Crystal-field and spin parameters inMg−Mnvia transmission electron spin resonance

We report transmission-electron-spin-resonance measurements at 9.2 and 35 GHz for a single-crystal 60-ppm $\mathrm{Mg}-\mathrm{M}\mathrm{n}$ alloy. The observed resonance exhibits an angular anisotropy and temperature dependence which is characteristic of unresolved fine structure in an axial field. We find the second-order crystal-field parameter $D=70\mathrm{}\pm 10$ G when we include a correction for coupling to the conduction electrons. Measurements of the conduction-electron spin resonance in pure Mg at 9.2 GHz are also reported. We suggest that the anisotropic properties of the observed resonances require additional theoretical development in order to satisfactorily interpret the coupled conduction-electron-local-moment spin system.