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

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(0.01μC-cm^(-2)),and the ferroelectricity is reported to exist below room temperature(25℃).Here,(Bi_(0.2)La_(0.2)Y_(0.2)Dy_(0.2)Tb_(0.2))FeO_(3)(BLYDTFO)high-entropy oxides that exhibit a saturation P of 5.3μC.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 noncentrosymmetric distortion and ferroelectricity at room temperature compared with other single components(LaFeO_(3),YFeO_(3),DyFeO_(3),and TbFeO_(3)).This high-entropy approach expands the compositional window of the rare-earth orthoferrites to enhance the ferroelectricity in multiferroic applications.