Berlin 2012 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 4: Spin-dependent Transport Phenomena
MA 4.12: Vortrag
Montag, 26. März 2012, 12:30–12:45, H 1012
Interlayer exchange coupling and transport properties of SrTiO3 based magnetic tunnel junctions — •Brahim Belhadji1, Hongxin Yang1, Julian Velev2, and Mairbek Chshiev1 — 1Spintec, UMR, CEA/CNRS/UJF Grenoble, France — 2University of Puerto Rico, San Juan, Puerto Rico 00931, USA
In view of further miniaturization of spintronic devices, alternative to MgO materials are required in order to maintain a high TMR as resistance-area product becomes smaller. A possible solution may be SrTiO3 due to its smaller bandgap compared to MgO. Here we present first-principle calculations of interlayer exchange coupling(IEC) and spin dependent transport in SrTiO3-based MTJs as a function of barrier thickness and electrode composition (Fe, FeCo and Co). We found that the IEC is antiferromagnetic for relaxed Co/SrTiO3/Co structures and decays exponentially as a function of SrTiO3 thickness and stronger compared to Fe|MgO|Fe. Furthermore, in case of CoFe|SrTiO3 MTJs the IEC amplitude has a clear tendency to decrease and even become positive as Fe content increases. Spin dependent transport calculations in these MTJs show that SrTiO3 seems not to be as good a spin filter as the MgO even though TMR values of 3000% for 9 monolayers of SrTiO3 (~ 1.6nm) were obtained for Co|SrTiO3|Co MTJs, in agreement with previous studies. We also calculated the dependence of TMR on the electrode composition and barrier oxidation conditions.
This work has been supported by French National Research Agency (ANR) Project CRYSTO and by Nanosciences Foundation in Grenoble, France.