Ⅰ. Chemical composition

1. Magnetic element content: 

The content of ferromagnetic elements (such as iron, cobalt, nickel or a combination thereof) plays a key role in magnetism. For example, in iron-based amorphous nanocrystalline materials, an increase in iron content usually increases saturation magnetization. 

2. The role of metal-like elements: 

Silicon, boron, carbon and other metal-like elements, also known as vitrified elements, their existence not only reduces the melting point of the alloy, makes it easier to form amorphous state, but also affects the magnetic properties of the material. . For example, an appropriate amount of boron can improve the soft magnetic properties of amorphous nanocrystalline materials. 

3. Adding trace elements:

Adding a small amount of other trace elements (such as niobium, molybdenum, etc.) may have a significant impact on magnetism by changing the crystal structure, defect state or electronic structure of the material. For example, the addition of niobium can improve the thermal stability of the amorphous phase, refine the grain size of the alloy after heat treatment, and thus improve soft magnetic properties and annealing brittleness. 

Ⅱ. Microstructure 

1. The ratio of amorphous state to nanocrystalline state: 

The relative content of amorphous state and nanocrystalline state will affect the overall magnetic properties of the material. Generally speaking, the presence of nanocrystalline phases can improve the saturation magnetization of the material, while the amorphous phases help reduce hysteresis loss. The optimization of the ratio of the two is the key to obtaining good magnetism. 

2. Grain size and distribution: 

The grain size and distribution of nanocrystals have an important impact on magnetism. Small and evenly distributed grain sizes are usually beneficial to improve the permeability of the material and reduce coercivity. If the grain size is too large or the distribution is uneven, it may lead to uneven magnetic domain structure inside the material, thereby affecting the magnetic properties. 

3. Defects and interfaces:

Defects in the material (such as vacancy, dislocation, etc.) and interfaces (such as the interface between the amorphous phase and the nanocrystalline phase) will affect the arrangement and movement of the magnetic moment, and thus affect the magnetism. For example, defects may hinder the movement of the magnetic domain walls, resulting in increased coercive forces; while a good interface structure helps improve the magnetic properties of the material. 

Ⅲ. Preparation process 

1. Cooling speed: 

During the material preparation process, rapid solidification is the key to forming amorphous state. Extremely high cooling speeds (such as more than one million degrees per second) can make atoms "freeze" into amorphous state without having time to be arranged neatly. The faster the cooling rate, the easier it is to form an amorphous state, and the more stable the amorphous structure, the greater the impact on magnetic properties. For example, for iron-based amorphous alloys, when the cooling rate is insufficient, partial crystallization may be caused, causing the material to decrease magnetic properties.

2. Annealing treatment: 

Annealing process parameters such as annealing temperature, time and atmosphere have an important influence on the magnetism of amorphous nanocrystalline materials. Appropriate annealing treatment can promote the formation and growth of nanocrystals in the amorphous matrix, optimize the microstructure of the material, and thus improve the magnetic properties; but if the annealing temperature is too high or the time is too long, it may lead to excessive crystallization and deteriorate the magnetic properties. 

3. Forming pressure: 

When preparing amorphous nanocrystalline materials using powder metallurgy and other methods, the forming pressure will affect the density and microstructure of the material. Suitable forming pressure can make the material denser, reduce pores and defects, and help improve magnetic properties; however, excessive forming pressure may cause stress inside the material, which will adversely affect the magnetism. 

Ⅳ. External conditions 

1. Temperature: 

Temperature changes will affect the magnetism of amorphous nanocrystalline materials. Generally speaking, as the temperature increases, the saturation magnetization of the material will decrease, the coercive force may decrease first and then increase, and the magnetic properties will change significantly near the Curie temperature. For example, below the Curie temperature, the material has ferromagneticity; above the Curie temperature, the ferromagneticity disappears and becomes paramagnetic. 

2. Magnetic field strength:

The magnitude and direction of the applied magnetic field strength will also affect the magnetic properties of the material. Within a certain range, increasing the magnetic field strength can increase the magnetization of the material and increase the saturation magnetization; and a strong magnetic field may cause changes in the magnetic structure of the material to affect its magnetic stability. 

3. Stress: 

The stress state of the material will change the arrangement of its magnetic domain structure and magnetic moment, thereby affecting the magnetic properties. For example, tensile stress may reduce the permeability of the material and increase the coercive force; while compressive stress acts the opposite.