Crystal and magnetic structure of NiMnGe

Abstract

NiMnGe is investigated by means of X-ray diffraction, neutron diffraction, and magnetometric methods. The orthorhombic distorsion of hexagonal lattice is observed below 470 K. The compound NiMnGe is antiferromagnetic with a Néel temperature TN = 346 K. The jump observed at temperature Tt = 185 K on the temperature dependence of magnetic susceptibility points at the change of a magnetic structure. From the analysis of the neutron diffraction patterns the following models of spiral magnetic structure are obtained; at T < Tt the spiral axis is in the bc-plane. The angle between the spiral axis and the b-axis is 45°, magnetic moment at 80 K is 2.75μB; at Tt < T < TN the spiral axis is along the a-axis. The magnetic moment at 295 K is 2.2μB. [Russian Text Ignored].