Electro-optic and ferroelectric properties of epitaxial 0.5(Ba_0.7Ca_0.3)TiO₃-0.5Ba(Ti_0.8Zr_0.2)O₃ thin films grown by pulsed laser deposition.

Ferroelectric oxides have long been used for signal processing in optical communication system for their excellent linear and nonlinear optical properties. Recently, (1-x)(Ba_0.7Ca_0.3)TiO₃-xBa(Ti_0.8Zr_0.2)O₃ ceramics have aroused great attention for its large ferroelectric response and strong electro-optic effect in the vicinity of the morphotropic phase boundary. In this work, we report our efforts on epitaxial growth of 0.5(Ba_0.7Ca_0.3)TiO₃-0.5Ba(Ti_0.8Zr_0.2)O₃ (BCZT-50) thin films on GdScO₃ (GSO) substrates by pulsed laser deposition. Structural characterizations show that the films are epitaxial and remain fully strained up to 200 nm. We have carefully investigated the ferroelectric properties of these films and observe large dielectric constant values of up to 1500. We also report our efforts on the measurement of electro-optic coefficients.