Evidence for independent motional processes on the two interstitial sublattices of a layer-structured metal hydride: hydrogen spin-lattice relaxation and motional narrowing in zirconium monohalide hemihydrides, ZrXH/sub 0. 5/
We report the results of a proton-magnetic-resonance investigation of hydrogen location and motion in the hemihydrides ZrXH/sub 0.5/ of the metallic layer-structured monohalides ZrX of zirconium (X = Br,Cl). Wide-line and pulsed NMR methods were employed to measure the temperature dependence of the linewidth and second moment and of the spin-lattice relaxation time in the laboratory and rotating frames. The results indicate that hydrogen forms an ordered structure on the tetrahedral (T) interstitial sublattice within the Zr metal bilayers, with some (small) random occupancy of octahedral (O) sites. Two stages of motional narrowing observed in the wide-line measurements and double minima found in the relaxation times are consistent with the occurrence of essentially independent hydrogen motional processes on the T and O interstitial sublattices. Hydrogen site occupancy probabilities, jump frequencies, activation energies for hydrogen diffusion, and conduction-electron contributions to the proton spin-lattice relaxation rate are deduced from the measurements.
- Research Organization:
- Ames Laboratory and Department of Physics, Iowa State University, Ames, Iowa 50011
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 6267463
- Journal Information:
- Phys. Rev. B: Condens. Matter; (United States), Vol. 27:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HALIDES
NUCLEAR MAGNETIC RESONANCE
ZIRCONIUM HYDRIDES
SPIN-LATTICE RELAXATION
ACTIVATION ENERGY
EXPERIMENTAL DATA
LAYERS
LINE NARROWING
LINE WIDTHS
MOTION
PULSES
RELAXATION TIME
SELF-DIFFUSION
TEMPERATURE DEPENDENCE
DATA
DIFFUSION
ENERGY
HALOGEN COMPOUNDS
HYDRIDES
HYDROGEN COMPOUNDS
INFORMATION
MAGNETIC RESONANCE
NUMERICAL DATA
RELAXATION
RESONANCE
TRANSITION ELEMENT COMPOUNDS
ZIRCONIUM COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties