  Skyrmions are nanoscale magnetic structures with features promising for
future low-power memory or logic devices. In this work, we demonstrate novel
scanning techniques based on nitrogen vacancy center magnetometry that
simultaneously probe both the magnetic dynamics and structure of room
temperature skyrmion bubbles in a thin film system Ta/CoFeB/MgO. We confirm the
handedness of the Dzyaloshinskii-Moriya interaction in this material and
extract the helicity angle of the skyrmion bubbles. Our measurements also show
that the skyrmion bubbles in this material change size in discrete steps,
dependent on the local pinning environment, with their average size determined
dynamically as their domain walls hop between pinning sites. In addition, an
increase in magnetic field noise is observed near all skyrmion bubble domain
walls. These measurements highlight the importance of interactions between
internal degrees of freedom of skyrmion bubble domain walls and pinning sites
in thin film systems. Our observations have relevance for future devices based
on skyrmion bubbles where pinning interactions will determine important aspects
of current-driven motion.
