Monte Carlo Study of the Magnetic Flux Lattice Fluctuations in High-Tc Superconductors
Our model correctly predicts the melting temperatures of the YBa2Cu3O6. 95 (YBCO) superconductor but largely underestimates the observed entropy jump. Also we failed to simulate the high field disordered phase, possibly because of a finite size limitation. In addition, we found our model unable to describe the first-order transition observed in the highly anisotropic Bi2Sr2CaCu2O8+y.
Our model predicts that for YBCO, the effect of thermal fluctuations on the field distribution is indistinguishable from a change in ξ. It also confirms the usual assumption that the effect of static fluctuations at low temperature can be efficiently modeled by convolution of the field distribution with a Gaussian function. However the extraction of ξ at low fields requires a very high resolution of the field distribution because of the low vortex density.
School:University of Waterloo
School Location:Canada - Ontario
Source Type:Master's Thesis
Keywords:physics astronomy high temperature superconductor flux line lattice melting magnetic vortices muon spin rotation monte carlo simulation coherence length penetration depth entropy jump ybco
Date of Publication:01/01/2005