Investigation of structural, optical, electrical and magnetic properties of magnetoelectric composite of NiFe2O4 and YMnO3

Magnetoelectric composites of Nickel Ferrite and Yttrium Manganite (xNiFe(2)O(4) - (1-x) YMnO3, x = 0.25 and 0.50) were prepared using solid state reaction method. Their structural, optical, magnetic and electric behavior was studied by X-ray diffraction (XRD), UV-Vis spectroscopy, vibrating sample magnetometer (VSM), dielectric and polarization versus electric field (P-E) measurement at room temperature. Coexistence of the both ferrite and ferroelectric phases in the composites was confirmed by X-ray diffraction. Structural analysis had shown that lattice strain corresponding to nickel ferrite (NFO) phase was increased while for Yttrium Manganite (YMO) it was not much affected after formation of composites. The values of direct band gap for the composite came out to be larger than that for YMnO3 (1.43 eV) and smaller than that for NiFe2O4 (1.74 eV). Existence of ferromagnetic ordering in the composites was confirmed by VSM. Value of saturation magnetization was found to be highest in nickel ferrite (46 emu/g) and it was decreased with increase in concentration of ferroelectric phase in the composites. The sample with 75% YMO has shown highest dielectric constant (similar to 700) among all the four samples. P-E loops were not saturated and polarization current was found mainly due to conduction of charge carriers.