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 N is the number of magnetic atoms (or molecules) per unit volume, g is the Landé g-factor, μ B (9.27400915e-24 J/T or A·m²) is the Bohr magneton, J is the angular momentum quantum number and k B is Boltzmann's constant. For a two-level system with magnetic moment μ , 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 χ , magnetization M and applied magnetic field H :

this shows that for a paramagnetic system of non-interacting magnetic moments, magnetization M is inversely related to temperature T (see Curie's Law).