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A rare-earth magnet is a strong permanent magnet made from alloys of rare earth elements, or lanthanide and actinide metals, with other metals. They are substantially stronger than ferrite or alnico magnets.

The magnetic field produced by rare-earth magnets can be well over 1.2 teslas. By comparison, ferrite or ceramic magnets typically exhibit around 50 to 100 milliteslas. Common applications of rare-earth magnets include computer hard drives, high-end speakers and bicycle dynamos. Some other applications of rare-earth magnets include experiments with diamagnetic levitation, the study of magnetic field dynamics, LSM launch technology (often found on Roller Coasters & Thrill Rides), and superconductor levitation.

Contents 1 Types of rare-earth magnets 1.1 Neodymium 1.2 Samarium-cobalt 2 Online References

[edit] Types of rare-earth magnets

[edit] Neodymium

The most powerful and affordable type of rare-earth magnet is a neodymium magnet. Neodymium magnets are made of neodymium, iron and boron in the formula Nd₂Fe₁₄B. These magnets are found in almost every computer hard drive as well as in various types of speakers.

[edit] Samarium-cobalt

Samarium-cobalt magnets (SmCo₅) are less common than neodymium magnets because they are more expensive and not as strong. These magnets are generally used in high temperature applications since they have a higher Curie point.

[edit] Online References

• Magnet University Resources from the fundamental theory of magnetism to advanced applications of magnetic materials.
• Rare-Earth Magnetics Association - Rare earth magnet informationnl:Rare Earth Magnet

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