Spin-filtering efficiency of ferrimagnetic spinels CoFe2O4 and NiFe2O4

Abstract

We assess the potential of the ferrimagnetic spinel ferrites CoFe2O4 and NiFe2O4 to act as spin filtering barriers in magnetic tunnel junctions. Our study is based on the electronic structure calculated by means of first-principles density functional theory within different approximations for the exchange correlation energy. We show that, in agreement with previous calculations, the densities of states suggest a lower tunneling barrier for minority spin electrons, and thus a negative spin-filter effect. However, a more detailed analysis based on the complex band-structure reveals that both signs for the spin-filtering efficiency are possible, depending on the band alignment between the electrode and the barrier materials and depending on the specific wave-function symmetry of the relevant bands within the electrode.

8 pages, 5 Figures, 1 Table

References in corpus (6)

• Electronic structure of normal and inverse spinel ferrites from first principles
• Room temperature spin filtering in epitaxial cobalt-ferrite tunnel barriers
• First-principles calculation of magnetoelastic coefficients and magnetostriction in the spinel ferrites CoFe2O4 and NiFe2O4
• A first-principles study of tunneling magnetoresistance in Fe/MgAl2O4/Fe(001) magnetic tunnel junctions
• Coexistance of giant tunneling electroresistance and magnetoresistance in an all-oxide magnetic tunnel junction
• Andreev reflection in ferrimagnetic CoFe2O4/SrRuO3 spin filters

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• Interface states in CoFe2O4 spin-filter tunnel junctions
• Surface spin canting in Fe3O4 and CoFe2O4 nanoparticles probed by high resolution electron energy loss spectroscopy
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