English

Inhomogeneous domain walls in spintronic nanowires

Analysis of PDEs 2020-06-24 v2 Mathematical Physics Dynamical Systems math.MP

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.

Keywords

Cite

@article{arxiv.1907.07470,
  title  = {Inhomogeneous domain walls in spintronic nanowires},
  author = {Lars Siemer and Ivan Ovsyannikov and Jens D. M. Rademacher},
  journal= {arXiv preprint arXiv:1907.07470},
  year   = {2020}
}

Comments

40 pages, 14 figures