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

L. Marnitz; K. Rott; S. Niehörster; C. Klewe; D. Meier; S. Fabretti; M. Witziok; A. Krampf; O. Kuschel; T. Schemme; K. Kuepper; J. Wollschläger; A. Thomas; G. Reiss; T. Kuschel

doi:10.1063/1.4917018

AIP Advances (Apr 2015)

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

L. Marnitz,
K. Rott,
S. Niehörster,
C. Klewe,
D. Meier,
S. Fabretti,
M. Witziok,
A. Krampf,
O. Kuschel,
T. Schemme,
K. Kuepper,
J. Wollschläger,
A. Thomas,
G. Reiss,
T. Kuschel

Affiliations

L. Marnitz: Center for Spinelectronic Materials and Devices, Physics Department, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
K. Rott: Center for Spinelectronic Materials and Devices, Physics Department, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
S. Niehörster: Center for Spinelectronic Materials and Devices, Physics Department, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
C. Klewe: Center for Spinelectronic Materials and Devices, Physics Department, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
D. Meier: Center for Spinelectronic Materials and Devices, Physics Department, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
S. Fabretti: Center for Spinelectronic Materials and Devices, Physics Department, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
M. Witziok: Fachbereich Physik, Universität Osnabrück, Barbarastraße 7, 49069 Osnabrück, Germany
A. Krampf: Fachbereich Physik, Universität Osnabrück, Barbarastraße 7, 49069 Osnabrück, Germany
O. Kuschel: Fachbereich Physik, Universität Osnabrück, Barbarastraße 7, 49069 Osnabrück, Germany
T. Schemme: Fachbereich Physik, Universität Osnabrück, Barbarastraße 7, 49069 Osnabrück, Germany
K. Kuepper: Fachbereich Physik, Universität Osnabrück, Barbarastraße 7, 49069 Osnabrück, Germany
J. Wollschläger: Fachbereich Physik, Universität Osnabrück, Barbarastraße 7, 49069 Osnabrück, Germany
A. Thomas: Center for Spinelectronic Materials and Devices, Physics Department, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
G. Reiss: Center for Spinelectronic Materials and Devices, Physics Department, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
T. Kuschel: Center for Spinelectronic Materials and Devices, Physics Department, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany

DOI: https://doi.org/10.1063/1.4917018
Journal volume & issue: Vol. 5, no. 4
pp. 047103 – 047103-7

Abstract

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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.

Published in AIP Advances

ISSN: 2158-3226 (Online)
Publisher: AIP Publishing LLC
Country of publisher: United States
LCC subjects: Science: Physics
Website: http://aipadvances.aip.org/

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