Interface states in CoFe2O4 spin-filter tunnel junctions
Abstract
Spin-filter tunneling is a promising way to generate highly spin-polarized current, a key component for spintronics applications. In this paper we explore the tunneling conductance across the spin-filter material CoFe2O4 interfaced with Au electrodes, a geometry which provides nearly perfect lattice matching at the CoFe2O4/Au(001) interface. Using density functional theory calculations we demonstrate that interface states play a decisive role in controlling the transport spin polarization in this tunnel junction. For a realistic CoFe2O4 barrier thickness, we predict a tunneling spin polarization of about -60%. We show that this value is lower than what is expected based solely on considerations of the spin-polarized band structure of CoFe2O4, and therefore that these interface states can play a detrimental role. We argue that this is a rather general feature of ferrimagnetic ferrites and could make an important impact on spin-filter tunneling applications.
- Publication:
-
Physical Review B
- Pub Date:
- October 2013
- DOI:
- 10.1103/PhysRevB.88.134430
- arXiv:
- arXiv:1308.3461
- Bibcode:
- 2013PhRvB..88m4430L
- Keywords:
-
- 72.25.-b;
- 73.40.Gk;
- 75.47.Lx;
- Spin polarized transport;
- Tunneling;
- Manganites;
- Condensed Matter - Mesoscale and Nanoscale Physics;
- Condensed Matter - Materials Science
- E-Print:
- 5 pages, 4 Figures plus 1 page supplement