Crystal growth direction dependence of microstructure and superconducting properties of novel shaped Dy123 melt-solidified bulk

We have fabricated a cylindrical DyBa2Cu3Oy melt-solidified bulk mainly composed of the c-growth region. Its critical current properties and microstructures were systematically evaluated at various positions in the a- and c-growth regions. Jc in low fields was strongly dependent on the local density of the Dy211 precipitates in the Dy123 matrix in both regions. Jc in the c-growth region far below the seed crystal was comparable to that in the a-growth region because of comparable density of Dy211. Moreover, the c-growth region maintained high Jc under high fields at 77 K accompanying the second peak effect in contrast with monotonous decrease in Jc observed in the a-growth region. Such prominent second peak effect was also responsible for the enhancement of the pinning force for the whole c-growth region. The newly developed cylindrical bulk is promising for practical applications as strong superconducting magnets.