Magnetic properties and magnetic structures of the CeScSi-type RMgPb (R=Ce–Nd, Sm, Gd–Tm) compounds

P. Lemoine (1) , A. Vernière (1) , G. Venturini (1) , J.F. Marêché (1) , S. Capelli (2) , B. Malaman (1)

1 IJL - Institut Jean Lamour
2 ILL - Institut Laue-Langevin

Investigations made by powder X-ray diffraction, magnetic measurements and neutron powder diffraction on the CeScSi-type ternary magnesium plumbides RMgPb (R=Ce–Nd, Sm, Gd–Tm) are reported. Macroscopic magnetic measurements performed in the 2–300 K temperature range show that these compounds follow a Curie–Weiss law in the paramagnetic state (except SmMgPb) and behave antiferromagnetically at low temperature (TΝ≤61 K). Field dependence of the magnetization performed at 5 K evidence metamagnetic-like behaviors (Hcrit<7 T). Neutron powder diffraction evidenced complex antiferromagnetic structures in fair agreement with the magnetic data. PrMgPb and NdMgPb compounds present a commensurate antiferromagnetic structure, while (Tb–Er)MgPb are characterized by incommensurate sine-wave modulated magnetic structure down to lower temperature or square-wave magnetic structure due to appearance of higher odd integer harmonics. CeMgPb and TmMgPb evidence more complex sine-wave modulated magnetic structures, never encountered with the CeScSi-type structure, characterized by two propagation vectors. These results are discussed and compared with those of the isotypic RMgSn compounds.

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Cristallographie; Matériaux; Chimie inorganique

P. Lemoine, A. Vernière, G. Venturini, J.F. Marêché, S. Capelli, et al.. Magnetic properties and magnetic structures of the CeScSi-type RMgPb (R=Ce–Nd, Sm, Gd–Tm) compounds. Journal of Magnetism and Magnetic Materials, 2012, 324 (19), pp.2937-2952. ⟨10.1016/j.jmmm.2012.03.037⟩. ⟨hal-02356163⟩