Ferrite absorbing materials are both a magnetic medium with magnetic absorption and a dielectric with electric absorption. They are a class of absorbing materials with excellent performance.
In the low frequency range, the loss of ferrite to electromagnetic waves is mainly caused by the loss of hysteresis effect, eddy current effect and magnetic aftereffect; in the high frequency range, the loss of electromagnetic wave by ferrite mainly comes from natural resonance loss and domain wall resonance. Loss and dielectric loss.
In different frequency ranges, the mechanism of the residual loss of the absorbing material is different due to the different mechanism of the magnetization relaxation process. In the low-frequency weak field, the residual loss is mainly the magnetic after-effect loss. In the case of high frequency, dimensional resonance loss, domain wall resonance loss and natural resonance loss all belong to the category of residual loss.
In summary, to obtain a high-loss ferrite absorbent, the ways are: increase the saturation magnetization of the ferromagnetic body; increase the impedance coefficient; reduce the magnetocrystalline anisotropy field; due to the resonance frequency and the magnetocrystalline anisotropy The anisotropy field is proportional, so the absorption band of the material can be controlled by changing the magnetocrystalline anisotropy field of the ferromagnet. In the actual preparation operation, the composition and preparation process of the material can be changed.