Curie-Weiss law

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:"T_{c" is the Curie temperature, measured in kelvins}

The susceptibility has a singularity at "T" = "T_c". 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.

ee also

*Curie's law
*Paramagnetism
*Pierre Curie

References

"Introduction to Solid State Physics 7th ed." (1996) by Charles Kittel