Electron spin resonance ofGdxLa1−xPd3intermetallic compounds

We have extended our ESR study of Gd in the intermetallic compound ${\mathrm{Gd}}_x{\mathrm{La}}_{1-x}{\mathrm{Pd}}_3$ to samples annealed at 940°C and cooled rapidly to room temperature. We have measured the ESR linewidths and $g$ shifts as a function of temperature and concentration of Gd. They were found to exhibit Korringa-like thermal broadening between 6 and 40°K. We have deduced the average value of $J_{\mathrm{eff}}$ for the effective-exchange integral to be 0.24 ± 0.03 eV. We have calculated also the magnitudes of the conduction-electron relaxation rates to the lattice, (i) due to the undisturbed host lattice, (ii) by spin-flip scattering due to the magnetic impurity Gd, and (iii) by spin-flip scattering due to the nonmagnetic impurity Th.