Ultrasonic Spin Echoes in Fe: MgO

Abstract

Ultrasonic spin echoes, or phonon echoes, have been observed under nearly ideal conditions from $\Delta M=1\mathrm{}$ and $\Delta M=2\mathrm{}$ transitions of ${\mathrm{Fe}}^{2+}$: MgO. The echo decays were found to be the same as the magnetic echo decay, and to follow an $\exp (-k{t}^2)$ dependence. These results are attributed to Lorentzian spectral diffusion.