Rayleigh's law (magnetism)

The Rayleigh law (named after its discoverer, John William Strutt, 3rd Baron Rayleigh ) describes the change in the magnetization of a ferromagnetic material in the magnetic field strength smaller than the coercive force ${\displaystyle H}$ ${\displaystyle H_{c}.}$

Ferromagnetic materials consist of Weiss areas , which are separated from each other by Bloch walls . If a small magnetic field is now applied to the material, these Weiss areas grow as the Bloch walls shift. Rayleigh derived the linear and quadratic dependence of the magnetization on the field strength: ${\displaystyle H}$ ${\displaystyle M}$

${\displaystyle M=\chi _{0}\cdot H+\alpha _{R}\cdot \mu _{0}\cdot H^{2}}$

With

• the magnetic initial susceptibility which the initial magnetization of matter in the small field indicating ${\displaystyle \chi _{0}}$ ${\displaystyle H}$
• the Rayleigh constant , the irreversible Barkhausen jumps describes ${\displaystyle \alpha _{R}}$
• the magnetic field constant ${\displaystyle \mu _{0}.}$

In an analogous manner, Rayleigh's law can also be used to describe the change in the electrical polarization of ferroelectric material with small electrical fields .

credentials

1. ↑ Lord Rayleigh: On the behavior of iron and steel under the operation of feeble magnetic forces . In: Phil. Mag. . 23, 1887, pp. 225-248. doi : 10.1080 / 14786437108216375 .
2. ↑ DV Taylor and D. Damajanovic, J. Appl. Phys. 82 (1997) 1973

literature

• Helmut Kronmüller, Manfred Fähnle: Micromagnetism and the microstructure of ferromagnetic solids . Cambridge University Press, 2003, ISBN 00521331358, p. 148.
• Cullity: Introduction to Magnetic Materials . Addison-Wesley, 1972, p. 342.

See also

• Preisach model
• Jiles-Atherton model