Enhanced ferroelectric and ferromagnetic performance of 2-2 type (Bi,Eu)(Fe,Mn)O₃/CoFe₂O₄ bilayered thin film

Bilayered multiferroic thin film consisting of Bi_0.90Eu _0.10Fe_0.98Mn_0.02O₃ (BEFMO) and CoFe₂O₄ (CFO) has been prepared on fluorine doped tin oxide (FTO)/glass substrates via the chemical solution deposition method. The results demonstrate that rhombohedral BEFMO and cubic CFO phases have perfect 2-2 connectivity structure without substantial diffusion and impurity. CFO layer interpolates between BEFMO layer and substrate, which is useful to enhance the insulativity of the bilayered thin film. The BEFMO/CFO thin film demonstrates dramatically improvement of ferroelectric and ferromagnetic behavior at room temperature. Furthermore, with excluded the effect of leakage current in polarization values, the huge polarization value (2P_r ∼ 208 μC/cm²) is also obtained, which is confirmed by PUND measurement. Ferromagnetic hysteresis loop with M_s ∼ 90.9 emu/cm³, M_r ∼ 47.5 emu/cm³ and H_c ∼ 920 Oe is observed in the BEFMO/CFO thin film. We believe that these findings can provide more possibilities for multifunctional applications.