The high-pressure synthesis and characterization of some praseodymium-substituted rare-earth based R2Ba4Cu7O14+delta (R = Nd, Sm, Eu, Gd, Ho, Tm)

Abstract

Samples of the (R1-xPrx)(2)Ba4Cu7O14+delta (R = Nd, Sm, Eu, Gd, Ho, Tm; Pr-doped R247) systems with x = 0 to 1.0 and with an increment of 0.1 in x was investigated. Single-phased samples were obtained with substitution limit equal to 0.4, 0.6, 0.5, 0.6, 0.8 and 0.5 for phases with R = Nd, Sm, Eu, Gd, Ho and Tm, respectively, as indicated by x-ray diffraction (XRD) data. T-c's of the Pr-doped R247 phases were found to be suppressed from 66, 69, 75, 70, 92 and 88K down to 41K (x=0.3), 20 K (x=0.4), 52K(x = 0.4), 18K (x = 0.5), 8K (x = 0.7) and 50K (x = 0.4) and the corresponding composition coefficients of T-c, dT(c)/dx, were found to be -41.3, -50.4, -28.0, -47.7, -53.0 and -46.0 K/Pr-atom per formula unit for Pr-doped R247 phases with R = Nd, Sm, Eu, Gd, Ho and Tm, respectively. The variation of T-c and dT(c)/dx coefficients ofthe Pr-doped R247 phases upon Pr doping are described and their implcations are discussed.