engleski

Highly efficient spin-current assisted domain wall depinning

The depinning of domain walls due to pure diffusive spin currents in a non-local spin valve was studied on a device consisting of two ferromagnetic permalloy elements, i.e. a wire and a half ring, with copper as the nonmagnetic spin conduit. An injected spin current is absorbed by the Py half ring where it exerts a spin torque on a domain wall placed below the Cu/Py interface. The wall depinning field was determined as a function of the spin current-density and the depinning efficiency is found to be 6 x 10^-14 Tm2/A, which is more than an order of magnitude larger than for conventional current induced domain wall motion. This high efficiency can also be reproduced theoretically, taking into account the strong surface torques exerted by the absorbed spin currents on the domain wall. Current work focuses on a somewhat different geometry consisting of two Py half rings which can be used to rule out possible Oersted field influences. Furthermore, geometries with a non-parallel alignment of the Py elements are being used to investigate the non-collinear spin transfer torque.

magnetic domain wall depinnig; pure diffusive spin currents; non-local spin valves

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