Microstructure and Superconducting Properties of Melt-Processed Bulk Gd123 Single Domain with Gd2Ba4CuMOx (M=Mo and Zr) Additions

摘要

Inclusion of the finely dispersed RE2BaCuO5 ( RE211 ) enhances flux pinning in bulk REBa2Cu3O7–. Recently, we tested the effect of Gd2Ba4CuMOx ( Gd2411; M= Zr, Mo) addition on the trapped field and critical current density ( Jc ) in single domain of bulk GdBa2Cu3O7– ( Gd123 ) with the additional amount ranging from 0.2 mol % to 20 mol %, ratio to Gd123. Around the seeding zone a novel band of the second phase distribution was observed for all Gd2411 additional levels. Second phase excess regions were followed by diluted second phase regions, those appeared alternatively, and formed an inhomogeneous band structure, while an uniform distribution of Gd211 appeared from 0.5 cm away from the seed to the edge of domain along 100/010 direction. Jc values strongly depend on the positions and the Gd2411 addition was proved to enhance Jc near the seeding site rather than edge-periphery zone of the bulk disk.