Influence of hydrogenation and mechanical grinding on the structural and ferromagnetic properties of GdFeSi

Bernard Chevalier (1) , Mathieu Duttine (1) , Alain Wattiaux (1)

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

Hydrogen insertion into GdFeSi induces (i) a structural transition from a tetragonal CeFeSi-type to a tetragonal ZrCuSiAs-type, (ii) an anisotropic expansion of the unit cell parameters because the a parameter decreases, whereas the c parameter increases, and (iii) a decrease in Curie temperature from 121 to 20 K. On the contrary, an amorphous ferromagnet (TC = 65 K) is obtained by mechanical grinding of GdFeSi. The three compounds (GdFeSi, GdFeSiH, and amorphous GdFeSi) were investigated by 57Fe Mössbauer spectroscopy. At 4.2 K, this study has revealed that the magnetically ordered Gd substructure produces a small transferred hyperfine magnetic field at the 57Fe nucleus.

Mots clés: hydrogenation; magnetization; mechanical grinding; Mössbauer spectroscopy

Domaines: Matériaux

Bernard Chevalier, Mathieu Duttine, Alain Wattiaux. Influence of hydrogenation and mechanical grinding on the structural and ferromagnetic properties of GdFeSi. Zeitschrift fur Naturforschung B, 2016, 71 (5), pp.419-424. ⟨10.1515/znb-2015-0225⟩. ⟨hal-01321186⟩