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Ferrite ceramics, Ni${}_{0.88}$Zn${}_{0.07}$Co${}_{0.05}$Fe${}_{1.98}$O₄, with the addition of 4wt.% Bi₂O₃ as sintering aid, were fabricated by using a simple one-step processing without involving the step of calcination. X-ray diffraction (XRD) results indicated that single phase ferrite ceramics can be achieved after sintering at 1000${}^{\circ }$C for 2h. The samples demonstrated relative densities in the range of 97–99%. Desired magneto-dielectric properties have been approached by adjusting the sintering temperature and sintering time duration. This technique is believed to be applicable to other ceramic materials.

${\text{Ni}}_{0.5}$${\text{Co}}_{0.5}$Fe₂O₄ (NCF) powders were obtained employing two alternative synthesis routes: solid-state reaction and Pechini’s methods. The ceramic powders were pressed and sintered in the temperature range of 1100${}^{\circ }$C to 1250${}^{\circ }$C. Microstructural and structural properties were evaluated by SEM, XRD, and Raman spectroscopy. Magnetic hysteresis loops of sintered samples were also recorded. A secondary phase was observed in samples synthesized by Pechini’s method, whereas samples obtained by the solid-state reaction method, with the mechanochemical activation of the reagents, only produced the spinel structure. Magnetic properties of samples obtained by the solid-state method displayed higher magnetic saturations and lower coercive fields than those obtained from the Pechini’s method.

The present investigations mainly focused on the colossal dielectric response and complex impedance analysis of LaFeO₃ ceramics. The studied sample was prepared by a citrate gel method. Structural and microstructural properties are analyzed from the XRD pattern and SEM micrograph. The anomalies in the dielectric constant versus temperature plots are analyzed on the basis of polarization induced by the Maxwell-Wagner mechanisms and ferromagnetic interaction between the Fe${}^{3+}$ ions driven by the oxygen vacancy mediated Fe${}^{3+}$–V${}_o$ –Fe${}^{3+}$ exchange interaction A giant dielectric permittivity in the order of $\sim$10⁵ was observed in the sample even at the room temperature for 100 Hz. The colossal dielectric constant in LaFeO₃ is mainly driven by the internal barrier layer capacitor (IBLC) formation. The formation of IBLC was explained on the basis of highly insulating grain boundary and less resistive/semiconducting grain, which was confirmed from both the resistance and capacitance of grain and grain boundary from the impedance analysis. The non-Debye-type relaxation process associated with the grain and grain boundary effect was investigated from the broad and asymmetric relaxation peak. The relaxation time for both the grain and grain boundary effect was also calculated. In addition to this, we have also analyzed the normalized bode plot of imaginary part of impedance and electrical modulus which suggests the relaxation process dominated by the short-range movement of charge carriers.