Enhancement of critical Pr ion concentration (x(cr)) in (La1-xPrx)Ba2Cu3Oz

The substitutional effect of Pr ion for La in (La1-xPrx)Ba2Cu3Oz bulk sampl es prepared under modified synthesis condition has been studied. Low field magnetization studies showed that superconductivity is retained up to the c ritical Pr ion concentration, x(cr) = 0.40. The effective magnetic moment o f Pr3+ free ion is very low in the present series of compounds. Results of X-ray absorption near-edge structure spectra for the series of (La1-xPrx)Ba 2Cu3Oz compounds with 0.00 < x < 0.60 reveal that the doped Pr ion reduces hole concentration within the CuO2 planes, leading to a destruction of supe rconductivity. (C) 1999 American Institute of Physics. [S0021-8979(99)05924 -1].