Magnetic And Transport Properties Of Epitaxial Stepped Fe₃O₄?100? Thin Films

Magnetite is a highly utilised transition metal oxide with many interesting magnetic and transport properties.The presence of anti-phase boundaries?APBs?and charge-orbital ordering?COO?are two of the most exciting properties of epitaxial magnetite thin films.Here,epitaxial stepped Fe₃O₄ films were prepared to investigate the competition between APBs and COO via measurements of in-plane anisotropy.The anisotropy was probed for two orthogonal configurations,with magnetic field applied or electrical-contacts aligned either along or perpendicular to the steps.We reveal that the APBs dominate the magnetic and transport properties of the films above the Verwey transition temperature?T_V?.However,below T_V film thickness becomes a decisive factor in determining the magnetic nature of stepped magnetite films,due to its correlation with domain size.When the film is thinner than a critical thickness,the anisotropy is dominated by the APBs,and a higher anisotropy constant and MR ratio are observed when the magnetic field or contacts are oriented along the steps.Conversely,for sufficiently thick films,below T_V,the magnetic and electrical transport properties are dominated by COO.Thus a higher anisotropy constant and MR ratio are observed when the magnetic field or contacts are oriented perpendicular to the steps.