Abstract
The quadrupole frequencies for and nuclei in a Lu single crystal have been determined by nuclear orientation at temperatures down to 6 mK as -128(16) MHz and +294(37) MHz, respectively. From the observed anisotropies several -ray multipole mixing ratios could be derived. With the known ground-state quadrupole moment of b for the electric field gradient of is found to be +3.6(5) × V/. This value does not fit into the frame of Raghavan's universal correlation. Taking into account recent data on other systems, a new classification of electric field gradients in hexagonal metals is proposed: The electronic contribution to the total electric field gradient is proportional to the ionic part, the proportionality constant being positive for all group- and - hexagonal metals and negative for all group-, -, and - metals.
- Received 17 November 1978
DOI:https://doi.org/10.1103/PhysRevB.19.4460
©1979 American Physical Society