  The Dzyaloshinskii Moriya interaction (DMI) generates intriguing chiral
magnetic objects such as magnetic skyrmions and chiral domain walls that can be
used as building blocks in emerging magnetic nanodevices. To achieve better
stability and functionality of these chiral objects, it is essential to achieve
a larger DMI. In this paper, we report an experimental observation that in
magnetic trilayer films, the DMI strength is mainly determined by the work
functions of the nonmagnetic layers interfaced with the magnetic layer. The
clear correlation with the intrinsic material parameters provides a guideline
for material selection to engineer the DMI strength.
