Spin-phonon coupling in the rare-earth orthoferrite DyFeO$_3$

The rare-earth orthoferrite (RFeO$_3$) canted antiferromagnets are known to exhibit a wide array of magnetic properties, including spin reorinetation transitions and compensation points between the rare-earth and iron sublattices. Furthermore, strong magnetoelastic coupling has been observed to lead to field-induced multiferroism with a large dielectric polarization. Here we present an infrared optical study of DyFeO$_3$, focusing on the evolution of the phonon structure with temperature. Polarized single-crystal relfectance measurements are supplemented with magnetization and dielectric constant measurements to illuminate the role of spin-phonon coupling in the lattice dynamics.