The magnetic-field-temperature phase diagram of high-temperature superconductors
Abstract
The magnetic-field-temperature (H-T) phase diagrams of YBa$\sb2$Cu$\sb3$O$\sb7$ (YBCO) and Tl$\sb2$Ba$\sb2$CaCu$\sb2$O$\sb8$ (Tl-2212) high-temperature superconductor (HTS) films, were constructed using magnetotransport, dc magnetization, and ac susceptibility measurements. Correlation of these measurements on a YBCO sample demonstrates that there is one irreversibility line (IRL), which is a continuous vortex-glass phase transition (VGT). Critical behavior of the VGT is investigated in YBCO and Tl-2212 under various conditions. Studies of YBCO as a function of oxygen content suggest that stoichiometric alteration of HTS materials can move the vortex-glass phase boundary with respect to the upper critical field.
Degree
Ph.D.
Advisors
McElfresh, Purdue University.
Subject Area
Condensation
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.