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I wish I were a magnate, of anything If you raise the temperature of a magnet above its curie temperature, it will lose its magnetism altogether (there may be a grey area around the curie temperature, but there is no progressive proportionality between temperature and magnetism).Cooling a magnet that is already well below its curie temperature should have no effect on its magnetism (excepting when you get to the regions of superconductivity).
What is the " Curie Temperature ?"
And what happens when you get to the realms of superconductivity?
Diamagnetism is a very weak form of magnetism that is only exhibited in the presence of an external magnetic field. It is the result of changes in the orbital motion of electrons due to the applied magnetic field. The induced magnetic moment is very small and in a direction opposite to that of the applied field. When placed between the poles of a strong electromagnet, diamagnetic materials are attracted towards regions where the magnetic field is weak. Diamagnetism is found in all materials, however because it is so weak it can only be observed in the absence of other forms of magnetism.An exception to the "weak" nature of diamagnetism occurs with the rather large number of materials that become superconducting, something that usually happens at lowered temperatures. Superconductors are perfect diamagnets and when placed in an external magnetic field expel the field lines from their interiors (depending on field intensity and temperature). Superconductors also have zero electrical resistance, a consequence of their diamagnetism. Superconducting structures have been known to tear themselves apart with astonishing force in their attempt to escape an external field. Superconducting magnets are the major component of most MRI systems, perhaps the only important application of diamagnetism.
Quote from: neilep on 23/09/2007 18:44:25What is the " Curie Temperature ?"Depends on the material - each substance has a different curie temperature.
Thanks George...but I meant 'fundamentally' what is the Curie Temperature !! ?...something to do with Madam Curie yes ?