Investigation of the Fe Binding Properties inZr(Al_xfe_{1 - x})₂ by Nuclear Resonant Photon Scattering

A study of the iron binding properties in the Zr(Al_xFe_1−x)₂ system, x = 0, 0.083, 0.2, is made by utilizing the nuclear resonant photon scattering (NRPS) of 8.512 MeV γ rays from 56Fe. Large samples of Zr(Al_xFe_1−x)₂ compounds, about 200 g each, were introduced into the photon beam emitted by a Cr(n,γ) source. The scattered 8.512 MeV γ radiation was detected by a large, 130 cm₃ HPGe detector. An experimental set-up was designed to enable a direct comparison of the scattered intensities, thus obviating complicated self-absorption and geometrical corrections. A substitution of small amounts of Fe in ZrFe₂ by Al, x = 0.083, 0.2 was found to cause a reduction of the resonantly scattered intensity. This result indicates a softening of the Fe bonding strength in the corresponding compounds. Since such a substitution is also known to cause a large increase in the hydrogen absorption capacity, our results seem to conform with a prediction of the rule of reverse capacity.