Dielectric, ferroelectric, and piezoelectric properties of (001) BiScO3–PbTiO3 epitaxial films near the morphotropic phase boundary

Abstract

The dielectric, ferroelectric, and piezoelectric properties of (001) BiScO3–PbTiO3 epitaxial films near the morphotropic phase boundary were investigated. Epitaxial films, 1-μm thick, were grown on (100) SrRuO3/(100) LaAlO3 substrates by pulsed laser deposition from a BiScO3–PbTiO3 (40/60) ceramic target. The films had room temperature dielectric constant of 850, tanδ = 0.08, and maximum dielectric constant of 5530 at 455 °C. Well-saturated hysteresis loops with a remanent polarization of 42 μC/cm2 and a coercive field of 75 kV/cm were observed. The effective transverse piezoelectric coefficient e31,f was −12 C/m2. This result is quite encouraging for sensor and actuator device development because the observed piezoelectric properties are as good as (001) oriented Pb(Zr,Ti)O3 films (e31,f ∼ –12 C/m2) while the transition temperature is 100 °C higher.