Dresden 2011 – scientific programme

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MA: Fachverband Magnetismus

MA 63: Poster II (Surface Magnetism/ Magnetic Imaging/ Topological Insulators/ Spin Structures and Magnetic Phase Transitions/ Graphene/ Magnetic Thin Films/ Magnetic Semiconductors/ Magnetic Half-metals and Oxides/ Spin-dependent Transport/ Spin Excitations and Spin Torque/ Spin Injection and Spin Currents in Heterostructures/ Spintronics/ Magnetic Storage and Applications)

MA 63.87: Poster

Friday, March 18, 2011, 11:00–14:00, P2

Ab initio calculations of spin dynamics in magnetic tunnel junctions — •Michael Czerner and Christian Heiliger — I. Physikalisches Institut, Justus Liebig University Giessen, D-35392, Germany

Magnetic tunnel junctions are widely used in spintronics. A key issue is a deep understanding of the physical mechanisms of spin dynamics in these systems. In particular, it is useful to have a theoretical model that can calculate the spin transfer torque as well as the magnetic damping in tunnel junctions. For this purpose we extend our non-equilibrium Keldysh formalism implemented in the Korringa-Kohn-Rostoker Green's function method [1] to treat the system full relativistically. In addition, we extend our implementation to a full potential description to investigate the role of exact cell treatment. The full relativistic treatment as well as the full potential description are compared to our previous results [2]. We will discuss different magnetic lead materials including Fe, Co, and FeCo alloys. These different materials are discussed with respect to their applicability for storage elements in magnetic memory. For this purpose a high spin-transfer torque but a low magnetic damping is desired. We calculate the spin-transfer torque for the whole tunnel junction whereas for the damping we use the bulk material neglecting interface effects.

[1] C. Heiliger, M. Czerner, B. Yu. Yavorsky, I. Mertig, M. D. Stiles, J. Appl. Phys. 103, 07A709 (2008)

[2] C. Heiliger and M.D. Stiles, Phys. Rev. Lett. 100, 186805 (2008).