Influence of hydrogen on the magnetic properties and electronic structures of intermetallic compounds: YFe sub 2 -D sub 2 system as an example

摘要

The magnetic and electronic properties of YFe sub 2 D sub x deuterides (1.2 <= x <= 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 from 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 structures to C15 cubic structure occurs below the Curie temperature and are therefore related to deuterium ordering. The analysis of the XAS spectra at the Fe-K edge shows a progressive filling of the 4p-3d band with increasing deuterium content. The evolution of the magnetic and electronic properties of the YFe sub 2 D sub x deuterides are discussed in relation with the evolution of the Fe-Fe distances in these compounds and band structure calculations.