The jump-like PTCR effect in Ca1-xYxCu3Ti4O12 ceramics hot quenched under high-pressure

Abstract

The PTCR effect is an important application phenomenon in the ferroelectric BaTiO3 electronic ceramic materials. In this work, the PTCR effect is also found in high pressure (HP) hot quenched Ca1-xYxCu3Ti4O12 (CYCTO) ceramics. Compared with the pure CaCu3Ti4O12 (CCTO) ceramic synthesized under ordinary pressure (OP), the low temperature resistivity of HP CYCTO samples is about 3 orders of magnitude lower than that of untreated CCTO samples, showing an obvious PTCR effect. The transition temperature is close to 178 K for x = 0.2 sample. The analysis of crystal and magnetic structures shows that the crystal and magnetic structures of HP CYCTO samples do not change before and after the resistance transition. X-ray photoelectron spectroscopy showed that the concentration of oxygen vacancy defects in HP CYCTO is higher than CCTO. By analyzing the conduction behaviors of HP CYCTO samples, it suggests that oxygen vacancies and Y3+ ions may be the important donors for the decrease of low temperature resistivity of HP CYCTO samples. The results in this work have important reference value for the application of the electrical conduction behaviors in CCTO.