SOME INVESTIGATIONS ON PRASEODYMIUM-SUBSTITUTED YTTRIUM BARIUM COPPER-OXIDE

The lattice parameters, dc and ac magnetic susceptibility, and electrical resistivity of PrxY1−xBa2Cu3Oz for 0 ≦ x ≦ 1 are presented. The lattice is found to be orthorhombic for all Pr concentrations including x = 1. Pr, unlike other rare earths (RE), depresses superconductivity in the REBa2Cu3Oz system and induces a transition from metallic to semiconducting behaviour at x ≈ 0.55. The observed superconducting behaviour is typical for granular systems with strong flux pinning. By fitting the experimental dc susceptibility results it is found that for all x‐values the Pr valence is close to 4+. The deduced values of the Curie‐Weiss‐constants are between 0 and −6 K suggesting weak antiferromagnetic interactions of the Perons. For Pr concentrations x = 1.0 and 0.95 a sharp magnetic phase transition at about 12 K is observed. Copyright © 1990 WILEY‐VCH Verlag GmbH & Co. KGaA