Magnets can be sensitive to temperature. The strength of a magnet depends on the alignment of its magnetic moments, which are formed by the angular momentum and spin of its electrons. When a magnet is exposed to cold, its molecules move more slowly and cause less vibration, which creates a more concentrated magnetic field. However, heat can cause the molecules to move faster and become more sporadic, which can weaken the magnet's strength and magnetic field.
The degree to which temperature affects a magnet depends on the type of material. For example, most magnets with the exception of ferrite
will actually display an increase in strength as the temperature drops. All permanent magnets (including ferrite) will lose a percentage of their performance for every degree increase.
If a magnet is exposed to high temperatures, the delicate balance between temperature and the domains in a magnet is destabilized. At around 80 °C, a magnet will lose its magnetic force and it will become demagnetized permanently if exposed to this temperature for a period, or if heated above its Curie temperature
.
The maximum operating temperature and Curie temperature are determined by the material a particular magnet is made of and the size and shape of the magnet.
So any magnet is imperfect because the spins of the particles that created the magnetism wonder around at random. This random motion lessens the magnetic fields that the magnet produces.
But in a condensate all the magnetic particles are identical. There is no random motion of the spins of these particles. In a condensate it is as if the condensate acts as one huge single particle. This coherent behavior insures that the magnetic field alway is at maximum strength. The strength of that single huge composite particle is 10^23 times more powerful than any single particle that forms the condensate.