Magnetic properties of RIrGe (R=Gd–Er) compounds from neutron diffraction and magnetic measurements

Abstract Polycrystalline samples of the ternary intermetallics RIrGe (R=Tb,Ho,Er) were investigated by means of magnetization, X-ray and neutron diffraction measurements. For GdIrGe and DyIrGe only magnetic and X-ray diffraction measurements were performed. They crystallize in the orthorhombic TiNiSi-type structure. Magnetic measurements show antiferromagnetic ordering with Neel temperatures of 24 K for R=Gd and Tb, 15 K for R=Dy and 6.5 K for R=Er. HoIrGe is paramagnetic down to 1.5 K. Neutron diffraction data for TbIrGe indicate sine modulated magnetic ordering with the propagation vector k =(0,0.4093(2),0) and the magnetic moment parallel to the c -axis. In HoIrGe, no magnetic ordering is observed down to 1.5 K, while in ErIrGe a sine modulated structure with the moment parallel to the a -axis is observed below T N . Below T t =2.9 K the coexistence two phases collinear and sine modulated is observed.