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. The magnetic field typically produced by rare-earth magnets can be in excess of 1.2 teslas. Ferrite or ceramic magnets typically exhibit fields of 50 to 100 milliteslas.

Applications

Common Applications

Common applications of rare-earth magnets include:

• Computer hard drives
• Audio speakers
• Bicycle dynamos.
• Fishing Reel brakes.

Other Applications

Other applications of rare-earth magnets include:

• Stop motion animation as tie-downs when the use of traditional screw and nut tie-downs is impractical
• Diamagnetic levitation experimentation, the study of magnetic field dynamics and superconductor levitation.
• Launched roller coaster technology found on roller coaster and other thrill rides.

Types of rare-earth magnets

Neodymium

Neodymium magnets (chemical formula: Nd₂Fe₁₄B) are the strongest and most affordable type of rare-earth magnet. Neodymium magnets are made of Neodymium, Iron and Boron. Neodymium magnets are typically used in most computer hard drives and a variety of audio speakers.

Samarium-cobalt

Samarium-cobalt magnets (chemical formula: SmCo₅) are less common than Neodymium magnets because they are more expensive to produce and create a weaker magnetic field than Neodymium magnets. However, Samarium-cobalt magnets have a relatively high Curie point, which makes them suitable for high-temperature environments.