On the Possible Magnetic Properties of Ultrathin Mn2GaC Films on Al2O3 Substrates

The possibility of growth of thin Mn2GaC MAX phase films on Al2O3 substrates with various orientations and their magnetic properties have been studied. The most favorable orientation relationships and interface planes in the Mn2GaC//Al2O3 system, which indicate the possibility of growth on C-face (0001), S-face $$(01\bar {1}\bar {1})$$ , N‑face $$(11\bar {2}\bar {3})$$ , and R-face $$(0\bar {1}1\bar {2})$$ sapphire substrates, have been predicted within a geometric approach. Using the electron density functional method, the possible magnetic properties of continuous ultrathin Mn2GaC films have been calculated under the condition of conservation of uniform expansions/compressions of the MAX phase lattice, which are induced by growth on the predicted substrates. The effect of the deformation of the Mn2GaC lattice on magnetic ordering and magnetic moments has been determined, and the possibility of a transition from an antiferromagnetic to a ferromagnetic state under the action of external magnetic fields has been evaluated. It has been shown that the growth of the ferromagnetic film of the Mn2GaC MAX phase is the most probable on the Al2O3 (0001), Al2O3 $$(11\bar {2}\bar {3})$$ , and Al2O3 $$(0\bar {1}1\bar {2})$$ substrates.