BaMO₃ (M=Zr, Hf, Sn) material dependence of T_c reduction in BaMO_3-doped SmBa₂Cu₃O_y, films

For the improvement of superconducting properties of BaMO₃ (M=Zr, Sn, HQ-doped REBa₂Cu₃O_y films, we focused on the T_c reduction caused by lattice misfit between BaMO₃ and REBa₂Cu₃O_y. We compared the influence on the Tc reduction of BaZrO₃, BaSnO₃ and BaHfO_3-doped SmBa₂Cu₃Or (SmBCO) films with various BMO contents. From the correlation between configuration of nanorods and c-axis expansion, it was suggested that the lattice strain working on the SmBCO matrix became stronger in the order of BaHfO₃, BaZrO₃ and BaSnO₃. Therefore, the combination of SmBCO and BaHfO₃ is better regarding the suppression of the Tc reduction compared with other combinations of SmBCO and BaMO₃.