Lattice strain measurements of deuteride (hydride) formation in epitaxial Nb: Additional results and further insights into past measurements

Abstract

The evolution of lattice strain during in situ gas-phase deuterium loading of epitaxial ͑110͒ Nb films on the ͑1120͒ sapphire was measured with x-ray diffraction. Two samples with film thicknesses 208 and 1102 Å were driven through the miscibility gap. Strains in three orthogonal directions were recorded, permitting the complete set of unit cell parameters to be determined for both the solid solution and deuteride phases. The overall film thickness was simultaneously measured by recording the glancing angle reflectivity response. The behavior of the two films was markedly different, with the thicker film exhibiting a much more compliant behavior and concomitant irreversible plastic deformation. The correlation between out-of-plane lattice and film expansion for both films is also consistent with this observation. These results help explain past inconsistencies observed by others.

Characterization of poly- and single-crystal uranium–molybdenum alloy thin films

“…A significant portion of the U-Mo film maintains a high degree of coherency, leading to a narrow rocking curve component (FWHM  10 -3 deg. for a true epitaxial thin film), while the balance of the film becomes incommensurate, resulting in a broad rocking curve component [27]. For x = 0.10 only one broad rocking curve component (FWHM  3.0 deg.)…”

Crossover from dirty to clean superconducting limit in dc magnetron-sputtered thin Nb films

“…The correlation between the structural and superconducting properties in thin films of Nb represents a widely studied problem [3][4][5][6][7][8][9][10][11][12][13][14][15]. In particular, the influence of the lattice parameter a, grain size D, and surface roughness Δd on the critical temperature T c and the normal-state resistivity ρ n has been a matter of thorough experimental investigations on nano-granular disordered [7][8][9], high-purity [10], and dirty [11] Nb films.…”

“…In particular, the influence of the lattice parameter a, grain size D, and surface roughness Δd on the critical temperature T c and the normal-state resistivity ρ n has been a matter of thorough experimental investigations on nano-granular disordered [7][8][9], high-purity [10], and dirty [11] Nb films. Different growth techniques have been used in these works [3][4][5][6][7][8][9][10][11][12][13][14][15]. For the growth of high-purity thin Nb films revealing outstanding structural quality, the molecular beam epitaxy (MBE) method has been shown to be the most efficient as compared to others [12][13][14], see also [15] for a topical review.…”

“…Different growth techniques have been used in these works [3][4][5][6][7][8][9][10][11][12][13][14][15]. For the growth of high-purity thin Nb films revealing outstanding structural quality, the molecular beam epitaxy (MBE) method has been shown to be the most efficient as compared to others [12][13][14], see also [15] for a topical review. At the same time, much less attention has been paid to optimize the growth conditions with emphasis on the tunability of the normal-state and superconducting properties of the films prepared by means of sputter deposition, in particular, by dc magnetron sputtering.…”

Abnormal Hydrogen Absorption/Desorption Properties of Nanoporous Pt with Large Lattice Strains

“…13,14) On the other hand, lattice strain effect on hydrogenation on Pd nanoparticles 15) and epitaxial Nb films 16) has been pointed by Langhammer et al 15) and Allain and Heuser 16) respectively, although the present abnormal PCT (Fig. 4) has not been reported so far.…”