TY - JOUR
T1 - Transmission electron microscopy studies of YBCO coated conductors prepared by pulsed-laser deposition and multiple-stage chemical vapor deposition processes
AU - Kato, Takeharu
AU - Sasaki, Hirokazu
AU - Iwai, Hiroyuki
AU - Ibi, Akira
AU - Kashima, Naoji
AU - Niwa, Toshiharu
AU - Muroga, Takemi
AU - Miyata, Seiki
AU - Watanabe, Tomonori
AU - Iijima, Yasuhiro
AU - Kakimoto, Kazuomi
AU - Sutoh, Yasunori
AU - Yamada, Yutaka
AU - Nagaya, Shigeo
AU - Saitoh, Takashi
AU - Izumi, Teruo
AU - Sasaki, Yukichi
AU - Hirayama, Tsukasa
AU - Shiohara, Yuh
AU - Ikuhara, Yuichi
N1 - Funding Information:
This work was supported by the New Energy and Industrial Technology Development Organization (NEDO) as the Collaborative Research and Development of Fundamental Technologies for Superconductivity Applications.
PY - 2005
Y1 - 2005
N2 - Three types of YBCO films were deposited on metal tapes with biaxially textured CeO2/Gd2Zr2O7 multilayer. One YBCO film 4 μm in thickness was formed by pulsed-laser deposition (PLD) on the stationary substrate and another film 3 μm in thickness by PLD using a reel-to-reel substrate tape transferring system. Ic values of the films were 173 A and 293 A, respectively A further film 1 μm in thickness was fabricated by multiple-stage chemical vapor deposition (MSCVD). The I c value of the MSCVD-YBCO film was 100 A. The microstructures of these YBCO films were characterized using transmission electron microscopy (TEM). In the PLD-YBCO films, the films less than 1 μm thick were predominantly composed of c-axis oriented grains which were considered to grow spirally, however, irregular instances of a-axis oriented grains were also found. The a-axis oriented grains size increased with increasing thickness of the YBCO films. In the 4 μm-thick PLD-YBCO film with an Ic value of 173 A, a-axis oriented grains were considered to nucleate on the CeO 2. We found many Y2O3 and cupper oxides at the boundaries between a- and c-axes oriented grains and the orientation relationships between YBCO and Y2O3 were determined to be as follows: (0 0 1)YBCO//(0 0 1)Y2O3 and (1 0 0)YBCO//(1 1 0)Y2O3. We also found many gaps and pores between YBCO grains. Nucleation of a-axis oriented grains was completely suppressed on the CeO2 in the 3 μm-thick PLD-YBCO film with an Ic value of 293 A. In the MSCVD-YBCO film, the YBCO film mostly consisted of c-axis oriented grains, however a-axis oriented grains and polycrystal also formed in the film. As the MSCVD-YBCO film became thicker, the a-axis oriented grains grew large, as same as in the PLD-YBCO films. The growth rate of a-axis oriented grain along the substrate normal was much higher than that of c-axis oriented grains in comparison to the difference in the growth rate between a- and c-axes oriented grains in the PLD-YBCO. In these specimens, the grain growth of the a-axis oriented grains was considered to be one of the most significant causes of degradation of Jc values in the YBCO films.
AB - Three types of YBCO films were deposited on metal tapes with biaxially textured CeO2/Gd2Zr2O7 multilayer. One YBCO film 4 μm in thickness was formed by pulsed-laser deposition (PLD) on the stationary substrate and another film 3 μm in thickness by PLD using a reel-to-reel substrate tape transferring system. Ic values of the films were 173 A and 293 A, respectively A further film 1 μm in thickness was fabricated by multiple-stage chemical vapor deposition (MSCVD). The I c value of the MSCVD-YBCO film was 100 A. The microstructures of these YBCO films were characterized using transmission electron microscopy (TEM). In the PLD-YBCO films, the films less than 1 μm thick were predominantly composed of c-axis oriented grains which were considered to grow spirally, however, irregular instances of a-axis oriented grains were also found. The a-axis oriented grains size increased with increasing thickness of the YBCO films. In the 4 μm-thick PLD-YBCO film with an Ic value of 173 A, a-axis oriented grains were considered to nucleate on the CeO 2. We found many Y2O3 and cupper oxides at the boundaries between a- and c-axes oriented grains and the orientation relationships between YBCO and Y2O3 were determined to be as follows: (0 0 1)YBCO//(0 0 1)Y2O3 and (1 0 0)YBCO//(1 1 0)Y2O3. We also found many gaps and pores between YBCO grains. Nucleation of a-axis oriented grains was completely suppressed on the CeO2 in the 3 μm-thick PLD-YBCO film with an Ic value of 293 A. In the MSCVD-YBCO film, the YBCO film mostly consisted of c-axis oriented grains, however a-axis oriented grains and polycrystal also formed in the film. As the MSCVD-YBCO film became thicker, the a-axis oriented grains grew large, as same as in the PLD-YBCO films. The growth rate of a-axis oriented grain along the substrate normal was much higher than that of c-axis oriented grains in comparison to the difference in the growth rate between a- and c-axes oriented grains in the PLD-YBCO. In these specimens, the grain growth of the a-axis oriented grains was considered to be one of the most significant causes of degradation of Jc values in the YBCO films.
KW - MOCVD-YBCO
KW - PLD-YBCO
KW - TEM
KW - YO
KW - a-Axis oriented grain
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U2 - 10.1016/j.physc.2005.01.058
DO - 10.1016/j.physc.2005.01.058
M3 - Conference article
AN - SCOPUS:25644449570
VL - 426-431
SP - 1033
EP - 1042
JO - Physica C: Superconductivity and its Applications
JF - Physica C: Superconductivity and its Applications
SN - 0921-4534
IS - II
T2 - Proceedings of the 17th Internatioanl Symposium on Superconductivity (ISS 2004) Advances in Superconductivity
Y2 - 23 November 2004 through 25 November 2004
ER -