Synthesis and magnetic properties of the quasi-one-dimensional compound Ca-0.83(Cu1-xCOx)O-2

摘要

A new solid solution of the quasi-one-dimensional composite crystal, Ca-0.83(Cu1-xCox)O-2 (0less than or equal toxless than or equal to0.30), has been synthesized under 1 atm of O-2 at 830degreesC. The non-doped compound Ca0.83CuO2 consists of two interpenetrating monoclinic subsystems of the [Ca] atoms and the edge-shared square planar [CuO2] chains. Upon increasing x, both the subsystems undergo a phase change from monoclinic to orthorhombic (M - O). The M - O change occurs at x similar to 0.04 for the [(Cu, Co)O-2] subsystem, while such a change occurs at x similar to 0.17 for the [Ca] subsystem. Magnetic susceptibility measurements show an evolution from a short-range ordered state near x = 0 to a long-range antiferromagnetic state (T-N = 10 - 15 K) for the samples with x greater than or equal to 0.15. The effective magnetic moment mu(eff) is found to increase with increasing x from 2.1 mu(B) for x = 0.10 to 3.0 mu(B) for x = 0.30, suggesting that the solid solution can be regarded as Ca-0.83[Cu-0.66(2+) Cu-0.34-x(3+) Co-x(3+)]O-2, in which a mixed state Cu2+(S = 1/2), Cu3+(S = 0) and high-spin Co3+(S = 2) ions is realized. (C) 2003 Elsevier Inc. All rights reserved. [References: 23]