Superconducting gap of UCoGe probed by thermal transport

Thermal conductivity measurements in the superconducting state of the ferromagnet UCoGe were performed at very low temperatures and under magnetic field on samples of different qualities and with the heat current along the three crystallographic axis. This allows one to disentangle intrinsic and extrinsic effects, confirm the situation of multigap superconductivity, and shed new light on the situation expected or claimed for the gap in these ferromagnetic superconductors, such as evidence of the absence of partially gapped Fermi surfaces.