Insulating state of granular superconductors in a strong-coupling regime
  We analyze the possibility of the formation of a magnetic-field-induced insulating state in a two-dimensional granular superconductor with relatively strong intergranular coupling and show that such a state appears in a model with spatial variations of the single-grain critical magnetic field. This model describes realistic granular samples with the dispersion in grain sizes and explains the mechanism leading to a giant peak in the magnetoresistance. 
I.S. Beloborodov, Ya.V. Fominov, A.V. Lopatin, and V.M. Vinokur