The earliest ferrite in China was found in the 4th century BC as a natural magnetite (Fe3O4). The compass invented by China was made from this natural magnetite. By the 1930s, the development of radio technology urgently demanded ferromagnetic materials with high frequency loss. The low resistivity of ferriferous oxide, can not meet this requirement. 1933 Tokyo University of Technology in Japan first created a ferrite containing cobalt permanent magnet materials, was called the OP magnet. From the 30s to the 40s, ferrites were successively carried out in France, Japan, Germany, the Netherlands and other countries. In 1935, JL Snooker, a Ph.D. laboratory physicist from the Netherlands, developed various spherulites with excellent properties Stone structure of zinc soft ferrite, in 1946 to achieve industrial production. In 1952, the chamber J.J. Weite et al. Had developed into a permanent magnet ferrite with BaFe12O19 as the main component. This ferrite has a similar hexagonal structure to the four types of VHF magnetic ferrites studied by G.H. In 1956 E.F. Bertolu and F. Fowler also reported the ferrimagnetic Y3Fe5O12 findings. The substituting ions Y have rare earth ions such as Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. Because of the crystal structure of these magnetic compounds and natural mineral garnet the same, it is called the garnet structure ferrite. Hitherto, except for the ferrite material having an amorphous structure obtained by ultra-rapid cooling by Japan's Sugimoto light man in 1981, none of the above-mentioned three types of crystal structures has been crystallized from the viewpoint of crystallization chemistry. Much of the work has been done to modify and in-depth research to suit new uses.