We demonstrate how nonlinear effects in high temperature superconducting thin films can be quantified based on a current-dependent penetration depth λ(J). Using an assumed form for λ(J), we calculate the expected third-order harmonic signals generated by this simplified nonlinearity. We show how such a calculation can be used to extract a geometry independent quantity, the pair-breaking current density, provided the current distribution of the device-under-test can be accurately determined. We demonstrate how we extract the pair-breaking current density of HTS thin films from linear and nonlinear measurements of coplanar waveguide transmission lines on the same thin film sample. We use this formalism to quantitatively compare the nonlinear response for several different HTS thin films.
Proceedings Title: Ext. Abstracts, 2003 Intl. Superconductive Electronics Conf. (ISEC)
Conference Dates: July 7-11, 2003
Conference Location: Sydney, AS
Pub Type: Conferences
high temperature superconductivity, nonlinear response, passive microwave devices