Influence of Mg²⁺ doping on the electromagnetic properties of Li-Zn ferrites

Li-Zn ferrites doped with Mg²⁺, Li_0.1Zn_0.8Mg_x Fe_2.1-xO₄ (x= 0, 0.02, 0.04, 0.06, 0.08), were prepared by Sol-Gel combustion method. The analysis methods of TG-DSC, XRD, FT-IR, SEM and network analyzer (Agilent 8722ET) were employed to analyze the formation process, structure, surface morphology and electromagnetic properties of samples. The results showed that ferrite powders with pure spinel phase were formed when x≤0.06. The lattice parameters of ferrites first increased and then decreased with substitution amount. Appropriate amounts of Mg²⁺ substitution could adjust microwave electromagnetic parameters magically. The tan δ exhibited two maximal peaks at the frequency of 6.5 GHz and 15 GHz, respectively, and the peak values of tan δ were about 0.11 and 0.54 when x = 0.06. It was indicated that the microwave electromagnetic loss properties were excellent when x = 0.06. Furthermore, the reasons had also been discussed using electromagnetic theory.