Observation of antiferromagnetic resonance in epitaxial films ofMnF2

Antiferromagnetic resonance has been observed in thin films for what we believe to be the first time. Epitaxial films of ${\mathrm{MnF}}_2$ on ${\mathrm{MgF}}_2$, ${\mathrm{ZnF}}_2$, and ${\mathrm{FeF}}_2$ substrates were used. The resonance positions were very close to, but slightly below, that extrapolated for the bottom of the spin-wave band in bulk ${\mathrm{MnF}}_2$. The linewidths ranged from 15 to 500 Oe, with the narrowest ones corresponding to films with the best degree of epitaxy as judged by texture camera photographs.