Abstract： The nearly single phase (R0.4Pr0.6)0.5Ca0.5Ba2Cu3O7-δ compounds (R= La, Pr, Nd, Sm, Eu, Gd and Y) with Tc about 100 K were prepared under high pressure and high temperature using the cubic anvil apparatus. The Tc is much higher than that of the traditional R-123 superconductors without doping Ca on the rare-earth site. For various rare earths with different ionic radius, the (R0.4Pr0.6)0.5Ca0.5Ba2Cu3O7-δ compounds have almost the same critical temperature. This is different from the result of the ion-size effect of rare-earth ions in R1-xPrxBa2Cu3O7-δ compounds. Our results show that Pr has the same properties as other rare earths in the 123-phase compounds due to the doping of Ca.
2001, Vol. 18 
