Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 91: [MA] Poster II
O 91.50: Poster
Freitag, 30. März 2012, 11:00–14:00, Poster A
Spin-transfer torque experiments on Co2MnSi/Ag/Co2MnSi (001) nanopillars — •Şaban Tirpanci1,2, Daniel E. Bürgler1, Yuya Sakuraba3, Subrojati Bosu3, Koki Takanashi3, and Claus M. Schneider1 — 1Electronic Properties (PGI-6) and JARA-FIT, Forschungszentrum Jülich, Jülich, Germany — 2GIT, Gebze, Turkey — 3IMR, Tohoku University, Sendai, Japan
The Heusler alloy Co2MnSi (CMS) is a half-metallic ferromagnet with a Curie temperature above room temperature (RT) and high spin polarization, which in combination with Ag spacer layers yields large GMR ratios of up to 36 percent at RT [1]. Therefore, CMS is a very promising material for new spintronic devices. Fully epitaxial CMS/Ag /CMS(001) thin films are prepared by UHV magnetron sputtering [1]. Ellipsoidal nanopillars with diameters between 120 nm to 300 nm are fabricated by e-beam lithography and ion-beam etching for spin-torque measurements in current-perpendicular-plane (CPP) geometry. The two CMS layers of 20 and 5 nm thickness act as fixed and free layer, respectively, and are separated by 8 nm Ag. Previous work [1,2] is extended by performing DC and HF measurements at low temperatures in order to study the influence of the increased polarization on critical currents for current-induced switching and magnetic excitation as well as the efficiency of injection locking [3] as a prerequisite for synchronization of several spin-torque oscillators.
[1] Y. Sakuraba et al.,. Phys. Rev. B 82, 094444 (2010)
[2] R. Okura et al., Appl. Phys. Lett. 99, 052510 (2011)
[3] R. Lehndorff et al., Appl. Phys. Lett. 97, 142503 (2010)