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

Abstract

(Y1−xPrx)Ba2Cu3O7−δ (Pr-YBCO, x<0.2) single crystals and single domain bulks were grown by the top-seededsolution-growth (TSSG) and the top-seeding melt-textured growth(TSMTG) methods, respectively. The superconducting critical temperature(Tc) was determined by magnetic measurements and the critical current density(Jc) was estimated by applying the modified Bean model. For a low-level substitution(x<0.025), an increasein the Jc value as compared with that for unsubstituted YBCO was found while no apparent change in theTc value was noticed. On the other hand, Pr substitution in YBCO leads to: (i) increasing liquid solubilityof the total rare earth element in the Ba–Cu–O solution, (ii) increasing peritectic temperature(Tp), and (iii) a decrease in the liquidus slope near theTp. As a result, the driving force for YBCO growth and the region of singlegrain growth are enhanced. Study of the compositional correlation betweenliquid and solid additionally indicates that the Pr distribution coefficient islarger than 1 in the Pr-YBCO system. Thus the Pr content and then theTp value of Pr-YBCO in the bulk reduce with the growth time during TSMTG. The lowerTp valuein 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.