コンピュータのメモリや高効率マイクロエレクトロニクスへの応用が期待できる。 Could be applicable to computer memory and high-efficiency microelectronics
2023-03-30 アルゴンヌ国立研究所(ANL)
Simulation capturing the different swirling textures of skyrmions and merons observed in ferromagnet thin film. (Image by University of Edinburgh/based on microscopy images collected by Argonne on samples prepared at MagLab.)
この物質は、数から10原子程度の薄いシート状で、2Dフェロマグネットと呼ばれている。このチームは、スカイルミオンとメロンの2種類の磁場が超薄い材料に共存できることを初めて観測し、これらの磁場をビットに使用できる可能性があることを示した。スカイルミオンは、約100ナノメートルの大きさで、ノットのストランドに似た複雑なパターンで磁場が流れる。
一方、メロンは大きさが同じくらいで、渦巻きのように磁場が流れる。
この調査は、Advanced Materialsに掲載された。
＜関連情報＞
- https://www.anl.gov/article/ultrasmall-swirling-magnetic-vortices-detected-in-ironcontaining-material
- https://onlinelibrary.wiley.com/doi/10.1002/adma.202212087
中心対称なファンデルワールス強磁性体Fe5-xGeTe2におけるメロンとスキールミンの共存 Coexistence of Merons with Skyrmions in the Centrosymmetric Van Der Waals Ferromagnet Fe5–xGeTe2
Brian W. Casas, Yue Li, Alex Moon, Yan Xin, Conor McKeever, Juan Macy, Amanda K. Petford-Long, Charudatta M. Phatak, Elton J. G. Santos, Eun Sang Choi, Luis Balicas
Advanced Materials Published: 13 February 2023
DOI:https://doi.org/10.1002/adma.202212087
Abstract
Fe5–xGeTe2 is a centrosymmetric, layered van der Waals (vdW) ferromagnet that displays Curie temperatures Tc (270–330 K) that are within the useful range for spintronic applications. However, little is known about the interplay between its topological spin textures (e.g., merons, skyrmions) with technologically relevant transport properties such as the topological Hall effect (THE) or topological thermal transport. Here, via high-resolution Lorentz transmission electron microscopy, it is shown that merons and anti-meron pairs coexist with Néel skyrmions in Fe5–xGeTe2 over a wide range of temperatures and probe their effects on thermal and electrical transport. A THE is detected, even at room T, that senses merons at higher T’s, as well as their coexistence with skyrmions as T is lowered, indicating an on-demand thermally driven formation of either type of spin texture. Remarkably, an unconventional THE is also observed in absence of Lorentz force, and it is attributed to the interaction between charge carriers and magnetic field-induced chiral spin textures. These results expose Fe5–xGeTe2 as a promising candidate for the development of applications in skyrmionics/meronics due to the interplay between distinct but coexisting topological magnetic textures and unconventional transport of charge/heat carriers.
