Crystal field effect on the effective magnetic moment in A2CoWO6 (A=Ca, Sr and Ba)

Abstract We prepared the antiferromagnetic Ca 2 CoWO 6 , Sr 2 CoWO 6 and Ba 2 CoWO 6 double perovskites with different crystalline structures, which are monoclinic, tetragonal and cubic respectively. The crystalline structures affect the Co–O distances and the local octahedral symmetry. Magnetic susceptibility experiments were performed as a function of magnetic field and temperature. We found that the effective magnetic moment ( μ eff ) of Co 2+ is partially unquenched and we also found that μ eff increases with the average of Co–O distances that form the CoO 6 octahedra. A simple model associates the behavior of the effective magnetic moment with crystal field effects.