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Wednesday, January 9, 2019
Abstract-Micromagnetic modeling of terahertz oscillations in an antiferromagnetic material driven by the spin Hall effect
V. Puliafito, R. Khymyn, M. Carpentieri, B. Azzerboni, V. Tiberkevich, A. Slavin, and G. Finocchio
The realization of terahertz (THz) sources is a fundamental aspect for a wide range of applications. Over different approaches, compact THz oscillators can be realized, taking advantage of dynamics in antiferromagnetic thin films driven by the spin Hall effect. Here we perform a systematic study of these THz oscillators within a full micromagnetic solver based on the numerical solution of two coupled Landau-Lifshitz-Gilbert-Slonczewski equations, considering ultrathin films. We find two different dynamical modes depending on the strength of the Dzyaloshinskii-Moriya interaction (DMI). At low DMI, a large-amplitude precession is excited, where both the magnetizations of the sublattices are in a uniform state and rotate in the same direction. At large enough DMI, the ground state of the antiferromagnet becomes nonuniform and the antiferromagnetic dynamics is characterized by ultrafast domain-wall motion.