Tuning magnetization compensation and Curie temperatures in epitaxial rare earth iron garnet films

An ab initio effective Hamiltonian is developed and used to reveal the effect of misfit strain on magnetic properties of epitaxial (001) films made of a prototypical rare earth iron garnet: Gadolinium iron garnet. It is found that both the magnetization compensation temperature (${T}_{\mathrm{M}}$) and the Curie temperature (${T}_{\mathrm{C}}$) can be significantly and linearly enhanced when varying the strain from tensile to compressive values. Consequently, ${T}_{\mathrm{M}}$ can be designed to coincide with room temperature, and the magnitude of the magnetization can be optimized at around 300 K when choosing the appropriate substrate. The microscopic origins of these technologically promising effects are further revealed.