A new type of pinning center in melt grown Nd123 and Sm123

Abstract REBa2Cu3Oy (RE: Nd, Sm) superconductors exhibit relatively high Jc values even at 77K when melt-processed in a reduced oxygen atmosphere. The Jc values of these superconductors are higher than those of melt processed YBa2Cu3Oy with fine Y2BaCuO5 inclusions in a high field region. The irreversibility field with H∥c axis was dramatically increased to 8T at 77K. We believe that flux pinning in these superconductors is ascribable to a finely distributed RE(Ba1−x, REx)2Cu3Oy phase in a good superconductive matrix.