Spin wave frequency hysteresis in Ir/Co/Pt multilayers with Dzyaloshinskii-Moriya interaction

The results of extensive combined experimental and theoretical investigations of static and dynamic properties of an Ir/Co/Pt multilayer with low uniaxial anisotropy and asymmetric Ir/Co and Co/Pt interfaces responsible for large interfacial Dzyaloshinskii-Moriya interaction (IDMI) are presented. Within longitudinal magneto-optical Kerr effect-based microscopy and magnetic force microscopy studies a complex magnetic configuration was detected: Large in-plane magnetized domains several dozen micrometers in size were modulated by a weak stripe domain pattern with periods of about 100 nm. Using Brillouin light scattering spectrometry, the hysteresis of the Stokes and anti-Stokes peaks frequencies was observed as a function of the magnetic field. This hysteretic behavior associated with IDMI-induced asymmetry of spin wave dispersion is correlated with the switching of the large macrodomains. Using micromagnetic simulations, we determine field-dependent magnetization distributions and dispersion relations, proposing an explanation of the observed behavior. The investigated nanostructure can be used as a nonvolatile spin wave velocity switcher.