Dynamic excitations and inertial effects of antiskyrmions in a synthetic antiferromagnet

We study the dynamics of antiskyrmions in synthetic antiferromagnets with respect to the interlayer coupling strength by micromagnetic simulations. As the system is excited with an in-plane oscillating magnetic field, we identify four eigenmodes: two gyrotropic and two azimuthal, which we categorize based on their radial and azimuthal numbers. Surprisingly, the excitation of the first gyrotropic mode is seen to be fully suppressed in the absence of interlayer coupling in contrast to the case of skyrmions. We qualitatively show that this suppression is due to the dipolar interaction between the antiskyrmions that is competing against the external field influence. Finally, based on the generalized Thiele equation, we calculate the inertial mass of the antiskyrmions in this system and report a strong dependence on the interlayer coupling strength. Our results provide useful insights for controlling the dynamic behavior of antiskyrmions via interlayer coupling for future skyrmion-based spintronic devices.