Magnetic properties of a new 3D-cobalt phosphonate: Co3(O3PC2H4CO2)2

Abstract

The magnetic properties of a new cobalt(II) phosphonate have been investigated. The compound is isostructural with the pillared layered metal phosphonates M ₃ (O ₃ PC ₂ H ₄ CO ₂ ) ₂ , M=Zn, Mn. In this structure, the magnetic transition metal ions are arranged within layers formed by the interconnection of CoO ₄ tetrahedra and CoO ₆ octahedra. The ac and dc magnetic susceptibilities and magnetization measurements show that Co ₃ (O ₃ PC ₂ H ₄ CO ₂ ) ₂ is a canted antiferromagnet 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 indicate that large short-range correlations are present above T _N in relation with the layered character of the structure.