ISBN 978-3-86853-829-8

978-3-86853-829-8, Reihe Physik

Stellan Bohlens
Interplay of Inhomogeneous Currents and Magnetization Textures

243 Seiten, Dissertation Universität Hamburg (2010), Softcover, B5

Zusammenfassung / Abstract

This thesis deals with the mutual interaction of non-equilibrium conduction electrons and spatially inhomogeneous ferromagnetic order parameters. For this purpose non-collinear magnetotransport is studied within linear response theory by means of a semiclassical transport framework. Particular emphasis is attached on spin-dependent transport properties with the prospect of spintronics applications. The magnetic vortex is as a selected aspect investigated in detail concerning current-induced magnetization dynamics.

For the case of a magnetic vortex the distinct manipulation of the magnetization texture via the spin-transfer torque phenomenon is exploited in a proposal for an unambiguous writing and reading mech- anism for a non-volatile magnetic memory device. A realization of a vortex random-access memory (VRAM) containing vortex cells that are controlled by alternating currents only is proposed. In a collinear electric current and magnetic field arrangement the dynamics of the vortex is entirely controlled by its handedness that is defined as the product of the vortex’ boolean, topological quantities chirality and core polarization. The vortex handedness as a bit representation allows direct mechanisms for reading and writing the bit information. The proposed scheme allows transferring the vortex into an unambiguous binary state regardless of its initial state within a sub-nanosecond time scale.