Studies of the electronic phase transition in Lu/sub 5/Ir/sub 4/Si/sub 10/ and Lu/sub 5/Rh/sub 4/Si/sub 10/ by /sup 175/Lu-NMR
Pulsed nuclear magnetic resonance of /sup 175/Lu (I = (7/2) was used to study the electronic phase transition of samples Lu/sub 5/Ir/sub 4/Si/sub 10/ and Lu/sub 5/Rh/sub 4/Si/sub 10/ under atmospheric pressure from 49 to 310 K. A calculation of the powder line shape in the quadrupole regime for I = (7/2 shows that the critical frequencies, particularly that of the singularity, are sensitive to the change of the electric-field-gradient (EFG) asymmetry and the Larmor frequency. From the singularity near ..nu.. = ..nu../sub 0/, the EFG asymmetry of the lutetium nucleus is estimated to be etaapprox. =0.4. The temperature coefficient of the lutetium EFG asymmetry as estimated from the temperature-dependent shift is close to 3 x 10/sup -5/ K/sup -1/. This small variation of the EFG asymmetry suggests that the crystal structure remains unchanged in the temperature range studied. The possible formation of charge-density-wave states at 83 and 145 K for the two compounds, respectively, is indicated by anomalous variations of the temperature-dependent Knight shift. A loss of the electronic density of states at the Fermi level, as inferred from the jump discontinuity of the Knight shift, is consistent with previous measurements of resistivity and the magnetic susceptibility on these samples. From the correlation of the Knight shift with the magnetic susceptibility, the hyperfine field is determined to be 0.5 and 0.7 MOe, a value consistent with the previous measurements of rare-earth metals. The NMR of /sup 45/Sc (I = (7/2) in Sc/sub 5/Ir/sub 4/Si/sub 10/, isostructural with the above two compounds, was used as a baseline measurement to illustrate the anomalous behavior observed for /sup 175/Lu in Lu/sub 5/M/sub 4/Si/sub 10/ (M = Ir,Rh).
- Research Organization:
- Department of Chemistry and Energy and Mineral Resources Research Institute, Iowa State University, Ames, Iowa 50010
- OSTI ID:
- 5554859
- Journal Information:
- Phys. Rev. B: Condens. Matter; (United States), Vol. 37:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
IRIDIUM SILICIDES
ENERGY-LEVEL DENSITY
SUPERCONDUCTIVITY
LUTETIUM 175
NUCLEAR MAGNETIC RESONANCE
LUTETIUM SILICIDES
RHODIUM SILICIDES
CRITICAL PRESSURE
PHASE TRANSFORMATIONS
TRANSITION TEMPERATURE
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
INTERMEDIATE MASS NUCLEI
IRIDIUM COMPOUNDS
ISOTOPES
LUTETIUM COMPOUNDS
LUTETIUM ISOTOPES
MAGNETIC RESONANCE
NUCLEI
ODD-EVEN NUCLEI
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
REFRACTORY METAL COMPOUNDS
RESONANCE
RHODIUM COMPOUNDS
SILICIDES
SILICON COMPOUNDS
STABLE ISOTOPES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
360603* - Materials- Properties
656100 - Condensed Matter Physics- Superconductivity