Anomalous Pr-Ordering in High-T, Cuprate Systems

H. C. Ku；Y. Y. Hsu；T. J. Lee；J. C. Ho

Chinese Journal of Physics

36卷2S期（1998 / 04 / 01）

292 - 296

英文

The systematic variation of anomalous Pr antiferromagnetic ordering for the two-CuO2-layer 1212 cuprate system MA2PrCu2O7 (M = Hg, Pb, Tl, Cu, Nb; A = Sr, Ba) was verified through the variation of Néel temperature TN(Pr) with Pr-0 bond length and Pr minimum magnetic entropy Sm. The importance of quasi-2D Pr-0-Pr superexchange magnetic coupling through the strong hybridization between the Pr-4f and the eight O-2pπ orbitals in the adjacent CuO2 layers is expected for all two-CuO2layer MmA2PrCu2Oy m212-type (m = 1,2,3) compounds, and similarly anomalous Pr compounds were observed in M2A2PrCu2O8 and M3A2PrCu2O8 (M = Pb, Cu; A = Ba, Sr). The only case with absence of long rang TN(Pr) down to 1.4 K was in the incommensurate modulated Bi-2212 compound Bi2Sr2PrCu2O8+δ.