Optimal control of magnetization dynamics in ferromagnetic heterostructures by spin--polarized currents

Abstract

We study the switching-process of the magnetization in a ferromagnetic-normal-metal multilayer system by a spin polarized electrical current via the spin transfer torque. We use a spin drift-diffusion equation (SDDE) and the Landau-Lifshitz-Gilbert equation (LLGE) to capture the coupled dynamics of the spin density and the magnetization dynamic of the heterostructure. Deriving a fully analytic solution of the stationary SDDE we obtain an accurate, robust, and fast self-consistent model for the spin-distribution and spin transfer torque inside general ferromagnetic/normal metal heterostructures. Using optimal control theory we explore the switching and back-switching process of the analyzer magnetization in a seven-layer system. Starting from a Gaussian, we identify a unified current pulse profile which accomplishes both processes within a specified switching time.

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References in corpus (7)

• Spin Transfer Torques
• Spin-Torque Driven Magnetization Dynamics: Micromagnetic Modelling
• Spin-torque switching: Fokker-Planck rate calculation
• Spin-Torque Ferromagnetic Resonance Measurements of Damping in Nanomagnets
• Theoretical limit of the minimal magnetization switching field and the optimal field pulse for Stoner particles
• Enhancement of the Gilbert damping constant due to spin pumping in noncollinear ferromagnet/nonmagnet/ferromagnet trilayer systems
• Optimal Control for Open Quantum Systems: Qubits and Quantum Gates

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