Role of Interstitial Pinning in the Dynamical Phases of Vortices in Superconducting Films

Abstract

We analyze the vortex dynamics in superconducting thin films with a periodic array of pinning centers. In particular, we study the effect of anisotropy for a Kagomé pinning network when longitudinal and transverse transport currents are applied. By solving the equations of motion for the vortex array numerically at zero temperature we find different phases for the vortex dynamics depending on the pinning and driving force. An unusual sequence of peaks along and perpendicular to the main hexagonal lattice axes is observed for the differential resistance reflecting the anisotropy of the transport properties and the complex behavior of the vortex system. This behavior may be understood in terms of interstitial pinning vacancies, which create channels of vortices with different pinning strength.

Commensurability effects in the critical forces of a superconducting film with Kagomé pinning array at submatching fields

“…In particular, for periodic pinning as, for example, square [12][13][14][15]35], triangular [3][4][5][6][7][34][35][36][37], rectangular [1,22,28], honeycomb [2,3,8,29,33] and Kagomé [2,3,8,[29][30][31][32][33][34][35], it is well accepted that for values of the external magnetic field (B) higher than the first matching field (B φ ), vortices organize themselves in a highly symmetric way that leads to a perfect cancelation of the vortex-vortex interaction, generally forming a pattern which is commensurate with the pinning landscape, leading to pronounced peaks of critical force.…”