`` Manganite-based Magnetic Tunnel Junctions: new ideas on Spin-polarised Tunnelling'',
J.M. de teresa, A. Barthélémy, J.P. Contour, A. Fert

Unité Mixte de Physique,

CNRS/Thomson,

domaine de Corbeville,

F-91404 Orsay (France)

deteresa@lcr.thomson-csf.com

Abstract

We present experimental evidence of the active role played by the barrier in magnetic tunnel junctions. We have prepared tunnel junctions of the type Co/I/La_0.7Sr_0.3MnO₃ with four different insulating barriers: I= Al₂O₃, SrTiO₃, Ce_1-xLa_xO₂, and double barrier Al₂O₃/SrTiO₃. Depending on the used barrier, the tunnel magnetoresistance can be normal (for Al₂O₃ and Al₂O₃/Sr TiO₃ ) or inverse (for SrTiO₃ and Ce_1-xLa_xO₂).