LFe6Sn4Ge2 (L=Dy, Ho, Er) studied by neutron diffraction and Mössbauer spectroscopy

Abstract The compounds LFe6Sn4Ge2 (L = Dy, Ho, Er) have been studied by neutron diffraction and 119Sn Mossbauer spectroscopy. At room temperature the magnetic structure consists of ferromagnetic Fe (0 0 1) planes which are coupled antiferromagnetically along the stacking direction, with the moments aligned along the hexagonal c axis. The lanthanoid sublattice orders around Tt = 21 and 11 K for the Dy and Ho compounds respectively. The erbium moment is not ordered at 1.7 K. Below Tt, LFe6Sn4Ge2 (L = Dy, Ho) display a helimagnetic structure with propagation vectors of (0, 0, 0.1262) and (0, 0, 0.1559) respectively. Ordering of the Dy and Ho moments causes a small distorsion of the high temperature AF structure of the iron sublattice and the development of a weak helimagnetic component (0.33 and 0.27 μB respectively). The orientation of the iron component with respect to the L moments suggests that the main magnetic interaction between the two sublattice takes place between the L plane and the next nearest Fe planes.