Thermal expansion and specific heat of non-random YBCO/Ag composites

We report on low-temperature thermal expansion and specific heat measurements in a series of non-random composites YBCO/Ag x wt% (x = 0, 6, 11 and 23). A reference YBCO polycrystalline sample is also investigated. At the lowest temperatures, the expansivities and specific heat are analysed as sums of a extrinsic T-linear term and a -Debye contribution. The Grüneisen parameters are determined and shown to be almost constant for . The values of the Grüneisen parameters increase with the silver content in the composites.