High-entropy enhanced room-temperature ferroelectricity in rare-earth orthoferrites

Abstract

Single-phase multiferroic materials of rare-earth orthoferrites with magnetism and ferroelectricity are of great technological importance in storage devices. However, the polarization (P) of these materials is generally weak (0.01 μC·cm−2), and the ferroelectricity is reported to exist below room temperature (25 ℃). Here, (Bi0.2 La0.2 Y0.2 Dy0.2 Tb0.2)FeO3 (BLYDTFO) high-entropy oxides that exhibit a saturation P of 5.3 μC·cm−2 at the electric field (E) of 45 kV·cm−1 at room temperature was designed and fabricated by the conventional solid-phase method. The results show that configurational entropy introduces atomic disorder and a larger tilt of BO6 octahedron, which facilitates non-centrosymmetric distortion and ferroelectricity at room temperature compared with other single components (LaFeO3, YFeO3, DyFeO3, and TbFeO3). This high-entropy approach expands the compositional window of the rare-earth orthoferrites to enhance the ferroelectricity in multiferroic applications.