NdBa 2Cu 3O 7 − δ single crystal growth by the traveling-solvent floating-zone method

• Published in: Journal of crystal growth Vol. 173; no. 1; pp. 73 - 80
• Main Authors: Kuroda, Kiyoshi, Choi, In-Hwan, Unoki, Hiromi, Koshizuka, Naoki
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1997
• Subjects: Crystal growth; NdBa 2Cu 3O 7 − δ; Traveling-solvent floating-zone method; Crystal growth; Traveling-solvent floating-zone method; NdBa 2Cu 3O 7 − δ; 74.72.Jt; 81.10.−h
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/S0022-0248(96)00799-3

We have succeeded in growing large size NdBa 2Cu 3O 7 − δ crystals (the cross-section was elliptical, the major and minor axes were about 4.5 and 3.5 mm, respectively, and the length about 30–60 mm that depended on the length of the feed rod) by improving the traveling-solvent floating-zone method. A typical one of these crystals has been proved to be of single crystal from X-ray Laue diffraction measurements. These crystals show superconducting properties throughout the crystal length, whose transition temperature T C (onset) is 94 K and transition width ΔT C is about 5 K. The success of growing these single crystals was achieved by selecting the optimum solvent composition, increasing the density of the feed rod, interchanging the crystal growing direction, setting up the temperature gradient for the region of the solvent and finding the appropriate growing rate for the crystal growth in the TSFZ method. The compositions of grown crystals deviate slightly from the stoichiometric ratio, Nd : Ba : Cu = 1 : 2 : 3. It seems that there are regions in the crystals in which Nd atoms substitute for the Ba-site. Therefore, these crystals have broad ΔT C compared to stoichiometric crystals.