Three models of magnetic ordering in typical magnetic materials

In this work, we review three models of magnetic ordering in typical magnetic materials that have been proposed based on atomic physics. The first model we discuss is the O 2p itinerant electron model for magnetic oxides, which is called the IEO model. Using this model, the magnetic structures of spinel ferrites MFe2O4, where M = Ti, Cr, Mn, Fe, Co, Ni, or Cu, and perovskite manganites La1−xSrxMnO3, where 0.0≤x≤0.4, can be explained. The second model considered is a new itinerant electron model for magnetic metals, called the IEM model. The IEM model can be employed to explain the relation between the average magnetic moment per atom and resistivity for Fe, Ni, and Co metals. According to this model, free electrons in magnetic metals should be distinguished from itinerant electrons. Then, when the free electrons are excluded, the itinerant electrons transitioning between adjacent metal ions in magnetic metals have similar characteristics to those transitioning between adjacent cations and O anions in magnetic oxides. The third model we address is the Weiss electron pair (WEP) model, which is based on the IEO and IEM models. The WEP model is used to explain the origin of the magnetic ordering energy in magnetic metals and oxides and provides a reason for the different Curie temperatures observed in typical magnetic metals and oxides.