Published the March 19, 2021

Helium Ions Put Magnetic Skyrmions on the Track

Magnetic skyrmions are deemed to be the forerunners of novel spintronic applications. Due to their nanometric size and predicted efficient current-induced manipulation, magnetic skyrmions hold great promise as future information carriers in ultra-fast, high-density non-volatile memory and logic devices. While their observation and their current-driven motion at room temperature have been demonstrated, certain issues regarding their nucleation, stability, pinning, and the skyrmion Hall effect still need to be overcome to realise functional devices. Here, we demonstrate that focused He+ irradiation can be used to create and guide skyrmions in magnetic racetracks. We show that the reduction of the perpendicular magnetic anisotropyand the Dzyaloshinskii−Moriya interaction in the track defined by ion-irradiationleads to the formation of stable isolated skyrmions. Current-driven, skyrmion motion experiments and simulations reveal that the skyrmions move along the irradiated track, resulting in the suppression of the skyrmion Hall effect, and that the maximum skyrmion velocity can be enhanced by tuning themagnetic properties. These results open up a new path to nucleate and guide magnetic skyrmions in racetrack devices, bringing them one step closer to applications.


Nano Lett. 2021, 21, 7, 2989–2996

Roméo Juge1, Kaushik Bairagi1, Kumari Gaurav Rana1, Jan Vogel2, Mamour Sall3, Dominique Mailly4, Van Tuong Pham1, Qiang Zhang1, Naveen Sisodia1, Michael Foerster5, Lucia Aballe5, Mohamed Belmeguenai6, Yves Roussigné6, Stéphane Auffret1, Liliana D. Buda-Prejbeanu1, Gilles Gaudin1, Dafiné Ravelosona4, and Olivier Boulle1

1Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, Spintec, 38000 Grenoble, France

2Univ. Grenoble Alpes, CNRS, CNRS, 38000 Grenoble, France

3Spin-Ion Technologies, 91120 Palaiseau, France

4Centre de Nanosciences et de Nanotechnologies, CNRS, Universit ́e Paris-Saclay, 91120 Palaiseau, France

5ALBA Synchrotron Light Facility, 08290 Cerdanyola del Valles, Barcelona, Spain

6Laboratoire des Sciences des Procédés et des Matériaux, CNRS, Université Sorbonne


Figure caption

On  the  left,  a  magnetic  microscopy  image  showing  trains  of  skyrmions  100  nm  in  size  (white)  in magnetic  tracks  defined  by  a  focused  He+ionbeam.  These  tracks  are  separated  by  a  uniformly magnetised  region  (black)  which  acts  as a  barrier,  creating  channels  for  the  skyrmions  to  move  in  a straight  line.  This  is  shown  in  the  diagram onthe  right,  which  shows  two  irradiated  tracks  (in  red) separated by a uniformly magnetised region (in white).