title: Hydrogenation inducing ferromagnetism in the ternary antiferromagnet NdCoSi.
abstract: The hydride NdCoSiH obtained by exposure at 523 K of the ternary antiferromagnet NdCoSi under a pressure of 4 MPa of hydrogen crystallizes in the tetragonal ZrCuSiAs-type structure where H atoms occupy the tetrahedral [Nd(4)] site. The hydrogenation induces an increase in the unit cell volume close to 6%. The investigation of NdCoSiH by magnetization measurements reveals its ferromagnetic behavior below T(C) = 20.5(5) K. Neutron powder diffraction shows that the T(C) temperature is associated with a ferromagnetic arrangement of the Nd moments (2.3(2) mu(B) at 1.5 K) parallel to the c axis as observed for NdFeSi. The magnetic properties, magnetic structure, and the value of the Nd ordered magnetic moment evidenced for NdCoSiH are discussed using both band structure calculations and a comparison with the behavior of NdCoSi and NdFeSi.
authors.affiliation: CNRS, Université de Bordeaux, ICMCB, 87 avenue du Docteur Albert Schweitzer, 33608 Pessac Cedex, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Tencé
authors.forename: Samir F
authors.initials: SF
authors.lastname: Matar
authors.forename: Gilles
authors.initials: G
authors.lastname: André
authors.forename: Etienne
authors.initials: E
authors.lastname: Gaudin
authors.forename: Bernard
authors.initials: B
authors.lastname: Chevalier