Magnetic Structure of Chromium Selenide

Abstract

The magnetic structure of the NiAs-type compound, CrSe, has been determined by means of neutron diffraction. The indexing of superstructure lines which appear below the N\'eel point requires a unit cell three times as large as the conventional unit ($a=\sqrt{3}{a}_{\mathrm{NiAs}}$). Planes parallel to the basal plane contain three chromium atoms whose spins form an "umbrella"-like array with threefold symmetry. Individual moments alternate in sign along lines parallel to the $c$ axis. A value of 2.90 \ensuremath{\mu}b has been deduced for the component of the chromium moment perpendicular to the $c$ axis.