LEAD-FREE BNT PIEZOELECTRIC THIN FILMS BY SOL-GEL METHOD.

Abstract

The objective of this work is to synthesize lead-free piezoelectric thin films by the Sol-Gel method:bismuth sodium titanate (Bi0.5Na0.5TiO3 or BNT).BNT films were annealed with the rapid thermal process (RTP).The film treated at 700°C is dense and well crystallized in the perovskite phase. The first results of electricalcharacterizations showed promising dielectric, ferroelectric and piezoelectric performance. At 12 kHz, thedielectric constant and losses are 430 and 0.07, respectively. Ferroelectric hysteresis measurements indicated aremanent polarization of 10μC/cm2, associated with a coercive field of 70 kV/cm. The piezoelectric properties ofBNT films were studied with a laser Doppler interferometer: a piezoelectric coefficient (d33effmax) of 42 pm/V was measured.