Strain-enhanced Dzyaloshinskii–Moriya interaction at Co/Pt interfaces

Abstract

The interfacial Dzyaloshinskii–Moriya interaction (DMI) is an essential ingredient for stabilizing chiral spin configurations in spintronic applications. Here, via first-principles calculations, we reveal the influence of lattice strain on DMI in Co/Pt interface. We observed a considerable enhancement for a certain lattice strain. Furthermore, a direct correlation is established between the DMI and interlayer distances dominated by the strain, which is attributed to a hybridization of electronic orbitals. This hybridization has also been presented as the microscopic origin of the interfacial DMI. We anticipate that our predictions provide new insights into the control of interfacial DMI for skyrmion-based spintronic devices.

Measuring interfacial Dzyaloshinskii-Moriya interaction in ultra-thin magnetic films

“…Also nucleation of domains occurs at pinning sites and single measurements may not be representative. In addition, strain in the thin films might play a role and in fact, several recent works investigate defect-or strain-induced DMI (Deger, 2020;Fernández-Pacheco et al, 2019;Michels et al, 2019). More research has to be dedicated to this complex, and a bit exotic topic, in order to understand defect related differences in the measurements.…”

Tuning the size of skyrmion by strain at the Co/Pt3 interfaces

“…For the well-studied theoretically and experimentally system Pd/Fe/Ir(111), the calculated skyrmion size is 6.5 nm ( Zhu et al., 2020a , 2020b ), which is very close to the experimental value, 5 nm ( Romming et al., 2013 ). Co layers on Pt(111) surface (Co/Pt) is a kind of classical metal interface with strong DMI, located in the interfacial Co layer, originating from spin-orbit energy provided by the adjacent nonmagnetic Pt layer ( Yang et al., 2015 ; Zimmermann et al., 2019 ; Deger, 2020 ; Gusev et al., 2020 ).…”

“…Among these Co/Pt researches, it is proved in both calculations ( Deger, 2020 ) and experiments ( Gusev et al., 2020 ) that strain could enhance the DMI at the interface. A strong variation (from 0.1 to 0.8 mJ/m 2 ) of the DMI constant is demonstrated at 0.1 in in-plane uniaxial deformation of the films and it even changes the sign of the DMI in the direction perpendicular to the strain direction ( Gusev et al., 2020 ).…”

“…Furthermore, it would be more convenient to reduce exchange coupling (EC) to reduce the size of skyrmions ( Zhu et al., 2020a , 2020b ). However, studies on the overall effect of deformation on skyrmions are still lacking for Co/Pt interface ( Deger, 2020 ; Gusev et al., 2020 ) and other systems ( Shibata et al., 2015 ; Nii et al., 2015 ; Wu et al., 2015 ; Liu et al., 2017 ; Yu et al., 2018 ; Koretsune et al., 2015 ). Therefore, we would investigate how the deformation in the Co/Pt interface simultaneously changes both EC and DMI, and jointly affects the size of the skyrmion.…”

First Principles Calculation of Dzyaloshinskii-Moriya Interaction: A Green's function Approach

“…Developing an accurate and efficient first principles approach to calculate the DMI and its manipulation via current [61], electric field [62], and strain [63,64] is of paramount importance in the spintronics community. In this paper, we employ Greens function method to calculate the atomistic exchange coupling from the magnon band structure in the spin-spiral regime.…”