Raman Scattering from Localized Magnetic Excitations in Ni2+ - and Fe2+ - Doped MnF2

Abstract

We have studied Raman scattering at low temperatures from Mn${\mathrm{F}}_2$ doped with ${\mathrm{Ni}}^{2+}$ and ${\mathrm{Fe}}^{2+}$. Three temperature- and polarization-dependent lines have been observed for each impurity. For each dopant we have identified one line as a two-magon excitation of the impurity and some linear combination of the host spins. When corrections are made for magnon-magnon interactions, the predicted energy is in excellent agreement with the experimental results.