As for the source of ferromagnetism of ferrite materials, it is not that the magnetism of ordinary metal magnetic materials is formed by the Exchange interaction of direct electron spin between adjacent magnetic atoms, but that the distance between two magnetic ions is far, and oxygen ions are sandwiched in the middle. In fact, the Exchange interaction between the electron spins that form ferromagnetism is formed due to the existence of oxygen ions. This type of Exchange interaction is called Superexchange in ferromagnetic theory. Because of the super exchange, the magnetic moments of magnetic ions on both sides of oxygen ions are arranged in the opposite direction, which is the reason why many metal oxides have Antiferromagnetism. If the magnetic moments arranged in the opposite direction are not equal and there are residual magnetic moments, then this kind of magnetism is called Ferrimagnetism, or ferrite magnetism. Because there are many relative positions between oxygen ions and magnetic ions in ferrite materials, there is more or less Superexchange between them. The results show that when the distance between oxygen ions and metal ions is relatively close, and the angle between magnetic ions and oxygen ions is about 180 °, the Superexchange effect is the strongest. The arrangement direction of magnetic ions in ferrite is mainly based on the strongest Superexchange effect, so the magnetic properties of ferrite materials are not only related to the crystal structure, but also related to the distribution of magnetic ions in the crystal structure. Changing the composition of magnetic or non magnetic ions in ferrite can alter the distribution of magnetic ions in the crystal structure. In addition, during the preparation process of ferrite, the sintering process conditions also affect the distribution of magnetic ions. Therefore, in order to grasp the basic characteristics of ferrite materials, it is necessary to understand the crystal structure of various ferrite materials; The distribution of metal ions in the crystalline structure; And how to change their distribution