Interplay between the ferrimagnetic and ferroelectric phases on the large magnetoelectric coupling of xLi_(0.1)Ni_(0.2)Mn_(0.6)Fe_(2.1)O_4-(1-x)Bi_(0.8)Dy_(0.2)FeO_3 composites

摘要

The multiferroic composites of ferromagnetic Li_(0.1)Ni_(0.2)Mn_(0.6)Fe_(2.1)O_4 (LNMFO) and ferroelectric Bi_(0.8)Dy_(0.2)FeO_3 (BDFO) with the general formula xLi_(0.1)Ni_(0.2)Mn_(0.6)Fe_(2.1)O_4-(1-x)Bi_(0.8)Dy_(0.2)FeO_3 have been prepared by the solid-state reaction route. The XRD analysis has ensured that the composites are composed of a mixture of cubic spinel LNMFO and orthorhombic perovskite BDFO phases. Field Emission Scanning Electron Microscope is used to investigate the surface morphology of the studied compositions. The average grain size of the composites has reduced slightly with the enhancement of ferrite part up to 20% and after that it has increased again. The real part of the initial permeability (μ'_i) was found to be increasing with ferrite content. The real part of dielectric constant (ε') exhibits dispersion at low-frequency region because of Maxwell-Wagner type interfacial polarization. The complex impedance spectroscopy has been used to separate the grain and grain boundary contribution to the total resistance. Existence of the hopping conduction mechanism has been confirmed through the study of electric modulus. The hysteresis loops of the compositions are studied to confirm the response of ferrite part to the applied magnetic field. The magnetoelectric voltage coefficients of the composites have reduced with the ferrite part. The maximum magnetoelectric voltage coefficient is nearly 158 ×10~(3) Vm~(-1) T~(-1) for the 0.1 LNMFO-0.9BDFO composite, which is about three times of the reported value compared to other composites.