Room temperature multiferroic properties of BiFeO3–MnFe2O4 nanocomposites

Abstract

ABSTRACT The novel functionalities of multiferroic magneto-electric nanocomposites have spawned substantial scope for fast-paced memory devices and sensor applications. Following this, herein we report the development of nanocomposites with soft ferromagnetic MnFe2O4 and ferroelectric BiFeO3 to fabricate a system with engineered multiferroic properties. A modified sol-gel route called Pechini method is demonstrated for the preparation of the (1-x) BiFeO3-x MnFe2O4 (x=10%, 30%, 50%, 70%) nanocomposites. The crystallographic phase, structure, and morphology are characterized by XRD, FESEM, and HRTEM. The accurate crystallite size and lattice strain are determined by Williamson-Hall plot method and a comparative study with Scherer’s equation is carried out. TEM image evidences the interface between BiFeO3 and MnFe2O4 nanoparticles in the composite. The room temperature magnetic response reveals the strong dependence of magnetic saturation, remanent magnetization, and coercivity of the nanocomposites on MnFe2O4 addition. The dielectric response and impedance analysis of the prepared nanocomposites are observed. The electrical performance of the composite is affected by grain, grain boundaries, and oxygen vacancies. The unsaturated P-E loops exhibit the leaky ferroelectric behavior for the nanocomposite. The intrinsic magnetoelectric coupling between ferroelectric BiFeO3 and ferromagnetic MnFe2O4 has been determined by varying Hdc/Hac and its maximum coupling coefficient (α) is found to be 25.39 mV/cmOe for 70% BiFeO3 -30% MnFe2O4 nanocomposite. These distinctive and achievable characteristics of the nanocomposite would enable the designing of magnetic field sensors, spintronic devices, and multiferroic memory devices.