出版日期：2000-06-01 00:00:00

著者：Luo, H. M.; Lin, B. N.; Lin, Y. H.; Chiang, H. C.; Hsu, Y. Y.; Hsu, T. I.; Lee, T. J.; Ku, H. C.; Lin, C. H.; Kao, H.-C. I.; Shi, J. B.; Ho, J. C.; Chang, C. H. [et. al]

單位：淡江大學化學學系

出版者：College Park: American Physical Society

著錄名稱、卷期、頁數：Physical Review B (Condensed Matter and Materials Physics) 61(21), pp.14825-14832

摘要：Structural, transport, magnetic, calorimetric, and neutron data were reported for the oxygen-annealed Pr1+xBa2-xCu3O7+y or 1212-type Cu(Ba2-xPrx)PrCu2O7+y system (0<~x<~1, -0.11<~y<~0.31). Powder x-ray Rietveld analysis indicates that due to subtle oxygen distribution in the CuO1+y plane for these oxygenated cuprates, two structural symmetry transitions were observed, from orthorhombic 1212C (CuO chain) O(I) phase (space group Pmmm) for 0<~x<~0.4, to tetragonal 1212 T phase (P4/mmm) for 0.4<~x<~0.65, and then to a different type of orthorhombic 1212 O(II) phase (Cmmm) for 0.65<x<1. Resistivity data indicate that Pr-in-Ba is not favorable for metallic state and no superconductivity can be detected for these insulating cuprates. Magnetic-susceptibility, heat-capacity, and neutron-diffraction data show that, regardless of the structural transitions, the anomalous Néel temperature TN(Pr) decreases monotonically and smoothly from 18 K for x=0 to 2.5 K for x=0.8, with the same c-axis antiferromagnetic Pr spin alignment. The increasing Pr-O bond length observed with decreasing TN(Pr) indicates that this unusual Pr magnetic ordering is closely correlated with the wave-function overlap between Pr-4f orbital and eight O-2pπ orbital in the CuO2 bilayer.

語言：en

ISSN：1098-0121

期刊性質：國外

收錄於：SCI

國別：USA

出版型式：紙本