Additionally, the ferromagnetism of an object is temperature dependent. As the temperature increases, the kinetic energy of molecules increases, and thermal motion becomes more intense. When the temperature reaches a critical point, the arrangement of atomic magnetic moments is no longer ordered, the net magnetic moment becomes zero, and ferromagnetism disappears. The temperature at this point is the Curie temperature. If the temperature drops below the Curie temperature, ferromagnetism will recover.

The Curie temperature of iron is 770 degrees Celsius, nickel is 354 degrees Celsius, dysprosium is -185 degrees Celsius, ferric oxide is 585 degrees Celsius, and neodymium magnet is 330 degrees Celsius. Therefore, if iron is burned red, it cannot be attracted by magnets. When the temperature drops below 770 degrees Celsius, the iron that has regained its magnetism can be attracted by the magnet.