Structure and magnetic properties of the ternary gallides CeMGa (M=Mn, Co and Cu) and their hydrides

Bernard Chevalier (1) , Jean-Louis Bobet (1) , Mathieu Pasturel (1) , Etienne Gaudin (1) , Jean Etourneau (1)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

The ternary gallides CeMGa present various structural properties since CeMnGa, CeCoGa and CeCuGa crystallize, respectively, in the cubic MgCu2-, monoclinic CeCoAl-, and orthorhombic CeCu2-type structure. These compounds absorb hydrogen at room temperature but hydrogenation induces a change of the crystalline structure: (i) CeCoGaH3.0 and CeCuGaH0.8 adopt the hexagonal AlB2-type; (ii) on the contrary, the cubic MgCu2 structure is preserved for CeMnGaH1.6. Moreover, in some cases hydrogenation leads to a valence change for Ce. For instance, CeCoGa is considered as intermediate valence compound, whereas CeCoGaH3.0 contains Ce3+. This paper demonstrates that hydrogenation strongly influences the Kondo effect in these intermetallics.

Mots clés: Cerium compounds; X-ray diffraction; Intermediate valence; Hydrogenation; Magnetism

Domaines: Matériaux

Bernard Chevalier, Jean-Louis Bobet, Mathieu Pasturel, Etienne Gaudin, Jean Etourneau. Structure and magnetic properties of the ternary gallides CeMGa (M=Mn, Co and Cu) and their hydrides. Journal of Alloys and Compounds, 2003, 356-357, pp.147-150. ⟨10.1016/S0925-8388(02)01223-9⟩. ⟨hal-00187777⟩