Low voltage tunable thin films of ferroelectric Ba0.65Sr0.35TiO3 synthesized by sol-gel method

The work done on tunable, ferroelectric thin films of Ba0.65Sr0.35TiO3 deposited on Pt/Si substrate by sol-gel method using spin coating. The tunability reported in this paper is the lowest voltage ever reported. Films were annealed at the temperature of 700degreesC The thickness of the Ba0.65Sr0.35TiO3 film was varied from 0.13 mum to 0.98 mum by applying multiple spin coatings. The ferroelectric properties of Ba0.65Sr0.35TiO3 thin film were confirmed and demonstrated by hysteresis loop. Remanent polarization (Pr) and coersive force (Ec) were found to be 1.8 muC/cm(2) and 13 kV/cm, respectively. Ba-0.65 Sr0.35TiO3 thin film fabricated in this work, exhibited a dielectric permittivity of 321 at 1 MHz. Our investigation showed that the tuning of dielectric permittivity could be possible by applying electric bias (from -10 V to + 10 V) to the film of thickness approximate to0.98 mum. The dielectric nonlinearity was also illustrated, which has a wide application in various tunable microwave devices. A high dielectric tunability of Ba0.65Sr0.35TiO3 thin film i.e. approximate to 32% at 1 KHz, was observed at 10 V Furthermore, properties, such as, dielectric permittivity, dissipation factor, figure of merit (K) of the Ba0.65Sr0.35TiO3 thin films were discussed as a function of frequency and bias voltage.