Structural, magnetic and electrical properties of multiferroic xLi0.1Ni0.2Mn0.6Fe2.1O4 – (1-x)Bi0.8Y0.2FeO3 composites

The room temperature magnetoelectric coupling was elucidated by the analysis of structural, magnetic, and electrical properties of xLi_0.1Ni_0.2Mn_0.6Fe_2.1O₄ – (1-x)Bi_0.8Y_0.2FeO₃ composites. The X-ray diffraction pattern shows that the ferromagnetic phase forms a cubic spinel structure and the ferroelectric phase forms a rhombohedral perovskite structure. The density of the composites decreases with ferrite content. The average grain size slightly decreases with ferrite content for x = 0.1 and increases for further increasing ferrite content. The real part of initial permeability and saturation magnetization increase with increasing ferrite content. The real part of the dielectric constant decreases rapidly with the increase of frequency showing dielectric dispersion at lower frequencies and then remains almost constant at higher frequencies. The dielectric loss of the samples reduces with the increase of the ferrite phase. The ac conductivity of composites increases with frequency, indicating that the conduction is due to small polaron hopping. The study of impedance spectroscopy suggests that grain contribution is effective for the conduction mechanism in the composite. The maximum magnetoelectric voltage coefficient is observed (~182 × 10³Vm⁻¹T⁻¹) for the 0.1LNMFO – 0.9BYFO composite which is useful for fabricating magnetic sensors.