inely divided powder in an external magnetic field, pressing into required shapes, and firing at temperatures between 1000-1300 degrees Celsius. The different ways to make magnets make different types of magnets and magnetism. Some examples are electromagnetism, geomagnetism, residual magnetism, induced magnetism, diamagnetism, and ferromagnetism. Electromagnetism is the magnetism obtained by a direct electric current. Geomagnetism is the natural magnetism of the planet Earth, which acts like a giant magnet. Residual magnetism is magnetism retained by a magnetized object after a magnet is no longer near the object. Induced magnetism is the temporary alignment of the magnetic domains in a magnetic material that is placed near a magnet. Diamagnetism is the kind of magnetism that is in the opposite direction to the magnetic field. Finally, a substance that is ferromagnetic, such as iron or steel is strongly attracted to a magnet and can keep its magnetic charge.Magnets are also made out of different materials. The most commonly recognized material is steel. Special alloys of metals are used instead of just plain steel. The alloy provides domains that tend to remain in a line better than steel. One alloy made up of aluminum, cobalt, nickel, copper and iron, called Alnico is one of the strongest magnets available. Another material used is ferrite which is an earthy, ceramic material composed of iron oxide and the oxide of another metal such as nickel, cobalt or magnesium. These ferromagnets as they are called are magnetic even before they are placed in a magnetic field. They become noticeably magnetic when placed in a comparatively week magnetic field. Also, their ferromagnetism disappears when the material is heated above a certain temperature. This temperature is called the Curie temperature.There is a theory as to why some metals make better magnets than others do; this theory is called the electron theory of magnetism. Th...
