Structural, magnetic, and ferroelectric properties of multiferroic BiFeO3-based composite films with exchange bias

Bi Fe O 3 -based composite films with excess iron content were fabricated, and the dependence of their magnetic and ferroelectric properties on the excess iron content was systematically investigated. Structural and magnetic analyses indicated that the specimens might be composed of large antiferromagnetic BiFeO3 grains and small ferromagnetic component. When the iron content was increased, saturation magnetization (Ms) increased and remanent polarization decreased. Antiferromagnetic coupling (Hex) between the antiferromagnetic BiFeO3 grains and the ferromagnetic grains was observed at 10K. It was revealed that grain growth is the key to increasing Ms and Pr and observing Hex at room temperature in BiFeO3-based composite films.