We investigated the thickness dependences of the interfacial Dzyaloshinskii-Moriya interaction (DMI) and the perpendicular magnetic anisotropy (PMA) in (Pt/Co/W) ₅ multilayers by systematically varying the Co (from 1. 3 to 1. 9 nm) and W (from 0 to 3 nm) layer thicknesses. Vibrating sample magnetometer has been used to measure the magnetization at saturation from the Co-thickness dependence of the surface magnetic moment at saturation. Increasing the W spacer thickness induces an exponential decay of the magnetization, emphasizing the strong influence of the top interface on overall magnetic coupling. Both surface and volume PMA constants were quantitatively extracted from microstrip line ferromagnetic resonance (FMR) and Brillouin light scattering (BLS) as well as the magnetic damping and the interfacial DMI. A clear evidence of interfacial effects and magnetic inhomogeneities across the multilayers was provided by the appearance of two distinct resonance modes in the FMR spectra. By combining FMR and BLS, the origin of these modes, attributed to the different magnetic properties of the internal and the external Co magnetic layers in the multilayer, was confirmed. The criterion of skyrmions stability, applied for our samples, revealed the possibility of the existence of such stable chiral structures in some samples.
Sbiaa et al. (Mon,) studied this question.