Temperature and Magnetic Field‐Driven Electrical Modulation in Ni ₀ . ₅ Co ₀ . ₅ Fe ₂ O ₄ Nanostructures

This study investigates the electrical properties of piezomagnetic Ni 0 . 5 Co 0 . 5 Fe 2 O 4 nanoparticles (NPs), emphasizing the effects of magnetic fields and temperature. Ni 0 . 5 Co 0 . 5 Fe 2 O 4 NPs were synthesized using the chemical pyrophoric reaction method, yielding nanocrystalline powders confirmed through XRD, field emission scanning electron microscopy (FE‐SEM), and energy‐dispersive X‐ray (EDX) analyses. Alternating current (AC) and direct current (DC) electrical measurements reveal significant nonlinear current–voltage behavior influenced by oxygen vacancies, interfacial polarization, and magnetic domain alignment. The application of applied magnetic field enhances electrical conductivity, increasing the magnetocurrent percentage up to 526%, while the temperature variations reveal a metal‐to‐insulator transition. Dielectric studies indicate a strong dependence of dielectric constant and dielectric loss on frequency and applied magnetic field. At low frequencies, the dielectric constant is significantly high due to space charge polarization, which diminishes at higher frequencies as polarization mechanisms lag. The application of a magnetic field increases the dielectric constant, with magnetodielectric and magnetoloss effects reaching up to 27% and 10%, respectively. Impedance spectroscopy further elucidates the interplay between grain and grain boundary conduction mechanisms, with resistance decreasing and capacitance increasing under an applied magnetic field. Temperature‐dependent measurements reveal a peak in impedance near 323 K, corresponding to a phase transition, with a shift in impedance peaks to higher frequencies as temperature rises due to enhanced charge carrier mobility. The findings underscore the dynamic interplay of magnetic, electrical, and thermal properties in Ni 0 . 5 Co 0 . 5 Fe 2 O 4 NPs, demonstrating their potential for advanced applications. This comprehensive analysis provides insights into the behavior of magnetic nanomaterials under varying environmental conditions, paving the way for innovative materials with multifunctional properties.