Conductance Switching and Inhomogeneous Field Melting in the Charge Ordered Manganites

The field induced switching of conductance in the charge ordered half-doped manganites is controlled by the combination of metastability, an inhomogeneous high field state, and cation disorder. We study this non-equilibrium problem via real space Monte Carlo on a disordered strong coupling model appropriate to the manganites. We reproduce the variation of the switching fields with the mean ionic radius r_A and cation disorder \sigma_A, and demonstrate how the experimental features arise from the proximity of several phases in the Landau free energy landscape. Our prediction for the field melted state is consistent with a growing body of experimental evidence.