Ac conductivity of BaTiO3 containing (90V(2)O(5)-10P(2)O(5)) oxide glassesdispersed with nanocrystalline particles

The frequency dependent AC conductivity (sigma (ac)) of some new multicompo nent (1 - x) (90V(2)O(5)-10P(2)O(5)) + xBaTiO(3) (x = 0.1 to 0.9) type glas ses containing nanocrystalline BaTiO3 particles (observed from the transmis sion electron microscopic study) has been reported in the temperature range 80-400 K. The behavior of sigma (ac) is broadly similar to what has been o bserved previously in many other amorphous semiconductors and polymers (nam ely nearly linear frequency dependence and weak temperature dependence). An alysis of the experimental conductivity data shows that Long's overlapping large polaron tunneling (OLPT) mechanism is the most probable mechanism of conduction for the present BaTiO3 doped glasses. The Quantum mechanical tun neling (QMT) model and the classical hopping of electrons over a barrier ca n, however, explain the AC conductivity data only below theta (D)/2-160 K ( theta (D) is the Debye temperature). Reasonable values of the relaxation ti me and barrier heights related to the models have been obtained from the fi ts of the conductivity data. (C) 2001 Kluwer Academic Publishers.