Degeneracy of antiferromagnetic Ising lattices at critical magnetic field and zero temperature

1978 ◽  
Vol 18 (5) ◽  
pp. 2304-2307 ◽  
Author(s):  
B. D. Metcalf ◽  
C. P. Yang

2016 ◽  
Vol 30 (25) ◽  
pp. 1650183 ◽  
Author(s):  
Yu. N. Ovchinnikov

The effect of spin-orbit (SO) interaction on the formation of the critical states in thin superconducting films in magnetic field oriented along the film is investigated. Hereby, the case of interband pairing is considered. It was found that eight branches exist in the plane of two parameters [Formula: see text] determined by the value of magnetic field and SO interaction. Six modes leads to inhomogeneous states with different values of the impulse [Formula: see text]. Each state is doubly degenerate over direction of impulse [Formula: see text]. The parameter values at critical point are found for all eight branches in explicit form for zero temperature. The optimal two branches are estimated, corresponding to largest critical magnetic field value for given SO interaction.



1992 ◽  
Vol 06 (16n17) ◽  
pp. 1037-1042 ◽  
Author(s):  
V. BUNTAR ◽  
U. ECKERN ◽  
C. POLITIS

The lower critical magnetic field Hc1 of superconducting Rb 3 C 60 (Tc=28.5 K ) is estimated by different methods. The zero temperature value is found to be given by Hc1=16.2±1.0 mT, and the penetration depth is λL=215±10 nm . The Bean model analysis leads to threshold fields of 5.3 mT for T=5 K , and 4.0 mT for T=17 K . The big influence of intergranular connections on Hc1 is demonstrated. Good agreement between the low- and the high-field analysis is found.



1993 ◽  
Vol 07 (11) ◽  
pp. 2163-2176 ◽  
Author(s):  
C. POLITIS ◽  
V. BUNTAR ◽  
V.P. SEMINOZHENKO

We present the results of magnetic measurements in fields up to 50 kOe for superconducting Rb 3 C 60. The temperature dependence of upper H c 2 critical magnetic field is determined, from which the zero temperature value Hc2(0)=465±50 kOe is evaluated. The magnitudes of penetration depth and coherence length are calculated as ξ(0)=26.7±3 Å; λ L (0)=2150±100 Å at zero temperature. The temperature dependence of ξ(T) and λ L (T) for T≧23 K is in good agreement with the Ginzburg-Landau theory. The critical current densities for different temperatures are calculated, showing a strong decrease of Jc with increasing temperature for T≤7 K . Two regions of fading critical current density on a magnetic field dependence are found.



2013 ◽  
Vol 28 (08) ◽  
pp. 1350024 ◽  
Author(s):  
D. MOMENI ◽  
EIJI NAKANO ◽  
M. R. SETARE ◽  
WEN-YU WEN

We analytically study the effect of magnetic field in a holographic superconductor by using Sturm–Liouville method. We estimate the coefficient of proportionality at critical temperature and find its dependence on bulk magnetic field. By exploring the phase diagrams of critical temperature and magnetic field for various condensates, we conclude that the existence of critical magnetic field is a general feature in holographic superconductors. We also study the quantum phase transition at zero temperature and find that the critical charge density increases linearly with the condensate dimension.



2021 ◽  
Vol 103 (8) ◽  
Author(s):  
Fumikazu Oguro ◽  
Yudai Sato ◽  
Kanta Asakawa ◽  
Masahiro Haze ◽  
Yukio Hasegawa


1966 ◽  
Vol 150 (1) ◽  
pp. 222-225 ◽  
Author(s):  
Rudolf Klein ◽  
Gaston Fischer


1985 ◽  
Vol 54 (5) ◽  
pp. 477-480 ◽  
Author(s):  
M. B. Maple ◽  
J. W. Chen ◽  
S. E. Lambert ◽  
Z. Fisk ◽  
J. L. Smith ◽  
...  


2018 ◽  
Vol 33 (25) ◽  
pp. 1850144
Author(s):  
Maryam Gholizadeh Arashti ◽  
Majid Dehghani

The Schwinger effect in the presence of instantons and background magnetic field was considered to study the dependence of critical electric field on instanton density and magnetic field using AdS/CFT conjecture. The gravity side is the near horizon limit of D3[Formula: see text]D(−[Formula: see text]1) background with electric and magnetic fields on the brane. Our approach is based on the potential analysis for particle–antiparticle pair at zero and finite temperatures, where the zero temperature case is a semi-confining theory. We find that presence of instantons suppresses the pair creation effect, similar to a background magnetic field. Then, the production rate will be obtained numerically using the expectation value of circular Wilson loop. The obtained production rate in a magnetic field is in agreement with previous results.



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