Magnetic Structures in the MnSb-CrSb System

Abstract

A magnetic and neutron diffraction investigation has been made on MnSb, CrSb, and their solid solutions, which crystallize in the hexagonal NiAs-type structure. MnSb is ferromagnetic and CrSb antiferromagnetic. As CrSb is substituted into MnSb, a canted spin structure is formed, the spins lying within ferromagnetic (001) sheets with the spins in adjacent sheets alternating in direction. The angle of cant increases with increasing Cr content in agreement with the model of de Gennes who considered the effects of double exchange on an antiferromagnetic system. The magnetic structure of CrSb consists of ferromagnetic (001) planes which are coupled antiferromagnetically. The spin axis is parallel to $c$. Between this structure and the canted spin structure with the spins perpendicular to $c$ is an intermediate region. This antiferromagnetic region has either a tilted spin axis structure or two coexisting structures. MnSb was found to have a change in the spin direction from a perpendicular to a parallel orientation with respect to $c$ as the temperature was increased. The temperature of the spin flip was found to depend on the preparative conditions as did the Curie temperature and saturation moment.