Definitions
Nearby Words

# Curie-Weiss law

[kyoor-ee-wahys, -vahys]
The Curie-Weiss law describes the magnetic susceptibility of a ferromagnet in the paramagnetic region above the Curie point:


chi = frac{C}{T - T_{c}}

where

$chi$ is the magnetic susceptibility
C is a material-specific Curie constant
T is absolute temperature, measured in kelvins
Tc is the Curie temperature, measured in kelvins

The susceptibility has a singularity at T = Tc. At this temperature and below there exists a spontaneous magnetization.

In many materials the Curie-Weiss law fails to describe the susceptibility in the immediate vicinity of the Curie point, since it is based on a mean-field approximation. Instead, there is a critical behavior of the form


chi sim frac{1}{(T - T_{c})^gamma}

with the critical exponent $gamma,$. However, at temperatures $T gg T_c$ the expression of the Curie-Weiss law still holds, but with $T_c,$ representing a temperature which is somewhat higher than the actual Curie temperature.