Substitution effects on magnetic properties of Mg1.3-xMnxAlyFe1.8-yO4 ferrite

Mg1.3-xMnxAlyFe1.8-yO4 (x = 0.1–0.2, y = 0.15–0.3) spinel ferrites were prepared using conventional ceramic technique. Highly densified Mg–Mn–Al ferrites (with 99% theoretical density) were obtained, and the influence of Mn and Al substitution on the characteristics of these ferrites has been systematically studied. The microstructure, magnetic properties, and ferromagnetic resonance linewidth (ΔH) of the Mg–Mn–Al ferrites have been analyzed by X-ray diffraction, B-H analyzer, and ferromagnetic resonance (FMR) spectrometer. The results showed that all of the samples were single spinel phase. As Mn content increases and Al content decreases, both saturation magnetization (4πMs) and squareness ratio increase, while the coercivity (Hc) first increases and then decreases. In addition, good ferromagnetic resonance linewidth properties were also obtained as 143.8 Oe at 9.3 GHz for the sample with x = 0.17 and y = 0.20. The results imply that Mg1.3-xMnxAlyFe1.8-yO4 ferrites may be applicable for X-band (8–12 GHz) microwave devices.