Rare-earth magnet
From Wikipedia, the free encyclopedia
Rare-earth magnets are strong, permanent magnets made from alloys of rare earth elements. Rare-earth magnets are substantially stronger than ferrite or alnico magnets.
Magnetic fields produced by rare-earth magnets can be in excess of 1.2 teslas. Ferrite or ceramic magnets typically exhibit 50 to 100 milliteslas. Common applications of rare-earth magnets include computer hard drives, audio speakers and bicycle dynamos. Rare-earth magnets are used in stop motion animation as tie-downs when the use of traditional screw and nut tie-downs is impractical. Rare-earth magnets are used for diamagnetic levitation experimentation, the study of magnetic field dynamics and superconductor levitation. LSM launch technology found on roller coaster and other thrill rides utilize rare-earth magnets.
[edit] Types of rare-earth magnets
[edit] Neodymium
Neodymium magnets are the most powerful and affordable type of rare-earth magnet. Neodymium magnets are made of neodymium, iron and boron. The formula for Neodymium magnets is Nd2Fe14B. Neodymium magnets are found in most computer hard drives and a variety of audio speakers.
[edit] Samarium-cobalt
Samarium-cobalt magnets (SmCo5) are less common than neodymium magnets. Samarium-cobalt magnets are more expensive to produce and are not as strong as Neodymium magnets because thay hve less earthrites. Samarium-cobalt magnets have a relatively high Curie point. The high Curie point makes Samarium-cobalt magnets suitable for high-temperature applications.
