Fine-grained BaZr[sub 0.2]Ti[sub 0.8]O₃ thin films for tunable device applications

Abstract

A study of the structure and in-plane dielectric properties of BaZr[sub 0.2]Ti[sub 0.8]O₃ thin film epitaxially grown on (LaAlO₃)[sub 0.3](Sr₂AlTaO[sub 6])[sub 0.35] (001) single-crystal substrates through pulsed-laser deposition has been carried out. X-ray diffraction measurements revealed a good crystallinity and tensile in-plane stress in the film. Fine grains with an average size of ~20 nm were observed using atomic force microscopy. Curie temperature of the film was found to be ~120 °C, which is 100 °C higher than that of the ceramic. Butterfly-shaped C-V curve confirmed the in-plane ferroelectric state in the film. A large dielectric tunability of ~50% was found in the film.