Direct Observation of Domain-Wall Surface Tension by Deflating or Inflating a Magnetic Bubble

作者:Zhang, Xueying; Vernier, Nicolas; Zhao, Weisheng*; Yu, Haiming; Vila, Laurent; Zhang, Yue; Ravelosona, Dafine
来源:Physical Review Applied, 2018, 9(2): 024032.
DOI:10.1103/PhysRevApplied.9.024032

摘要

The surface energy of a magnetic domain wall (DW) strongly affects its static and dynamic behaviors. However, this effect is seldom directly observed, and some of the related phenomena are not well understood. Moreover, a reliable method to quantify the DW surface energy is still absent. Here, we report a series of experiments in which the DW surface energy becomes a dominant parameter. We observe that a semicircular magnetic domain bubble can spontaneously collapse under the Laplace pressure induced by DW surface energy. We further demonstrate that the surface energy can lead to a geometrically induced pinning when the DW propagates in a Hall cross or from a nanowire into a nucleation pad. Based on these observations, we develop two methods to quantify the DW surface energy, which can be very helpful in the estimation of intrinsic parameters such as Dzyaloshinskii-Moriya interactions or exchange stiffness in magnetic ultrathin films.