Which substance obeys Curie's Law ; feromagnetic or paramagnetic or both of them? give reason ,why they obey this law?
Hi Anandita!
According to Curie’s law, the susceptibility of a paramagnetic substance is inversely proportional to absolute temperature. Or, in other words, the magnetic susceptibility of a paramagnetic substance decreases with increase in temperature.
The paramagnetic materials obey this law because, as the temperature increases, the individual atomic magnetic moments of the material are randomized. This reduces the intensity of magnetization and susceptibility.
For ferromagnetic material, the law is modified. This is known as Curie-Weiss equation. It is given as
where, TC is the critical temperature and C’ is constant.
According to this modified law, when the ferromagnetic material is heated, it becomes paramagnetic at certain temperature. This temperature is known as Curie tempertature.
Cheers!!