Fig. 4: D and σ obtained from pattern recognition and machine learning.

a Experimentally obtained magnetic domain images using a magnetic microscope equipped with a MTJ sensor. The bright and dark contrast represent magnetization pointing from and into the paper. The thickness of the Ta seed layer (d) is denoted in each image. b, c DM exchange constant (D) (b) and distribution of \(K_{\mathrm{u}}\) (\(\sigma\)) (c) estimated from the domain images using the trained system. Two different values of \(K_{{\mathrm{eff}}}\) are used in the simulations to generate the training images: the estimated values (D and \(\sigma\)) obtained from the trained systems are denoted using open and solid squares. The error bars show 95% confidence interval (see “Methods”). D from Fig. 3c is shown together by the red circles in (b).