Thermal boundary resistance problems in melt-texturized YBCO in a Ni sheath

Melt-texturized YBCO in a Ni sheath involves a neodymium gallate layer on the inner surface of the sheath and a NiO layer on the outer surface. The thermal boundary resistances of these two layers are measured at low temperatures by a novel method. It is found that the boundary resistance of the neodymium gallate layer is negligibly small but that of the NiO layer is large and can compromise the transverse heat flow in the conductor.