Abstract
Self-supported (Bi0.5Na0.5)TiO3 (BNT) dense ceramic films with a thickness of approximately 20 µm have been fabricated by use of an aerosol deposition method with heat treatment and sapphire single crystal substrates. Investigations of their constitution phase and crystal structure, observation of their microstructure, and measurement of polarization properties and leakage current density (J) were performed. Wlile the films heat-treated at 800 and 900°C in air indicated the low J ≈ 10−7 A/cm2 at 150 kV/cm, the sintered bulks and the films annealed at 900°C in the BNT starting raw powder showed the relatively high J of approximately 10−6 A/cm2 at 150 kV/cm. These films heat-treated at 800 and 1000°C in air and sintered bulks showed the almost the same coercive field (Ec) of approximately 57 kV/cm (in the 56 to 58 kV/cm range), and the films heat-treated at 1000°C in air exhibited good polarization properties and remanent polarization (Pr) of 25 µC/cm2. The AD method is proposed to be effective for obtaining self-supported BNT thick films with good saturated hysteresis loops and low J.
