Rare-earth-iron-boron magnets

Rare-earth iron boron nanocomposite magnets... 

An effective strategy of modifying the magnetic properties of iron-rich rare-earth intermetallics is to incorporate small interstitial atoms into the crystal lattice. Besides hydrogen, only boron, carbon, and nitrogen atoms are small enough to enter the structure in this way, and they preferentially occupy interstitial sites surrounded by the largest number of rare-earth atoms. For example, in... 

Capellen, J., K.A. Menzel and K.A. Gschneidner Jr, 1986, Source Book on Neodymium-Iron-Boron Permanent Magnets, IS-RIC-9 (Rare-earth Information Center, Iowa State University, Ames, lA). 

The intermetallic compound SmCo, with markedly ferromagnetic properties, was invented in the 1970s. Rare earth metals are nowadays very much used in magnetic alloys, for instance samarium-quartz watches and other miniaturized systems. Still better is the compound Sm COj with a certain content also of iron, copper and zirconium. For heavier magnets, alloys of neodymium, iron and boron are used. 

Boron has an increasing use in high technology in connection with the introduction of the iron-boron-neodymium magnet. This has been treated in the neodymium section in Chapter 17 Rare Earth Metals. 

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