Nuclear magnetic resonance study of the low-temperature localized H(D) motion in {alpha}-ScH{sub x}(D{sub x}): Isotope effects
- Department of Physics, Washington University, St. Louis, Missouri 63130-4899 (United States)
- Ames Laboratory, and Department of Physics, Iowa State University, Ames, Iowa 50011 (United States)
- Institute of Metal Physics, Urals Branch of the Academy of Sciences, Ekaterinburg 620219 (Russia)
Nuclear magnetic resonance measurements of the {sup 45}Sc, {sup 1}H, and {sup 2}D spin-lattice relaxation rates in the solid solutions {alpha}-ScH{sub x} (x=0, 0.11, and 0.27) and {alpha}-ScD{sub x} (x=0.05 and 0.22) have been performed over the temperature range 4.2{endash}294 K. For the hydrided and deuterided samples we have found pronounced deviations of the {sup 45}Sc relaxation rate measured at 86.2 MHz from the Korringa behavior in the range 30{endash}180 K. The excess {sup 45}Sc relaxation rate displays a peak near 100 K in {alpha}-ScH{sub x} and near 110{endash}140 K in {alpha}-ScD{sub x}, resulting from the quadrupole interaction modulated by fast localized hopping of H(D) atoms. The amplitude of the {sup 45}Sc relaxation rate peak in the deuterided samples is found to be much higher than in the hydrided samples with comparable hydrogen content. This unusual isotope effect indicates that the fraction of D atoms participating in the fast localized motion in {alpha}-ScD{sub x} is approximately six times as large as the corresponding fraction of H atoms in {alpha}-ScH{sub x}. The results of our measurements of the {sup 1}H and {sup 2}D relaxation rates are consistent with this conclusion. The strong effect of H{leftrightarrow}D substitution on the fraction of atoms involved in the localized hopping should be accounted for in any microscopic model of hydrogen motion in Sc. {copyright} {ital 1999} {ital The American Physical Society}
- OSTI ID:
- 351890
- Journal Information:
- Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 2 Vol. 60; ISSN PRBMDO; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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