Abstract: The development of magnetic domain wall based technologies is limited by the stochastic nature of domain wall depinning. While depinning from pre-defined, engineered pinning sites has been extensively studied and is often modeled as a single strong pinning site, imperfections in magnetic thin films create numerous uncontrolled weak pinning sites that are difficult to characterize and understand. Here, we investigate and model domain wall motion in Co/Pt multilayers with perpendicular anisotropy following depinning from photolithographically patterned notches using a scanning magneto optical Kerr apparatus. The subsequent depinning reveals multiple depinning paths across numerous weak pinning sites. Strain, in the form of surface acoustic waves, modifies the pinning landscape, with increasing strain resulting in shorter characteristic depinning times for all paths. A simplified Markov probability model shows that the depinning probability varies with strain as the zeroth order Bessel function for all pinning sites, in agreement with expectations. Because strain driven depinning operates from a different mechanism than field driven depinning, these results further demonstrate that strain provides an effective means of controlling and driving domain wall motion.
