Resistivity switching induced in ferroelectric phase of PbTiO3 studied by XPS and electric conductivity tests

The PbTiO3 crystals aged during 24 years were annealed in ferroelectric phase at 720 K and in paraelectric phase at 820 K. The reference fresh ceramics were sintered from powders obtained by hydrothermal growth. The resistive switching to metallic-type dependence occurred in the crystal samples annealed in ferroelectric phase. The other samples, i.e. aged crystals, crystals annealed in paraelectric phase, and ceramics exhibited semiconductor features. The electric conductivity relaxation was related to defects. Electronic structure was tested by XPS. The annealing changed contributions from various charge states of Pb, Ti, and O ions. The conditions for the resistive switching were discussed in accordance to literature models, which concern defects drift and occurrence of conductive channels along vortices formed by ferroelectric domains.