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

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...

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Detalles Bibliográficos
Autores: Galceran, R., Balcells, Ll., Martínez-Boubeta, C., Bozzo, B., Cisneros-Fernández, J., Mata, M. de la, Magén, C., Arbiol, J., Tornos, J., Cuéllar Jiménez, Fabian Andrés, Sefrioui, Zouhair, Cebollada, A., Golmar, F., Huesos, L.E., Casanova, F., Santamaría Sánchez-Barriga, Jacobo, Martínez, B.
Tipo de recurso: artículo
Fecha de publicación:2015
País:España
Institución:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/24217
Acceso en línea:https://hdl.handle.net/20.500.14352/24217
Access Level:acceso abierto
Palabra clave:537
Spin polarization
Fe/MgO interface
Room-temperature
X-ray. Barrier
MgO
Oxide
Fe.
Electricidad
Electrónica (Física)
2202.03 Electricidad
Descripción
Sumario: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.

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