Enhancement of dielectric and ferroelectric properties by Ca doping BaTiO3

The temperature dependent dielectric and ferroelectric properties of polycrystalline Ba1-xCaxTiO3 (x=0.08) have been investigated. Our temperature dependent complex dielectric measurement confirms that Ba0.92Ca0.08TiO3 (BCTO) undergoes three frequency independent transitionswith thermal hysteretic behavior in the temperature range 120to 410 K. These transitions correspond to cubic to tetragonal, tetragonal to orthorhombic and orthorhombic to rhombohedral transitions at 403, 228 and 132 K (during cooling), respectively. The P-E loops across each transition confirm the ferroelectric nature of the studied sample. The remnant polarization is maximum in rhombohedral phase. Interestingly, the value of dielectric constant and remnant polarization enhanced as compared to un-doped BaTiO3. We have also explored the effect of dc bias field on these transitions and found that in the presence of dc field all three transitionsare shifted towards higher temperature.