Explain Curie temperature.

The ferromagnetic property of a material depends on its temperature.
As the temperature of a ferromagnetic substance increases, the thermal agitation causes the magnetic dipole moments of its molecules to become random, thereby destroying the spontaneous magnetization.
At a sufficiently high temperature, a ferromagnetic substance loses its ferromagnetic properties and becomes paramagnetic.
The specific temperature at which this transition from ferromagnetic to paramagnetic behavior occurs is known as the Curie temperature $(T_{c})$.
For temperatures above the Curie temperature $(T > T_{c})$, the magnetic susceptibility $(\chi)$ in the paramagnetic phase is described by the Curie-Weiss law:
$\chi = \frac{C}{T - T_{c}}$
where $C$ is the Curie constant.
The Curie temperature $(T_{c})$ for some common ferromagnetic materials is given below:

Material	$T_{c} \text{ (K)}$
Cobalt	$1394$
Iron	$1043$
$Fe_{2}O_{3}$	$893$
Nickel	$631$
Gadolinium	$317$