chapter  5
34 Pages

NANOMAGNETISM

What Is a Magnet? A magnet is normally known as a piece of iron, steel, or magnetite that has the property of attracting iron or steel. The most well-known magnet is probably the lodestone, also often called magnetite, which is a naturally occurring rock that was fi rst discovered in a region known as magnesia and was hence named after this region. Magnetism may be naturally present in a material or the material may be artifi cially magnetized and magnets can either be permanent or temporary. After being magnetized, a permanent magnet retains the properties of magnetism indefi nitely while a temporary magnet (e.g., a magnet made of soft iron) is usually easy to magnetize but it loses most of its magnetic properties when the magnetizing cause is discontinued. Permanent magnets are usually more diffi cult to magnetize, but they remain magnetized pra ctically forever. These materials which can be magnetized are called ferromagnetic materials.