Structural and magnetic properties of tetragonal distorted spinel CuMn2O4 prepared by single step method

A polycrystalline CuMn2O4 was attempted to prepare by using single step method without involving any quenching etc. The prepared sample was analyzed for crystal structure by employing neutron diffraction, it was found that sample crystallizes in tetragonal distorted spinel with lattice constant a = 5.874A, c = 8.317A with space group I41/amd (s g no.= 141) with small amount of CuMnO2 as impurity phase. The temperature dependent magnetization shows a broad maximum around 22K in zero-field cooling (ZFC) which is absent in field cooling (FC). Though both the curves are merged above 50K, they follow the Curie-Weiss behavior i.e. χ = C/(T-θ) + χ0 above 80K with temperature independent van-vleck paramagnetism χ0 = 0.15emu/mole and Weiss temperature θ=80K