Electric Field–Induced Magnetization Rotation in Magnetoelectric Multiferroic Fluids

Abstract

Abstract Multiferroics are of interest for applications as the magnetoelectric coupling effect between ferroelectric and magnetic order parameters. Here, an approach to control and switch the ferromagnetic orientation with an electric field using the multiferroic fluids is reported. A new multiferroic material, the so‐called magnetoelectric multiferroic fluids, has been prepared by distributing surface treated Ni 0.5 Zn 0.5 Fe 2 O 4 @CoFe 2 O 4 core–shell structured particles in to a highly insulating silicone oil. An electromagnetic coupling phenomenon is used that is manifested in core–shell structure consisting of a ferromagnetic Ni 0.5 Zn 0.5 Fe 2 O 4 wrapped tightly with the ferroelectric BaTiO 3 in the fluid, which is based on magnetoelectric coupling at the interface between a ferromagnet and the ferroelectric. Three general manifestations of the coupling interactions are discovered, the first is that the hysteresis loops tend to shift from the origin along the voltage axis toward the positive or positive direction, an exchange bias like behavior, a consequence of pinned effect; the second is an enhancement of the coercive field of the ferromagnet as a consequence of enhanced rotate drag effect; and the third one is the improved residual magnetization. The results imply that conventional core–shell structured multiferroic fluids may have an opportunity to gain electrical control of the magnetization.