Abstract
Nonstoichiometric BaTiO 3 PTCR type materials are investigated with various amounts of MnO 2 , Sb 2 O 3 and MgO dopants. Specimens fired with a nonisothermal rate-controlled sintering profile exhibit a rather fine and uniform microstructure as compared to those processed by conventional sintering techniques. The temperature at which the resistivity anomaly begins is observed to decrease with Sb 2 O 3 and MgO contents. The Curie point of BaTiO 3 -based ceramics can be altered by addition of Sb 2 O 3 , and the dielectric peak is maintained by the presence of MgO additive. Magnesium ions act as acceptors in the BaTiO 2 lattice, while antimony ions as donors. The presence of magnesium compensates some of the antimony, hence the doped-BaTiO 3 seminonductive region is pushed to higher contents. © 1987 Chapman and Hall Ltd.