Sm2BaCuO5 refinement via an attrition milling and CeO2 addition in Sm-Ba-Cu-O systems melt-textured at oxygen partial pressures of 0.001-1 atm

Sm2BaCuO5 (Sm211) refinement was achieved in Sm-Ba-Cu-O systems melt-textured at various oxygen partial pressures (P-O2 of 0.001-1 atm) via 1 wt% CeO2 addition and size control of a precursor powder (a mixture of SmBa2Cu3O7-y (Sm123) plus Sm211 powder) by means of attrition milling. The resulting Sm211 of the Sm1.8Ba2.4Cu3.4O7-y (Sm1.8) sample melt-textured without CeO2 addition was as large as a few tens of mu m while the Sm211 of the Sm1.8 sample melt-textured from the attrition-milled powder with 1 wt% CeO2 addition was as small as 1-2 mu m, with uniform Sm211 distribution. The Sm211 refinement achieved is ascribable to both the controlled Sm211 nucleation during incongruent melting and the growth inhibition of the Sm211 in the partial melting state. Furthermore, the Sm211 shape was changed from equiaxed granular in the undoped sample to anisotropic in the samples containing CeO2. Effects of oxygen partial pressure on the Sm211 size and the shape was not significant in either the undoped Sm1.8 sample and the CeO2-added Sm1.8 sample.