Strongly pinned skyrmionic bubbles and higher-order nonlinear Hall resistances at the interface of Pt/FeSi bilayer

T. Hori; N. Kanazawa; K. Matsuura; H. Ishizuka; K. Fujiwara; A. Tsukazaki; M. Ichikawa; M. Kawasaki; F. Kagawa; M. Hirayama; Y. Tokura

arXiv · 2311.08730

Strongly pinned skyrmionic bubbles and higher-order nonlinear Hall resistances at the interface of Pt/FeSi bilayer

T. Hori·N. Kanazawa·K. Matsuura·H. Ishizuka·K. Fujiwara·A. Tsukazaki·M. Ichikawa·M. Kawasaki·F. Kagawa·M. Hirayama·Y. Tokura

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Abstract

Engineering of magnetic heterostructures for spintronic applications has entered a new phase, driven by the recent discoveries of topological materials and exfoliated van der Waals materials. Their low-dimensional properties can be dramatically modulated in designer heterostructures via proximity effects from adjacent materials, thus enabling the realization of diverse quantum states and functionalities. Here we investigate spin-orbit coupling (SOC) proximity effects of Pt on the recently discovered quasi-two-dimensional ferromagnetic state at FeSi surface. Skyrmionic bubbles (SkBs) are formed as a result of the enhanced interfacial Dzyloshinskii-Moriya interaction. The strong pinning effects on the SkBs are evidenced from the significant dispersion in size and shape of the SkBs and are further identified as a greatly enhanced threshold current density required for depinning of the SkBs. The robust integrity of the SkB assembly leads to the emergence of higher-order nonlinear Hall effects in the high current density regime, which originate from nontrivial Hall effects due to the noncollinearity of the spin texture, as well as from the current-induced magnetization dynamics via the augmented spin-orbit torque.

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T. Hori, N. Kanazawa, K. Matsuura, H. Ishizuka, K. Fujiwara, A. Tsukazaki, M. Ichikawa, M. Kawasaki, F. Kagawa, M. Hirayama, Y. Tokura. 2023-11-15. Strongly pinned skyrmionic bubbles and higher-order nonlinear Hall resistances at the interface of Pt/FeSi bilayer. https://arxiv.org/abs/2311.08730

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