Effect of Pr doping on the growth and superconducting properties of (Y1-xPrx)Ba2Cu3O7-δ

(Y1-xPrx) Ba2Cu3O7-delta (Pr-YBCO, x < 0.2) single crystals and single domain bulks were grown by the top-seeded solution-growth (TSSG) and the top-seeding melt-textured growth (TSMTG) methods, respectively. The superconducting critical temperature (T-c) was determined by magnetic measurements and the critical current density (J(c)) was estimated by applying the modified Bean model. For a low-level substitution (x < 0.025), an increase in the J(c) value as compared with that for unsubstituted YBCO was found while no apparent change in the T-c value was noticed. On the other hand, Pr substitution in YBCO leads to: (i) increasing liquid solubility of the total rare earth element in the Ba-Cu-O solution, (ii) increasing peritectic temperature (T-p), and (iii) a decrease in the liquidus slope near the T-p. As a result, the driving force for YBCO growth and the region of single grain growth are enhanced. Study of the compositional correlation between liquid and solid additionally indicates that the Pr distribution coefficient is larger than 1 in the Pr-YBCO system. Thus the Pr content and then the T-p value of Pr-YBCO in the bulk reduce with the growth time during TSMTG. The lower T-p value in the final crystallized part is beneficial to a slow cooling process. Using the TSMTG method, Pr-YBCO (x = 0.02) monodomains up to 42 mm in diameter were grown with a high growth rate.