Ferroelectric properties of heteroepitaxial PbTiO3 and PbZr1-xTixO3 films on Nb-doped SrTiO3 fabricated by hydrothermal epitaxy below Curie temperature

Abstract

PbTiO3 (PTO) and PbZr1-xTixO3 (PZT) films on a (100) Nb-doped SrTiO3 (NSTO) substrate were fabricated at 160 and 210 degrees C, respectively, by hydrothermal epitaxy below the Curie temperature, T-C. The PTO capacitor had a square hysteresis curve compared to the rounded hysteresis curve of the PZT capacitor. These differing behaviors in the polarization-electric hysteresis curves can be explained by the existence of an interfacial layer formed between the PZT film and the NSTO substrate. The PZT capacitor showed almost no polarization fatigue after 10(11) switching cycles. However, the PTO capacitor revealed a slightly different fatigue behavior due to the microvoids that formed as a result of the agglomeration of the island growth mode. However, the fatigue behavior of both capacitors revealed that defects, such as the lead or oxygen vacancies, were suppressed by the hydrothermal epitaxy using a very low fabrication temperature below T-C.