Magnetoresistance Anisotropy in Amorphous Superconducting Thin Films: A Site-Bond Percolation Approach

Abstract

Recent measurements of the magnetoresistance (MR) of amorphous superconducting thin films in tilted magnetic fields have displayed several surprising experimental details, in particular a strong dependence of the MR on field angle at low magnetic fields, which diminishes and then changes sign at large fields. Using a generalized site-bond percolation model, that takes into account both the orbital and Zeeman effects of the magnetic field, we show that the resulting MR curves reproduce the main experimental features. Such measurements, accompanied by the corresponding theory, may be crucial in pinpointing the correct theory of the superconductor-insulator transition and of the MR peak in thin disordered films.