Magnetic ordering of R₃Cu₄Sn₄(R   Tb, Dy, Ho and Er)

Abstract

Neutron diffraction studies of polycrystalline R3Cu4Sn4 (R = Tb, Dy, Ho, Er) intermetallic compounds with the orthorhombic Gd3Cu4Ge4-type crystal structure indicate the existence of different magnetic structures. Rare earth atoms occupy two non-equivalent 2d and 4e sublattices. The rare earth magnetic moments order at low temperatures. For R = Tb and Dy the magnetic structures below the Néel temperature are described by the propagation vectors k = (0, 0, 1/2 + δ). In these compounds both rare earth sublattices order. For R = Ho the magnetic structure is more complicated. There are two vectors; one of them is k = (0, 1/2, 0) whereas the second one changes with temperature. For the Er compound there is the propagation vector k = (1/2, 1/2, 0) which describes the magnetic ordering in the 2d sublattice and at low temperatures is accompanied by the propagation vector k = (0, 0,δ) describing the ordering in the 4e sublattice.