Regensburg 2007 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

MA: Fachverband Magnetismus

MA 12: Spindependent Transport I

MA 12.1: Vortrag

Dienstag, 27. März 2007, 10:15–10:30, H22

Spin-valve effect and spin precession in lateral all-metal spin-valve devices — •Jeannette Wulfhorst, Alexander van Staa, Ulrich Merkt, and Guido Meier — Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Jungiusstrasse 11, 20355 Hamburg (Germany)

The efficiency of electronic devices could be improved drastically by the use of spin polarized currents. Important properties like the spin precession and the spin-diffuson length can be analyzed with the help of lateral spin valves. At low temperatures and with an applied external magnetic field we examine spin valves which consist of two ferromagnetic permalloy electrodes and an aluminum strip either with or without integrated aluminum oxide tunnel barrier. A tunnel barrier can enlarge the spin polarization of the injected current [1]. Due to the shape anisotropy the electrodes are quasi-single domain and can be oriented parallel or antiparallel in an external magnetic field. To obtain the coercive fields of the electrodes we have measured the anisotropic magnetoresistance of both. The nonlocal spin-valve effect is determined by using the first electrode to inject a spin polarized current into the aluminum strip and to detect it with the aid of the other electrode [2]. With an out-of-plane external magnetic field spin precession, i.e. the Hanle-effect, is observed and fitted with the model used in Ref. [1]. We estimate a spin diffusion length in aluminum of 329 ± 19 nm.

[1] F.J. Jedema et al., Nature 416, 713 (2002)

[2] A. van Staa and G. Meier, Physica E 31, 142 (2006)