P. Wodniecki et al., PAC STUDIES OF AG-HF INTERMETALLIC COMPOUNDS, Zeitschrift fur Naturforschung. A, A journal of physical sciences, 51(5-6), 1996, pp. 437-441
The hyperfine quadrupole interaction of Ta-181 and Cd-111 probes in Hf
Ag and Hf2Ag compounds was studied at 24 to 1100 K with the time -diff
erential perturbed angular correlation (TDPAC) technique. The EFGs mea
sured in HfAg on Ta-181 and Cd-111 are 1.388(5)x10(18) Vcm(-2) and 0.3
40(5)x10(18) Vcm(-2), respectively. For both probe atoms a linear decr
ease of the EFG with temperature was observed with slopes 1.11(2)x10(-
4) K-1 and 1.73(5)x10(-4) K-1 for Ta-181 and Cd-111, respectively. In
Hf2Ag, 0.469(2)x10(18) Vcm(-2) was determined on Ta-181 nuclei and 0.4
28(5)x10(18) Vcm(-2) on Cd-111. Also a linear EFG temperature dependen
ce with the large slope of 2.39(6)x10(-4) K-1 was observed for Cd-111
probes in Hf2Ag, while the EFG measured on Ta-181 nuclei in this compo
und exhibits a very weak temperature variation which can be fitted nei
ther with a linear T nor a T-3/2 dependence. In all cases the electron
ic contributions to the EFG are very small indicating that these trans
ition element systems do not obey the universal correlation between th
e electronic and the ionic EFG observed in numerous other systems not
belonging to the transition metal series.