Experimental observation of the correlation between the interfacial Dzyaloshinskii–Moriya interaction and work function in metallic magnetic trilayers

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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. Precise control of the DMI strength is one of the key issues for achieving better stability and functionality of these chiral objects. In this paper, we report that in magnetic trilayer films, the DMI strength exhibits a noticeable correlation with the work functions of the non-magnetic layers interfaced to the magnetic layer. This correlation with the intrinsic material parameters provides a guideline for material selection for engineering the DMI strength. We experimentally observe that D, the strength of the Dzyaloshinskii–Moriya interaction (DMI), is correlated with the difference of work function W of Co and nonmagnetic material X in Pt/Co/X trilayer system. The spin–orbit-scattering-mediated spin–chiral effect may plays leading role in this system, and this phenomena may be affected by work function difference which may be linked to electrostatic potential that may affect the scattering potential at the interface. Such correlation with the intrinsic material parameter provides a guideline for material selection to engineer the DMI and helps control properties for applications of chiral objects such as magnetic skyrmion. A study that correlates magnetic nanostructure formation with an easy-to-measure property of metals may help engineers design better devices for manipulating and storing data. A team led by Byoung-Chul Min at the Korea Institute of Science and Technology in Seoul and Sug-Bong Choe from Seoul National University investigated thin films that sandwich a ferromagnetic cobalt layer between two non-magnetic metals. In this system, magnetic spins can interact with other atoms where the layers contact, and create asymmetric swirling patterns known as skyrmions that are useful in high-speed spin-based computing. Experiments demonstrated that the strength of this magnetic interaction relates directly to the energy it takes to remove electrons from the non-magnetic layers. These energy values may serve as accessible guidelines for selecting materials for use in magnetic thin-film devices.