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What are the characteristics of ferromagnetic materials?

Release Time:2019-09-03

Source: Shanghai Fuyu Magnetic Industry Co., Ltd.


  • 询价

  Materials with ferromagnetic properties have the following characteristics:

  1 Even if there is no external magnetic field, there is still a permanent magnetic moment in each small area (magnetic domain) inside the material. However, in the case of an unmagnetized magnetic material, the magnetic moment direction of each magnetic domain is arbitrarily distributed in the absence of an external magnetic field, and the vector sum is zero, so that the material as a whole has no magnetic properties.

  2 is easy to magnetize. This is because the direction of the magnetic moment of each magnetic domain in the action of the external magnetic field is turned to the direction of the magnetic field, so that a large magnetic induction B can be obtained. According to the formula B = μrB0 (B0 is the magnetic induction in vacuum), the relative permeability μr of the magnetic material is large. In fact, the μr of the magnetic material reaches 10 to 10 instead of μr≈1 of the magnetic material.

  3 There is a magnetic saturation phenomenon, that is, B increases as H increases, but increases to a certain value Bs, and then does not increase with H. BS is the saturation magnetic induction of the magnetic material. The reason for the saturation phenomenon is that the magnetic moment of all the magnetic domains is turned to the direction of the magnetic field after H reaches a certain value. For this reason, B and H are not linear, and thus the magnetic permeability is not constant, but is related to the strength of the magnetic field.

  4 There is hysteresis. That is, the change in magnetic induction lags behind the change in the magnetic field.

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