Anisotropy of the thermal conductivity of bulk melt-cast Bi-2212 superconducting tubes. (7th January 2020)

• Record Type: Journal Article
• Authors: Szewczyk, Daria; Stachowiak, Piotr; Mucha, Jan; Rikel, Mark; Fagnard, Jean-François; Vanderbemden, Philippe
• Is Part Of: Superconductor science & technology. Volume 33:Number 2(2020:Feb.)
• Publication Date: 2020-01-07
• Subjects: thermal conductivity -- specific heat -- thermal properties -- bulk high-temperature superconductors -- cuprates; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/1361-6668/ab601c
• Languages: English
• ISSNs: 0953-2048

Abstract

Abstract: We investigate experimentally the anisotropy of the temperature dependence of the thermal conductivity of bulk Bi2 Sr2 CaCu2 O8 (Bi-2212) cylinders fabricated by the melt-cast process. The thermal conductivity κ ( T ) along the axial and azimuthal directions are found to be equal within experimental uncertainty, while κ along the radial direction is found to be ∼40% larger than the other two. The results are in qualitative agreement with the weak partial texture of such tubes, corresponding also to an anisotropy of the resistivity ρ ( T ) above the critical temperature T c . This resistivity anisotropy in the normal state is responsible for an anisotropy of the electronic contribution of thermal conductivity (Δκe ), which is much smaller than the anisotropy Δκ of the total thermal conductivity. This indicates an anisotropic contribution of the phonons. The temperature dependence of the specific heat C ( T ) is also measured and shows that C ( T )/ T exhibits a well-defined maximum close to T c . The combination of these experimental data can be used for assessing the thermal effects in bulk melt-cast Bi-2212, and underline the importance of taking the anisotropy of κ into account, e.g. for predicting the self-heating when the material is subjected to losses.