Effect of Temperature on the Dielectric and Magnetic Properties of NiFe2O4@MgFe2O4 and ZnFe2O4@MgFe2O4 Core-Shell

The core-shell NiFe 2 O 4 @MgFe 2 O 4 (NiF@MgF) and ZnFe 2 O 4 @MgFe 2 O 4 (ZnF@MgF) are stable nanocomposites. The experimental results showed perfect dielectric and magnetic properties different than their components. The experimental data revealed that the mutual effect between the core and the shell increases the space charge polarization. Also, the samples showed semiconducting-metallic behavior, which varies according to the temperatures and the frequencies. Furthermore, the magnetization M(T) was studied using the Faraday balance method of all samples. The obtained results of M(T) exhibit good magnetic properties of the core-shell samples, particularly the sample ZnF@MgF, where it possesses magnetization higher than the pure ferrite phase (MgFe 2 O 4 ) and Curie temperature (T Cm ) higher than the room temperature, and this is new for Zn-ferrite. Besides, the effective magnetic moment (µ Eff ) and the Curie-Weiss constant (θ) were obtained from the magnetic susceptibility χ(T) protocols.