Electric field gradient at Ru nuclei in the series of intermetallic compounds Ce1−xLaxRu2 synthesized at high pressure

Parameters of the electric quadrupole interaction for the first excited state (E=89.7 keV) of ⁹⁹Ru nuclei for a number of the cubic Laves phase compounds Ce_1−xLa_xRu₂, synthesized at high pressure, were determined by the perturbed angular γγ-correlation method. Compounds were synthesized at 8 GPa. It was revealed that the decrease of the average valence of a rare earth ion, caused by the substitution of La for Ce, results in the monotonous decrease of the quadrupole frequency ν_Q from 43.3 MHz for CeRu₂ to 33.1 MHz for LaRu₂.