Spin-Polarized Resonant Tunneling in Magnetic Tunnel Junctions
S. Yuasa,*
T. Nagahama,
Y. Suzuki
Insertion of a thin nonmagnetic copper Cu(001) layer between the
tunnel barrier and the ferromagnetic electrode of a magnetic tunnel
junction is shown to result in the oscillation of the tunnel magnetoresistance as a function of the Cu layer thickness. The effect
is interpreted in terms of the formation of spin-polarized resonant
tunneling. The amplitude of the oscillation is so large that even the
sign of the tunnel magnetoresistance alternates. The oscillation period
depends on the applied bias voltage, reflecting the energy band
structure of Cu. The results are encouraging for the development of
spin-dependent resonant tunneling devices.
NanoElectronics Research Institute, National Institute of Advanced
Industrial Science and Technology, Tsukuba 305-8568, Japan, and Core
Research for Evolutional Science and Technology, Japan Science and
Technology Corporation, 4-1-8 Honcho, Kawaguchi 332-0012, Japan.
*
To whom correspondence should be addressed. E-mail:
yuasa-s{at}aist.go.jp
