2021/02/02 by Zhendong Chi, Yong‐Chang Lau, Chi, Zhendong +33
Engineering · Materials Science · Physics and Astronomy · #FOS: Physical sciences #Magnetic Properties and Applications #Magnetic properties of thin films #Magneto-Optical Properties and Applications #Materials Science (cond-mat.mtrl-sci)
paper · pdf · doi:10.48550/arxiv.2102.01283
openalex publication_date 2021/02/02 · openalex created_date 2022/08/17 · openalex updated_date 2026/07/28
We have studied the Co layer thickness dependences of magnetocrystalline anisotropy (MCA), Dzyaloshinskii-Moriya interaction (DMI), and orbital moment anisotropy (OMA) in W/Co/Pt trilayers, in order to clarify their correlations with each other. We find that the MCA favors magnetization along the film normal and monotonically increases with decreasing effective magnetic layer thickness (teff). The magnitude of the Dzyaloshinskii-Moriya exchange constant (|D|) increases with decreasing teff until teff ∼1 nm, below which |D| decreases. The MCA and |D| scale with 1/teff for teff larger than ∼1 nm, indicating an interfacial origin. The increase of MCA with decreasing teff continues below teff ∼ 1 nm, but with a slower rate. To clarify the cause of the teff dependences of MCA and DMI, the OMA of Co in W/Co/Pt trilayers is studied using x-ray magnetic circular dichroism (XMCD). We find non-zero OMA when teff is smaller than ∼0.8 nm. The OMA increases with decreasing teff more rapidly than what is expected from the MCA, indicating that factors other than OMA contribute to the MCA at small teff. The teff dependence of the OMA also suggests that |D| at teff smaller than ∼1 nm is not related to the OMA at the interface. We propose that the growth of Co on W results in a strain and/or texture that reduces the interfacial DMI, and, to some extent, MCA at small teff.