Ⅰ. Microstructure factors 

1. Grain size: 

According to the random anisotropy theory, the equivalent magneto crystal anisotropy constant of nanocrystalline materials is related to the grain size. Usually, the smaller the grain, the smaller the coercive force. This is because when the grain size decreases, the effective anisotropy of the material decreases, and the magnetic moment is more likely to turn during magnetization, resulting in a decrease in coercive force. 

2. Phase composition:

Amorphous nanocrystalline materials are generally biphasic structures composed of amorphous phase and nanocrystalline phase. The proportion, distribution and interaction of the two phases have an important influence on coercive force. If the nanocrystalline phase is uniformly distributed in the amorphous phase, and the interface energy between the two phases is low, it is conducive to the movement of the magnetic domain wall and the coercive force will be lower. If the phase composition is unreasonable, if there are too many hard magnetic phases or non-uniform phase distributions, it will hinder the movement of the magnetic domain wall and increase the coercive force. 

3. Defects and impurities: 

Defects such as lattice incompleteness, dislocation, etc., and the presence of impurities will change the magnetoelastic properties, diffusion field energy, exchange energy and anisotropy properties of the material, thereby affecting the movement of the domain wall. and magnetization process. Generally speaking, the number of defects and impurities increases. On the one hand, the anti-magnetization nucleus is easier to form, and on the other hand, it will also act as the center of the pinned domain wall, hindering the movement of the domain wall, thereby increasing coercive force. 

Ⅱ. Internal stress factors 

The existence of internal stress will cause additional magnetic anisotropy inside the material, changing the magnetic domain structure and magnetization process. For materials whose internal stress is difficult to eliminate, the magnetic domain wall needs to overcome greater resistance when moving, resulting in increased coercive force. For example, during the preparation or processing process, internal stress will be introduced into the material due to rapid cooling, mechanical processing, etc., which will affect the coercive force.

Ⅲ. Component factors 

1. Main elements: 

Different ferromagnetic elements and their content have an impact on coercive force. For example, in iron-based amorphous nanocrystalline alloys, cobalt elements are added, and the strong ferromagnetic exchange coupling between cobalt atoms and iron atoms will change the atomic magnetic moment, thereby affecting the coercive force of the material. 

2. Trace elements: 

Some trace elements such as copper and niobium also play an important role in amorphous nanocrystalline materials. For example, copper can promote the nucleation of nanocrystals, and niobium can inhibit grain growth. Their content and proportion will affect the microstructure of the material and indirectly affect the coercive force. 

Ⅳ. External environmental factors 

1. Temperature: 

Generally speaking, as the temperature increases, the thermal motion inside the material intensifies, the movement of the magnetic domain wall becomes easier, and the orientation of the magnetic moment is more likely to change, resulting in coercive force. reduce. However, in some special amorphous nanocrystalline materials, abnormal coercive forces may occur within a specific temperature range. 

2. Magnetic field history: 

The magnetic field history experienced by a material during preparation or use will affect its coercive force. For example, the pre-applied strong magnetic field may change the magnetic domain structure inside the material, forming a certain magnetic memory effect, causing the coercive force obtained by subsequent measurement to change.

Ⅴ. Preparation process factors 

1. Annealing process: 

Annealing process parameters such as annealing temperature, time and cooling speed have significant impact on the coercive force of amorphous nanocrystalline materials. A suitable annealing temperature and time can fully crystallize the amorphous phase, form a uniform and fine nanocrystalline structure, and reduce coercive force; if the annealing temperature is too high or the time is too long, it may lead to the growth of grains and deterioration of phase composition, causing The coercive force increases. 

2. Preparation method: 

Different preparation methods will lead to different microstructures and defect distributions of materials, which will affect coercive forces. For example, the amorphous nanocrystalline strip material prepared by the single-roller belt swing method has a fast cooling rate, a more uniform amorphous phase, relatively few defects, and may have a lower coercive force; while other preparation methods such as sputtering method, Vapor deposition method, etc., may introduce different degrees of impurities and defects during the preparation process, which will have different effects on coercive forces.