Interfacial engineering of BFMO/BTO heterostructured films for enhanced multiferroic and energy storage applications

Multiferroic materials exhibit significant potential for next-generation microelectronics and energy storage applications due to their coupled ferroelectric and magnetic properties. Herein, BiFe 0.98 Mn 0.02 O 3 (BFMO) thin films were deposited on BaTiO 3 (BTO)/Pt/Ti/SiO 2 /Si substrates using sol-gel spin coating, with BTO serving as a buffer layer. X-ray diffraction and scanning electron microscopy revealed well-oriented growth and densified microstructures with reduced grain size in the BiFe 0.98 Mn 0.02 O 3 /BaTiO 3 (BFMO/BTO) bilayer. The BFMO/BTO heterostructure exhibited a marginally higher dielectric constant and lower dielectric loss compared to single-layer BTO films, attributed to interfacial polarization and synergistic interactions between layers. Moreover, a notably low leakage current density on the order of 10 −6 A/cm 2 is observed for the BFMO/BTO films at an applied field of ±300 kV/cm. Furthermore, the BFMO/BTO heterostructure films exhibit remarkably enhanced saturation magnetization of 52 emu/cc and improved maximum polarization of 31.43 μC/cm 2 at RT compared to single-layer films. The polarization-electric field ( P - E ) hysteresis loops indicated slim hysteresis with reduced coercive fields in the BFMO/BTO heterostructure, suggesting improved ferroelectric switching dynamics. In particular, the BFMO/BTO film achieved a remarkable recoverable energy storage density ( W rec ) of 9.99 J/cm 3 at 450 kV/cm. These findings highlight the critical role of interfacial engineering in optimizing multiferroic and energy storage properties, offering valuable insights for moderate electric field energy storage devices.