Magnetization

The magnetization (symbol ) is a physical quantity to characterize the magnetic state of a material, which is calculated as the magnetic moment per unit volume:

Which describes the relationship between magnetization magnetic flux density and the magnetic field strength:

Here, the magnetic field and the permeability constant.

If μ is smaller than μ0, it is called negative magnetization ( diamagnetic material ), or of positive magnetization ( paramagnetic material ). Ferromagnetic magnetization is also positive, but much larger than paramagnetic magnetization and can not be expressed by a simple proportionality ( see diagram right). A ferromagnetic body can be permanent magnetic.

Description by the susceptibility

The magnetization can also be described by the magnetic field strength and the magnetic susceptibility:

The susceptibility is dimensionless and can take values ​​from -1 to infinity almost. The magnetization can thus be opposite to the magnetic flux density.

Magnetization of a nail

A nail made ​​of iron, whose magnetic domains are randomly oriented initially, can be magnetized by an external field. Here, some magnetic domains enlarged at the expense of neighboring domains and the result is so in total magnetization, which runs approximately parallel to the external field. This change of the magnetic domain can eg be increased by external shocks or vibrations. Due to the ferromagnetic characteristics of the nail retains its magnetization in partially, even after removal of the external field.

Magnetization in the Geology / Mineralogy

Minerals and rocks can get a permanent magnetization when they arise in different ways, the magnetic field of the earth each pretending the polarization:

  • Thermally remanent magnetization (TRM ): The magnetic orientation of the mineral in a melt is fixed by cooling below the Curie temperature.
  • Chemical remanent magnetization ( CRM): minerals, which are by a chemical reaction (eg, oxidation, reduction ) to magnetizable minerals align themselves in the conversion.
  • Detritisch remanent magnetization (DRM ): magnetizable mineral grains depend on the sedimentation in the water column by the magnetic field of the Earth and settle with this alignment onto the sediment.
  • Postdetritisch remanent magnetization ( PDRM ): minerals align themselves with the deposit in unconsolidated sediment.
System of measurement Ampere
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