Berlin 2005 – wissenschaftliches Programm

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MA: Magnetismus

MA 20: Poster:Schichten(1-29),Spintrsp(30-45),Ex-Bias(46-63),Spindyn(64-75),Mikromat.(76-80),Cluster(81-94),Abbv.(95-99),Obflm(100-02),SpElek.(103-09),E-Theo(110-14),Mikromag.(115-16),Spin+PÜ(117-26),Mag.Mat.(127-51),Meth.(152-55),Mol.Mag(156-59),Kondo(160-65

MA 20.39: Poster

Montag, 7. März 2005, 14:00–18:00, Poster TU C

Heusler alloy based MTJs with afm coupled reference layer system — •J. Schumann, H. Vinzelberg, R. Kaltofen, D. Elefant, I. Mönch, J. Thomas, and M. Hecker — IFW Dresden, POB 270116, 01171 Dresden

For advanced TMR switching elements applied e.g. in MRAMs, magnetic thin films with high spin polarization are indispensable. Half-metallic Heusler alloys are expected to be promising candidates for the magnetic components in prospective spin-electronic devices. Band structure studies for the compound Co₂CrAl [1] have proved the half-metallic state to be preserved in the immediate surface region. This is important for the spin transport through MTJs. A partial substitution of Fe for Cr enhances the Curie temperature ensuring thus stable working parameters at 300 K. Co₂Cr_1−xFe_xAl based MTJs with an Al_xO_y barrier and an IrMn pinned CoFe top electrode present the typical switching behavior and a TMR ratio of ca. 28 % at 4.2K. The influence of the sputter conditions (growth rate, Ar-pressure, substrate temperature) on the structural and magnetic properties of the Heusler films is studied and the consequences on the TMR process are discussed.

[1] I. Galanakis, J. Phys. C. 14, 6329 (2002).