On Electrostriction of a Granular Superconductor

Zero-temperature field-induced polarization, supercurrent density, and the related electrostriction (ES) of a granular superconductor are calculated within a model of 3D Josephson junction arrays. Both the "bulk-modulus-driven ES" (the change of the sample's volume in the free energy upon the applied stress) and the "change-of-phase ES" (due to the stress dependence of the weak-links-induced polarization) are considered. In contrast to magnetostriction of a granular superconductor, its electroelastic behavior is predicted to be dominated by the former contribution for all applied fields.