Specific Heat and Thermal Diffusivity of YBCO Coated Conductors

Abstract

Abstract We have measured the temperature dependence of specific heat, C ( T ), for Ag deposited YBCO coated conductor (YCC),YCC reinforced by a thin Cutape (YCC-Cu), andthe Hastelloy substrate with buffer layer. C ( T ) of HastelloyC–276 with buffer layer agrees well with the reported oneof HastelloyC-276, indicating that the contribution of the buffer layer to the measured C ( T ) is negligibly small. C ( T )of both YCC and YCC-Cu tapes was successfully reproduced by the simple sum rule using the C ( T ) values reported for Hastelloy, Ag and Cu. The results demonstrate that C ( T ) of various YCC tapes can be estimated using the reported C ( T )of constitutional materials. The estimated thermal diffusivity, a = K/ C , at 300K of YCC, which was estimated using the thermal conductivity, K, did not agree with the reported a of Ag. This resultwas in consistent with the fact that the applied heat flew through the Aglayer, suggesting that a relation of a = K/ C for homogeneous material cannot be applicable for the layered material such as YCC.