Magnetic Structure and Ordering of Multiferroic Hexagonal LuFeO3

We report on the magnetic structure and ordering of hexagonal LuFeO3 films of variable thickness grown by molecular-beam epitaxy on YSZ (111) and Al2O3 (0001) substrates. These crystalline films exhibit long-range structural uniformity dominated by the polar P63cm phase, which is responsible for the paraelectric to ferroelectric transition that occurs above 1000 K. Using bulk magnetometry and neutron diffraction, we find that the system orders into a ferromagnetically canted antiferromagnetic state via a single transition below 155 K regardless of film thickness, which is substantially lower than that previously reported in hexagonal LuFeO3 films. The symmetry of the magnetic structure in the ferroelectric state implies that this material is a strong candidate for linear magnetoelectric coupling and control of the ferromagnetic moment directly by an electric field.