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The effect of the observational frequency upon the Conduction Electron Spin Resonance recorded from silver foils and sodium in quartz tubes is reported. For both materials an increase in frequency results in an increase in linewidth, a linear relationship being indicated for silver. We interpret some features of the results as being due to surface effects, additional evidence for the influence of the surface on CESR coming from surface treatment of copper foils.

EPR spectra at 35 and 60 GHz of Gd3+ diluted (∼1%) in powdered SnMo6S8 and PbMo6S8 are presented and interpreted. The crystal field is found to be axial, with D = b20=-760 gauss and -740 Gauss for the tin and lead compounds respectively. Values are obtained for and J(q = 0). Below Tc the impurity to conduction electron relaxation rate is no longer proportional to temperature but decreases more rapidly. From this temperature dependence we extract a value for 2Δ kT c of roughly 5 for both compounds.

Conduction-electron spin resonance in thin aluminium platelets, coated with a plastic surface layer, has been studied in a reflection spectrometer at 60 GHz. It is shown that the data on linewidth and g -factor fall in line with recent measurements at 21 GHz by the present authors and partly also with earlier measurements at 1.27 GHz 9.27 GHz, 35 GHz and 79 GHz by others.

The rise in g factor and linewidth with decreasing temperature below 30 K usually observed in CESR of aluminium samples, is almost absent in samples coated with a plastic layer. The properties of untreated samples are slowly restored after removal of the plastic layer. These observations, together with previous results on ion implanted samples, point towards interactions of the conduction electrons with a layer of localized moments on the surface.