CRYSTAL-STRUCTURE, SHORT-RANGE AND LONG-RANGE MAGNETIC-ORDERING IN CUSB2O6

CuSb2O6 crystallizes in a monoclinically distorted trirutile structure. Atomic positions were determined by profile refinement of neutron powder diffraction data, space group P21 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 μeff = 1.758 and θ = -48 K. Although the crystal structure indicates a nearly square planar Cu2+ lattice as in other trirutiles, a CuOOCu 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. © 1991.