Enhanced ferroelectricity of BaTiO3 film by optimizing its conducting electrode layer

Abstract

Conductive Pt-added LaNiO₃ (PLNO) electrode films were prepared on Si substrates using radio frequency magnetron sputtering. The PLNO films demonstrate a reduced resistivity as compared with LaNiO₃, which is consistent with X-ray photoelectron spectroscopy analysis. Preferred (001)-orientated texture is observed for the PLNO and BaTiO₃ (BTO) films with Pt up to 36 at%. Grain size and BTO/PLNO interfacial characterization are also strongly dependent on the Pt contents. Cross-sectional high-resolution transmission electron microscopy reveals formation of an additional amorphous layer at the BTO/PLNO interface due to high Pt contents in the PLNO. It is found that the BTO film grown on PLNO with 36 at% Pt exhibits an increased remnant polarization, 5.63 µC cm⁻² as compared with LaNiO₃, 2.50 µC cm⁻², while BTO grown on PLNO with 83 at% Pt shows a linear ferroelectric property. Strain dependence of the ferroelectric properties is also discussed. The present work demonstrates that optimizing the structure and conductivity of the bottom electrode can enhance the polarization of ferroelectric films, which may provide guidance for designing high-performance ferroelectric devices in future.