Structural characterization and magnetic properties of divanadates ZnMV2O7 (M = Co, Ni and Cu)

Abstract

Divanadates of general formula ZnMV2O7 (M = Co, Ni and Cu) have been prepared as powdered samples and the X-ray structural determination and magnetic studies have been carried out. Both ZnCoV2O7 and ZnNiV2O7 crystallize with the so-called dichromate structure type, showing monoclinic symmetry, space group P21/c, while the third member of this family of vanadates ZnCuV2O7 shows the thortveitite structure type with monoclinic symmetry, space group C2/c. Magnetic susceptibility and specific heat measurements reveal that these derivatives behave as antiferromagnets and the estimated Néel temperatures are 4.5, 3.5 and 5.3K for cobalt, nickel and copper vanadates, respectively. In all cases, the one-dimensional magnetic behavior that present the M2V2O7 vanadates is broken down when the magnetic cation M is half replaced by the diamagnetic Zn2+ to give the ZnMV2O7 samples studied in the present work.