Magnetic susceptibility

In electrical engineering, the magnetic susceptibility is the degree of magnetization of a material in response to a magnetic field. The dimensionless mass magnetic susceptibility is represented by the symbol χ (lowercase Greek letter chi).

Related Topics:
Electrical engineering - Magnetization - Magnetic field - Greek letter - Chi

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:

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chi = rac {M} {H}

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where

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M is the magnetization of the material (the magnetic dipole moment per unit mass), measured in A/m (i.e. amperes per metre)

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H is the applied field, measured in A/m (where the magnetic induction B is related to H by the relationship B = mu_0(H + J) where μ0 is the permeability of vacuum (see table of physical constants).)

Related Topics:
Applied field - Physical constant

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If χ is positive the material is called paramagnetic, and the magnetic field is strengthened by the presence of the material. If χ is negative then the material is diamagnetic and the magnetic field is weakened in the presence of the material.

Related Topics:
Paramagnetic - Diamagnetic

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The magnetic susceptibility of a ferromagnetic substance is not linear. Response is dependent upon the state of sample and can occur in directions other than that of the applied field. To accommodate this, a more general definition using a tensor derived from derivatives of components of M with respect to components of H

Related Topics:
Ferromagnetic - Tensor - Derivative

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:chi_{ij} = rac{part M_j}{part H_i}

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called the differential susceptibility describes ferromagnetic materials. When the coercivity of the material parallel to an applied field is the smaller of the two, the differential susceptibility is merely a function of the applied field.

Related Topics:
Ferromagnetic - Coercivity

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The magnetic susceptibility and the magnetic permeability (μ) are related by the following formula:

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:mu = mu_0(1+chi) ,

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