Magnetic properties of a new 3D-cobalt phosphonate: Co-3(O3PC2H4CO2)(2)

The magnetic properties of a new cobalt(II) phosphonate have been investiga ted. The compound is isostructural with the pillared layered metal phosphon ates M-3(O3PC2H4CO2), M = Zn, Mn. In this structure, the magnetic transitio n metal ions are arranged within layers formed by the interconnection of Co O4 tetrahedra and CoO6 octahedra. The ac and de magnetic susceptibilities a nd magnetization measurements show that Co-3(O3PC2H4CO2)(2) is a canted ant iferromagnet at T-N = 15,5 K. Below T-N, the hysteresis cycles exhibit an S shape related to a spin flop effect. The specific heat measurements indica te that large short-range correlations are present above T,in relation with the layered character of the structure.