Electrical and magnetic studies of the CdxCryV zSe4 Spinels

The electrical and magnetic investigations carried out on the polycrystalline spinels with the general chemical formula CdxCryVzSe4 (where z = 0:06, 0.12, 0.24, and 0.31) revealed semiconducting and ferromagnetic properties with a Curie temperature of 127.5 K. A step-like structure of the electrical conductivity, ¾(T), was observed for the polycrystal containing 6% V ions in the octahedral sites while the remaining samples showed a typical Arrhenius behaviour of ¾(T). These effects are interpreted in terms of ferromagnetic spin clusters which finally dissolve on going towards the paramagnetic limit including non-stoichiometry