EPR study of cold-worked dilute gold-erbium alloys

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Abstract
The results of an electron paramagnetic resonance (EPR) study of the effects of cold-working (rolling and polishing) on the EPR spectrum of Er in Au are reported. Pellets of dilute alloys of Au doped with Er were prepared in an arc furnace. From the pellets, samples were made by rolling at room temperature. The resonance experiments were carried out at X-band and at temperatures between 1.65 and 4.2 K. Heating of the rolled samples reduced the EPR linewidth and intensity and increased the asymmetry parameter (the A/B ratio). Gradual deformation by successive rolling resulted in almost complete recovery of the linewidth and A/B ratio to values observed before heating. No appreciable variations were detected in the g-factor, hyperfine structure constant or the Korringa relaxation rate. Results are interpreted in terms of segregation of Er ions to subgrain boundaries. The EPR of magnetic impurities in metals appears to be a promising technique for the study of interactions between the magnetic impurities and the defects produced by cold-working.