title: Drastic change of the ferromagnetic properties of the ternary germanide GdTiGe through hydrogen insertion.
abstract: Hydrogen absorption of the CeFeSi- and CeScSi-type forms of GdTiGe was performed. Before hydrogenation they show an antiferromagnetic transition at around 412 K and a ferromagnetic transition at 376 K, respectively. Hydrogenation of both forms leads to formation of the same hydride GdTiGeH which crystallizes with a filled CeScSi-type structure where all the [Gd(4)] tetrahedra are filled by hydrogen. This hydride is paramagnetic in the temperature range 4-300 K. The slightly negative value of the paramagnetic Curie temperature θ(p) confirms that all ferromagnetic interactions were destroyed in the case of the CeScSi-type form. From first-principles calculations with the PAW GGA methodology, the localization of hydrogen within the [Gd(4)] tetrahedra was confirmed through energetic stabilization. It was also seen that the energy changes significantly with volume, indicating the itinerant (delocalized) role of the electrons in the magnetism.
authors: CNRS, Université de Bordeaux, ICMCB, 87 Avenue du Docteur Albert Schweitzer, 33608 Pessac Cedex, France. gaudin@icmcb-bordeaux.cnrs.fr
authors: Etienne
authors: E
authors: Gaudin
authors: Samir F
authors: SF
authors: Matar
authors: Rainer
authors: R
authors: Pöttgen
authors: Matthias
authors: M
authors: Eul
authors: Bernard
authors: B
authors: Chevalier