Impurity-induced magnetic fields in unconventional superconductors

Abstract

An impurity in an unconventional superconductor perturbs the order parameter out to distances of order \ensuremath{\xi}(T). When the order parameter is ``ferromagnetic'' in character a localized flow of supercurrent is also induced; this supercurrent creates a magnetic field at the site of the impurity. We discuss these supercurrents, and estimate the size of the resulting magnetic field.