Structural and magnetic properties of some AB₂H_x hydrides (A = Gd; B = Ru)

We report ¹⁵⁵Gd Mössbauer studies and magnetization measurements of the hydrides GdRh₂H_x (x = 3, 2, 1.3, 0) and GdRu₂H_x (x = 3, 1, 0). The Mössbauer spectra can be interpreted as the sum of two spectra, one corresponding to the β-phase hydride and the other to the hydrogen free compound; the relative intensities of the two subspectra depend on x. Our measurements confirm the phase diagram recently found for these hydrides by Jacob and Shaltiel. The Mössbauer data yield information on the isomer shift, the Gd hyperfine field and the electric field gradients.