Q-Switch and Polarization Domains in Antiferromagnetic Chromium Observed with Neutron-Diffraction Topography

The $Q$-switch and polarization domain configurations in a nearly perfect Cr single crystal has been directly observed by neutron-diffraction topography in the A${\mathrm{F}}_1$ and A${\mathrm{F}}_2$ phases. The size of the domains proves to be as large as ${10}^{-3\mathrm{}}$ to ${10}^{-2\mathrm{}}$ ${\mathrm{cm}}^3$ in either phase. As far as the present observation is concerned, each domain in the A${\mathrm{F}}_2$ phase splits into domains in the A${\mathrm{F}}_1$ phase, with two possible polarizations of the transverse spin-density wave.