Highly a-oriented growth and enhanced ferroelectric properties of Bi3TaTiO9 thin films

Ferroelectric perovskites are favored for integrated device applications due to their high dielectric constants and strong piezoelectric responses. However, the commonly used lead zirconate titanate system has disadvantages such as toxicity, current leakage, and fatigue. As an alternate lead-free material, this study examines the strain-induced ferroelectric properties of Bi3TaTiO9 (BTTO) thin films. BTTO thin films grown on single crystal Rh and Nb-doped SrTiO3 (Nb:STO) substrates via a pulsed laser deposition were compared. The Rh substrate has induced compressive stress in the BTTO thin film, whereas the Nb:STO substrate has induced tensile stress in the BTTO thin film. The BTTO thin film grown on the Rh substrate displayed a highly a-oriented crystallinity compared with the Nb:STO substrate. Significantly, the BTTO thin film on the Rh substrate exhibited improved ferroelectric properties, such as stronger hysteretic behavior, faster polarization switching, and higher piezoelectric coefficients. The surface morphologies and ferroelectric domains of the BTTO thin films were investigated via atomic force microscopy and piezoelectric force microscopy. Our findings provide insights into strain-engineered ferroelectric thin films and their potential device applications. •Bi3TaTiO9 (BTTO) was chosen as a representative bi-layered perovskite.•BTTO thin films were deposited on Rh and Nb:STO substrates via pulsed laser deposition.•The BTTO thin film on the Rh substrate displayed a highly a-oriented crystallinity.•Improved ferroelectric and piezoelectric properties in the BTTO thin film on the Rh substrate.