Physical properties of spinel iron oxide thin films

Abstract

This paper describes the complexity of the spinel iron oxides in thin-film configuration. First, the experimental deposition conditions are determined for the parameters of substrate temperature and oxygen flow such that only the “Fe₃O₄” phase is formed. Then a study is made of how the structural (grain size, lattice parameter, texture), magnetic (M), and optical (visible and infrared transmission) properties of the films depend on the deposition and postdeposition (air annealing) conditions. The experimental deposition region is defined where the films have the most similar physical properties to bulk Fe₃O₄ and subsequently, after annealing, to bulk gamma Fe₂O₃. Finally, a discussion is presented of a model that accounts for the anomalous, low values of the magnetic moment for the samples deposited at room temperature. The model proposes an overpopulation of the iron tetrahedral A sites.