Figure 1: Hc2 in UCoGe from a bulk sensitive probe.
From: Pairing mechanism in the ferromagnetic superconductor UCoGe
(a) Hc2 for the three principal axis of UCoGe, from thermal conductivity measurements. The S-shape of Hc2 for H//b-axis is well visible, as well as the enormous anisotropy between the c-axis, and the (a,b) plane. (b) Zoom along the c-axis. Red circles: from thermal conductivity; Yellow circles: from ac-susceptibility; Diamonds: from the onset of the resistive transition; Squares: from the resistive transition at ρ=0; Solid line: guide to the eyes, showing the strong upward curvature of Hc2. Dotted line: by contrast, the classical Hc2 behaviour with negative curvature.
