Oxides for spintronics
|Manuel Bibes 1, Vincent Garcia 1, Martin Bowen 1, Pierre Seneor 1, Manuel Munoz 1, Agnes Barthélémy 1, Karim Bouzehouane 1, Stéphane Fusil 2, Vincent Cros 1, Julian Carrey 1, Michael Besse 1, Annie Vaures 1, Jean-Pierre Contour 1, Albert Fert 1|
1. Unité Mixte de Physique CNRS-Thales, Domaine de Corbeville, Orsay 91404, France
In spintronics, to obtain large effects it is of paramount importance to master sources of highly spin-polarized charge carriers. The simplest way to achieve this is to use half-metallic materials, like mixed-valence manganites (A1-xA'xMnO3). When integrated as electrodes in magnetic tunnel junctions (MTJs), manganites have proved to yield large tunnelling magnetoresistance (TMR) values, which underscores their usefulness for spintronics applications. In this talk, we will review recent results obtained at Orsay in manganite MTJs. At low temperature, a TMR of 1800 % is obtained in a La2/3Sr1/3MnO3 / SrTiO3 / La2/3Sr1/3MnO3 junction. This corresponds to a spin-polarization of 95% for La2/3Sr1/3MnO3 (LSMO) at the interface with SrTiO3 (STO). The bias voltage dependence of the TMR shows a very peculiar behaviour, from which quantitative information on the spin-dependent DOS above EF can be extracted. We have also studied the temperature dependence of the TMR in MTJs with STO and TiO2 barriers. In both systems, the TMR vanishes in the 280K range. Even if, at low temperature, the spin-polarization of the LSMO / TiO2 interface is only 70 % as opposed to 95 % in the case of LSMO / STO), the decay upon rising T of both PLSMO/STO and PLSMO/TiO2 is very similar, and differs from that of the spin-polarization of a free LSMO surface. We will discuss the possible reasons for this behaviour.
Presentation: invited oral at E-MRS Fall Meeting 2003, Symposium D, by Manuel Bibes
See On-line Journal of E-MRS Fall Meeting 2003
Submitted: 2003-05-21 13:54 Revised: 2009-06-08 12:55