In the race toward next-generation electronics and energy systems, ceramic nanocomposites have taken center stage due to their remarkable dielectric and ferroelectric functionalities. By pushing the boundaries of nanoscale engineering, recent studies have shown how microstructural control and interfacial design can unlock unprecedented levels of polarization, permittivity, and frequency stability. This review presents a critical and up-to-date synthesis of the last decade’s progress in ceramic-based nanocomposites, with a special focus on the structure property processing nexus. Diverse processing techniques ranging from conventional sintering to advanced spark plasma sintering and scalable wet-chemical methods are analyzed for their influence on phase purity, grain boundary behavior, and interfacial polarization. The review also explores breakthroughs in lead-free and eco-friendly systems, flexible ferroelectric nanocomposites, and high-k dielectrics suitable for miniaturized devices. By identifying both the scientific opportunities and persistent challenges in this rapidly evolving field, this work aims to guide future innovations in material design, device integration, and sustainable performance.

Maghemite (γ-Fe₂O₃) nanoparticles have attracted considerable interest for electronic applications due to their tunable electrical properties. Doping strategies offer an effective way to optimize their resistive behavior for use in electronic devices. In this study, cobalt (Co) was incorporated into γ-Fe₂O₃ to enhance its resistive properties. X-ray diffraction (XRD) confirmed the retention of the cubic P4₃32 phase, with Co doping inducing subtle lattice distortions due to ionic substitution. Scanning and transmission electron microscopy (SEM/TEM) revealed morphological changes, where Co incorporation influenced particle shape and size distribution. Electrical conductivity analysis demonstrated a decrease in both AC and DC conductivity with the increase in Co content, indicating enhanced resistive behavior. The increase in activation energy suggests a reduction in charge carrier mobility, leading to higher resistivity. Impedance spectroscopy further confirmed increased real and imaginary impedance values, reinforcing the role of Co in suppressing charge transport. These results position cobalt-doped maghemite as a promising material for electronic resistive devices, such as tunable resistors and negative temperature coefficient (NTC) thermistors, where controlled conductivity and stable resistive behavior are essential.