Adhesion and electric structure at Fe3O4/FeCr2O4 interface: A first principles study

Abstract

The adhesion energy, interfacial energy, interfacial fracture toughness, electronic structure and valence bond of Fe3O4 (001) / FeCr2O4 (001) interface have been studied by first principles density functional method. When the number of atomic layers on (001) plane is more than 15 and 13, the Fe3O4 (001) and FeCr2O4 (001) slabs can reach the characteristics of their respective bulk phases. The effects of different stacking positions on the interfacial bonding and fracture toughness of 12 kinds of interface models with different terminal combinations were studied. The interface configuration Model E which is composed of Fe3O4 (001) - FeO termination / FeCr2O4 (001) - Fe termination has the maximum adhesion work. The interfacial fracture toughness of Model E is the largest among the interface configurations and is between the fracture toughness of bulk Fe3O4 and that of bulk FeCr2O4. This model is the most stable in thermodynamics. The electronic structure of the interface indicates that there are ionic/covalent bonds and metallic bonds between the atoms at the interface.