Today most magnets are made from alloys. The most common alloys are neodymium-iron-boron, samarium-cobalt, aluminum-nickel-cobalt, and strontium-iron. Orderly to magnetize the alloy, the alloy is revealed to a magnetic field. It actually modifies structure by readjusting the molecules into bar through a procedure which is called polarization.
For each article of magnet, there is temperature at which the heat will tear down the polarization of the material causing it to loses its magnetic properties also known as or a Curie temperature. Temperatures underneath than the Curie temperature can erode a magnet.
Ferromagnet materials will lose track their magnetism if warmed above a point which is the Curie temperature. At this moment, the energy being put into the magnet from the heat will everlastingly disrupt the magnetic dominion structure of the article will be turning it into a paramagnetic substance.
Demagnetizing Magnetic Field:
Everlasting magnets exhibit an attribute called coercivity. It is the ability of a material to resist being demagnetized by an appealed magnetic field. Older materials such as Alnico or ceramic materials have lower coercivities and modern permanent magnet materials such as Sm-Co and Nd-Fe-B have high coercivities. It is therefore possible to demagnetize the magnet with a powerful enough magnetic field of contrary polarity. The article becomes attractive when an electrical current is flowed through it. However, when the electricity stops the material will no longer be magnetic.
Ironically, an opposing magnetic field is sometimes applied to a magnet just to ‘knock it down’, or to lower its mostly magnetic output, so that it can be used appropriately in an utilization.
This really only applies to mature materials such as magnetic steels and Alnico materials. Modern materials do not sustain this type of problem. The apparatus that creates coercivity means that they are operation to being demagnetized if enough energy is transmitted through the material through a shock or such when dropped or hit with a hammer.
Time is a very abortive means of demagnetizing a magnetic object. Magnets only lose their magnetic energy very steadily. For example, samarium cobalt magnets might lower down their magnetic power about 1 percent over a decade.