Spatial distribution of superconducting properties in single-grained Sm-Ba-Cu-O bulks

We report the effects of initial composition and partial oxygen pressure (P_ox) on the spatial distribution of the superconducting transition and critical current characteristics in c-axis-oriented Sm-Ba-Cu-O superconductors fabricated by the top-seeded melt growth method. The magnetic properties are significantly dependent on the position within a large single-grained Sm-Ba-Cu-O bulk fabricated in air, which is attributed to the facts that growth temperature of Sm-Ba-Cu-O varies with location in a massive sample and the range of the substitution of Sm for Ba is dependent on growth temperature. In contrast, for samples processed in a reduced oxygen atmosphere, the variation of superconducting properties is notably small. Such difference can be understood in terms of the range of Sm-Ba solid solution, which can greatly be narrowed in a reduced oxygen atmosphere.