spin-density wave

spin-density wave [′spin ¦den·səd·ē ′wāv]

(solid-state physics)

The ground state of a metal in which the conduction-electron spin density has a sinusoidal variation in space.

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Spin-density wave

The ground state of a metal in which the conduction-electron-spin density has a sinusoidal variation in space, with a wavelength usually incommensurate with the crystal structure. This antiferromagnetic state normally occurs in metals, alloys, and compounds with a transition-metal component. It occurs also, however, in quasi-one-dimensional organic conductors. See Antiferromagnetism, Crystal structure, Electron spin

There are well over 100 materials which, over a temperature range, support a spin-density wave. These include some of the rare-earth elements of the lanthanide series and the 3d transition metals, manganese and chromium, the latter being the prototypical itinerant electron antiferromagnet. The occurrence of inelastic neutron-scattering peaks at incommensurate points indicates the existence of spin-density-wave fluctuations in some metals thought to be nonmagnetic (for example, copper and yttrium) when doped with magnetic impurities (manganese and gadolinium, respectively). This behavior suggests that the spin-density-wave instability may be common, even in nontransition metals.