Surface Morphology of Cerium Oxide Layer and its Effect on the Performance of Superconducting Layer
- 200 Downloads
So far, huge progress has been achieved in coated superconductor wires with high performance, where cerium oxides (CeO2) usually figure as superior buffer layer. However, the influence of CeO2 layer’s surface morphology on the performance of YBCO layer is still illusive. In this work, we fabricated CeO2 layers with similar texture and diverse surface characteristics by altering process parameters on IBAD-MgO substrate and then deposited YBCO layers on these CeO2 layers by a reel-to-reel pulsed laser deposition (PLD) system. The abnormal relationship between the quality of YBCO layer and the surface morphology of CeO2 layer was investigated. Instead of texture quality, the critical current density of YBCO-coated layer is highly susceptible to the surface morphology of CeO2 layer, once their surface roughness root mean square (RMS) outstrips the threshold of atomic flat. And our study indicates RMS and flat area fraction are all key issues for PLD epitaxial multilayers but play in different priority. The possible defect formation process of YBCO/CeO2 was also discussed on the basis of the SEM images.
KeywordsCerium oxides Thin film Superconductor Morphology Critical current density YBCO
This work was supported by the Ministry of Science and Technology of the People’s Republic of China ITER project (Grant 2011GB113004) and 863 project (Grant 2014AA032402), the Shanghai Commission of Science and Technology (Grants 11DZ1100402 and 13DZ0500100), and Natural Science Foundation of China (Grants 11204174 and 51372150).
- 1.Solutions, S.: Basic Research Needs for Superconductivity. In: Workshop on Superconductivity May, vol. 8, p 11 (2006)Google Scholar
- 8.Bhuiyan, M.S., Paranthaman, M., Sathyamurthy, S., Aytug, T., Kang, S., Lee, D.F., Goyal, A., Payzant, E.A., Salama, K.: Approach for the growth of epitaxial CeO2 buffer layers on biaxially textured Ni–W substrates for YBCO coated conductors. Supercond. Sci. Tech. 16(11), 1305 (2003)ADSCrossRefGoogle Scholar
- 9.Engel, S., Knoth, K., Hühne, R., Schultz, L., Holzapfel, B.: An all chemical solution deposition approach for the growth of highly textured CeO2 cap layers on La2Zr2O7-buffered long lengths of biaxially textured Ni–W substrates for YBCO-coated conductors. Supercond. Sci. Tech. 18(10), 1385 (2005)ADSCrossRefGoogle Scholar
- 10.Obradors, X., Puig, T., Pomar, A., Sandiumenge, F., Mestres, N., Coll, M., Cavallaro, A., Roma, N., Gazquez, J., Gonzalez, J.C., Castano, O., Gutierrez, J., Palau, A., Zalamova, K., Morlens, S., Hassini, A., Gibert, M., Ricart, S., Moreto, J.M., Pinol, S., Isfort, D., Bock, J.: Progress towards all-chemical superconducting YBa2Cu3O7-coated conductors. superconductor. Supercond. Sci. Tech., 19 (2006)Google Scholar
- 16.Coll, M., Pomar, A., Puig, T., Obradors, X.: Atomically flat surface: the key issue for solution-derived epitaxial multilayers. Appl. Phys. Express., 1 (2008)Google Scholar