Antiferromagnetism of Dilute Cr Alloys with Co and Ni

Abstract

The magnetic properties of single crystals of Cr alloys containing a small amount of Co and Ni have been studied by neutron diffraction and thermal expansion. The alloy with less than 1 at%Co has the same magnetic structure as that of pure Cr. With increasing Co concentration, the Néel temperature decreases, and the wave vector of the S.D.W. increases, while the magnetic moment remains constant. For 2 at%Co–Cr, the commensurable antiferromagnetic structure becomes stable. The Néel temperature slightly increases and the magnetic moment still remains constant. With the further increase of Co concentration, the antiferromagnetic structure tends to be destroyed by Co–Co pairs. The alloys with Ni have been found to show the magnetic behavior as the alloys with impurities which decrease the electron to atom ratio. All of wave vector, Néel temperature and magnetic moment decrease with an increase of Ni concentration.