Disorder Effects on the Intrinsic Nonlinear Current Density in ${\rm YBa}_{2}{\rm Cu}_{3}{\rm O}_{7-\delta}$

Abstract

We present harmonic generation measurements of the intrinsic nonlinear current density j 2 of YBa 2 Cu 3 O 7 (YBCO) films at temperatures close the T c . Experiments on a range of different quality samples allow us to extract the dependence of j 2 on the penetration depth of the superconductor.In order to model these results, we calculate the intrinsic nonlinear current response of -wave superconductors in the Meissner regime in the presence of nonmagnetic impurities within the self-consistent T-matrix approximation.Index Terms-High temperature superconductor, nonlinear current density, nonlinear microwave response.

Nonlinear Response of Combined Superconductor/Ferroelectric Devices: First Experimental Step

“…Therefore, in order to significantly improve the linearity of HTS microwave devices, one needs to consider new approaches. Some of the approaches explored include multilayer (YBCO) thin-film configurations [5], disorder effects [6], and combinations of HTS thin film with other materials (with different types of nonlinear effects), such as ferroelectrics [7].…”