Enhanced ferroelectric properties derived at low voltages in manganese and cobalt Co-doped lead-free BNT-based films

Ferroelectric thin films have emerged as a research focus in recent years due to their outstanding performance and eco-friendliness. This study reports on the fabrication of high-quality 0.55Bi_0.5Na_0.5TiO₃-0.45SrTiO₃+0.5 mol% Mn+x mol% Co (BNT-ST-Mn-x%Co) thin films on LaNiO₃/Si (100) substrates using the sol–gel and spin–coating techniques. Through comprehensive structural analysis using multiple techniques, including X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy, we demonstrate that cobalt incorporation enhances both the breakdown strength and relaxation properties of these films. Notably, the BNT-ST-Mn-1%Co film exhibits exceptional characteristics, achieving a maximum polarization of 73.62 µC/cm² under an electric field of 900 kV/cm, coupled with a dielectric constant of 1119 at 1 kHz. The co-doping of cobalt and manganese yields films with high polarization intensity even at lower electric fields, showcasing promising potential for a wide range of applications.