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‐δ 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‐δ, 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‐δ, 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‐δ single crystals with an acceptable size up to a × b × c = 11.2 × 11 × 4.8 mm3. Moreover the wetting modes of solution on various kinds of crucibles for TSSG in growing doped YBa2Cu3O7‐δ single crystals were also elucidated. Most importantly, the understanding gained from this work is broadly applicable for producing other desirable doped‐crystals. The reactive wetting and spreading performance of the Ca‐Y‐Ba‐Cu‐O solution on Y2O3 and Ca stabilized ZrO2 crucibles.