The reflection-electron-spin-resonance residual linewidth for varying concentrations (125 to 2000 atomic ppm) of silver doped with erbium has been investigated at 9.0 and 1.7 GHz. The frequency-independent (homogeneous) broadening scales linearly with concentration and can be attributed to dipole-dipole interactions between the impurity spins. The frequency-dependent (inhomogeneous) broadening, also linear in concentration, is attributed to an increase in Kohn-Vosko oscillations of the charge density.
Bibliographical noteFunding Information:
Supported in part by the NSF Grant No. DMR 72-02935 A03, and the US Office of Naval Research Contract No. NO0014-75-C-0245.