Field and temperature dependence of the penetration depth and the electrical resistance in YBCO from the imaginary AC susceptibility

Abstract

The intragrain AC loss peak of YBCO was quantitatively described using a model that considers the effect of penetration depth electrical resistance on the eddy currents. The peak can be simulated with two field dependent parameters: the rate at which the penetration depth and the electrical resistance decrease with temperature as the sample undergoes transition to the superconducting state. The penetration depth extracted from χ" data was shown to increase with AC field amplitude, whereas the corresponding electrical resistance decreases with increase in field amplitude.