Crystallinity of Large YBa 2 Cu 3 O y Single Crystals Grown by the Solute Rich Liquid-Crystal Pulling Method

• Published in: Japanese Journal of Applied Physics 2000-01, Vol.39 (1R), p.41
• Main Authors: Kuroda, Kiyoshi, Kamiyama, Takashi, Oikawa, Ken-ichi, Yamada, Yasuji, Koshizuka, Naoki, Koyama, Satoshi, Namikawa, Yasuo, Yamaguchi, Yasuo, Torii, Shuki, Asano, Hajime
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.39.41

The solute rich liquid-crystal pulling method, a modified Czochralski-pulling technique, can be used to grow very large single crystals, larger than 1 cm along each axis. In order to examine the crystallinity of the YBa 2 Cu 3 O y single crystals grown by this technique, neutron diffraction was applied for six crystals subjected to various annealing conditions. The typical mosaicity was smaller than 1° along the c -axis and 2° in the a b -plane. Some crystals were of high quality, with a mosaicity of less than 0.2° for every direction. The oxygen inhomogeneity present in the as-grown samples was eliminated by prolonged-duration oxygen annealing. Furthermore, we succeeded in observing the orthorhombic II and III (ortho-II and III) phases, and determined the correlation lengths along the a -axis as ξ a =16 Å and ξ a =19 Å for y ≈6.60 (ortho-II) and y ≈6.70 (ortho-III), respectively.