Dynamic behavior of paramagnetic ions and conduction electrons in intermetallic compounds:GdxLu1−xAl2

Electron-spin resonance of Gd in ${\mathrm{Gd}}_x{\mathrm{Lu}}_{1-x}{\mathrm{Al}}_2$ intermetallic compounds exhibits significant changes in the $g$ shift and thermal broadening upon (i) varying the Gd concentration, (ii) adding a second nonmagnetic imputity Th, and (iii) varying the temperature. These behaviors indicate the presence of the "bottleneck" and "dynamic" effects in the relaxation mechanism. The results were analyzed using a recent band calculation. The $q$ dependence of the exchange interaction and the spin-flip scattering rates of the conduction electrons caused by the Gd and Th impurities were extracted. Our data are compared with previous results on isoelectronic systems La${\mathrm{Al}}_2$ and Y${\mathrm{Al}}_2$ doped with the same impurities.