The anomalous Pr antiferromagnetic order with high Néel temperature TN(Pr) are reported throughout the whole Pr1+xBa2-xCu3O7-y or 1212-type Cu(Ba2-xPrx)PrCu2O7-y system (-0.2<x<1; -0.4<y<1), where three distinct crystal structures were observed: orthorhombic 1212-chain O(I) (space group Pmmm), tetragonal T (P4/mmm), and orthorhombic O(II) (Cmmm). Systematic variation of TN(Pr) in this system as well as in other 1212 and 2212 cuprates MnA2PrCu2O7 (n = 1, 2, M = Hg, Tl, Pb/Cu, Bi, Nb, Cu; A = Sr, Ba, Ba/Pr) was discussed through the correlation of TN(Pr) with Pr-O bond length. The importance of quasi-two-dimensional Pr-O-Pr superexchange magnetic coupling through strong wave function overlap between the overextended Pr-4f orbital with eight O-2pπ orbitals in the adjacent CuO2 bi-layer is discussed. No superconductivity was observed in the present study.
ASJC Scopus subject areas
- 化學 (全部)