Simultaneously achieving large ferroelectric polarization and high-TC in sol-gel deposited PbTiO3-based perovskite thin films

Abstract

Perovskite-type thin films based on BiMeO₃-PbTiO₃ have been intensively studied due to their promising applications in ferroelectric and electronic devices. Nevertheless, achieving high Curie temperature (T_C) while maintaining robust ferroelectric polarization in BiMeO₃-PbTiO₃ thin films remains a significant challenge. In this study, we deposited 0.1Bi(Zn_2/3Nb_1/3)O₃-0.9PbTiO₃ perovskite thin films onto Pt(111)/Ti/SiO₂/Si substrates using the traditional sol-gel method. Through the incorporation of a PbO seeding layer, the thin films manifested excellent crystallization characteristics, featuring a phase-pure perovskite structure accompanied by a uniform and dense microstructure. Consequently, the films demonstrate large ferroelectric remanent polarization (P_r) values of 2P_r ~ 174 and 118 μC cm⁻² under normal mode and PUND mode measurements, respectively, highlighting the P_r values reported in BiMeO₃-PbTiO₃ thin films to date. Furthermore, the thin films exhibit a high TC of 468 °C. First-principles calculations revealed that the strong hybridizations of Pb/Bi-O and Ti/Zn/Nb-O bonds are responsible for the large ferroelectric polarization. The comprehensive high-performance ferroelectric properties of the present 0.1Bi(Zn_2/3Nb_1/3)O₃-0.9PbTiO₃ thin films highlight their potential for applications in ferroelectric or electronic devices.