Role of Metal-Oxide Interface in Determining the Spin Polarization of Magnetic Tunnel Junctions
Jose Maria De Teresa
Agnès Barthélémy,
Albert Fert,
*
Jean
Pierre Contour,
François Montaigne,
Pierre Seneor
The role of the metal-oxide interface in determining the
spin polarization of electrons tunneling from or into ferromagnetic transition metals in magnetic tunnel junctions is reported. The spin
polarization of cobalt in tunnel junctions with an alumina barrier is
positive, but it is negative when the barrier is strontium titanate or
cerium lanthanite. The results are ascribed to bonding effects at the
transition metal-barrier interface. The influence of the electronic
structure of metal-oxide interfaces on the spin polarization raises
interesting fundamental problems and opens new ways to optimize the
magnetoresistance of tunnel junctions.
Unité Mixte de Physique, CNRS-Thomson CSF, Laboratoire
Central de Recherche, Domaine de Corbeville, 91404 Orsay, France, and
Université Paris-Sud, 91405 Orsay, France.
*
To whom correspondence should be addressed. E-mail:
fert{at}lcr.thomson-csf.com
