The systematic variation of anomalous Pr antiferromagnetic ordering temperature TN(Pr) for the two-CuO2-layer cuprate system MA2PrCu2Oy (M=Cu, Hg, Tl, Pb; A=Ba, Sr) was verified through the observation of a new Hg-1212 HgSr2PrCu2O6+δ tetragonal compound with a TN(Pr) of 6 K and a Pr-O bond length of 2.492 Å between Pr and oxygen in the adjacent CuO2 layers. For the tetragonal/orthorhombic 1212 compounds including the PrBa2Cu3O7-y system, TN(Pr) was found to decrease monotonically with increasing Pr-O distance. The importance of Pr-O-Pr superexchange magnetic coupling is expected for all two-CuO2-layer MmA2PrCu2Oy w212-type (m=1, 2, 3) compounds. A similar Pr anomaly in the 2212-type system was first observed on the new tetragonal (Pb0.5Cu0.5)2(Ba0.5Sr 0.5)2PrCu2O8 compound with a high TN(Pr) of 9 K.
ASJC Scopus subject areas
- Physics and Astronomy(all)