Rare earth magnets are strong, permanent magnets, that are made of alloys of rare earth elements. They are named after these elements, which are found in the rare earth or lanthanide part of the periodic table. Lanthanides are elements, which have an f-shell that is not fully filled. Electrons in such cases are strongly confined and restricted which makes them retain their magnetic properties and attributes to them the potential to create a paramagnetic force field around them.

These magnets, as stated earlier, are stronger (almost fifteen times stronger) than ferrite or alnico magnets. These rare-earth magnets are so strong that they can lift up to four hundred times their own weight. They are used in expensive electronic gadgets such as cell phones, computer hard drives and the like; and since they are expensive, to save them from chipping and breaking, these magnets are coated with nickel. This nickel coating also protects them from rust and stains, and gives them a shiny appearance.

Types

These magnets can be distinguished into two broad categories which are as follows:
  • Neodymium (Nd-Fe-B) magnets - Neodymium magnets consist of neodymium, iron, and boron. These magnets are the strongest and most affordable of the lot. These are the magnets that are used in computer hard drives and speakers as they have the strongest magnetic field. These magnets are expensive as the cost of raw materials required is quite high and also because of the cost of the licensing of the patents. These magnets are also not very resistant to oxidation and temperature, thus they have to be coated with nickel or gold. Neodymium magnets are also corrosive but the main advantage is that they have a high-energy output for their size. These magnets can be used in microphones, computer printers, and speakers as well.
  • Samarium-cobalt (Sm Co) magnets - Samarium cobalt magnets consist of samarium, cobalt, and iron. These magnets are not as commonly available as neodymium magnets since the latter type is easy to produce. Samarium Cobalt magnets are resistant to demagnetization and also stable under high temperature unlike Neodymium magnets. These magnets are also resistant to oxidation but shaped magnets are prone to breaking and chipping when exposed to thermal shocks. These magnets can be used in satellite systems and traveling wave tubes.
Rare earth magnets are very strong and thus, they have to be handled carefully. Small children should not be allowed to play with such magnets. These magnets should not be put in one's mouth or consumed. Since these magnets are very strong and their magnetic fields, large and powerful, people who have pacemakers should avoid being anywhere in proximity to these magnets. They should also be kept away from credit cards, computers, cell phones, and any other electronic equipment that can be influenced by the strong magnetic field of these magnets.