Some possible effects of periodic pinning in high Tcsuperconductors

✍ Scribed by N. Rezlescu; R. Anghelache; I. Ciobotaru; I. Puha

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 140 KB
• Volume: 21
• Category: Article
• ISSN: 0749-6036
• DOI: 10.1006/spmi.1996.0413

✦ Synopsis

We are assuming that the pinning points could be created in the center of each unit cell of the planar superconducting lattice. The existence of periodic pinning suggests a particular dynamics of vortices in the mixed state of 2D and 3D high T c superconductors. Such a moving mechanism may be studied using a planar Potts model. We used such a model to perform some numerical simulations focusing on the melting of the Abrikosov lattice of vortices in a system of Josephson arrays of superconducting grains. A Monte Carlo analysis on the resulting hamiltonian in a field given by a starting filling factor of f = 1/2 exhibits two phase transitions, in both 2D and 3D. The 2D model gives the critical temperatures T c1 0.325 and T m 0.65. The 3D one gives T c1 0.67 and T m 1.325. The numerical estimation of the Challa parameters for both transitions indicates their continuous nature in both 2D and 3D versions of this model. The results suggest that, below T c1 , the superconductor is in the Meissner phase, between T c1 and T m it is in the mixed state and above T m it is in the melted flux state, i.e. technological normal state.