Hydrogen site occupancy and strength of forces in nanosized metal hydrides

• The dipole force components in nanosized metal hydrides are quantitatively determined with curvature and x-ray diffraction measurements. Ab initio density functional theory is used to calculate the dipole components and the symmetry of the strain field. The hydrogen occupancy in a 100-nm-thick V film is shown to be tetrahedral with a slight asymmetry at low concentration, and a transition to octahedral occupancy is shown to take place at around 0.07 [H/V] at 360 K. When the thickness of the V layer is reduced to 3 nm and biaxially strained, in a Fe0.5V0.5/V superlattice, the hydrogen unequivocally occupies octahedral z-like sites, even at and below concentrations of 0.02 [H/V].

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NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

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