title: Highly stable skyrmion state in helimagnetic MnSi nanowires.
abstract: Topologically stable magnetic skyrmions realized in B20 metal silicide or germanide compounds with helimagnetic order are very promising for magnetic memory and logic devices. However, these applications are hindered because the skyrmions only survive in a small temperature-field (T-H) pocket near the critical temperature Tc in bulk materials. Here we demonstrate that the skyrmion state in helimagnetic MnSi nanowires with varied sizes from 400 to 250 nm can exist in a substantially extended T-H region. Magnetoresistance measurements under a moderate external magnetic field along the long axis of the nanowires (H∥) show transitions corresponding to the skyrmion state from Tc ∼32 K down to at least 3 K, the lowest temperature in our measurement. When the field is applied perpendicular to the wire axis (H⊥), the skyrmion state was not resolvable using the magnetoresistance measurements. Our analysis suggests that the shape-induced uniaxial anisotropy might be responsible for the stabilization of skyrmion state observed in nanowires.
authors.affiliation: High Magnetic Field Laboratory, Chinese Academy of Science , Hefei 230031, Anhui, People's Republic of China.
authors.forename: Haifeng
authors.initials: H
authors.lastname: Du
authors.forename: John P
authors.initials: JP
authors.lastname: DeGrave
authors.forename: Fei
authors.initials: F
authors.lastname: Xue
authors.forename: Dong
authors.initials: D
authors.lastname: Liang
authors.forename: Wei
authors.initials: W
authors.lastname: Ning
authors.forename: Jiyong
authors.initials: J
authors.lastname: Yang
authors.forename: Mingliang
authors.initials: M
authors.lastname: Tian
authors.forename: Yuheng
authors.initials: Y
authors.lastname: Zhang
authors.forename: Song
authors.initials: S
authors.lastname: Jin