Stress-Induced Resistivity Anomaly in Semiconducting Barium Titanate Ceramic Wire

Thin, semiconducting BaTiO₃ ceramic wires prepared in the present study exhibited reversible stress-induced, nonlinear current—;voltage characteristics across several grain boundaries. A remarkable change in resistance with the application (by the three-point bending method) of only ∼1% tensile deformation indicated that the BaTiO₃ wires may have potential as stress-sensing devices. Resistance in the BaTiO₃ wires bot increased and decreased with increasing tensile stress parallel to the electric fields, far below the ferroelectric transition temperature, T _c; in Sr-substituted wires near T _c, on the other hand, resistance only increased. Detailed studies of the patterns and fluctuation of polarization at grain boundaries could be meaningful, because stress-sensing characteristics may be induced by changes in the relative angle between polarization vectors of adjacent grains.