Dielectric properties of (001)-oriented Ba(Zr0.25Ti0.75)o3 thin films prepared by pulsed laser deposition

Ba(Zr 0.25 Ti 0.75 )O 3 (BZT) thin film was deposited on LaAlO 3 (001) single crystal substrate using pulsed laser deposition. The X-ray diffraction examination reveals that the film is highly (001)-oriented with a pure perovskite phase. Fine grains with size of 20–30 nm in diameter were observed in atomic force microscope image. Dielectric properties of the Ba(Zr 0.25 Ti 0.75 )O 3 thin film was characterized in a broad frequency range (1 kHz–10 GHz). Curie temperature of the film was found to be ∼90°C, which is nearly 100°C higher than that of the Ba(Zr 0.25 Ti 0.75 )O 3 bulk ceramics. The relative permittivity of the film exhibits strong dependence of the dc bias field over the whole frequency range. Microwave measurements, performed between 50 MHz–1 GHz, suggest our Ba(Zr 0.25 Ti 0.75 )O 3 thin film is highly tunable (tunability up to 26.1% at 1 GHz under a dc electric field of 13.3 MV/m).