Interlayer exchange coupling in Pt/Co/Ir multilayers films

Magnetic Skyrmions with fascinating hurricane-like twisted spin textures have attracted intense attention recently because of their unusual physical properties and potential applications in new magnetic storage media and devices. In magnetic multilayer thin films with perpendicular magnetic anisotropy (PMA), the interfacial Dzyaloshinskii-Moriya interaction (iDMI) favors a faster rotation of the spins and can stabilize Skyrmions at room temperature [1].
Recently, Skyrmions have been realized in Pt/Co/Ir multilayer films with PMA and iDMI [2]. In this work, we find that the interlayer exchange coupling (IEC) can also be introduced in Pt/Co/Ir multilayer films. The IEC has an oscillatory behavior with film thickness. Its magnitude is comparable to that of PMA and iDMI. It can be antiferromagnetic coupling with characteristic multiple-step switching in the hysterics loops. Our results suggest IEC in Pt/Co/Ir can be an additional magnetic energy to tune Skyrmions. Moreover, the antiferromagnetic IEC in Pt/Co/Ir thin films can be exploited to realize new types of Skyrmions such as antiferromagnetic Skyrmions.

[1] SampaioJ, et al., Nat Nano 8, 839 (2013).
[2] C. Moreau Luchaire, et al., Nat Nano 11, 444 (2016).