) and on the temperature dependence of the magnetic susceptibility of a helicoidal ferromagnetic MnSi was analyzed as part of the LDA+U-model augmented with the account of the relativistic antisymmetric Dzyaloshinskii-Moriya interaction. It was shown that the Fermi level is in the area of DOS local minimum. This causes instability of magnetic solutions and the occurrence of higher amplitude zero spin fluctuations simulating the pattern of local magnetic moments. An increase in temperature-dependent spin-fluctuation effects with an increase in pressure leads to a decrease in TN. As a result, at pressures above 14.45 kbar, zero spin fluctuations are retained over the entire temperature range below TN. After disappearance of helicoidal ferromagnetism, a paramagnetic state occurs where the effect of the abrupt suppression of local magnetic moments takes place upon a temperature increase.

Temperature dependence of spin fluctuation scattering of neutrons on pyrrhotite

1964 ◽  
Vol 25 (5) ◽  
pp. 634-641 ◽  
Author(s):  
Sz. Kraśnicki ◽  
A. Wanic ◽  
Ž. Dimitrijević ◽  
R. Maglić ◽  
V. Marković ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Spin Fluctuation

19F Nuclear Quadrupole Coupling in some Halomethanes

1986 ◽  
Vol 41 (1-2) ◽  
pp. 171-174 ◽  
Author(s):  
M. Frank ◽  
F. Gubitz ◽  
W. Ittner ◽  
W. Kreische ◽  
A. Labahn ◽  
...  
Keyword(s):  
Angular Distribution ◽  
Simple Model ◽  
Temperature Dependence ◽  
Coupling Constants ◽  
Temperature Dependent ◽  
Distribution Method ◽  
Quadrupole Coupling ◽  
Time Differential ◽  
Nuclear Quadrupole

The 19F quadrupole coupling constants in CF4, CHF3, CClF3 and CHClF2 are reported. The measurements were carried out temperature dependent using the time differential perturbed angular distribution method (TDPAD). The temperature dependence can be satisfactorily described in the framework of the Bayer-Kushida theory. A simple model is used to explain the appearance of H-F and Cl-F coupling constants in CHF3/CHClF2 and CClF3, respectively.

Self-consistent calculation of excited3P state wave functions of atoms

1971 ◽  
Vol 5 (6) ◽  
pp. 647-655 ◽  
Author(s):  
P. K. Mukherjee ◽  
A. K. Bhattacharya ◽  
A. Mukherji
Keyword(s):  
Wave Functions ◽  
Consistent Calculation ◽  
State Wave ◽  
Self Consistent
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