For all magnets, it is not magnetic at any temperature. In general, the magnets have a critical temperature Tc above which the arrangement of the magnetic moments of the atoms is disorganized due to the intense thermal motion of the atoms at high temperatures. Below this temperature, the atomic moments are arranged neatly, producing spontaneous magnetization, and the object becomes magnetic.
Take advantage of this feature, people have developed a lot of control components. For example, the rice cookers we use take advantage of the Curie point characteristics of the magnetic material. In the bottom of the rice cooker fitted with a magnet and a Curie point of 105 degrees of magnetic material. When the water in the pan is dry, the temperature of the food will rise from 100 degrees. When the temperature reaches approximately 105 ° C, the magnet loses its attraction to the magnet due to the disappearance of the magnetism of the magnetised material, and the spring between the magnet and the magnet separates them and the power switch is turned off Open, stop heating.
Curie temperature refers to the temperature at which a material can change between ferromagnetic and paramagnetic. The material becomes ferromagnetic below temperature, and the material-dependent magnetic field is hard to change at this time. When the temperature is higher than the Curie temperature, the material becomes paramagnetic, and the magnetic field of the magnet easily changes with changes in the surrounding magnetic field. At this time the magnetic sensitivity of about 10 negative 5 power.
When two magnets together can be heated to a temperature of about two hundred degrees Celsius, at this temperature greatly reduced the magnetism of the magnet, the attraction between the magnet will be reduced, so it is very easy to suck the two together Strong magnet separate powerful magnet maximum working temperature is 300 ℃, so that can not be heated to more than 300 ℃, 200 ℃ enough.
Of course, for some small magnets can be very easy to break apart by hand, but for some magnet with a larger magnetic area can only slide down along the surface of the magnet. This is how to separate two powerful magnets.