Electrical and magnetic properties of MF/CuAl nanocomposites

This study investigated the effects of CuAl2O4 (CuAl) on four types of spinel ferrites: CoFe2O4 (CoF), NiFe2O4 (NiF), MgFe2O4 (MgF), and ZnFe2O4 (ZnF) with regards to their electrical characteristics and microscopic magnetic behavior. According to the Seebeck coefficient (φ), the nanocomposites have a mixture of positive and negative charge carriers, except for CoF/CuAl, which has a positive charge carrier only. Depending on the temperature, the DC conductivity of all MF/CuAl nanocomposites has a conductor and semiconductor behavior. The dielectric properties were studied at different frequencies (100–10^8 Hz) and temperatures (300–673 K). The results demonstrated how temperature and frequency affect AC operating mechanisms. The high values of dielectric loss for all nanocomposites confirm their applicability in high-frequency microwave devices. The impedance study revealed that the equivalent circuit for all MF/CuAl nanocomposites is a mixture of R, L, and C. Temperature-magnetization graphs were obtained for all nanocomposites, indicating ferrimagnetic behavior except ZnF/CuAl. The magnetic transition temperature (T Cm), the Curie–Weiss constant (θ CW), and the effective magnetic moments (μ eff) for all nanocomposites were determined. The MF/CuAl samples were analyzed using ESR spectroscopy at room temperature. The spectra were distorted but remained distinct, potent, and sweeping. The g-factor values deviate from the free electron, which suggests that the Fe3+–O–Fe3+ superexchange interaction has changed. In addition, the interaction effect between MF and CuAl is discussed.