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

We report the effects of initial composition and partial oxygen pressure (Pox) 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.