Key Points in the Determination of the Interfacial Dzyaloshinskii-Moriya Interaction From Asymmetric Bubble Domain Expansion

Different models have been used to evaluate the interfacial Dzyaloshinskii-Moriya interaction (DMI) from the asymmetric bubble expansion method using magneto-optics. Here, we investigate the most promising candidates over a range of different magnetic multilayers with perpendicular anisotropy. Models based on the standard creep hypothesis are not able to reproduce the domain wall (DW) velocity profile when the DW roughness is high. Our results demonstrate that the DW roughness and the interface roughness of the sample layers are correlated. Furthermore, we give guidance on how to obtain reliable results for the DMI value with this popular method. A comparison of the results with Brillouin light scattering (BLS) measurements on the same samples shows that the BLS approach often results in higher measured values of DMI.

Automated summary

Experimental studies using magneto-optics have shown a correlation between domain wall roughness and interface roughness of sample layers, with standard creep hypothesis models unable to accurately reproduce domain wall velocity profiles under high roughness conditions. Comparison with Brillouin light scattering measurements revealed that the latter method often yields higher measured values of Dzyaloshinskii-Moriya interaction.