Extended Data Fig. 5: Four classes of contours exhibited by the resistance maps shown in Fig. 1b-d and Fig. 3.
Some contours are clearly visible in the \({\rm{Re}}\,Z(T, H)\) maps directly (top left), others, in particular the parabolas (Fig. 1h) are revealed by the \(\partial {\rm{Re}}\,Z/\partial T\) derivative maps (bottom and right), shown with no overlayed contours for clarity. Very clear parabolas with onset at Tc0 = 4.5 mK and 8.1 mK are exhibited by sample C. The latter, as well as some other contours in the AFM1 phase are marked by negative \(\partial {\rm{Re}}\,Z/\partial T\). These coincide with a sharp drop in contact resistance (see Extended Data Fig. 1c) and reflect the current redistribution in heterogeneous samples at the onset of superconductivity in the contact regions. In contrast below TA negative \(\partial {\rm{Re}}\,Z/\partial T\) represents the transition into the re-entrant normal state in the sample. Here for simplicity the contours of linear suppression are extrapolated to T = 0 as straight lines. Typical curvature of lines of orbital suppression is illustrated in Supplementary Fig. 5.
