Magnetic structures of R3Cu4Si4 (R=Dy, Ho and Er)

Abstract

Polycrystalline samples of R3Cu4Si4 (R=Dy, Ho, Er) intermetallics were studied with neutron diffraction methods. All of them crystallize in the orthorhombic structure of Gd3Cu4Ge4-type and order antiferromagnetically at low temperatures. Magnetic moments localized at the rare earth atoms, that occupy two non-equivalent 2d and 4e sublattices, order simultaneously in Dy3Cu4Si4. The order is described by the propagation vector k=(0,12,0) accompanied by k=(0,12+δ,12+δ), δ=0.025(2). In Ho3Cu4Si4 two propagation vectors are needed to model the magnetic order. These are: k=(12,0.316(2),12) for the 4e sublattice, which disorders as the first when the temperature increases, and k=(0,12,0) for the 2d sublattice. A similar situation is observed for Er3Cu4Si4 where the propagation vectors are: k=(0,1−δ,0), δ=0.097(2) for the 4e sublattice, which disorders as the first with increasing temperature, and k=(0,12+δ,0), δ=0.0015(6) for the 2d sublattice.