Synthesis, characterization and semiconducting properties of solid solutions with rutile structure

A new family of oxides Ti 3(1−x)M xM′ 2xO 6 (0.1 ≤ x ≤ 0.3) is obtained by partial substitution of Ti by M (Co or Ni) and M′ (Sb or Nb) elements in the rutile structure. These solid solutions develop previous works concerting related systems with disordered cation distribution, which show semiconductivity properties. The activation energies lies between 0.5 and 1.1 eV and the Seebeck's effect suggests different charge carriers depending on the nature of the divalent cation. Thus, cobalt compounds are p-type semiconductors where as nickel compounds are of n-type. Magnetic susceptibility data agree with the proposed structural model.