Neodymium magnet on a bracket from a hard drive

A neodymium magnet or NIB magnet (also, but less specifically, called a rare-earth magnet) is a powerful magnet made of a combination of neodymium, iron, and boron — Nd₂Fe₁₄B. They have replaced marginally weaker and significantly more heat-resistant samarium-cobalt magnets in most applications, due mainly to their lower cost. These magnets are very strong in comparison to their mass, but are also mechanically fragile and the most powerful grades lose their magnetism at temperatures above 80 degrees Celsius. High-temperature grades will operate at up to 200 and even 230 °C but their strength is only marginally greater than that of samarium-cobalt. Neodymium magnets (or “neo” as they are known in the industry) are graded in strength from N24 to the strongest N54. The number after the N represents the magnetic energy product, in megagauss-oersteds (MGOe) (1 MG·Oe = 7,958 T·kA/m = 7,958 kJ/m³). 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 one requires about 18 times as much ceramic magnet material for the equivalent magnet strength. The neodymium magnet industry is continually working to push the maximum energy product (strength) closer to the theoretical maximum of 64 MGOe. Scientists are also working hard to improve the maximum operating temperature for any given strength. Download high resolution version (1211x591, 276 KB)Neodymium magnet on a bracket from a computer hard drive. ... Download high resolution version (1211x591, 276 KB)Neodymium magnet on a bracket from a computer hard drive. ... Typical hard drives of the mid-1990s. ... A rare-earth magnet is a special permanent magnet made out of the elements located in the lanthanides and actinides series of the periodic table. ... Iron filings in a magnetic field generated by a bar magnet A magnet is an object that has a magnetic field. ... General Name, Symbol, Number neodymium, Nd, 60 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white, yellowish tinge Atomic mass 144. ... General Name, Symbol, Number iron, Fe, 26 Chemical series transition metals Group, Period, Block 8, 4, d Appearance lustrous metallic with a grayish tinge Atomic mass 55. ... General Name, Symbol, Number boron, B, 5 Chemical series metalloids Group, Period, Block 13, 2, p Appearance black/brown Atomic mass 10. ... Samarium-cobalt magnets (SmCo5) are composed of samarium and cobalt. ... The Curie point is a term in physics and materials science, named after Pierre Curie (1859-1906), and refers to a characteristic property of a ferromagnetic material. ... Celsius is, or relates to, the Celsius temperature scale. ... The tesla (symbol T) is the SI derived unit of magnetic flux density (or magnetic induction). ... The oersted is old CGS unit of magnetic field strength (or magnetic induction). ... A multimeter can be used to measure current The ampere (symbol: A) is the SI base unit of electric current. ... Fixed Partial Denture, or Bridge The word ceramic is derived from the Greek word κεραμικός (keramikos). ...

A neodymium magnet lifting 1300 times its own mass

Used for stabilization and angular head motors in computer hard drives, neodymium 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 for students to see the effects of Lenz's Law in non-ferrous metals may be performed by dropping a strong neodymium 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. Neodymium magnets are used for the transducers in many headphones. Image File history File links Download high resolution version (400x1200, 144 KB)Three solid steel ball bearings (spheres) easily suspended by miniscule neodymium magnets. ... Image File history File links Download high resolution version (400x1200, 144 KB)Three solid steel ball bearings (spheres) easily suspended by miniscule neodymium magnets. ... Rotating magnetic field as a sum of magnetic vectors from 3 phase coils. ... Typical hard drives of the mid-1990s. ... This article or section does not cite its references or sources. ... Lenzs law (pronounced (IPA) ) was formulated by German physicist Heinrich Lenz in 1833 and gives the direction of the induced emf resulting from electromagnetic induction, thus: Definition The induced current produced in the conductor always flows in such a direction that the magnetic field it produces will oppose the... Earth (IPA: , often referred to as the Earth, Terra, the World or Planet Earth) is the third planet in the solar system in terms of distance from the Sun, and the fifth largest. ... Compass in a wooden box A compass (or mariners compass) is a navigational instrument for finding directions on the earth. ... A transducer is a device, usually electrical or electronic, that converts one type of energy to another. ... Headphones (also known as earphones, earbuds, stereophones, headsets, or by the slang term cans) are a pair of transducers that receive an electrical signal from a media player or receiver and use speakers placed in close proximity to the ears (hence the name earphone) to convert the signal into audible...

A toy containing dozens of NIB magnets

As NIB magnets produced in China have become less expensive in the last few years, the toy industry has used millions of them in magnetic building sets and other juvenile products including magnetic jewelry. Rose Art Industries of New Jersey, now owned by Mega Brands, Inc. of Montreal, Canada, manufactures a popular line of Magnetix and Magna Man toys containing neodymium magnets the size and shape of aspirin tablets. The small cylindrical magnets are used at the ends or corners of plastic pieces in order to allow connections of multiple pieces. The Magnetix brand was the subject of a March, 2006 recall notice by the Consumer Product Safety Commission as well as numerous consumer lawsuits due to product safety concerns. In defective kits the NIB magnets became dislodged from their plastic housing, and many children of varying ages consumed the small magnets. Image File history File links Magnetix_toy. ... Image File history File links Magnetix_toy. ... Official language(s) None, English de facto Capital Trenton Largest city Newark Area  Ranked 47th  - Total 8,729 sq mi (22,608 km²)  - Width 70 miles (110 km)  - Length 150 miles (240 km)  - % water 14. ... Downton from Mount Royal, winter Motto: Concordia Salus Coordinates: Country Canada Province Quebec Founded 1642 Established 1832 City Mayor Gérald Tremblay Area    - City 366. ... Magnetix toy with loose magnet Magnetix is a construction toy imported and sold by Rose Art Industries, Inc. ... Magnetix toy with loose magnet Magnetix is a construction toy imported and sold by Rose Art Industries, Inc. ... The Consumer Product Safety Commission (CPSC) is an independent agency of the U.S. federal government created in 1972 through the Consumer Safety Act to protect “against unreasonable risks of injuries associated with consumer products”. As of 2006 its acting chairman is Nancy Nord, a Republican. ...

Caution

Neodymium magnets should always be handled carefully. Some that are slightly larger than the size of a penny are powerful enough to lift over 10 kilograms. They are hazardous; able to interfere with pacemakers and implanted heart devices with deadly consequences [[1]]. An NIB's magnetic force increases with the size of the piece of ferromagnetic metal and larger neodymium magnets can severely pinch skin or fingers, or even break bones when suddenly attracted to a magnetic object. Operating a large neodymium magnet close to smaller magnetic objects (keys, pens, etc.) and larger magnetic surfaces (radiator or a car, for example) can be dangerous if the person is caught between the magnet and the magnetic object or surface. A variety of low value coins, including an Irish 2p piece and many U.S. pennies. ... Ferromagnetism is a phenomenon by which a material can exhibit a spontaneous magnetization, and is one of the strongest forms of magnetism. ...

On an episode of MythBusters, it was demonstrated that large neodymium magnets cannot pull a paper clip (or other small metal objects) through a hand. MythBusters is an American pop science television program on the Discovery Channel starring special effects experts Adam Savage and Jamie Hyneman, who use their skills and expertise to test the validity of various rumors and urban legends in popular culture. ...

Neodymium magnets are made with special powders and coatings, so they are very fragile. They are often plated with a metal such as nickel. The magnets can fracture at temperatures over 150 °C, or under impact as a result of their own acceleration. When this happens, in some cases the magnets may break apart so suddenly that flying pieces can cause injury. General Name, Symbol, Number nickel, Ni, 28 Chemical series transition metals Group, Period, Block 10, 4, d Appearance lustrous, metallic Atomic mass 58. ... A fracture is the separation of a body into two, or more, pieces under the action of stress. ... Fig. ...

Caution must be taken when using neodymium magnets. Even a small neodymium magnet is powerful enough to destroy the contents of a floppy disc to such an extent that the information is unrecoverable, a guarantee not present with techniques such as formatting the disk. It can also erase information contained on the magnetic stripes of credit cards, rendering them unreadable. Neodymium magnets are often strong enough to not only magnetize color CRT shadow masks, but also physically deform the mask itself. Such damage is typically irreparable by degaussing. A floppy disk is a data storage device that comprises a circular piece of thin, flexible (hence floppy) magnetic storage medium encased in a square or rectangular plastic wallet. ... Look up format in Wiktionary, the free dictionary. ... Credit cards A credit card system is a type of retail transaction settlement and credit system, named after the small plastic card issued to users of the system. ... It has been suggested that Crookes tube be merged into this article or section. ... The shadow mask is one of two major technologies used to manufacture cathode ray tube (CRT) televisions and computer displays that produce color images (the other is aperture grille). ... Degaussing is the process of reducing or eliminating an unwanted magnetic field. ...

See also

• Lanthanide series of rare-earth magnets LnFeB
• Transition metal substitutions like NdCoB