Surface effect on the magnetization of superconducting lead

Abstract

By sandblasting surfaces of a superconducting lead bar, the irreversibility of the magnetization curve is increased. This effect is accompanied in these experiments by a slight increase of the critical field. It depends on the orientation of the sanded surfaces with respect to the applied field and almost disappears after etching the surfaces. It is suggested that the effect is due to modifications of the surface superconducting properties by the sandblasting rather than to pinning of domain walls by surface defects.