Proposal for a standard problem for micromagnetic simulations including spin-transfer torque

• Main Authors: Najafi, M. (Author), kruger, B. (Author), Bohlens, S. (Author), Franchin, M. (Author), Fangohr, H. (Author), Vanhaverbeke, A. (Author), Allenspach, R. (Author), Bolte, M. (Author), Merkt, U. (Author), Pfannkuche, D. (Author), Moller, D.P.F (Author), Meier, G. (Author)
• Format: Article
• Language: English
• Published: 2009-06.
• Subjects: Article
• Online Access: Get fulltext

 The spin-transfer torque between itinerant electrons and the magnetization in a ferromagnet is of fundamental interest for the applied physics community. To investigate the spin-transfer torque, powerful simulation tools are mandatory. We propose a micromagnetic standard problem includingthe spin-transfer torque that can be used for the validation and falsication of micromagnetic simulation tools. The work is based on the micromagnetic model extended by the spin-transfer torque in continuously varying magnetizations as proposed by Zhang and Li. The standard problem geometry is a permalloy cuboid of 100 nm edge length and 10 nm thickness, which contains a Landau pattern with a vortex in the center of the structure. A spin-polarized dc current density of 1012 A/m2 flows laterally through the cuboid and moves the vortex core to a new steady-state position. We show that the new vortex-core position is a sensitive measure for the correctness of micromagnetic simulatorsthat include the spin-transfer torque. The suitability of the proposed problem as a standard problem is tested by numerical results from four different finite-difference and finite-element-based simulation tools.