  Understanding the dynamics of the magnetic skyrmion, a particle-like
topologically stable spin texture, and its response dynamics to external fields
are indis-pensable for the applications in spintronic devices. In this letter,
the Lorentz transmis-sion electron microscopy (LTEM) was used to investigate
the spin chirality of the mag-netic skyrmion bubbles (SKBs) in the
centrosymmetric magnet MnNiGa at room tem-perature. The reversal of SKBs
excited by the in-plane magnetic field has been revealed. Moreover, the
collective behavior of interacting spin chirality can be manipulated by
reversing the directions of the magnetic fields on a wedge-shaped thin plate.
The dy-namic behavior of the bubbles at different position of the thin plate
has been explored with the micromagnetic simulation, indicating a non-uniform
and nontrivial dynamic magnetization on the surfaces and center of the thin
plate during the spin chirality re-versal. The results suggest that the
controllable symmetry breaking of the SKBs arising from thickness variation
provides an ability to manipulate the collective behavior of the spin chirality
with small external fields, leading to a promising application in nonvola-tile
spintronic devices for magnetic skyrmions.
