We report systematic measurements of the interfacial Dzyaloshinskii-Moriya interaction (iDMI) by employing Brillouin light scattering in Pt/Co/AlOx and Ta/Pt/Co/AlOx structures. By introducing a tantalum buffer layer, the saturation magnetization and the interfacial perpendicular magnetic anisotropy are significantly improved due to the better interface between heavy metal and ferromagnetic layer. From the frequency shift between Stokes- and anti-Stokes spin-waves, we successively obtain considerably larger iDM energy densities (Dmax = 1.65 ± 0.13 mJ/m2 at tCo = 1.35 nm) upon adding the Ta buffer layer, despite the nominally identical interface materials. Moreover, the energy density shows an inverse proportionality with the Co layer thickness, which is the critical clue that the observed iDMI is indeed originating from the interface between the Pt and Co layers.

The interfacial Dzyaloshinskii-Moriya interaction (iDMI), surface anisotropy energy, and spin pumping at the Ir/Co interface are experimentally investigated by performing Brillouin light scattering. Contrary to previous reports, we suggest that the sign of the iDMI at the Ir/Co interface is the same as in the case of the Pt/Co interface. We also find that the magnitude of the iDMI energy density is relatively smaller than in the case of the Pt/Co interface, despite the large strong spin-orbit coupling (SOC) of Ir. The saturation magnetization and the perpendicular magnetic anisotropy (PMA) energy are significantly improved due to a strong SOC. Our findings suggest that an SOC in an Ir/Co system behaves in different ways for iDMI and PMA. Finally, we determine the spin pumping effect at the Ir/Co interface, and it increases the Gilbert damping constant from 0.012 to 0.024 for 1.5 nmthick Co. a)

We numerically investigate the interaction between propagating spin waves and a transverse domain wall in a nanowire by using micromagnetic simulations. In order to understand the mechanisms that lead to domain wall motions, we calculate domain wall velocity in a defect-free nanowire and the depinning fields for a pinned domain wall that is depinned in and against the direction of the spin-wave propagation. We find that the physical origin of the spin-wave-induced domain wall motion strongly depends on the propagating spin-wave frequency. At certain spin-wave frequencies, transverse domain wall vibrations lead to transverse wall displacements by the spin waves, while at other frequencies, large spin-wave reflection drives domain wall motion. By analyzing the depinning field calculations, the different underlying physical mechanisms are distinguished.

Using a homodyne detection scheme, we show that we can determine the polarity and chirality of a magnetic vortex in an asymmetric magnetic disk as well as the resonance frequency and phase shift of the dynamic vortex gyration excited by a spin-polarized current. From systematic phase measurements, we deduce the relative contributions of the spin torque and the Oersted field, which is found to dominate the excitation. Local pinning sites in the disk lead to an increased resonance frequency and a reduced amplitude. This allows us to draw a map of the pinning sites and thus to characterize the full potential in the disk.

Magnetic storage and logic devices based on magnetic domain wall motion rely on the precise and synchronous displacement of multiple domain walls. The conventional approach using magnetic fields does not allow for the synchronous motion of multiple domains. As an alternative method, synchronous current-induced domain wall motion was studied, but the required high-current densities prevent widespread use in devices. Here we demonstrate a radically different approach: we use out-of-plane magnetic field pulses to move in-plane domains, thus combining field-induced magnetization dynamics with the ability to move neighbouring domain walls in the same direction. Micromagnetic simulations suggest that synchronous permanent displacement of multiple magnetic walls can be achieved by using transverse domain walls with identical chirality combined with regular pinning sites and an asymmetric pulse. By performing scanning transmission X-ray microscopy, we are able to experimentally demonstrate in-plane magnetized domain wall motion due to out-of-plane magnetic field pulses.