Dielectric relaxor behaviors and tunability of (1−x)Ba(Zr0.2Ti0.8)O3–x(Ba0.7Ca0.3)TiO3 thin films fabricated by sol–gel method

Temperature dependence of dielectric properties of (1−x)Ba(Zr0.2Ti0.8)O3–x(Ba0.7Ca0.3)TiO3 (x=0.15, 0.30, and 0.50) (BZT–xBCT) thin films prepared by a sol–gel method has been investigated. The results show that there is a broad dielectric maximum near Tm and the diffuse parameter γ is close to 2, indicating a nearly complete diffuse phase transition in BZT–xBCT thin films. The dielectric relaxor behaviors of the thin films well follow Vogel–Fulcher relation. The thin films show a high dielectric tunability up to 65 %, with a small variation in the temperature range from 248.15 to 373.15 K. This study indicates that the thin films, especially for x=0.50, are promising candidates for tunable device applications with good temperature stability.