Negative spin polarization of the Fe3O4/gamma-Al2O3 interface measured by spin-resolved photoemission

We report on spin-resolved photoemission spectroscopy measurements at the interface between a 25-nm-thick Fe3O4 (111) thin film and a 2-nm-thick gamma- Al2O3 (111) layer. The Fe3O4 layer remains stoichiometric even after being covered by gamma-Al2O3 and exhibits a negative spin polarization of similar to-40%, after remanence correction. This value should be considered as a lower bound for the spin polarization and demonstrates that Fe3O4 remains a spin polarized material even after incorporation in a bilayer.