Thickness dependence of the magnetic properties in YBa2Cu3O7−δ thin films

Abstract

We report on magnetization measurements in laser ablated YBa2Cu3O7−δ films with thickness 800 – 3000Å. The persistent current density j and the magnetic relaxation rate decrease with increase of the thickness. At certain conditions this leads to a crossing of the relaxation curves measured in films of different thickness. These results are explained considering surface effects which cause a non-homogeneous distribution of j along the film thickness.