Dzyaloshinskii-Moriya interaction in symmetric epitaxial [Co/Pd(111)]N superlattices with different numbers of Co/Pd bilayers

Heavy metal/ferromagnetic superlattices are of great interest since Neel skyrmions may be stabilized in them due to an interfacial Dzyaloshinskii-Moriya interaction even at room temperature. Here we report on evidence of the strong Dzyaloshinskii-Moriya interaction in symmetric epitaxial [Co/Pd(111)](N) superlattices with high perpendicular magnetic anisotropy. The structural and magnetic properties of epitaxial [Co/Pd(111)](N) superlattices were investigated dependent on the number of Co/Pd bilayers. Based on comparison of the periodicity of experimentally obtained demagnetized patterns and simulated magnetic structures, a strong increase of the effective Dzyaloshinskii-Moriya interaction constant with increase of the period N of [Co/Pd(111)](N) superlattices is established. The origin of Dzyaloshinskii-Moriya interaction and its behavior in the symmetric [Co/Pd(111)](N) system is discussed.