Incommensurate spin density waves in iron aluminides.

Neutron diffraction in Fe(Al) reveals incommensurate spin density waves (SDWs) in alloys known to be spin glasses. The wave vectors for crystals of Fe(34Al), Fe(40Al), and Fe(43Al) show n varying from 11 to 6 for q-->=2pi(h+/-1/n,k+/-1/n,l+/-1/n)/a(0), where (h,k,l) and a(0) characterize the parent bcc lattice of the CsCl structure. The magnetic reflections are present far above the spin-glass freezing temperatures.