Modulations of interfacial magnetic properties using structurally inverted magnetic tri-layer systems: Toward skyrmion formation

Various magnetic properties such as the interfacial Dzyaloshinskii–Moriya interaction (DMI) and the perpendicular magnetic anisotropy (PMA) in structurally inverted Pd/Co/Pt and Pt/Co/Pd tri-layer stacks are systematically investigated by performing an inelastic light scattering method. Two examined individual multilayer structures are identical, but the stacking order is inverted for each other. Here, we demonstrate that the interfacial DMI energy densities and the saturation magnetization values for both systems are almost similar. However, the surface magnetic anisotropy energy densities of Pd/Co/Pt systems are dramatically decreased up to 34% compared with Pt/Co/Pd system, while the interfacial DMI is kept. Since a large interfacial DMI and a small PMA (or domain wall energy) are required to form magnetic skyrmion phases, the Pd/Co/Pt system can be one of the promising candidates. According to the thickness dependent measurements, we show a possibility of the existence of skyrmion phases in the Pd/Co/Pt system within a certain range of Co layer thickness at room temperature without external magnetic fields.