Magnetic structures of R 3Cu 4Sn 4 (R=Tb–Er)

Abstract

Neutron powder diffraction studies of the R 3Cu 4Sn 4 (R=Tb, Dy, Ho, Er) intermetallic compounds with the orthorhombic Gd 3Cu 4Ge 4-type crystal structure indicate the existence of different magnetic structures. Rare earth atoms occupy two nonequivalent 2d and 4e sublattices. For R=Tb and Dy the magnetic structures below the Néel temperatures equal to 17.5 and 15 K, respectively, are described by the propagation vectors k =(0,0, 1 2 +δ). In these compounds both rare earth sublattices order and do not change up to the Néel temperatures. 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 it is accompanied with the propagation vector k =(0,0,δ) describing the ordering in the 4e sublattice.