Large electric polarization in multiferroic BaFe10.8Sc1.2O19 thin film

High-quality (001)-oriented BaFe₁₂O₁₉(BFO) and BaFe_10.8Sc_1.2O₁₉(BFSO) thin films were fabricated by pulse deposition techniques. Magnetic characterization revealed that the substitution of Sc³⁺ for Fe³⁺ changed transitions the room-temperature magnetic properties from hard to soft magnetism and alters the magnetic structure from linear ferrimagnetism to conical magnetism. Concomitantly, the strip-type magnetic domains become significantly finer and shorter. The refined domain structure facilitates inversion of magnetic moment reversal under reduced applied field and induces robust ferroelectric polarization. Dielectric properties measurements on the BFSO thin film demonstrated room-temperature ferroelectricity arising from the conical magnetic structure. By optimizing annealing processes, leakage current was substantially suppressed, enabling a well-defined ferroelectric hysteresis loop was achieved at 300 K with a remarkable remnant polarization (Pr) of ~2.6 μC/cm². This achievement establishes a foundation for magnetoelectric device applications.