Orthoferrites are a class of magnetic materials with a magnetic ordering temperature above 600 K, predominant $G$-type antiferromagnetic ordering of the Fe-spin system and, depending on the rare-earth ion, a spin reorientation of the Fe spin taking place at lower temperatures. ${\mathrm{DyFeO}}_3$ is of particular interest since the spin reorientation is classified as a Morin transition with the transition temperature depending strongly on the Dy-Fe interaction. Here, we report a detailed study of the magnetic and structural properties of microcrystalline ${\mathrm{DyFeO}}_3$ powder and bulk single crystal using neutron diffraction and magnetometry between 1.5 and 450 K. We find that, while the magnetic properties of the single crystal are largely as expected, the powder shows strongly modified magnetic properties, including a modified spin reorientation and a smaller Dy-Fe interaction energy of the order of 10 μeV. Subtle structural differences between powder and single crystal show that they belong to distinct magnetic space groups. In addition, the Dy ordering at 2 K in the powder is incommensurate, with a modulation vector of 0.0173(5) $c^{*}$, corresponding to a periodicity of ∼58 unit cells.

• Received 1 December 2021
• Revised 25 April 2022
• Accepted 14 June 2022

DOI:https://doi.org/10.1103/PhysRevMaterials.6.074401