| AVS 62nd International Symposium & Exhibition | |
| Magnetic Interfaces and Nanostructures | Tuesday Sessions |
| Session MI-TuM |
| Session: | Oxides, Fluorides, and Spin Structures |
| Presenter: | Lucas Caretta, Massachusetts Institute of Technology |
| Authors: | L. Caretta, Massachusetts Institute of Technology M. Mann, Massachusetts Institute of Technology AJ. Tan, Massachusetts Institute of Technology G.S.D. Beach, Massachusetts Institute of Technology |
| Correspondent: | Click to Email |
The Dzyaloshinskii-Moriya interaction (DMI) at heavy-metal/ferromagnet interfaces can stabilize chiral spin textures [1]. It has recently been shown that field-driven bubble domain expansion in perpendicularly-magnetized thin films is asymmetric under the application of an in-plane field, which can be used to quantify the DMI effective field in the domain wall (DW) [2]. We have imaged domain expansion in Pt(3nm)/Co(0.9nm)/Pt(x)/GdOx(3nm) films using wide-field Kerr microscopy to characterize this behavior systematically as a function of DMI strength. In the case of null or weak DMI, realized when top and bottom Pt layers are of similar thickness, the in-plane field dependence of the DW velocity is well-described by the simple expansion model derived in Ref. [2]. However, in the case of strong DMI, we find a strongly nonmonotonic behavior due to flattening of the DW, minimizing Zeeman energy and DMI energy. Moreover, we show that when the ratio of the DMI effective field to the perpendicular anisotropy field is large, expanding bubble domains leave behind fine-scale dendritic structures, consisting of coupled 360 degree DWs. These dendritic structures can be manipulated to form stable skyrmion bubbles. We show that the stability of skyrmion bubbles is a strong function of the applied in-plane field near the DMI field. The skyrmion bubble annihilation field becomes deterministic at large in-plane fields.
1. A. Fert et al., Nat. Nano., 8, 152-156 (2013)
2. S.G. Je et al., PRB 88, 214401 (2013)