Countersunk Hole in Block Neodymium Magnet

Countersunk Hole in Block Neodymium Magnet

What are the general methods of isolating magnetism?

In order to shielding the magnetism, it would be better if the material has a high magnetic permeability. With same material, thicker is better. With same material and same thickness, the more layers, the better. Besides, to avoid the magnetic lines will be concentrated on one side and leak out more, the strong neodymium magnets should be put in the center of shielding box. Second, material will be magnetized. The permeability magnetic material is always magnetized in the magnetic field. But except hard magnetic material, the magnetism will be immediately eliminated once external magnetic field is removed. Therefore, if the shielding material is made from hard magnetic material and form a new independent magnetic field, it will influence the shield effects. That’s the reason why we can only use soft magnetic material as shielding material.

If you ask now that the soft magnetic material also can be magnetic in the magnetic field, so how it isolate the magnetism? This is because the resulting new magnetic field strength completely changes according to the external original magnetic field strength when the soft magnetic material is magnetized. Then according to the principle of high frequency magnetic field shielding, achieve the shielding effect by magnetic mutual offset.