Regulation of Fe²⁺ contents in yttrium iron garnet by doping with different valence states of Mn and its dielectric and magnetic properties

The regulation of Fe²⁺ in yttrium iron garnet is a crucial factor in determining its dielectric and magnetic properties. This study successfully prepared Y₃Mn_0.2Fe_4.8O₁₂ ceramics, and studied their microstructure, magnetism, dielectric properties, and ferromagnetic linewidth through Mnⁿ⁺ ion doping. The microstructural analysis revealed that the doping of low-valence Mn led to an increase in the grain size and density of ceramics, while the Mn⁴⁺–YIG showed the emergence of the second phase of YFeO₃. Chemical composition analysis confirmed that the Fe²⁺ content was regulated by the Mn valence and that the lowest value was observed in Mn²⁺–YIG. The hysteresis loop demonstrated that the saturation magnetization decreased with the increase of Mn valence. In addition, low-valence Mn doping also reduced the dielectric loss and ferromagnetic resonance linewidth. Therefore, this study confirmed that low-valence metal doping could be a promising approach for regulating the Fe²⁺ content in YIG.