  Recent theoretical and experimental studies of the interlayer
Dzyaloshinskii-Moriya interaction (DMI) has sparked great interest in its
implementation into practical magnetic random-access memory (MRAM) devices, due
to its capability to mediate long-range chiral spin textures. So far,
experimental reports focused on the observation of interlayer DMI, leaving the
development of strategies to control interlayer DMI's magnitude unaddressed.
Here, we introduce an azimuthal symmetry engineering protocol capable of
additive/subtractive tuning of interlayer DMI through the control of wedge
deposition of separate layers, and demonstrate its capability to mediate
field-free spin-orbit torque (SOT) magnetization switching in both orthogonally
magnetized and synthetic antiferromagnetically coupled systems. Furthermore, we
showcase the spatial inhomogeneity brought about by wedge depositon can be
suppressed by specific azimuthal engineering design, ideal for practical
implementation. Our findings provide guidelines for effective manipulations of
interlayer DMI strength, beneficial for future design of SOT-MRAM or other
spintronic devices utilizing interlayer DMI.
