Regensburg 2013 – scientific programme

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MA: Fachverband Magnetismus

MA 26: Magnetic Thin Films I of 2

MA 26.6: Talk

Wednesday, March 13, 2013, 11:00–11:15, H3

High TMR ratio in Co₂FeSi and Fe₂CoSi based magnetic tunnel junctions — •Christian Sterwerf¹, Markus Meinert¹, Manuel Glas¹, Jan-Michael Schmalhorst¹, Günter Reiss¹, and Elke Arenholz² — ¹Thin Films and Physics of Nanostructures, Department of Physics, Bielefeld University, 33501 Bielefeld, Germany — ²Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

Co and Fe based Heusler compounds are promising materials for spintronic applications, especially because of their high magnetic moments and their high Curie temperatures. More recently, inverse Heusler compounds such as Fe₂CoSi have been proposed as half-metallic electrode materials. [1]

Epitaxial Co_2−xFe_1+xSi thin films with x ranging from 0 to 1 were prepared by DC and RF magnetron co-sputtering on MgO (001) substrates. The crystallographic order and the transition from regular to the inverse Heusler compound Fe₂CoSi was investigated by x-ray diffraction. The films exhibit a high degree of structural order. Soft x-ray absorption, magnetic circular dichroism (XMCD) and ferromagnetic resonance (FMR) measurements were performed to determine the magnetic properties.

Magnetic tunnel junctions with MgO tunneling barrier and CoFe counter electrode exhibit TMR ratios ranging up to 159% at room temperature.

[1] Luo et al., JPD 40, 7121 (2007)