Magnetic properties and magnetic structures of RPtGe 2 and RIrGe 2 ( R=Gd–Er) compounds

Abstract

Magnetic properties and magnetic structures of RTGe 2 ( R=Gd–Er, T=Pt, Ir) series of ternary intermetallic compounds were determined by X-ray and neutron diffraction and by magnetometric methods. All these compounds exhibit the orthorhombic YIrGe 2-type crystal structure and except ErIrGe 2, are antiferromagnetic at low temperatures. The rare earth atoms occupy the 4(i) and 4(h) sites. In the case of TbPtGe 2, TbIrGe 2 and HoIrGe 2 only the magnetic moments at the 4(i) site order below the Néel temperature (with the simple propagation vector k=0). At low temperatures the Tb and Ho moments at the 4(h) site order with different propagation vectors. In the DyPtGe 2 compound, the Dy magnetic moments at both crystallographic sites order in a collinear antiferromagnetic structure below the Néel temperatures. For ErPtGe 2 in the temperature range between 1.5 K and T N=2.8 K, only the Er magnetic moments at the 4(i) site are ordered.