ENHANCED TUNABILITY AND RELAXOR CHARACTERISTICS IN CALCIUM SUBSTITUTED BARIUM ZIRCONIUM TITANATE THIN FILMS.

Thin films of BaZr0.25Ti0.75O3 in which Ba2 + is partially substituted by Ca2 + are prepared by a sol-gel method. Phases and dielectric properties of the films are studied.The crystal structure of BaZr0.25Ti0.75O3 is cubic and does not change with Ca substitution upto x = 0.25 in Ba1-xCaxZr0.25Ti0.75O3. A change from a normal to relaxor behavior is observed for x = 0.20 as indicated by a change in the frequency of dielectric maxima with temperature and other parameters.The dielectric constant and transition temperatures are found to increase with increasing Ca substitution. A tunabilty of 71%, much higher than reported in literature for this material, is observed for x = 0.1 i.e for Ba0.9Ca0.1Zr0.25Ti0.75O3. [ABSTRACT FROM AUTHOR]