Fig. 2: Evolution of ρ^THE across the phase transition between isolated skyrmions and a disordered skyrmion lattice in T − κ space.

a Phase diagram of skyrmion configurations in T − κ space obtained by varying T and Fe/Co composition. The shaded area in blue is the transition region from isolated skyrmions to a disordered skyrmion lattice revealed by MFM imaging. The spatial evolution of skyrmion configuration is analyzed using Delaunay triangulation: details of the analysis including the nearest-neighbor (NN) coordination number and NN angular orientation can be found in Section 1 of the Supplementary Information⁵. Details of our estimation of the T-dependent κ are presented in Section 2 of the Supplementary Information. b Evolution of ρ^THE with (T, κ). Arrows with dotted lines point to the specific samples in (a) for which ρ^THE is studied as a function of T. c Evolution of ρ^THE with κ at a fixed T. Arrows with dotted lines point to the various samples in (a) for which ρ^THE(κ) is studied at a fixed T. d Schematic T − κ phase diagram illustrating the phase boundary T_c(κ) and the use of the effective temperature \({T}^{\prime}=T\cdot \kappa\) to describe the phase transition. The error bars on ρ^THE in (b) and (c) are ≤2 nΩ cm.