Room-Temperature Zero-Field <i>kπ-</i>Skyrmions and Their Field-Driven Evolutions in Chiral Nanodisks.

Zhang, Yongsen; Shi, Meng; Wang, Weiwei; Xu, Xitong; Tian, Mingliang; Song, Dongsheng; Du, Haifeng · Nano Lett · 2023

basic_science · Level V

Where this comes from

Abstract

Target skyrmion, characterized by a central skyrmion surrounded by a series of concentric cylinder domains known as <i>kπ-</i>skyrmions (<i>k</i> ≥ 2), holds promise as a novel storage state in next-generation memories. However, target skyrmions comprising one or more concentric cylindrical domains have not been observed in chiral magnets, particularly at room temperature. In this study, we experimentally achieved <i>kπ-</i>skyrmions (<i>k</i> = 2, 3, and 4) with diameters of ∼220, 320, and 410 nm, respectively, and room-temperature stability under zero magnetic field by tightly confining these topological spin textures in β-Mn-type Co<sub>8</sub>Zn<sub>10</sub>Mn<sub>2</sub> nanodisks. The magnetic configurations and their field-driven evolutions were simultaneously investigated by using in situ off-axis electron holography. In combination with numerical simulations, we further investigated the dependence of <i>k</i><sub>max</sub> on the nanodisk diameter. These findings highlight the potential of <i>k</i>π-skyrmions as information carriers and offer insights into manipulation of <i>k</i>π-skyrmions in the future.