Creation and annihilation of topological meron pairs in in-plane magnetized films.

Gao, N; Je, S -G; Im, M -Y; Choi, J W; Yang, M; Li, Q; Wang, T Y; Lee, S et al. · Nat Commun · 2019

basic_science · Level V

Where this comes from

Abstract

Merons which are topologically equivalent to one-half of skyrmions can exist only in pairs or groups in two-dimensional (2D) ferromagnetic (FM) systems. The recent discovery of meron lattice in chiral magnet Co<sub>8</sub>Zn<sub>9</sub>Mn<sub>3</sub> raises the immediate challenging question that whether a single meron pair, which is the most fundamental topological structure in any 2D meron systems, can be created and stabilized in a continuous FM film? Utilizing winding number conservation, we develop a new method to create and stabilize a single pair of merons in a continuous Py film by local vortex imprinting from a Co disk. By observing the created meron pair directly within a magnetic field, we determine its topological structure unambiguously and explore the topological effect in its creation and annihilation processes. Our work opens a pathway towards developing and controlling topological structures in general magnetic systems without the restriction of perpendicular anisotropy and Dzyaloshinskii-Moriya interaction.