# Curie constant

The **Curie constant** is a material-dependent property that relates a material's magnetic susceptibility to its temperature.

The Curie constant, when expressed in SI units, is given by

where is the number of magnetic atoms (or molecules) per unit volume, is the Landé g-factor, (9.27400915e-24 J/T or A·m^{2}) is the Bohr magneton, is the angular momentum quantum number and is Boltzmann's constant. For a two-level system with magnetic moment , the formula reduces to

The constant is used in Curie's Law, which states that for a fixed value of a magnetic field, the magnetization of a material is (approximately) inversely proportional to temperature.

This equation was first derived by Pierre Curie.

Because of the relationship between magnetic susceptibility , magnetization and applied magnetic field :

this shows that for a paramagnetic system of non-interacting magnetic moments, magnetization is inversely related to temperature (see Curie's Law).

## See also

## References

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