Regensburg 2013 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 5: Spintronics: mainly interfaces and heterostructures
HL 5.1: Vortrag
Montag, 11. März 2013, 09:30–09:45, H16
Spin Transport and Spin Dephasing in ZnO — Matthias Althammer1,2, Eva-Maria Karrer-Müller1, Sebastian T. B. Goennenwein1, •Matthias Opel1, and Rudolf Gross1,3 — 1Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany — 2University of Alabama, Center for Materials for Information Technology MINT, Tuscaloosa, AL 35487 USA — 3Physik-Department, TU München, 85748 Garching, Germany
The wide bandgap semiconductor ZnO is interesting for spintronic applications because of its small spin-orbit coupling implying a large spin coherence length. Utilizing vertical spin valve devices with ferromagnetic electrodes (TiN/Co/ZnO/Ni/Au), we create and detect a spin-polarized ensemble of electrons and demonstrate the transport of this spin information across several nanometers in ZnO [1]. The measured magnetoresistance of up to 8.4% at 2 K agrees well with the prediction of a two spin channel model with spin-dependent interface resistance [2]. Fitting the data yields spin diffusion lengths of 10.8 nm (2 K), 10.7 nm (10 K), and 6.2 nm (200 K) in ZnO, corresponding to spin lifetimes of 2.6 ns (2 K), 2.0 ns (10 K), and 31 ps (200 K) [1]. The evolution of the measured spin relaxation rates with temperature is consistent with the D’yakonov-Perel’ mechanism above 30 K. For future semiconductor spintronic devices, such all-electrical experiments will be mandatory to extract the relevant spin transport parameters.
This work was supported by the DFG via SPP 1285 (GR 1132/14).
[1] M. Althammer et al., Appl. Phys. Lett. 101, 082404 (2012).
[2] A. Fert and H. Jaffrès, Phys. Rev. B 64, 184420 (2001).