Neodymium magnet

A neodymium magnet (also, but less specifically, called a rare-earth magnet) is a powerful magnet made of a combination of neodymium, iron, and boron — Nd2Fe14B. These magnets are very strong in comparison to their mass, but are also mechanically fragile and lose their magnetism at temperatures above 80 degrees Celsius. They have replaced marginally weaker and significantly more heat-resistant samarium-cobalt magnets in most applications, due mainly to their lower cost. They are graded in strength from N24 to the strongest N52. The number after the N represents the magnetic energy product, in megagauss-oersteds (MGOe) (1 MG·Oe = 7,957 T·A/m = 7,957 J/m³) .

Related Topics:
Rare-earth magnet - Magnet - Neodymium - Iron - Boron - Lose their magnetism - Celsius - Samarium-cobalt magnet

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There is constantly work to increase the power until a limit of about N60 will be reached. N48 has a remnant static magnetic field of 1.38 teslas and an H (magnetic field intensity) of 13,000 oersteds (1.0 MA/m). By volume it requires about 18 times as much Ceramic8 magnet material for the equivalent magnet strength.

Related Topics:
Tesla - Oersted - MA

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Used for stabilization and angular head motors in computer hard drives, Nd2Fe14B magnets are also popular with hobbyists, and a small magnet can have amazing properties — it exhibits magnetic braking when moved near a non-magnetic metal due to induced eddy currents. An excellent demonstration to students of the eddy currents created in non-ferrous metals may be performed by dropping a strong Nd magnet through a copper pipe. The magnet will travel through the pipe remarkably slowly as it falls, the effect may be greatly enhanced by immersing the pipe in liquid nitrogen (thus increasing its conductivity even further) prior to dropping the magnet through. A somewhat larger magnet interacts strongly enough with the magnetic field of the Earth to allow its tendency to align with that field to be perceived directly when holding it, essentially forming a compass. Cylinder- and disc-shaped neodymium magnets are especially responsive to the Earth's magnetic fields.

Related Topics:
Motor - Hard drive - Eddy current - Earth - Compass

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