The E-J Characteristic of YBaCuO Films Determined by Inductive Measurements
An inductive method is used to determine the critical current density and the E-J characteristic for ring-, disk-, or plate-shaped YBaCuO films down to a sensitivity of 10–14 V/cm in magnetic fields up to 0.2 T and at varying temperature. A miniature Hall sensor monitors the field produced by screening currents, which flow as a response to an external field sweep. — Results are compared to existing theories describing the resistive state of high-Tc superconductors due to flux movement. Except for small intervalls of the measured E(J) relation, no satisfying agreement was found. This led us to extend the flux creep theory by introducing flux flow dissipation also in the creep regime, which results in a qualitative understanding of the observed E(J) behavior.
KeywordsCritical Current Density Sweep Rate Hall Sensor Vortex Loop Hall Voltage
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