Antisymmetric interlayer exchange coupling in magnetic multilayers
일 시 : 2021년 10월 13일 수요일 16:30
연 사 : 정 명화 교수 (서강대학교 물리학과)
장 소 : 온라인 진행 (https://us02web.zoom.us/j/84242109522)
HOST : 김 재 용 교수님
초 록
The exchange interaction governs static and dynamic magnetism. This fundamental interaction comes in two flavors - symmetric and antisymmetric. While the symmetric interaction leads to ferro- and antiferromagnetism, the antisymmetric interaction has attracted significant interest owing to its major role in promoting topologically non-trivial spin textures that promise fast, energy-efficient devices. So far, the antisymmetric exchange interaction has been found to be rather short–ranged and limited to a single magnetic layer. Here, we report a long-range antisymmetric interlayer exchange interaction in perpendicularly magnetized synthetic antiferromagnets with parallel and antiparallel magnetization alignments. Asymmetric hysteresis loops under an in-plane field reveal a unidirectional and chiral nature of this interaction, resulting in canted magnetic structures. We explain our results by considering spin-orbit coupling combined with reduced symmetry in multilayers. Our discovery of a long-range chiral interaction provides an additional handle for engineering magnetic structures and could enable three-dimensional topological structures.