Investigations on the sol-gel-derived barium zirconium titanate thin films

Barium zirconium titanate thin films are attractive candidates for dynamic random access memories and tunable microwave devices. In the present work, a wide range of Zr-doped BaTiO3 thin films has been prepared by sol-gel technique. X-ray diffraction and micro-Raman scattering studies confirmed the structural phases in the powder and films of BZT and various structural transitions of BaTiO3, as a function of different Zr content, and compared well with the published result on ceramics and single crystalline BZT. The deposited films were smooth, crack-free and have homogeneous microstructure, and Zr content strongly influences the evolution of the microstructures of the films. Some selected compositions of these films are characterized in terms of their dielectric properties and phase transition behavior. BZT films with 20 at.% Zr have shown a ferroelectric to paraelectric transition in the vicinity of room temperature. Efforts are underway to optimize the annealing conditions and to grow epitaxial BZT films with various Zr contents on suitable single-crystalline substrates. (C) 2002 Elsevier Science B.V. All rights reserved.