The effect of interfacial charge-induced multiferroic properties of Bi0.993La0.007FeO3/BaTiO3 bilayer thin films: Performance modulation and energy storage applications

Abstract

Multifunctional and multiferroic materials assure a tantalizing perspective of applications in next-generation microelectronics, memory, energy harvesting, and energy storage technologies. The current study aims to deposit a bilayer thin film of BLFO/BTO with varying top layer (BLFO) thickness on n-type Si and Pt/Ti/SiO2/Si (Pt-Si) substrate by the PLD technique. Bilayer films with dense and packed microstructures show evidence of both tetragonal (T) and rhombohedral (R) symmetry. The bilayer films exhibit remarkably enhanced saturation magnetization of 35.9 emu/cm3 and improved maximum polarization of 34 μC/cm2 at RT compared to single-layer films. Moreover, the higher top layer thickness (BTO/BLFO3) hetero-structures achieved a high recoverable energy storage density of 11.65 J/cm3 with an energy efficiency of 85 % simultaneously. These films display excellent energy storage performance and produce a maximum power density of 0.9 MW/cm3 at 100 Hz. Further, the leakage current density of BLFO/BTO3 film is found ∼102 times lower than the monolayer BTO thin film suggesting the lower oxygen vacancies, defects, and impurities in the bilayer stacked films with higher top layer thickness. The drop in leakage current density, slim hysteresis loop, and enhancement in large saturation polarization for BTO/BLFO3 highlight the improved result demonstrating the interface effect and coupling between ferroelectric and magnetic properties. Hence, the acquired ferroelectric and magnetic properties are promising for spintronic devices and energy storage capacitor applications.