Experimental and Simulation Study of BaTiO ₃ -Based Thin Films Deposited by Pulsed Laser Deposition for Piezoelectric Applications

Lead (Pb)-free piezoelectric thin films are gaining attention due to their versatility in microelectromechanical systems (MEMS), including actuator, sensor, and memory applications. In the present work, pristine and doped BaTiO 3 (BTO) ferroelectric polycrystalline thin films with chemical configuration Ba 0.95 Ca 0.05 Sn 0.09 Ti 0.91 O 3 (BCST) were deposited on the SrTiO 3 substrate by the pulsed laser deposition (PLD) technique. X-ray diffraction and Raman patterns ensure the formation of a pure phase tetragonal structure in both films. Cross-sectional focus ion beam scanning electron microscopy (FIB-SEM) analysis of the films revealed densely packed columnar structures in each layer, showing strong interlayer bonding. The BCST film shows a high value of saturation polarization of 37.53 μC/cm 2 as well as dielectric constant of 175 as compared to the BTO film at room temperature. This linear enhancement is due to Ca 2+ substitution at the Ba 2+ site and Sn 4+ substitution at the Ti 4+ site. These substitutions introduce lattice distortion and displacement of Ti ions in the TiO 6 octahedral geometry, which enhances the polarization as well as the dielectric constant. Furthermore, the films have a very high effective piezodisplacement of about 992 pm and converse piezoelectric coefficient ( d 33 *) of about 49.6 pm/V. The COMSOL simulation results show good qualitative agreement and similar trends with the experimental data, confirming the validity of the modeling approach. This study demonstrates the potential of Pb-free BaTiO 3 -based films and their applications in piezoelectric sensors/actuators and pulsed power devices.