Magnetic suspension, critical current, and morphology in YBa2Cu3O7−x-silver composites

Abstract

In this article we try to elucidate the link between the morphological structure of YBa2Cu3O7−x (YBCO)-silver composite sintered at 980 °C and the high flux pinning observed in this material. This YBCO/Ag system exhibits the suspension phenomenon in magnetic field gradient. The surface of the large YBCO grains is doped with silver and exhibits a high Tc=95 K. This doped phase shows a longer c axis than regular YBCO ceramic material. We believe that this high Tc phase forms a network of superconducting ‘‘rings’’ localized on the YBCO large grains. This network is probably the source of the high flux trapping phenomenon in the composite material.