Room Temperature Dy Spin-Flop Switching in Strained DyFeO3 Thin Films

Epitaxial strain in thin films can yield surprising magnetic and electronic properties not accessible in bulk. One materials system destined to be explored in this direction are orthoferrites with two intertwined spin systems where strain is predicted to have a significant impact on magnetic and polar properties by modifying the strength of the rare earth-Fe interaction. Here we report the impact of epitaxial strain is reported on the linear magneto-electric DyFeO3, a canted bulk antiferromagnet with a high Neel temperature (645 K) exhibiting a Dy-induced spin reorientation transition at approx. 50 K and antiferromagnetic ordering of the Dy spins at 4 K. An increase in the spin transition of > 20 K is found and a strictly linear, abnormal temperature magnetic response under an applied magnetic field between 100 and 400 K for [010]-oriented DyFeO3 thin films with an in-plane compressive strain between 2% and 3.5%. At room temperature and above, we found that application of approx. 0.06 T causes a spin-flop of the Dy spins coupled to the antiferromagnetic Fe spin lattice, whereby the Dy spins change from an antiferromagnetic alignment to ferromagnetic. The spin-flop field gives a lower energy bound on the Dy-Fe exchange interaction of approx. 15 microeV.