Ferroelectric phase-transition-assisted anomaly in the electric resistivity (FPTAA) of lead-free PTC thermistors

Abstract

Ceramic composites in the BaTiO3–(Bi1/2Na1/2)TiO3 system exhibiting a positive temperature coefficient of electrical resistivity effect were prepared using a conventional solid-state reaction method. The composite samples were sintered in nitrogen to achieve their final-phase properties, a high resistivity jump of ∼ 103 at about 170 °C. The resistivity anomaly of the composite composed of a conducting network based on a conducting BaTiO3 and a highly resistive ferroelectric phase with a Curie temperature (TC) of 170 °C was explained in the light of ferroelectric phase-transition-assisted anomaly in the resistivity (FPTAA).