Rare-earth magnet

A rare-earth magnet is a permanent magnet made with one or more rare-earth elements, usually combined with transition metals. Its high magnetic strength comes from the interaction of rare-earth atoms’ magnetic moments with the material’s crystal structure.

Neodymium magnet: A permanent magnet made primarily from neodymium, iron, and boron, with very high magnetic strength. It is the most widely used rare-earth magnet and sets the benchmark for strength.
Magnetic domain: A region in a magnetic material where atomic magnetic moments share a common orientation. Permanent magnetization requires domains to remain aligned after the external field is removed.
Permanent-magnet synchronous motor: An electric motor whose rotor uses permanent magnets and rotates in synchrony with the stator’s magnetic field. Rare-earth magnets provide strong, compact rotor fields in many such motors.
Ferrite magnet: A permanent magnet made from iron oxide and ceramic compounds, generally less powerful but inexpensive and corrosion-resistant. Ferrite magnets trade lower strength for lower cost and reduced reliance on rare earths.
Rare-earth element mining: The extraction and processing of ores containing rare-earth elements. Mining supplies magnet materials but can generate substantial waste and pollution.
Samarium–cobalt magnet: A permanent magnet made from samarium and cobalt, valued for high-temperature stability and corrosion resistance. It is the other major commercial rare-earth magnet family.
Magnetocrystalline anisotropy: The preference of a crystal’s magnetization to align along particular crystallographic directions. Rare-earth atoms create strong preferred directions that stabilize magnetization.
Wind turbine: A machine that converts wind’s kinetic energy into electrical power. Direct-drive turbine generators can use rare-earth magnets to avoid a gearbox.
Alnico magnet: A permanent magnet alloy made mainly from aluminum, nickel, cobalt, and iron. Alnico tolerates high temperatures but generally has lower coercivity than rare-earth magnets.
Rare-earth element recycling: The recovery of rare-earth elements from discarded products and manufacturing scrap. Recycling can return valuable magnet materials to production and reduce primary demand.

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