Dresden 2006 – wissenschaftliches Programm
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MA: Magnetismus
MA 20: Poster: Films(1-36) Transp(37-56) Ex.Bias(57-67) Spindyn(68-80) Micromag(81-95) Particle(96-109) Imag.+Surface(110-113) Spinelectr(114-122) Theory+Micromag(123-131) Spinstr+Aniso(132-142) MagMat(143-156) Meas(157,158) MolMag+Kondo(159-162) Postdead(163-)
MA 20.42: Poster
Dienstag, 28. März 2006, 15:15–19:15, P1
Growth, Structure, and Electronic Properties of Epitaxial Fe/MgO/Fe(110) Trilayers — •Mikhail Fonin1, Yuriy S. Dedkov2, Jan Hauch3, Ulrich Rüdiger1, and Gernot Güntherodt3 — 1Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany — 2Institut für Festkörperphysik, Technische Universität Dresden, 01062 Dresden, Germany — 3II. Physikalisches Institut, Rheinisch-Westfälische Technische Hochschule Aachen, 52056 Aachen, Germany
Recently high tunneling magnetoresistance (TMR) values in fully epitaxial Fe/MgO/Fe(100) magnetic tunnel junctions (MTJs) have been reported with magnetoresistance ratio of about 180 % measured at room temperature (RT) [1]. However, (110)-oriented Fe films can be even more attractive as electrode material for MTJs due to the high spin polarization value of about -80% observed for Fe(110)[2].
In this study the surface morphology of ultra thin MgO films grown on Fe(110) was investigated by low energy electron diffraction (LEED) and scanning tunneling microscopy (STM) at RT as well as at 250∘ C. The structural studies reveal a three dimensional growth mode of MgO on the Fe(110) surface giving dense MgO(111) films. As observed by STM, the initial deposition of MgO leads to the partial oxidation of the Fe(110) surface. Auger-electron spectroscopy as well as spin-polarized photoelectron spectroscopy measurements on the MgO/Fe(110) system confirm the FeO layer formation at the MgO/Fe(110) interface. TMR values of about 28 % at RT were measured in the Fe/MgO/Fe(110) MTJs.
[1] S. Yuasa et al., Nature Materials 3, (2004) 868.
[2] Yu. S. Dedkov et al., Phys. Rev. B 65, 064417 (2002).