A case study of bilayered spin-1/2 square lattice compound [VO(HCOO)2·(H2O)]
Abstract
We present the synthesis and a detail investigation of structural and magnetic properties of polycrystalline [VO(HCOO)2·(H2O)] by means of x-ray diffraction, magnetic susceptibility, high-field magnetization, heat capacity, and electron spin resonance measurements. It crystallizes in a orthorhombic structure with space group Pcca. It features distorted VO6 octahedra connected via HCOO linker (formate anions) forming a two-dimensional square lattice network with a bilayered structure. Analysis of magnetic susceptibility, high field magnetization, and heat capacity data in terms of the frustrated square lattice model unambiguously establish quasi-two-dimensional nature of the compound with nearest neighbour interaction J1/k B 11.7~K and next-nearest-neighbour interaction J2/k B 0.02~K. It undergoes a N\'eel antiferromagnetic ordering at T N 1.1~K. The ratio θ CW/T N 10.9 reflects excellent two-dimensionality of the spin-lattice in the compound. A strong in-plane anisotropy is inferred from the linear increase of T N with magnetic field, consistent with the structural data.