Fully epitaxial Fe(110)/MgO(111)/Fe(110) magnetic tunnel junctions: Growth, transport, and spin filtering properties

J. O. Hauch (1) , Mikhail Fonin (2) , M. Fraune (1) , Pascal Turban (3) , R. Guerrero (4) , Farkhad G. Aliev (4) , Joachim Mayer (5) , Ulrich Rüdiger (2) , Gernot Güntherodt (1)

1 II. Physikalisches Institut [Aachen]
2 Fachbereich Physik [Konstanz]
3 Surfaces et interfaces
4 Departamento de Física de Materiales [Madrid]
5 Gemeinschaftslabor für Elektronenmikroskopie

Fully epitaxial Fe(110)/MgO(111)/Fe(110) magnetic tunnel junctions (MTJs) have been tested with respect to symmetry-enforced spin filtering. The Fe(110) electrodes exhibit Σ1↑ and Σ1↓ spin states, both crossing the Fermi level, but with a group velocity about 50% smaller for the minority states compared to the majority ones. These epitaxial but symmetry-mismatched MTJs yield tunneling magnetoresistance (TMR) values of 54% at 1.5 K and 28% at room temperature. The TMR value and the estimated tunneling spin polarization are consistent with a partial spin filtering due to the Σ1↑ states partially compensated by the Σ1↓ states.

Mots clés: electrodes; Fermi level; iron; magnesium compounds; magnetic epitaxial layers; magnetic tunnelling; MIM structures; spin polarised transport; tunnelling magnetoresistance

J. O. Hauch, Mikhail Fonin, M. Fraune, Pascal Turban, R. Guerrero, et al.. Fully epitaxial Fe(110)/MgO(111)/Fe(110) magnetic tunnel junctions: Growth, transport, and spin filtering properties. Applied Physics Letters, 2008, 93 (8), pp.3512. ⟨10.1063/1.2976546⟩. ⟨hal-00673047⟩