ESR of CuMn Dilute Alloys Studied in Thin Films

The bottleneck between the conduction electron spins and the lattice system in CuMn dilute alloys is opened by making the specimens into thin films. In the paramagnetic region, an additional relaxation due to surface collisions makes the resonance line broader. The probability of a conduction electron losing its spin memory by a single collision with surfaces is concluded to be 0.04, which is consistent with that in pure copper deduced from the experiments of Schultz et al. (0.02) and much larger than by a collision with an impurity Mn atom in the alloy. In the antiferromagnetic region, the shift in the resonance field as well as the linewidth in thin films is clearly enhanced compared with those in bulk samples. Less detailed experiments in dilute AgMn alloys show the similar results. The origins of the shift are discussed.