A series of multiferroic composites, (1-x)Ba0.6(Ca1/2Sr1/2)0.4Ti0.5Fe0.5O3+(x)Ni0.4Zn0.45 Cu0.15Fe1.9Eu0.1O4 ((1-x)BCSTFO+(x)NZCFEO) where x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 1.0 have been synthesized by standard double sintering ceramic method sintered for 3 hours at 1200°C in air. The X-ray diffraction patterns reveal that the multiferroics and the parent ceramic samples crystallize in simple cubic structure with a slightly distored lattice parameter. The X-ray and bulk density increase with the increasing ferrite content. Consequently, the porosity decreases indicating better crystallization. A decreasing trend in dielectric constant is observed while the relative quality factor (RQF) increases significantly with the increasing ferromagnetic NZCFEO. At the same time, M–H hysteresis loops reveal that ferromagnetic property enhances with the addition of Ni0.40Zn0.45Cu0.15Fe1.9Eu0.1O4 (NZCFEO). The highest values of coercive field ∼ 92 O and saturation magnetization ∼1.37 emu/g are observed for x = 10% and x = 50% compositions respectively. Additionally, the permeability enhances up-to x = 30% but decreases with further doping. The room temperature resistivity rises due to the decrease in hopping mechanism. The samples exhibit a decreasing trend for resistivity with the increase of temperature. The dopant concentration has also shown an impressive impact on the activation energy. As a result, the multiferroic properties of (1-x)BCSTFO+(x)NZCFEO have been significantly improved considering the measured magnetic and ferroelectric properties.

We have investigated the Vanadium- (V) substituted Ni–Zn–Co ferrites where the samples are prepared using the solid-state reaction technique. The impact of V5+ substitution on the structural, magnetic, dielectric and electrical properties of Ni–Zn–Co ferrites has been studied. The XRD analysis confirms the formation of a single-phase cubic spinel structure. The lattice constants have been calculated both theoretically and experimentally along with other structural parameters such as bulk density, x-ray density and porosity. The FESEM images are studied for analyzing the surface morphology. FTIR measurement confirms spinel structure formation. The saturation magnetization (M s), coercive field (H c) and Bohr magnet on (μ B) are calculated from the obtained M-H loops. The temperature-dependent permeability is studied to obtain the Curie temperature. The frequency and the composition dependence of permeability are also analyzed. Frequency dependent dielectric behavior and ac resistivity are also investigated. An inverse relationship is observed between the composition dependent dielectric constant and ac resistivity. The obtained results such as the electrical resistivity, dielectric constants and magnetic properties suggest the appropriateness of the studied ferrites in microwave device applications.

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Mixed spinel–perovskite multiferroic (1 − x)BaTi0.5Mn0.5O3 + (x)Ni0.6Zn0.4Fe1.85Sm0.15O4 [(1 − x)BTMO + (x)NZFSO] ceramic composites with different concentrations, x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0, have been prepared by the effective double sintering ceramic method. X-ray diffraction confirms the coexistence of the cubic spinel structure of the ferrimagnetic phase, Ni0.6Zn0.4Fe1.85Sm0.15O4 (NZFSO), and the tetragonal structure of the ferroelectric phase, BaTi0.5Mn0.5O3 (BTMO), in the composites. The theoretical density decreases while the bulk density increases with the substitution of ferrimagnetic NZFSO into ferroelectric BTMO. Scanning electron microscopy shows an increment in the grain size with ferrite doping. Increasing permeability with ferrite doping indicates the enhancement of magnetic properties of the composites. The Cole–Cole plot affirms the contribution of grains, grain boundaries, and electrodes to the resistive properties of the samples. The variation in polarization and magnetization is correlated with the ferrite content. The composite with x = 0.8 has a high saturation magnetization, Ms = 28.67 emu/g, and has a maximum remanent polarization, Pr = 258.123 µC/cm2.

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