Formations of Narrow Stripes and Vortex-Antivortex Pairs in a Quasi-Two-Dimensional Ferromagnet K2CuF4 Yoshihiko Togawa 1,2, Tetsuya Akashi 3, Hiroto Kasai 3, Gary W. Paterson 2, Stephen McVitie 2, Yusuke Kousaka 1, Hiroyuki Shinada 3, Jun-ichiro Kishine 4, and Jun Akimitsu 5 1 Department of Physics and Electronics, Osaka Prefecture University, 1-1 Gakuencho, Sakai, Osaka 599-8531, Japan 2 SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom 3 Research and Development Group, Hitachi Ltd., Hatoyama 350-0395, Japan 4 Division of Natural and Environmental Sciences, The Open University of Japan, Chiba 261-8586, Japan 5 Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan Contact E-mail: Dr.Gary.Paterson@gmail.ac.uk Journal of the Physical Society of Japan: https://journals.jps.jp/journal/jpsj Opendata deposit: http://dx.doi.org/10.5525/gla.researchdata.1079 Deposit Description ------------------- The data for the Fresnel image analysis of Figure 5 of the above manuscript. Multiple files are included. These are: mask.png: A png image of the mask used in the presentation of the data. This file may be opened in any png image viewer. dyx.npz: A numpy array formatted copy of the y- and x-axis displacement vector fields, in pixels, used for all panels of the figure. This file may be opened in Python using the numpy package, or any binary file reader. https://numpy.org/ Details of the experimental conditions, acquisition procedure, and data processing are described in the manuscript.