High Permittivity (1 – x)Ba(Zr0.2Ti0.8)O3 – x(Ba0.7Ca0.3)TiO3 (x = 0.45) Epitaxial Thin Films with Nanoscale Phase Fluctuations

Epitaxial (1 – x)­Ba­(Ti0.8Zr0.2)­TiO3 – x(Ba0.7Ca0.3)­TiO3, x = 0.45 (BCZT 45), thin films have been deposited on (001) SrTiO3 (STO) and (001/100) SrLaAlO4 (SLAO) substrates by pulsed laser deposition. X-ray diffraction and high-resolution transmission electron microscopy (HRTEM) confirmed the epitaxial growth of the films. A high structural quality has been evidenced for the BCZT/STO films. Geometric phase analysis (GPA) associated with the HRTEM enabled us to obtain microstrain analysis and the in-plane and out-of-plane lattice parameter variation on different areas. Tetragonality ratio fluctuations at nanoscale level which are relevant for the existence of nanodomains have been evidenced on the BCZT/STO films. The in-plane dielectric constant has been measured on interdigital electrodes deposited by lift-off technique on the top of the films. High values of dielectric permittivity (>3000) combined with low dielectric loss (