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

Electron-spin resonance of Gd in GdxLu1-xAl2 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 LaAl2 and YAl2 doped with the same impurities.