Enhancement in the trapped fields of YBCO at 77 K by cation doping

Magnetic field trapping capability is one of the most important properties of YBCO large grain materials. It is dependent on the pinning forces exerting on the magnetic flux lines by various crystal defects in YBCO, including nanometer scale weak superconducting regions which are either induced by doping or simply fine second phase inclusions. The present study establishes the optimum fabrication conditions of YBCO large grains with properties enhanced by Zn and Er doping. These property enhancements are interpreted on the basis of local depression in superconductivity as well as the changes in solubility of the dopants under certain undercooling conditions during grain growth.