Curie temperatures is the temperature above which

Ferromagnetism decreases with rise in temperature. If we heat a ferromagnetic substance, then at a definite temperature the ferromagnetic property of the substance suddenly disappears and the substance becomes paramagnetic. The temperature above which a ferromagnetic substance becomes paramagnetic is called the Curie temperature of the substance. Note: The Curie temperature of iron is $770^{\circ} \mathrm{C}$ and that of nickle in $358^{\circ} \mathrm{C}$.