Magnetic properties of high-oxygen pressure prepared PrBa2Cu3O7-y cuprates

High oxygen pressure annealed PrBa2Cu3O7-y (y similar to 0) cuprates were p repared in order to study the effect of oxygen stoichiometric parameter y o n the unusual Pr/Cu magnetic properties and/or recently reported supercondu ctivity. The oxygen-rich orthorhombic 123-chain phase is highly unstable un der high-oxygen pressure synthesis and decomposes completely in 10 bar pres sure. For a smaller 2 bar prepared sample a relatively clean phase was pres erved with an oxygen parameter y = 0.05, as compared with y = 0.11 from a c onventional 1 bar flowing oxygen method. No superconductivity can be detect ed for all high-oxygen pressure prepared samples. Instead, Mott-insulator b ehavior with anomalous high Pr ordering T-N(Pr) = 19 K was observed for PrB a2Cu3O6.95. Comparison with other Pr/Ba intersubstituted Pr1-xBa2-xCu3O7-y cuprates is discussed. (C) 2001 American Institute of Physics.