Uncovering Microscopic Interactions in Skyrmion Hosts via Lattice Dynamics

NSLS-II’s Coherent Soft X-ray (CSX) beamline has world leading coherent soft x-ray flux and, as such, can provide insight to materials traditionally studied with either neutrons or electron microscopy (EM). In other words, bulk versus neara-surface, respectively. The highly tunable CSX beamline can close this gap since “bulk-like” and EM specific free-standing films are readily investigated using soft x-ray resonant elastic scattering (REXS). Capitalizing on this capability, we turn to study interacting skyrmions. Most skyrmion hosting materials are conducting metal alloys (the B20 metals), and these materials do exhibit interesting skyrmion lattice dynamics. However, Cu₂OSeO₃ (CSO) offers an interesting comparison since it is a vastly different material, being an insulator and exhibiting magnetoelectric coupling – which are attractive properties for devices. We will present new findings associated with skyrmion lattice (SkL) dynamics in CSO. Recently reported rotational dynamics of the SkL are currently thought to be induced by either thermal gradients [1] or magnetic field gradients [2]. By combining coherent X-rays and REXS, we can interrogate the structure and dynamics of rotating and non-rotating SkL points in a highly controlled manner. In collaboration with LTEM researachers, we are able to expand our findings with complementary LTEM experiments.<br/><br/>1. Mochizuki et. al, Nature Materials 13, 241, 2014.<br/>2. Zhang et. al, Nature Communications 9, 2115 , 2018.