Asymmetric Flux Pinning in a Regular Array of Magnetic Dipoles

Abstract

The effect of a regular array of magnetic dipoles embedded in a superconducting film was investigated. A large asymmetry in critical currents was found between when the magnetic dipoles are aligned and antialigned with respect to an externally applied magnetic field. Enhanced pinning effects were observed when the flux lattice and the dipole lattice were commensurate. The data are used to infer pinning mechanisms, strengths, and sites.