Sign change in the tunnel magnetoresistance of Fe3O4/MgO/Co-Fe-B magnetic tunnel junctions depending on the annealing temperature and the interface treatment

Abstract

Magnetite (Fe3O4) is an eligible candidate for magnetic tunnel junctions (MTJs) since it shows a high spin polarization at the Fermi level as well as a high Curie temperature of 585°C. In this study, Fe3O4/MgO/Co-Fe-B MTJs were manufactured. A sign change in the TMR is observed after annealing the MTJs at temperatures between 200°C and 280°C. Our findings suggest an Mg interdiffusion from the MgO barrier into the Fe3O4 as the reason for the change of the TMR. Additionally, different treatments of the magnetite interface (argon bombardment, annealing at 200°C in oxygen atmosphere) during the preparation of the MTJs have been studied regarding their effect on the performance of the MTJs. A maximum TMR of up to -12% could be observed using both argon bombardment and annealing in oxygen atmosphere, despite exposing the magnetite surface to atmospheric conditions before the deposition of the MgO barrier.

5 pages, 5 figures, 2 tables

References in corpus (3)

• Unambiguous separation of the inverse spin Hall and anomalous Nernst Effects within a ferromagnetic metal using the spin Seebeck effect
• Magnetic properties of epitaxial Fe${}_3$O${}_4$ films with various crystal orientations and TMR effect in room temperature
• Negative spin polarization of Mn2VGa probed by tunnel magnetoresistance

Cited by in corpus (3)

• Cation- and lattice-site-selective magnetic depth profiles of ultrathin $\mathrm{F}{\mathrm{e}}_3{\mathrm{O}}_4$(001) films
• Time-resolved diffraction and photoelectron spectroscopy investigation of the reactive molecular beam epitaxy of $\mathrm{F}{\mathrm{e}}_3{\mathrm{O}}_4$ ultrathin films
• Structural and magnetic investigation of the interfaces of $\mathrm{F}{\mathrm{e}}_3{\mathrm{O}}_4/MgO(001)$ with and without NiO interlayer