Wetting and spreading of Ca-Y-Ba-Cu-O solution on Y2O3 and CaSZ crucible in growing Y1-xCaxBa2Cu3O7-δ single crystal

Sizable and uniform Y1-xCaxBa2Cu3O7-delta single crystals are of significant importance to study high-temperature superconductivity. However, the severe liquid loss resulting from intrinsic wetting property during top-seeded solution-growth (TSSG), makes it difficult to obtain such crystals. Here the reactive wetting performance of the Ca-Y-Ba-Cu-O solution on two types of crucibles was studied. It was identified that the spreading process on the Y2O3 crucible is characterized by forming double-layer of Y2BaCuO5 and YBa2Cu3O7-delta, while that on the CaSZ crucible (Ca-stabilized ZrO2) produces the BaZrO3 layer with CuO phase. In the former case, the liquid has a low energy interface with the top layer of YBa2Cu3O7-delta, leading to strong spreading and creeping behaviors. Conversely, due to a high interfacial energy between solution and BaZrO3, the CaSZ crucible has a low wettability, particularly beneficial to solve the liquid loss problem. Consequently, with negligible liquid creeping out of CaSZ crucibles, we succeeded in growing a series of homogeneous Y1-xCaxBa2Cu3O7-delta single crystals with an acceptable size up to a x b x c = 11.2 x 11 x 4.8 mm(3). Moreover the wetting modes of solution on various kinds of crucibles for TSSG in growing doped YBa2Cu3O7-delta single crystals were also elucidated. Most importantly, the understanding gained from this work is broadly applicable for producing other desirable doped-crystals.