Curie temperature \(\left(\mathrm{T}_{\mathrm{C}}\right)\) is the temperature at which certain materials lose their permanent magnetic properties, to be replaced by induced magnetism.
Above the Curie temperature, the material is paramagnetic, as the atoms lose their ordered magnetic moments when the material undergoes a phase transition.
The ordered magnetic moments change and become disordered at the Curie temperature. Higher temperatures make magnets weaker, as spontaneous magnetism only occurs below the Curie temperature.