Enhanced multiferroic properties of Bi0.89Tb0.11Fe0.96Mn0.02Co0.02O3/Zn1-xNixFe2O4 bilayer thin films by Ni2+-doped magnetic functional layer

In the field of multifunctional electronic components, multiferroic material which possesses both ferroelectricity and ferromagnetism has important application prospect. Here, the Bi 0.89 Tb 0.11 Fe 0.96 Mn 0.02 Co 0.02 O 3 /Zn 1-x Ni x Fe 2 O 4 (BTFMCO/ZN x FO) bilayer thin films ( x = 0.0, 0.1, 0.2, 0.3, 0.4) are fabricated by the sol-gel spin-coating technique. The influence of ZN x FO magnetic layer on the structural, dielectric, ferroelectric, and ferromagnetic properties of the bilayer thin films is systematically investigated. The BTFMCO/ZN 0.2 FO bilayer exhibits the lowest surface roughness (Ra=1.44 nm), a markedly reduced Fe 2+ concentration and minimized oxygen vacancy density, leading to a suppressed leakage current density of 3.7 × 10 –4 A/cm 2 at 200 kV/cm. Consequently, enhanced multiferroic properties with a ferroelectric remnant polarization (2P r ) of 118.5 µC/cm² and saturation magnetization (M s ) of 63.2 emu/cm³, respectively, are observed in the BTFMCO/ZN 0.2 FO sample. These findings reveal that interfacial modulation via Ni 2+ -doped ZN x FO layers is an effective strategy to simultaneously enhance ferroelectric and ferromagnetic performance.