Fe3O4-Metal interfaces: Magnetization and charge localization

J. PEREA ACOSTA; M. A. BARRAL; M. AGUIRRE; G. E. MURGIDA; A. M. LLOIS

Lausanne

Conferencia; PSI-K CONFERENCE; 2022

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Magnetite (Fe3O4)-Metal bilayers are some of the most promising materials to develop energy devices based on the Spin Seebeck Effect. To optimize such devices and to elucidate fundamental mechanisms, the understanding of the magnetic proximity effect as well as the electric charge localization are crucial. Using the DFT+U approach we study the charge localization process in Fe2+ polarons of magnetite, showing that it can be achieved still in the cubic phase without previous structural deformations, allowing electric conduction by polaron hopping. Magnetite-Metal interfacial properties are analyzed considering thin films of no magnetic metals (Pt, Au, Nb, Ta, and W) deposited on (001) magnetite surface. We found appreciable magnetization only in the first o the first two atomic layers of the metals, reaching up to 0.2μB per atom in some cases. The metals with more (less) than half of d orbitals occupied exhibit a ferromagnetic (antiferromagnetic) coupling with the magnetite surface.