Electron Holography and Magnetotransport Measurements Reveal Stabilized Magnetic Skyrmions in Fe1-xCoxSi Nanowires

• Published in: ACS nano Vol. 13; no. 7; pp. 7833 - 7841
• Main Authors: Mathur, Nitish, Stolt, Matthew J, Niitsu, Kodai, Yu, Xiuzhen, Shindo, Daisuke, Tokura, Yoshinori, Jin, Song
• Format: Journal Article
• Language: English
• Published: 23.07.2019
• ISSN: 1936-086X
• DOI: 10.1021/acsnano.9b02130

Magnetic skyrmions are topological spin textures that have shown promise for future nonvolatile memory devices. Herein, we report on the stability of magnetic skyrmions in alloyed cubic B20 Fe1-xCoxSi nanowires (NWs) determined using off-axis electron holography and magnetotransport measurements. This study presents the real space observation of one-dimensional skyrmion lattice in a NW of Fe1-xCoxSi which shows that the skyrmion phase in a Fe0.75Co0.25Si NW exists at lower applied magnetic fields (200 Oe) with a reduced domain size (28 ± 2 nm) in comparison to bulk and thin film samples. Magnetotransport measurements were used to observe the helimagnetic transition temperature dependence on the cobalt concentration in the Fe1-xCoxSi NWs. Field-dependent magnetoresistance measurements of Fe1-xCoxSi NWs under applied magnetic field parallel to the NW axis and their second derivative plots reveal the critical fields for the magnetic state transition at different temperatures. A representative magnetic phase diagram constructed with the results from transport measurements of a Fe0.81Co0.19Si NW clearly shows expanded stability region for magnetic skyrmions in the Fe1-xCoxSi NWs.