The influence of hydrogen on the magnetic properties and electronic structures of intermetallic compounds: YFe2-D-2 system as an example

The magnetic and electronic properties of YFe2Dx deuterides (1.2 less than or equal to x less than or equal to 4.2) have been studied by bulk magnetic measurements and X ray absorption spectroscopy (XAS). The magnetic moment increases with deuterium content whereas the Curie temperature increases fr om 560 K (x=0) to 720 K (x=1.2) then decreases almost linearly down to 300 K (x=4.2). For x=1.2, 1.75 and 1.9, structural transitions from distorted s tructures to C15 cubic structure occurs below the Curie temperature and are therefore related to deuterium ordering. The analysis of the XAS spectra a t the Fe-K edge shows a progressive filling of the 4p-3d band with increasi ng deuterium content. The evolution of the magnetic and electronic properti es of the YFe2Dx deoterides are discussed in relation with the evolution of the Fe-Fe distances in these compounds and band structure calculations. (C ) 1999 Elsevier Science S.A. All rights reserved.