2021/08/24 by Jeffrey A. Brock, Brock, Jeffrey A., Eric E. Fullerton +1
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Magnetic Properties and Applications #Magnetic Properties of Alloys #Magnetic properties of thin films #Materials Science (cond-mat.mtrl-sci)
paper · pdf · doi:10.48550/arxiv.2108.10973
openalex publication_date 2021/08/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report the experimental observation of micron-scale magnetic skyrmions at\nroom temperature in several Pt/Co-based thin film heterostructures designed to\npossess a low exchange stiffness, perpendicular magnetic anisotropy, and a\nmodest interfacial Dzyaloshinskii-Moriya interaction (iDMI). We find both\nexperimentally and by micromagnetic and analytic modeling that the combined\naction of low exchange stiffness and modest iDMI eliminates the energetic\npenalty associated with forming domain walls in thin film heterostructures.\nWhen the domain wall energy density approaches negative values, the remanent\ndomain morphology transitions from a uniform state to a labyrinthian stripe\nphase. A low exchange stiffness, indicated by a reduction in the Curie\ntemperature below 400 K, is achieved in Pt/Co, Pt/Co/Ni, and Pt/Co/Ni/Re\nstructures by reducing the Co thickness to the ultrathin limit (< 0.3 nm). A\nsimilar effect occurs in thicker Pt/Co/NixCu1-x structures when the Ni layer is\nalloyed with Cu. At this transition in domain morphology, skyrmion phases are\nstabilized when a small (< 1 mT) perpendicular magnetic field is applied and\ncurrent-induced skyrmion motion including the skyrmion Hall effect is observed.\nThe temperature and thickness-induced morphological phase transitions observed\nare similar to the well-studied spin reorientation transition that occurs in\nthe ultrathin limit, but we find that the underlying energy balances are\nsubstantially modified by the presence of an iDMI.\n