Impact of growth conditions on the domain nucleation and domain wall propagation in Pt/Co/Pt stacks

Abstract

Understanding the effect of fabrication conditions on domain wall (DW) motion in thin films with perpendicular magnetization is a mandatory issue in order to tune their properties aiming to design spintronics devices based on such phenomenon. In this context, the present work intends to show how different growth conditions may affect DW motion in the prototypical system Pt/Co/Pt. The trilayers were deposited by dc sputtering, and the parameters varied in this study were the Co thickness, the substrate roughness and the base pressure in the deposition chamber. Magneto-optical Kerr effect-based magnetometry and microscopy combined with x-ray reflectometry, atomic force microscopy and transmission electron microscopy were adopted as experimental techniques. This permitted us to elucidate the impact on the hysteresis loops and on the DW dynamics, produced by different growth conditions. As other authors, we found that Co thickness is strongly determinant for both the coercive field and the DW velocity. On the contrary, the topographic roughness of the substrate and the base pressure of the deposition chamber evidence a selective impact on the nucleation of magnetic domains and on DW propagation, respectively, providing a tool to tune these properties.