Metal insulator phase transition and magnetic properties of VnO2n-1

Magnetic properties of VnO2n-1system, which shows the temperature induced metal insulator phase transition at Tt, were studied by the measurement of magnetic susceptibility and Mössbauer effect. It was observed that V3O5, V4O7, V5O9, V6O11, V7O13, and V8O15order anti-ferromagnetically at 70, 40, 30, 23, 51, and 7 K, respectively. V3O5behaves like a low dimensional antiferromagnet. V7O13is a metallic antiferromagnet. Above Tt(metallic phase) the total susceptibility χmolcan be represented by χmol= Cobs/ T-θ + χ0. Cobsis in a good agreement with calculated value Ccal, assuming that the material is ionic (V⁺³and V⁺⁴in a paramagnetic state). Density of electronic state of Fermi level was calculated from χ0assuming Pauli paramagnetism and compared with the obtained by specific heat measurement.