Long-Range Phase Coherence in Double-Barrier Magnetic Tunnel Junctions with a Large Thick Metallic Quantum Well

B. S. Tao (1, 2) , H. X. Yang (3) , Y. L. Zuo (2) , Xavier Devaux (2) , Gwladys Lengaigne (2) , Michel Hehn (2) , Daniel Lacour (2) , Stéphane Andrieu (2) , M. Chshiev (3) , Thomas Hauet (2) , François Montaigne (2) , Stéphane Mangin (2) , X. F. Han (1) , Yuan Lu (2)

1 IoP/CAS - Beijing National Laboratory for Condensed Matter Physics and Institute of Physics
2 IJL - Institut Jean Lamour
3 SPINTEC - SPINtronique et TEchnologie des Composants

Double-barrier heterostructures are model systems for the study of electron tunneling and discrete energy levels in a quantum well (QW). Until now resonant tunneling phenomena in metallic QWs have been observed for limited thicknesses (1-2 nm) under which electron phase coherence is conserved. In the present study we show evidence of QW resonance states in Fe QWs up to 12 nm thick and at room temperature in fully epitaxial double MgAlOx barrier magnetic tunnel junctions. The electron phase coherence displayed in this QWis of unprecedented quality because of a homogenous interface phase shift due to the small lattice mismatch at the Fe-MgAlOx interface. The physical understanding of the critical role of interface strain on QW phase coherence will greatly promote the development of spin-dependent quantum resonant tunneling applications.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

B. S. Tao, H. X. Yang, Y. L. Zuo, Xavier Devaux, Gwladys Lengaigne, et al.. Long-Range Phase Coherence in Double-Barrier Magnetic Tunnel Junctions with a Large Thick Metallic Quantum Well. Physical Review Letters, 2015, 115 (15), pp.157204. ⟨10.1103/PhysRevLett.115.157204⟩. ⟨hal-01284017⟩