DISSIPATION MECHANISM IN HIGH-TEMPERATURE SUPERCONDUCTORS

Certain applications of the superconductors require the use of samples which exhibit high critical current under the presence of an external magnetic field. It is therefore important to comprehend the dissipation mechanism in high temperature superconductors (HTSCs). Results of studies carried out to understand the dissipation mechanism in HTSCs have been briefly reviewed in this paper. The current-voltage (I-V) plots for epitaxial YBa2Cu3Ox (YBCO) films have been studied with current and magnetic field in different configurations. The current direction was fixed in ab-plane and magnetic field direction was oriented differently i.e. (a) along the c-axis, (b) in the ab-plane at different angles to current direction and (c) normal to current at different angles to ab-plane. The data show power law behavior of I-Vs in disagreement with conventional nux flow/flux creep models. New models developed to account for the observed results have been presented and discussed.