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miffy
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what is the average size of a domain?
and how are "permanent" magnets made?
thanks, erin.
and how are "permanent" magnets made?
thanks, erin.
Average domain size is a measure of the size of the magnetic domains within a material. It is typically measured in nanometers (nm) or micrometers (µm). To determine the average domain size, a technique called small-angle neutron scattering (SANS) is often used, which involves shooting neutrons at the material and analyzing the scattered pattern to determine the domain size.
The average domain size is directly related to the coercivity of a material, which is its ability to resist demagnetization. Generally, a smaller average domain size results in a higher coercivity and therefore a stronger permanent magnet. Additionally, a smaller average domain size can lead to a higher remanence, or residual magnetization, which is important for the strength of a permanent magnet.
The average domain size in permanent magnet creation is influenced by several factors, such as the composition and microstructure of the material, the processing techniques used, and the external magnetic field applied during production. For example, adding certain elements to the material can decrease the average domain size, resulting in a stronger magnet.
There are several methods for controlling the average domain size in permanent magnet creation, including adjusting the composition of the material, using different processing techniques, and applying a strong external magnetic field during production. Additionally, the use of additives or annealing processes can also help to control the average domain size.
The most commonly used materials for creating permanent magnets with small average domain size are rare-earth metals, such as neodymium, samarium, and dysprosium. These materials have a high magnetic anisotropy, meaning their magnetic domains align in a specific direction, resulting in smaller average domain sizes and stronger permanent magnets. Other materials, such as ferrites and alnico, can also be used to create permanent magnets with smaller average domain sizes.