title: Observation of stable Néel skyrmions in cobalt/palladium multilayers with Lorentz transmission electron microscopy.
abstract: Néel skyrmions are of high interest due to their potential applications in a variety of spintronic devices, currently accessible in ultrathin heavy metal/ferromagnetic bilayers and multilayers with a strong Dzyaloshinskii-Moriya interaction. Here we report on the direct imaging of chiral spin structures including skyrmions in an exchange-coupled cobalt/palladium multilayer at room temperature with Lorentz transmission electron microscopy, a high-resolution technique previously suggested to exhibit no Néel skyrmion contrast. Phase retrieval methods allow us to map the internal spin structure of the skyrmion core, identifying a 25 nm central region of uniform magnetization followed by a larger region characterized by rotation from in- to out-of-plane. The formation and resolution of the internal spin structure of room temperature skyrmions without a stabilizing out-of-plane field in thick magnetic multilayers opens up a new set of tools and materials to study the physics and device applications associated with chiral ordering and skyrmions.
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Singapore.
authors.forename: Shawn D
authors.initials: SD
authors.lastname: Pollard
authors.affiliation: Material Science and Engineering Department, Stony Brook University, Stony Brook, New York 11794, USA.|Condensed Matter Physics and Material Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Garlow
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Singapore.
authors.forename: Jiawei
authors.initials: J
authors.lastname: Yu
authors.affiliation: Condensed Matter Physics and Material Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA.|Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Material Science and Engineering Department, Stony Brook University, Stony Brook, New York 11794, USA.|Condensed Matter Physics and Material Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Yimei
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Singapore.
authors.forename: Hyunsoo
authors.initials: H
authors.lastname: Yang