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arXiv · 1907.07470

Inhomogeneous domain walls in spintronic nanowires

Lars Siemer·Ivan Ovsyannikov·Jens D. M. Rademacher
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Abstract

In case of a spin-polarized current, the magnetization dynamics in nanowires are governed by the classical Landau-Lifschitz equation with Gilbert damping term, augmented by a typically non-variational Slonczewski term. Taking axial symmetry into account, we study the existence of domain wall type coherent structure solutions, with focus on one space dimension and spin-polarization, but our results also apply to vanishing spin-torque term. Using methods from bifurcation theory for arbitrary constant applied fields, we prove the existence of domain walls with non-trivial azimuthal profile, referred to as inhomogeneous. We present an apparently new type of domain wall, referred to as non-flat, whose approach of the axial magnetization has a certain oscillatory character. Additionally, we present the leading order mechanism for the parameter selection of flat and non-flat inhomogeneous domain walls for an applied field below a threshold, which depends on anisotropy, damping, and spin-transfer. Moreover, numerical continuation results of all these domain wall solutions are presented.

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Lars Siemer, Ivan Ovsyannikov, Jens D. M. Rademacher. 2019-07-17. Inhomogeneous domain walls in spintronic nanowires. https://doi.org/10.1088/1361-6544%2Fab6f4e

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