Effect of A and B site cations on the dielectric and electrical propertiesof PbTiO3

Simultaneous addition of Bi3+ and Fe3+ at A and Bi sites of PbTiO3 is found to increase the ferroelectric transition temperature (T-C). The Te showed a marginal shift with frequency. Doping of Fe3+ at the B-site showed a rema rkable decrease in T-C, when compared to pure PbTiO3. In the doubly doped s ample, due to A-site cation ionic radii mismatch, large grain boundary effe cts are created, which do not appear in the case of Fe3+ doped PbTiO3. Anal ysis of the impedance data shows that grain boundaries are non-capacitive a nd the total capacitance arises from the bulk of the material. The absence of grain boundary effects may be because of a small grain size in the sampl e which is singly doped with Fe3+.