Magnetic properties and magnetic structures of RIrSi (R=Tb–Er) series of compounds

Abstract

Magnetic properties and magnetic structures of RIrSi (T=Tb, Dy, Ho, Er) series of ternary intermetallic were determined by X-ray and neutron diffraction and by magnetometric methods. All these compounds exhibit the orthorhombic TiNiSi-type crystal structure and are antiferromagnetic at low temperatures. Below the Néel point ( T N=32 K) TbIrSi shows a sine modulated magnetic order described by the wave vector k=[0, 02938(2), 0] with the Tb magnetic moments equal 8.96(16) μ B and parallel to the c-axis at 1.5 K. The collinear antiferromagnetic structure with the wave vector k=[1/2, 0, 1/2] and the magnetic moment of 9.9(1) μ B parallel to the b-axis is observed in HoIrSi at 1.5 K. In the vicinity of the Néel temperature ( T N=4.6 K) this structure coexists with the sine modulated order described by the wave vector k=[0.215(2), 0, 0.458(2)]. DyIrSi is antiferromagnetic below the Néel temperature ( T N=7 K). Below the Néel temperature ( T N=3.8 K), ErIrSi has a sine modulated magnetic structure described by the wave vector k=[0, 0.184(1), 0.297(3)] and the magnetic moment of 6.5(2) μ B is aligned in the (100) plane at 1.5 K.