Impact and bridge measurement methods for magnetic materials
Magnetism is a fundamental property of matter. Broadly speaking, any material can exhibit some type of magnetism, but by magnetic materials we mean "strong magnetic materials" that exhibit significant magnetism in weaker magnetic fields. The impact method and the bridge method are important testing methods for the macroscopic magnetic properties of ferromagnetic materials. Some so-called "weak magnetic materials" in engineering are actually weakly strong magnetic materials.
Strong magnetic materials include two categories of ferromagnetic materials and ferrimagnetic materials. From the perspective of the arrangement of atomic magnetic moments, they are all composed of some large or small magnetic domains separated by domain walls. Since the adjacent atoms in the domain are arranged in an orderly parallel (for ferromagnetic materials) and anti-parallel (for ferrimagnetic materials) by overcoming thermal motion due to the large exchange effect, each domain has strong spontaneous Therefore, as long as a weak magnetic field is applied, the domain wall moves or the spontaneous magnetization in the domain rotates as a whole, and a strong magnetization can be exhibited macroscopically.
The movement of the magnetic domain is hindered by various kinds of obstacles, so that the magnetization process under the action of the magnetic field is sometimes reversible, sometimes irreversible, sometimes carried out by the movement of the domain wall, and sometimes carried out by the rotation of the magnetic domain. Generally speaking, these processes are carried out. They are all mixed together, so that the relationship between the magnetization and magnetic field strength of ferromagnetic materials is far more complicated than that of "non-magnetic materials" (paramagnetic, diamagnetic, and antiferromagnetic materials). In general, this relationship is both non-linear and related to magnetization history. Magnetization is not only a complex function of the strength of the magnetic field, but also a function of temperature and stress, and it is also something we need to pay full attention to.
The irreversible behavior of magnetic domain motion is caused by various dissipative resistances (i.e. damping). Due to the effect of damping, it takes a period of time to complete the corresponding change of magnetization for each change of magnetic field strength, and the time effect and energy loss of magnetization will be more obvious.
The magnetic measurement we say is to determine the functional relationship between the magnetization (or magnetic induction) and the magnetic field strength in a material or sample and the measurement of various magnetic parameters derived therefrom. To get a positive result, the definition of the measurand and the experimental conditions are extremely important.
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Beijing Jinzhengmao Technology Co., Ltd. is a professional enterprise engaged in the R&D and production of magnetic field generation, magnetic field measurement, precision magnetoelectric instruments and equipment, and magnetic application technology.
The company's main business: Gauss meter, flux meter, electromagnet, Helmholtz coil, Hall effect system, magnetic material inspection system and other magnetoelectric instruments and equipment.
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