Observation of Robust Néel Skyrmions in Metallic PtMnGa. Issue 7 (26th December 2019)

• Record Type: Journal Article
• Authors: Srivastava, Abhay K.; Devi, Parul; Sharma, Ankit K.; Ma, Tianping; Deniz, Hakan; Meyerheim, Holger L.; Felser, Claudia; Parkin, Stuart S. P.
• Is Part Of: Advanced materials. Volume 32:Issue 7(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-12-26
• Subjects: Lorentz transmission electron microscopy -- non‐centrosymmetric -- skyrmions -- spintronics; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201904327
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Over the past decade the family of chiral noncollinear spin textures has continued to expand with the observation in metallic compounds of Bloch‐like skyrmions in several B20 compounds, and antiskyrmions in a tetragonal inverse Heusler. Néel like skyrmions in bulk crystals with broken inversion symmetry have recently been seen in two distinct nonmetallic compounds, GaV4 S8 and VOSe2 O5 at low temperatures (below ≈13 K) only. Here, the first observation of bulk Néel skyrmions in a metallic compound PtMnGa and, moreover, at high temperatures up to ≈220 K is reported. Lorentz transmission electron microscopy reveals the chiral Néel character of the skyrmions. A strong variation is reported of the size of the skyrmions on the thickness of the lamella in which they are confined, varying by a factor of 7 as the thickness is varied from ≈90 nm to ≈4 µm. Moreover, the skyrmions are highly robust to in‐plane magnetic fields and can be stabilized in a zero magnetic field using suitable field‐cooling protocols over a very broad temperature range to as low as 5 K. These properties, together with the possibility of manipulating skyrmions in metallic PtMnGa via current induced spin–orbit torques, make them extremely exciting for future spintronic applications. Abstract : Robust Néel skyrmions are observed in the metallic compound PtMnGa. The structure of this material is shown to be non‐centrosymmetric, thereby supporting the observation of a chiral spin texture. Of great interest, the size of the skyrmions increases significantly from ≈90 to ≈720 nm as the thickness of a [0001] oriented lamella is varied from 90 nm to 4 µm.