Structure, magnetic and electrical properties of CeIrSb and its hydride CeIrSbH_0.8

Etienne Gaudin (1) , Bernard Chevalier (1) , Wilfried Hermes (2) , Ute Ch. Rodewald (2) , Rainer Pöttgen (2)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
2 Institut für Anorganische und Analytische Chemie

The ternary antimonide CeIrSb absorbs hydrogen under moderate temperature and pressure conditions (4 MPa and 573 K), leading to the hydride CeIrSbH_0.8. The crystal structures of both compounds have been investigated by X-ray diffraction on powders and single crystals: TiNiSi type, space group Pnma, a=735.07(7), b=456.93(4), c=792.8(1) pm, R1/wR2=0.0206/0.0395, 601 F² values for CeIrSb and a=728.16(14), b=460.35(6), c=825.87(2) pm, R1/wR2=0.0322/0.0735, 528 F² values for CeIrSbH_0.8 with 20 variables per refinement. Hydrogenation induces both an increase of the cell volume V (+4%) and a strongly anisotropic expansion of the unit cell with a maximum of 4.3% in the c direction, leading to a significant increase of the Ce–Ir and Ce–Ce distances in this direction. The H-insertion into CeIrSb leads to a magnetic transition from intermediate valence to antiferromagnetic behavior (T_N=7.0 K) evidenced by magnetization, electrical resistivity and specific heat measurements. This transition can be explained on the basis of the Doniach diagram considering the J_cf interaction between the 4f(Ce) and conduction electrons.

Keywords: Intermetallic compounds; Crystal chemistry; CeIrSb; Kondo system; Metal hydrides

Domains: Material chemistry

Etienne Gaudin, Bernard Chevalier, Wilfried Hermes, Ute Ch. Rodewald, Rainer Pöttgen. Structure, magnetic and electrical properties of CeIrSb and its hydride CeIrSbH_0.8. Journal of Solid State Chemistry, 2009, 182 (7), pp.1827-1832. ⟨10.1016/j.jssc.2009.04.031⟩. ⟨hal-00406973⟩