Electrical features of ferroelectric (Ba0.83Ca0.17)TiO3 ceramics with diffused phase transition under pressure

Ferroelectric (Ba0.83Ca0.17)TiO3 ceramics was sintered by the solid state reaction method. The material was sintered in three steps that allowed remarkably modifying structure and electrical features important from an application point of view. Major tetragonal phase of the material was detected using X-ray diffraction study. The scanning electron microscope test showed fluctuation in chemical composition. The ferroelectric to paraelectric phase transition was diffused and markedly shifted to lower temperature, TC = 339 K, respectively to barium titanate. Moreover, it showed the pressure sensitivity dTC/dp = −37 K/GPa. These effects were attributed to local disorder both in Ba/Ca and Ti sublattices. The high magnitude dielectric permittivity, e′~1000–2000, was observed in 200–400 K temperature range. The net polarization, which was estimated from the pyroelectric effect, decreased from ~3 µC/cm2 to zero in ~100–400 K range. The ceramics displayed the piezoelectric coefficient, d33 = 58 pC/N, the spontaneous polarization, PS = 11–14 µC/cm2, the remnant polarization, PR~2 µC/cm2, the coercive field, EC~1.5–3 kV/cm, and the energy density storage efficiency factor, ξ ≈ 33%, at room temperature.