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MA: Fachverband Magnetismus

MA 49: POSTER II

MA 49.26: Poster

Donnerstag, 19. März 2015, 15:00–18:00, Poster A

Preparation and characterization of perpendicularly magnetized Mn_{3± x}Ge thin films — •Manuel Glas¹, Daniel Ebke², and Günter Reiss¹ — ¹Center for Spinelectronic Materials and Devices, Physics Department, Bielefeld University, Germany. — ²Max-Planck-Institute for Chemical Physics of Solids, Dresden, Germany

The continuous miniaturization process for spintronic devices requires consistently new materials with a low current density for spin transfer torque (STT) switching. The tetragonally distorted Mn_3−xGa seemed to be a promising candidate for STT-switching MRAM devices. However, to achieve a high TMR effect the interface between the ferromagnetic electrodes and MgO barrier plays an important role. Recent results showed that a Ga/MgO interface lowers the TMR effect drastically.[1] Therefore we replaced the Ga by Ge, due to the predicted non-vanishing TMR effect.[1] Different Mn_{3± x}Ge (x = -0.4, 0.2, 0.6) stoichiometries were prepared on SrTiO₃ substrates to achieve epitaxial (001)-oriented thin films. The crystallographic and magnetic properties were investigated by X-ray diffraction, X-ray reflection and anomalous Hall effect. All samples showed a single D0₂₂ phase. However, the surface roughness and magnetic properties exhibit a strong dependence on the stoichiometry. The lowest surface roughness of 1.3 nm and highest perpendicular anisotropy (µ₀ H_c = 3.7T) was found for Mn_3.2Ge. By increasing the Mn content to Mn_3.6Ge an increasing in-plane anisotropy was observed.
Y. Miura and M. Shirai, Magnetics, IEEE Transactions on 50, 1 (2014).