Thermal properties of bulk GdBa2Cu3O7 / Ag superconductors prepared by Single Direction Melt Growth (SDMG) process

This work deals with bulk GdBa2Cu3O7 superconductors prepared by 'single-direction melt growth' (SDMG) [1,2]. This process improves significantly the homogeneity of the trapped field distribution measured close to the top or bottom faces of the sample [3]. Bulk samples processed this way offer therefore great ability as trapped field superconducting magnets [4] or magnetic shields and screens [5]. During pulsed field magnetization or magnetic screening, the sample experiences a timevarying applied field, which causes magnetic losses and a certain self-heating. This may alter the magnetic properties, especially for large size samples. To model and predict the subsequent temperature increase, detailed knowledge of thermal properties is therefore required. In this work, we characterized the temperature dependence of the specific heat cp(T) and thermal
conductivity of a single-domain melt-textured bulk GdBCO/Ag (GdBa2Cu3O7 + 0.4 mol
Gd2BaCuO5 + 10% Ag2O) prepared by SDMG. Remarkably, the thermal conductivity kappa measured along the ab planes is found to display maximum values (14 W m-1 K-1) that are similar to those reported for high quality single crystals, both close to the top and bottom faces. Electrical resistivity vs. temperature is used to determine the electronic contribution of the thermal conductivity, which is found to be a small fraction of the total kappa, as well as the temperature dependence of the irreversibility fields for H||ab and H||c. We discuss the practical implications of these sets of thermal property data by estimating the
resulting self-heating of the sample in typical magnetic screening or trapping experiments.
Acknowledgement: This work is partially funded by a collaboration programme between the FRS-FNRS (Belgium) and the PAN (Poland) under reference PINT-BILAT-M R.M002.24. Nicolas Rotheudt is recipient of an FRS-FNRS Research Fellow Grant.
References
[1] T. Motoki et al. Appl. Phys. Express 13 (2020) 093002
[2] F. Antoncik et al. IEEE Trans. Appl. Supercond. 35 (2025) 6800205
[3] T. Motoki et al. Supercond. Sci. Technol. 35 (2022) 094003
[4] T. Motoki et al. IEEE Trans. Appl. Supercond. 33 (2023) 6800205
[5] N. Rotheudt et al. Supercond. Sci. Technol. 38 (2025) 025012