Direct evidence of spin filtering across MnFe$_2$O$_4$ tunnel barrier by Meservey-Tedrow experiment

S. Matzen (1) , J.-B. Moussy (1) , G. X. Miao (2) , J. S. Moodera (3, 2)

1 LCSI - Laboratoire de Chimie des Surfaces et Interfaces
2 Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology
3 Department of Physics [MIT Cambridge]

A spin filtering effect has been evidenced in epitaxial MnFe$_2$O$_4$ tunnel barriers directly by Meservey-Tedrow experiments. The asymmetry of the Zeeman-split tunneling conductance curves of the superconducting Al spin analyzer in Pt(111)/MnFe$_2$O$_4$(111)/$\gamma$-Al$_2$O$_3$(111)/Al tunnel junctions revealed a positive spin-polarization (up to + 9%), proving the potential of manganese ferrite for generation of a spin-polarized current. A negatively polarized spin filtering being expected theoretically, different mechanisms are discussed to explain both sign and amplitude of the measured spin-polarization.

Domaines: Physique [physics]

S. Matzen, J.-B. Moussy, G. X. Miao, J. S. Moodera. Direct evidence of spin filtering across MnFe$_2$O$_4$ tunnel barrier by Meservey-Tedrow experiment. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2013, 87, pp.184422. ⟨10.1103/PhysRevB.87.184422⟩. ⟨cea-01481041⟩