Low-temperatureHe3NMR studies in aged palladium tritide
| Autor: | D.F. Cowgill, G.C. Abell |
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| Rok vydání: | 1991 |
| Předmět: | |
| Zdroj: | Physical Review B. 44:4178-4184 |
| ISSN: | 1095-3795 0163-1829 |
| DOI: | 10.1103/physrevb.44.4178 |
| Popis: | Experimental results from a NMR study of {sup 3}He in nanometer-sized microbubbles in aged palladium tritide over the temperature range 4--300 K are presented. A determination of the rigid-lattice--line-shape second moment at 4 K provides a value for the density of {sup 3}He that is in good agreement with the value inferred for the same sample from an analysis of {sup 3}He spin-lattice relaxation data over the range 50--300 K. This latter analysis is based on the hypothesis of a melting transition for a distribution of densities, and assumes that the bulk helium equation of state applies to helium in the nanometer-sized bubbles. This latter assumption is supported by the agreement between the two independent density determinations. Line-shape analyses reveal narrowing of the {sup 3}He spectrum at about 35 K, which agrees with a prediction of motional narrowing based on an extrapolation of {sup 3}He diffusivity data determined over the range 100--250 K in an earlier study of aged palladium tritide. The observation of coexisting broad and narrow components in the free-induction decay at 40 K provides direct evidence for a distribution of {sup 3}He densities in aged palladium tritide. Because the melting temperature and the rigid-lattice second moment aremore » both strong functions of density, the NMR techniques described here provide a sensitive measure of the density distribution and related properties.« less |
| Databáze: | OpenAIRE |
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