Crystal structure, short range and long range magnetic ordering in CuSb 2O 6

Abstract

CuSb 2O 6 crystallizes in a monoclinically distorted trirutile structure. Atomic positions were determined by profile refinement of neutron powder diffraction data, space group P2 1 n , a = 4.6349(1), b = 4.6370(1), c = 9.2931(1) , β = 91.124(2). Magnetic susceptibility data exhibit a broad maximum at about 60 K and an abrupt transition at 8.5 K. The high temperature data can be fitted to a Curie-Weiss Law giving μ eff = 1.758 and θ = −48 K. Although the crystal structure indicates a nearly square planar Cu 2+ lattice as in other trirutiles, a CuOOCu superexchange pathway seems to be dominant, giving rise to short range correlations which are approximately one dimensional. The high-temperature susceptibility is explained well by the 1-d Heisenberg model with J k = −43.1 K . Analysis by Oguchi's method gives a ratio of interchain to intrachain coupling constants of about 2 × 10 −3.