Preparation and magnetic properties of Ti1−xVxPO4

The solid solutions of Ti_1?xV_xPO₄ were prepared under the reductive circumstance, although there seems to be immiscibility near x=0.5. Their magnetic susceptibility was analysed by the temperature-independent and Curie-Weiss contribution. The temperature-independent contribution increased gradually with x until x=0.4 and then decreased to 0 at x=1.0. A bent was observed at x=0.5 in the curve for the Curie constant against x and at x>0.5 the Curie temperature became strongly negative with x.In the region of x≦0.4, the Curie constant corresponded to the electronic configuration of d¹ for a vanadium ion. On the other hand, the Curie constant reflected the d² configuration for a vanadium ion in the range of $\text{x}\text{≧0.6}$. This fact indicates that Ti³⁺/1bV³⁺ homopolar bonds are formed in accordance with the replacement of Ti³⁺ with V³⁺ at x≦0.4. Vanadium ions added further, which substitute for Ti³⁺ in Ti³⁺/1bV³⁺ pairs, do not form the homopolar bond with V³⁺ ions and both V³⁺ ions contribute magnetically as ions with d² configuration.