Nuclear magnetic resonance and unstable rare-earth magnetism in CeAl/sub 3/
/sup 27/Al nuclear magnetic resonance (NMR) experiments have been carried out in the unstable-moment compound CeAl/sub 3/ to probe the nature of the hyperfine field at the /sup 27/Al site, and to obtain effective Ce-4f spin fluctuation rates. From the reported Fermi-fluid-like properties of CeAl/sub 3/ at low temperatures, a characteristic temperature T/sub char/ approx. 0.5K is estimated, below which electron-electron correlations are strong. A change of slope in a plot of the /sup 27/Al isotropic frequency shift K/sub i/ versus the susceptibility chi in the temperature range 1.5-20K is therefore probably not associated with a change in the hyperfine interaction at T/sub char/. NMR absorption spectra of CeAl/sub 3/ qualitatively indicate a considerable anisotropy in the /sup 27/Al shift below 20K, which increases with decreasing temperature or increasing applied field. Since these K(chi) anomalies begin to occur at a temperature of the order of the lowest crystal-electric-field (CEF) splitting of the Ce-ion states as derived from neutron quasielastic scattering, they are tentatively attributed to CEF effects which can cause anisotropy in the hyperfine interaction. The observed increase in the /sup 27/Al spin-lattice relaxation rate 1/T/sub 1/ from 300K to a broad maximum near 10K is ascribed to possible electron-spin pair-correlation and/or CEF effects. The behavior of the effective 4f-spin fluctuation rate indicates the onset of short-range spatial correlations between the Ce-4f spins at low temperatures, but the nature of these correlations is uncertain due to difficulties in reconciling the NMR and neutron data.
- OSTI ID:
- 5679605
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALUMINIUM 27
NUCLEAR MAGNETIC RESONANCE
ALUMINIUM ALLOYS
MAGNETISM
CERIUM ALLOYS
ABSORPTION SPECTRA
ANISOTROPY
MAGNETIC SUSCEPTIBILITY
SPIN-LATTICE RELAXATION
ALLOYS
ALUMINIUM ISOTOPES
ISOTOPES
LIGHT NUCLEI
MAGNETIC PROPERTIES
MAGNETIC RESONANCE
NUCLEI
ODD-EVEN NUCLEI
PHYSICAL PROPERTIES
RARE EARTH ALLOYS
RELAXATION
RESONANCE
SPECTRA
STABLE ISOTOPES
360104* - Metals & Alloys- Physical Properties