Heat capacity of pancake vortices in layered superconductors

1996 ◽  
Vol 54 (22) ◽  
pp. 16116-16123 ◽  
Author(s):  
Alexander L. Fetter ◽  
Satyadev Rajesh Patel
2016 ◽  
Vol 94 (2) ◽  
Author(s):  
H. J. Zhao ◽  
Wenjuan Wu ◽  
Wei Zhou ◽  
Z. X. Shi ◽  
V. R. Misko ◽  
...  

Author(s):  
John H. Miller Jr. ◽  
Martha Y. S. Villagrán

The nucleation and dynamics of Josephson and Abrikosov vortices determine the critical currents of layered high-Tc superconducting (HTS) thin films, grain boundaries, and coated conductors, so understanding their mechanisms is of crucial importance. Here we treat pair creation of Josephson and Abrikosov vortices in layered superconductors as a secondary Josephson effect, in which each full vortex is viewed as a composite fluid of micro-vortices, such as pancake vortices, which tunnel coherently via a tunneling matrix element. We introduce a two-terminal magnetic (Weber) blockade effect that blocks tunneling below a threshold current, and simulate time-correlated vortex tunneling above threshold. The model shows nearly precise agreement with voltage-current (V-I) characteristics of HTS cuprate grain boundary junctions, which becomes more concave rounded as temperature decreases, and also explains the piecewise linear V-I behavior observed in iron-pnictide bicrystal junctions and other HTS devices. When applied to either Abrikosov or Josephson pair creation, the model explains a plateau seen in plots of critical current vs. thickness of HTS coated conductors. The observed correlation between theory and experiment strongly supports the proposed quantum picture of vortex nucleation and dynamics in layered superconductors.


2000 ◽  
Vol 14 (32) ◽  
pp. 3831-3879 ◽  
Author(s):  
TODOR MISHONOV ◽  
EVGENI PENEV

A detailed theoretical analysis of the Gaussian fluctuations of the order parameter in layered superconductors is performed within the Ginzburg–Landau (GL) theory. The available results for the Gaussian fluctuations are systematized and a number of novel formulae for the fluctuation magnetization, nonlinear magnetic susceptibility, heat capacity and high-frequency conductivity in layered superconductors are derived. We propose several new prescriptions: how to determine the life-time constant of fluctuation Cooper pairs τ0, the in-plane coherence length ξab(0), the energy cutoff parameter [Formula: see text] and the Ginzburg number ∊ Gi . It is demonstrated, for example, how the spectroscopy of the life-time can be used to verify the existence of depairing mechanisms in layered cuprates. The ultraviolet regularization of the GL free energy is carried out by means of the well-known from the field theory ζ-function method. We further show that the archetype of the latter method has its origin in the century of enlightenment and the novel result is that the fluctuation part of the thermodynamic variables of the layered superconductors can be expressed in terms of the Euler Γ-function and its derivatives. Universal scaling curves for the magnetic field dependence of the paraconductivity σab(T c ,B), fluctuation magnetization M(T c ,B) and the heat capacity C(T c ,B) are found for the quasi-2D superconductors at T c and further related to the form-factor of the Cooper pairs.


2012 ◽  
Vol 171 (1-2) ◽  
pp. 148-155 ◽  
Author(s):  
T. L. Hung ◽  
I. A. Chen ◽  
C. H. Huang ◽  
C. Y. Lin ◽  
C. W. Chen ◽  
...  

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