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Interfacial effects on the tunneling magnetoresistance in La_(0.7)Sr_(0.3)MnO_(3)/MgO/Fe tunneling junctions



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Galceran, R. and Balcells, Ll. and Martínez-Boubeta, C. and Bozzo, B. and Cisneros-Fernández, J. and Mata, M. de la and Magén, C. and Arbiol, J. and Tornos, J. and Cuéllar Jiménez, Fabián Andrés and Sefrioui, Zouhair and Cebollada, A. and Golmar, F. and Huesos, L.E. and Casanova, F. and Santamaría Sánchez-Barriga, Jacobo and Martínez, B. (2015) Interfacial effects on the tunneling magnetoresistance in La_(0.7)Sr_(0.3)MnO_(3)/MgO/Fe tunneling junctions. Physical review B, 92 (9). ISSN 1098-0121

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Official URL: http://dx.doi.org/10.1103/PhysRevB.92.094428


We report on magnetotransport properties on La_(0.7)Sr_(0.3)MnO_(3)/MgO/Fe tunnel junctions grown epitaxially on top of (001)-oriented SrTiO_(3) substrates by sputtering. It is shown that the magnetoresistive response depends critically on the MgO/Fe interfacial properties. The appearance of an FeOX layer by the interface destroys the 1 symmetry filtering effect of the MgO/Fe system and only a small negative tunneling magnetoresistance (TMR) (∼ −3 %) is measured. However, in annealed samples a switchover from positive TMR (∼ +25% at 70 K) to negative TMR (∼ −1 %) is observed around 120 K. This change is associated with the transition from semiconducting at high T to insulating at low T taking place at the Verwey transition (TV ∼ 120 K) in Fe3O4, thus suggesting the formation of a very thin slab of magnetite at the MgO/Fe interface during annealing treatments. These results highlight the relevance of interfacial properties on the tunneling conduction process and how it can be substantially modified through appropriate interface engineering.

Item Type:Article
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© 2015 American Physical Society. We acknowledge financial support from the Spanish MINECO through grants (MAT2012-33207, MAT2011- 27470-C02, MAT2012-37638 and Consolider Ingenio 2010 - CSD2009-00013 (Imagine)), from CAM through Grant No. S2009/MAT-1756 (Phama) and Basque Government (PI2011- 1). Financial support from EC through FEDER program and Marie Curie Actions (256470-ITAMOSCINOM) is also acknowledged. C.M.B. thanks the Spanish MINECO for the financial support through the RyC program. The authors would like to thank the technical staff of the ICMAB for their assistance

Uncontrolled Keywords:Spin polarization, Fe/MgO interface, Room-temperature, X-ray. Barrier, MgO, Oxide, Fe.
Subjects:Sciences > Physics > Electricity
Sciences > Physics > Electronics
ID Code:33751
Deposited On:29 Oct 2015 09:18
Last Modified:10 Dec 2018 14:57

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