Comparative study of magnetoelectric composite system Ba0.95Sr0.05TiO3–Ni0.8Co0.2Fe2O4 with ferrite prepared by different methods

In this paper, effect of addition of Ni0.8Co0.2Fe2O4 (NCF), prepared by three different methods namely solid state reaction method, sol–gel and co-precipitation, has been studied on microstructural, magnetic, dielectric, ferroelectric and magnetoelectric properties of multiferroic composite system 0.95 Ba0.95Sr0.05TiO3–0.05 Ni0.8Co0.2Fe2O4. Ba0.95Sr0.05TiO3 (BST) has been prepared by solid state reaction method. Titular representation of NCF samples prepared by sol–gel, co-precipitation, solid state reaction method is N–SG, N–CP, N–SS respectively and that of corresponding magnetoelectric composite is C–SG, C–CP, C–SS. X–ray diffraction analysis of the composite samples (C–SG, C–SS, C–CP) indicated the presence of both NCF and BST phases. Rietveld analysis of XRD pattern further confirmed the proper phase formation in the composite samples. Sol–gel and co-precipitation processes result in finer NCF particles as confirmed by Transmission electron microscopy (TEM). Sample N–SG possesses uniform particle size and shape. Magnetization versus magnetic field (M–H) loops of samples C–SS and C–CP possess respectively highest value of remanant magnetization and magnetic coercive field. Dielectric properties of BST, NCF and composite samples have been measured in the frequency range of 20 Hz–1 MHz and temperature range of 50–170 °C. The composite sample C–CP results in highest value of dielectric constant in comparison to samples C–SS and C–SG. Polarization versus electric field (P – E) measurements pointed that composite sample C–SG possesses highest value of remanant and saturation polarization and C–SS possesses lowest value of coercive electric field. The composite sample C–SS possesses highest value of magnetoelectric coefficient.