Preparation method of magnetic core

The invention relates to the technical field of manganese-zinc ferrite magnetic cores, and discloses a preparation method of a magnetic core, a ferrocenyl polymer magnet containing a bipyridine structure and metal ions in manganese-zinc ferrite have a coordination effect, so that metal ions such as La < 3 + > are doped into a molecular chain of the polymer magnet, the polymer magnet and the manganese-zinc ferrite are tightly combined, and the magnetic core is prepared. Therefore, the magnetic performance of the composite magnetic core is greatly improved; according to the preparation method, CaCO3 and SiO2 serve as crystal boundary enhancers, CaSiO3 with high resistivity can be generated and accumulated on the crystal boundary at high concentration, the resistivity of the crystal boundary is improved, Al2O3 generates a protective film with low conductivity under the action of high-temperature sintering, a shell-core structure is formed, the resistivity in crystal grains is improved, and the power loss of the