MAGNETIC FIELD RESPONSES OF HARMONIC SUSCEPTIBILITIES OF HIGH TC SUPERCONDUCTOR YBCO

Abstract

The temperature dependence of the harmonic susceptibilities has been measured on a melt textured YBCO for different amplitudes of the AC magnetic field with combination of a DC magnetic field. The model calculations have been performed on the basis of a model which incorporates the effects of the collective creep concept in a critical-state equation. The temperature dependencies of the activation energy and the critical current density chosen as U = [U0(1 - (T/Tc)4)/μ)][(Jc/J)μ - 1] and Jc = J0[(1 + (T/Tc)2)]-1/2[(1 - (T/Tc)2)]5/2 respectively have been used to explain the DC bias field and temperature dependencies of the harmonic susceptibilities. The predictions of the model for fundamental and higher harmonic susceptibilities were consistent with the experimental data.