Crystal and magnetic structures of the R(=Y, Dy–Tm)MnGe compounds

摘要: Abstract Powder and single-crystal X-ray diffraction, susceptibility measurements powder neutron diffraction studies on RMnGe compounds (R=Dy–Tm, Y) are reported. The R(=Dy–Er, Y)MnGe crystallize in the TiNiSi-type (S.G. Pnma) while two polytypic forms (H.T.-ZrNiAl L.T.-TiNiSi) characterize TmMnGe compound. All exhibit antiferromagnetic ordering of Mn sublattice above room temperature, R orders antiferromagnetically at 85 (5), 70 60 (5) 30 (5) K for R=Dy, Ho, Er Tm, respectively. At 2 K, DyMnGe is characterized by a cycloid structure ( q x ∼0.227) whereas HoMnGe exhibits conical ∼0.259). YMnGe, ErMnGe simple collinear antiferromagnets, spin-reorientation process occurs below 25 (2) K. values magnetic moments are: μ =3.37(14)  B , Dy =8.87(13)  ; =3.35(9)  Ho =8.03(12)  =3.25(18)  =7.51(39)  =3.19(12)  Tm =6.40(11)  =3.51(15)  DyMnGe, HoMnGe, ErMnGe, In all cases, structures [0 1 0] chains. results discussed terms R–R, R–Mn, Mn–Mn interactions anisotropy effects.