Influence of undercooling and Nd4Ba2Cu2O10 content on the growth rate of large-grain bulk Nd-Ba-Cu-O superconductor

The dependence of growth rate on isothermal undercooling and composition ha s been investigated for Nd-Ba-Cu-O single grains containing various amounts of nonsuperconducting Nd4Ba2Cu2O10 (Nd-422) phase inclusions and fabricate d under a 1% O-2 in N-2 atmosphere using a top seeded melt growth technique . The growth rate along the crystallographic c-direction is observed to exc eed that along the a/b direction at all undercooling temperatures and exhib its a maximum for a Nd-422 content of approximate to 10 mol%, The samples h ave been examined by optical microscopy and the results interpreted within an established planar solidification model.