Dresden 2014 – scientific programme

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MA: Fachverband Magnetismus

MA 37: Spin Torque and Spin Excitations I

MA 37.5: Talk

Thursday, April 3, 2014, 10:30–10:45, HSZ 401

Self-consistent determination of the key spin transfer torque parameters from spin wave Doppler experiments — •Helmut Körner, Jean-Yves Chauleau, Hans Bauer, Johannes Stigloher, Georg Woltersdorf, and Christian Back — Department of Physics, Universität Regensburg, D-93040 Regensburg, Germany

Action of spin-polarized electric currents on magnetic textures is now well established both from experimental and theoretical viewpoints [1]. These effects are known as spin-transfer torques (STT). In the case of continuous magnetic distributions, current-induced domain wall (DW) dynamics is a recurrent system of investigation. However, DWs are fairly complicated magnetic structures whose dynamics is consequence of a subtle combination of damping, spin-drift velocity and non-adiabatic parameter. An alternative to domain walls dynamics has been reported by Vlaminck and Bailleul. The current-induced shift of spinwave resonances (spinwave Doppler shift) has been experimentally evidenced using an inductive approach [2].

In this study, we experimentally determine the key spin transfer torque parameters in a fully self-consistent approach by optically accessing current-induced spinwave dynamics in Permalloy stripes using time-resolved scanning Kerr microscopy (TRMOKE). Our technique allows precise access to spinwave characteristics and their current-induced changes, especially the change in decay length which carries the information about the non-adiabaticity.

[1] D.C. Ralph and M.D. Stiles, JMMM 321, 2508 (2009) [2] V. Vlaminck and M. Bailleul, Science 322, 410 (2008)