engleski

The effect of absorbed hydrogen on the chemical short-range order in Zr_68Fe_32 metallic glass

Electrical resistivity and x-ray diffraction measurements have been made on the hydrogen-doped (Zr68Fe32)1-xHx metallic glass. We find that the relationship between /(273 K) and the hydrogen concentration of the sample is linear for n(H)/n(Zr68Fe32) < 0.13 then saturates at /(Zr68Fe32)  0.35, for 0.28<n(H)/n(Zr68Fe32)<0.48 whereas for larger hydrogen content /(Zr68Fe32) increases. The position of the first and second broad maximum diffraction halo in XRD spectra of (Zr68Fe32)1-xHx metallic glasses is shifted to smaller values of 2 with increasing hydrogen concentration. Thus, the nearest-neighbour distance increases from r=(0.2460.001) nm in Zr68Fe32 to r=(0.2550.001) nm in (Zr68Fe32)0.60H0.40. These values correspond to the Zr-Fe nearest-neighbour distance. In the paramagnetic Zr68Fe32 system the hydrogen produces a pronounced positive anomaly in the electrical resistivity below about 50 K leading to a maximum in (T) before the curve resumes a monotonic decrease with increasing temperature. This is attributed to the increase of the screening parameter for the Coulomb interaction F* associated with the enhancement of the spin fluctuations with hydrogen concentration.

disordered systems; electronic transport; metals; quantum loclization

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