1 research outputs found
Hydrogen site occupancy and strength of forces in nano-sized metal hydrides
The dipole force components in nano-sized 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 Fe_0.5V_0.5/V superlattice, the hydrogen unequivocally occupies octahedral
z-like sites, even at and below concentrations of 0.02 [H/V]