Experimental Confirmation of Ruderman–Kittel–Kasuya–Yosida type interlayer Dzyaloshinskii-Moriya interaction across Ru spacers

In recent years, as the attention in spintronics expands from collinear to noncollinear magnetism, the interlayer Dzyaloshinskii-Moriya interaction (IL-DMI) has been proven capable of mediate long-range chiral spin textures between magnetic layers. Here, we experimentally confirm that analogous to the Ruderman–Kittel–Kasuya–Yosida (RKKY) interaction, where indirect coupling oscillates between parallel and antiparallel states with spacer thickness, a damped oscillation in IL-DMI strength and direction is observed. Specifically, an oscillation period of ≈ 0.96 nm is obtained when mediated by a Ru spacer, close to the 1.15 nm reported for conventional RKKY while well fitted by theoretical predictions. In contrast, no oscillation is observed when IL-DMI is mediated by a Pt spacer, consistent with the negligible RKKY coupling across Pt. This work experimentally confirms the physical origin of IL-DMI as stemming from the RKKY mechanism, while also providing a tuning knob in controlling IL-DMI’s polarity and strength by adjusting spacer thickness, beneficial to the development of future three-dimensional spintronics memory devices.