Magnetic measurement and powder X-ray Rietveld analysis are performed on oxygenated Pr1.5Ba1.5Cu3O7.2cuprate. This tetragonal compound with lattice parameters a = 0.38916 nm and c = 1.16177 nm is found to form the TlBa2CaCu2O71212-type structure when written as Cu[Ba1.5Pr0.5]PrCu2O7.2. Low temperature magnetic data indicate that anomalous Pr order temperature TN(Pr) decreases from 18 K for orthorhombic PrBa2Cu3O6.9to 10.5 K for Pr1.5Ba1.5Cu3O7.2. The increasing Pr-O bond length with decreasing TNindicates that Pr ordering is closely correlated with the wave function overlap between Pr-4f orbital and O-2pπorbital in the CuO2bi-layers.
Journal of low temperature physics 117(3-4), pp.885-890