A DFT study of Mn3O4 Hausmannite thin films supported on coinage metals

Mn3O4 Hausmannite thin films supported on (Cu, Ag, Au) coinage metals have been studied for the first time by means of DFT calculations. The different lattice and ionic match at the interface with the metal support gives raise to different type of interactions. On copper, Mn3O4 (1 1 0) films subject to tensile strain strongly adhere to the metal surface, undergoing a remarkable structural change. On the contrary, Mn3O4 (0 0 1) films adhere weakly to Cu (1 1 1) and Au (1 1 1), where the structural match is unfavourable, and strongly on Ag(1 0 0), where the lattice is commensurate and epitaxial films can grow. A negative charge flow from the support to the film is reported, in particular when strong bonds at the interface are formed. This causes the reduction of the film and the subsequent increase in the magnetic moments of some metal ions in the octahedral sublattice. The reduced centres are prevalently located at the film surface. The ferrimagnetic ordering is different in supported films exposing the (0 0 1) or the (1 1 0) face.