초교환 상호작용 제어를 통해 강유전 BiFeO3-BaTiO3 시스템에서 유도된 상온 강자성 거동

Abstract

Multiferroics exhibiting the coexistence and a possible coupling of ferromagnetic and ferroelectric order are attracting widespread interest in terms of academic interests and possible applications. However, room-temperature single-phase multiferroics with soft ferromagnetic and displacive ferroelectric properties are still rare owing to the contradiction in the origin of ferromagnetism and ferroelectricity. In this study, we demonstrated that sizable ferromagnetic properties are induced in the ferroelectric bismuth ferrite-barium titanate system simply by introducing Co ions into the A-site. It is noted that all modified compositions exhibit well-saturated magnetic hysteresis loops at room temperature. Especially, 70Bi0.95Co0.05FeO3-30Ba0.95Co0.05TiO3 manifests noticeable ferroelectric and ferromagnetic properties; the spontaneous polarization and the saturation magnetization are 42 μC/cm2 and 3.6 emu/g, respectively. We expect that our methodology will be widely used in the development of perovskite-structured multiferroic oxides.