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Fabrication of long REBCO coated conductors by PLD process in China
Physica C xxx (2015) xxx–xxx
Contents lists available at ScienceDirect
Physica C journal homepage: www.elsevier.com/locate/physc
Fabrication of long REBCO coated conductors by PLD process in China Yijie Li a,b,⇑, Linfei Liu a, Xiang Wu a a Key Laboratory of Artificial Structure and Quantum Control, Ministry of Education, Department of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 20040, China b Shanghai Superconductor Technology Corporation, Ltd, 28 Jiang Chuan Road, Shanghai 200240, China
a r t i c l e
i n f o
Article history: Received 13 January 2015 Received in revised form 22 February 2015 Accepted 30 March 2015 Available online xxxx Keywords: REBCO coated conductor IBAD Pulsed laser deposition Microstructure Surface morphology Superconducting properties
a b s t r a c t In China, the First National Key Project on CC Program started in 2009, which was focused on developing hundred meter long class CC tapes based on PLD/RABiTS processes. In this project, SJTU mainly worked on all of functional layer deposition process development. Northwest Institute for Non-ferrous Metal Research worked on RABiTS tape fabrication. At the end of the project in 2011, SJTU successfully fabricated hundred meter long CC tapes with over 300 A/cm (at 77 K, self field) on RABiTS tapes. To develop high performance CC tapes by PLD/IBAD-MgO processes, a pilot CC fabrication line was set up at Shanghai Superconductor Technology Corporation, Ltd. in 2013. High quality long REBCO coated conductors have been successfully fabricated on flexible polycrystalline metal tapes by PLD plus magnetron sputter and IBAD processes. Under optimized conditions, the IBAD-MgO layers showed pure (0 0 1) orientation and excellent in-plane texture. The in-plane phi-scan rocking curve is 4–6 degrees. AFM observation showed MgO layer had very smooth surface. The RMS is less 1 nm. On the textured MgO layer, sputter deposited single cerium oxide cap-layer showed pure (0 0 1) orientation and excellent in-plane texture of 4–6 degree. Reel-to-reel PLD process with high deposition rate was already scaled up to 100 m/h tape speed. Hundred meters long coated conductor tapes with over 500 A/cm performance have been routinely fabricated. And now, the process optimization for kilometer long coated conductor tapes is underway. Ó 2015 Elsevier B.V. All rights reserved.
1. Introduction Since the discovery of oxide high temperature superconductors in 1986 [1], significant progress has been made on research and development (R&D) work for commercial applications, especially the fabrication of kilometer-long class REBa2Cu3O7 x (REBCO) high temperature superconductor tapes. Comparing with silver sheathed Bi–Sr–Ca–Cu–O (BSCCO) first generation high temperature superconducting wires, the so-called REBCO second generation high temperature superconductor (2G HTS) tapes are fabricated by thin film coating technology. Therefore, REBCO superconducting tapes are also called REBCO coated conductors. So far, several R&D groups have reported the kilometer long REBCO coated conductor results in the world [2–4]. In China, the first National Key R&D project for 2G wires started in 2009, which was supported by the Ministry of Science and Technology (MOST). ⇑ Corresponding author at: Key Laboratory of Artificial Structure and Quantum Control, Ministry of Education, Department of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 20040, China. Tel.: +86 21 54743149; fax: +86 21 54743017. E-mail address: [email protected] (Y. Li).
In this program, Shanghai Jiao Tong University (SJTU) concentrated on developing all of functional layer depositions for 2G tapes. Northwest Institute for Nonferrous Metal Research (NIN) mainly worked on Ni–W alloy RABiTS (rolling assisted bi-axially textured substrate) tape fabrication. At the end of 2010, SJTU successfully fabricated the first 100 m long coated conductor tape with 194 A/ cm at 77 K, self field. Northwest Institute for Nonferrous Metal Research (NIN) has established a Ni–W alloy RABiTS tape fabrication line with 30–50 km/year capacity. In 2011, SJTU switched from RABiTS tape to IBAD-MgO tape. A pilot PLD/IBAD-MgO line was set up in 2013 under collaboration with Shanghai Superconductor Technology Co. for long 2G tape fabrication. In this paper, we will report our recent progress in high performance thick film deposition and long tape fabrication. 2. Experimental REBCO superconducting layers were deposited by pulsed laser deposition. In research lab, the maximum excimer laser power is 80 W, and the maximum repetition rate is 200 Hz [5]. In pilot line, the maximum excimer laser power is 300 W, and the maximum repetition rate is 300 Hz. The thickness of RABiTS tape is
http://dx.doi.org/10.1016/j.physc.2015.03.020 0921-4534/Ó 2015 Elsevier B.V. All rights reserved.
Please cite this article in press as: Y. Li et al., Fabrication of long REBCO coated conductors by PLD process in China, Physica C (2015), http://dx.doi.org/ 10.1016/j.physc.2015.03.020
2
Y. Li et al. / Physica C xxx (2015) xxx–xxx
Fig. 1. SEM images of 2.0 lm thick REBCO layer deposited on RABiTS tapes. (a) Pure c-axis oriented grains and (b) a-axis oriented grains.
Fig. 2. I–V curves of REBCO films with different thickness.
80–100 lm. And 50 lm thick C-276 tape was used for IBAD-MgO process. On RABiTS tapes, all of CeO2 seed layer, YSZ barrier layer, CeO2 cap layer and REBCO superconducting layer were grown in a reel-to-reel research PLD system which could fabricate several hundred meters long tapes. On IBAD-MgO tapes, kilometer-long class CeO2 cap layers were deposited by reactive sputtering and REBCO superconducting layer were grown by PLD in pilot line. The width of RABiTS tape and IBAD-MgO tape was 1.0 cm. Superconducting properties of REBCO tapes were measured by TapeStar system and four-probe method (77 K, self-field). 3. Results and discussion 3.1. REBCO coated conductor based on RABiTS tapes On RABiTS tapes, during superconducting layer optimization, it was found that pure (0 0 1) oriented YSZ layer, CeO2 cap layer could be easily grown by PLD process. Thinner REBCO layers had pure
Fig. 4. XRD Phi scan pattern of a kilometer long class CeO2 cap layer coated IBADMgO tape.
c-axis orientation and high critical current density with over 4 106 A/cm2. But as REBCO layer thickness increased over 2 lm, it can be seen from Fig. 1 that REBCO layers had a-axis and c-axis mixed orientations. Since the average grain size of Ni–W tapes was just several tens of micrometers, it was concluded that the formation of a-axis oriented grains did not resulted from the heater temperature homogeneity deviation. The substantial variability of the YBCO orientation from grain to grain was previously reported by other group [6]. The source of the variation was due to a difference in crystallographic orientation of the underlying substrate grains. The YBCO grains inherit the orientation of the underlying Ni–W grains. Ni–W grain with different out-plane tilt had different density of YBCO nuclei. Large distances between the nuclei allowed the formation of secondary phases between the YBCO grains, thus degrading the overall structural integrity of the YBCO layer, which was supported by the study by Coll et al. [7]. Under optimized
Fig. 3. SEM images of REBCO films with different thickness, (a) 0.4 lm and (b) 2.0 lm thickness.
Please cite this article in press as: Y. Li et al., Fabrication of long REBCO coated conductors by PLD process in China, Physica C (2015), http://dx.doi.org/ 10.1016/j.physc.2015.03.020
Y. Li et al. / Physica C xxx (2015) xxx–xxx
3
Fig. 5. Longitudinal Ic profile of a 100 m long class REBCO tape measured by TapeStar.
conditions, hundred meter long class REBCO tapes had 300 A end-to-end superconducting critical current (77 K, self-field). It was difficult to improve superconducting performance further on RABiTS tapes by PLD process. 3.2. REBCO thick film deposition on IBAD-MgO tapes In order to fabricate long REBCO coated conductors with high Ic performance, it is necessary to fully understand the epitaxial growth mechanism of thick REBCO films on metal tape substrates. For REBCO thick film deposition, the most difficult thing is how to avoid Jc degradation. Fig. 2 shows the relationship between superconducting critical current Ic values and REBCO layer thickness. As shown in Fig. 2, under optimized conditions, for less than 0.8 lm REBCO films, Jc was 5 106 A/cm2. With increasing the thickness from 1.0 lm to 1.4 lm, Jc decreased from 4.5 106 A/cm2 to 3.6 106 A/cm2. When REBCO thickness increased to 2.0 lm, Ic was 680 A and still nearly linearly increasing with thickness. To understand the Jc degradation of thick REBCO films, the samples with different thickness were analyzed by SEM and XRD. It was found that all the samples had only (0 0 l) peaks and no (l 0 0) peaks from XRD results. The SEM images of thin and thick REBCO films were shown in Fig. 3. For thinner REBCO film, the surface was very flat and showed layer-by-layer growth mode. But for thicker film, the surface became rougher and REBCO grain became larger. So the Jc of the sample was not only dependant on the orientation, but also the REBCO growth mode and grain size. The key elements to maintain high Jc value was to control REBCO grain size in submicrometer range and keep layer-by-layer epitaxial growth mode. Once REBCO top layer changed from layer-by-layer growth mode to island growth mode, REBCO grains subsequently became large particles, and Jc rapidly decreased below 4 106 A/cm2. So far, we have achieved highest Ic value of 780 A at 2.8 lm thickness. This result is close to achieve the final goal of 1000 A/cm at 3.0 lm thickness. Further research work on increasing REBCO layer thickness is ongoing.
processes, except for PLD, already reached kilometer long range at a deposition tape speed of over 100 m/h speed. PLD YBCO process is currently developed in 100 m long range. Fig. 5 shows a longitudinal Ic profile of a 100 m long class REBCO tape measured by TapeStar. The lowest Ic value measured by four probe method from the end part of the tape was 500 A. As shown in Fig. 5, the Ic profile along longitudinal direction is quite uniform. 4. Conclusions REBCO deposition processes by PLD have been systematically investigated on RABiTS and IBAD-MgO tapes. On RABiTS tapes, although thin REBCO layer showed high Jc of >4 106 A/cm2, over 2.0 lm thick films showed lower Jc of <3 106 A/cm2 due to mixed a/c axis orientations. On IMAD-MgO tapes, REBCO films deposited by PLD showed layer-by-layer growth mode. When REBCO thickness increased to 2.0 lm, Ic was still nearly linearly increasing with thickness. Short sample at 2.8 lm thickness had Ic value of 780 A. This is very close to the final goal of 1000 A/cm at 3.0 lm thickness. On pilot PLD line, hundred meter long class REBCO tapes with 500 A (at 77 K, self-field) had been successfully fabricated. Currently, the process optimization for kilometer long coated conductor tapes is underway. Acknowledgements This work was supported by Shanghai Science and Technology Committee (Grant Nos. 11DZ1100402, 11DZ1100401, 11DZ1100400, and 13DZ0500100), the Ministry of Science and Technology of China (Grant No. 2014AA032702), the National Natural Science Foundation of China (Grant No. 51372150), the Natural Science Foundation of China for Youths (Grant No. 11204174), the China’s domestic International Thermonuclear Experimental Reactor (ITER) Plan matched project (Grant No. 2011GB113004). References
3.3. REBCO long tape fabrication In 2013, a pilot REBCO long tape fabrication line was set up at Shanghai Superconductor Technology Corporation Ltd. Since then, the laboratory developed process parameters which have been transferred to pilot line. On pilot line, to reduce the cost, a simplified buffer architecture was used, i.e. a single sputter-deposited CeO2 on IBAD-MgO tapes for YBCO depositions. The in-plane texture of sputter deposited CeO2 cap layer was less than 5 degree, as shown in Fig. 4. The in-plane phi scan full width at half maximum, FWHM, DU, was 4.89° and the out-plane omega scan, Dx, was 1.65°. The best in plane texture result was 2.9°. So far, all
[1] J.G. Bednorz, K.A. Muller, Z. Phys. B 64 (1986) 89. [2] M. Igarashi, K. Kakimoto, S. Hanyu, R. Kikutake, Y. Sutoh, R. Suzuki, M. Daibo, H. Fuji, H. Kutami, Y. Iijima, M. Itoh, T. Saitoh, Phys. Procedia 36 (2012) 1412. [3] Jae-Hun Lee, Hunju Lee, Jung-Woo Lee, Soon-Mi Choi, Sang-Im Yoo, Seung-Hyun Moon, Supercond. Sci. Technol. 7 (2014) 1. [4] V. Selvamanickam, Y. Chen, X. Xiong, Y. Xie, M. Martchevski, A. Rar, Y. Qiao, R.M. Schmidt, A. Knoll, K.P. Lenseth, C. Weber, IEEE Trans. Appl. Supercond. 19 (2009) 3225. [5] Y. Li, Z. Zhao, L. Liu, Q. Ye, H. Zheng, IEEE Trans. Appl. Supercond. 19 (2009) 3295. [6] V.F. Solovyov, D. Abraimov, D. Miller, Q. Li, H. Wiesmann, J. Appl. Phys. 105 (2009) 113927. [7] M. Coll, J. Gàzquez, R. Hühne, B. Holzapfel, Y. Morilla, J. García-López, A. Pomar, F. Sandiumenge, T. Puig, X. Obradors, J. Mater. Res. 24 (2009) 1446.
Please cite this article in press as: Y. Li et al., Fabrication of long REBCO coated conductors by PLD process in China, Physica C (2015), http://dx.doi.org/ 10.1016/j.physc.2015.03.020
Contents lists available at ScienceDirect
Physica C journal homepage: www.elsevier.com/locate/physc
Fabrication of long REBCO coated conductors by PLD process in China Yijie Li a,b,⇑, Linfei Liu a, Xiang Wu a a Key Laboratory of Artificial Structure and Quantum Control, Ministry of Education, Department of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 20040, China b Shanghai Superconductor Technology Corporation, Ltd, 28 Jiang Chuan Road, Shanghai 200240, China
a r t i c l e
i n f o
Article history: Received 13 January 2015 Received in revised form 22 February 2015 Accepted 30 March 2015 Available online xxxx Keywords: REBCO coated conductor IBAD Pulsed laser deposition Microstructure Surface morphology Superconducting properties
a b s t r a c t In China, the First National Key Project on CC Program started in 2009, which was focused on developing hundred meter long class CC tapes based on PLD/RABiTS processes. In this project, SJTU mainly worked on all of functional layer deposition process development. Northwest Institute for Non-ferrous Metal Research worked on RABiTS tape fabrication. At the end of the project in 2011, SJTU successfully fabricated hundred meter long CC tapes with over 300 A/cm (at 77 K, self field) on RABiTS tapes. To develop high performance CC tapes by PLD/IBAD-MgO processes, a pilot CC fabrication line was set up at Shanghai Superconductor Technology Corporation, Ltd. in 2013. High quality long REBCO coated conductors have been successfully fabricated on flexible polycrystalline metal tapes by PLD plus magnetron sputter and IBAD processes. Under optimized conditions, the IBAD-MgO layers showed pure (0 0 1) orientation and excellent in-plane texture. The in-plane phi-scan rocking curve is 4–6 degrees. AFM observation showed MgO layer had very smooth surface. The RMS is less 1 nm. On the textured MgO layer, sputter deposited single cerium oxide cap-layer showed pure (0 0 1) orientation and excellent in-plane texture of 4–6 degree. Reel-to-reel PLD process with high deposition rate was already scaled up to 100 m/h tape speed. Hundred meters long coated conductor tapes with over 500 A/cm performance have been routinely fabricated. And now, the process optimization for kilometer long coated conductor tapes is underway. Ó 2015 Elsevier B.V. All rights reserved.
1. Introduction Since the discovery of oxide high temperature superconductors in 1986 [1], significant progress has been made on research and development (R&D) work for commercial applications, especially the fabrication of kilometer-long class REBa2Cu3O7 x (REBCO) high temperature superconductor tapes. Comparing with silver sheathed Bi–Sr–Ca–Cu–O (BSCCO) first generation high temperature superconducting wires, the so-called REBCO second generation high temperature superconductor (2G HTS) tapes are fabricated by thin film coating technology. Therefore, REBCO superconducting tapes are also called REBCO coated conductors. So far, several R&D groups have reported the kilometer long REBCO coated conductor results in the world [2–4]. In China, the first National Key R&D project for 2G wires started in 2009, which was supported by the Ministry of Science and Technology (MOST). ⇑ Corresponding author at: Key Laboratory of Artificial Structure and Quantum Control, Ministry of Education, Department of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 20040, China. Tel.: +86 21 54743149; fax: +86 21 54743017. E-mail address: [email protected] (Y. Li).
In this program, Shanghai Jiao Tong University (SJTU) concentrated on developing all of functional layer depositions for 2G tapes. Northwest Institute for Nonferrous Metal Research (NIN) mainly worked on Ni–W alloy RABiTS (rolling assisted bi-axially textured substrate) tape fabrication. At the end of 2010, SJTU successfully fabricated the first 100 m long coated conductor tape with 194 A/ cm at 77 K, self field. Northwest Institute for Nonferrous Metal Research (NIN) has established a Ni–W alloy RABiTS tape fabrication line with 30–50 km/year capacity. In 2011, SJTU switched from RABiTS tape to IBAD-MgO tape. A pilot PLD/IBAD-MgO line was set up in 2013 under collaboration with Shanghai Superconductor Technology Co. for long 2G tape fabrication. In this paper, we will report our recent progress in high performance thick film deposition and long tape fabrication. 2. Experimental REBCO superconducting layers were deposited by pulsed laser deposition. In research lab, the maximum excimer laser power is 80 W, and the maximum repetition rate is 200 Hz [5]. In pilot line, the maximum excimer laser power is 300 W, and the maximum repetition rate is 300 Hz. The thickness of RABiTS tape is
http://dx.doi.org/10.1016/j.physc.2015.03.020 0921-4534/Ó 2015 Elsevier B.V. All rights reserved.
Please cite this article in press as: Y. Li et al., Fabrication of long REBCO coated conductors by PLD process in China, Physica C (2015), http://dx.doi.org/ 10.1016/j.physc.2015.03.020
2
Y. Li et al. / Physica C xxx (2015) xxx–xxx
Fig. 1. SEM images of 2.0 lm thick REBCO layer deposited on RABiTS tapes. (a) Pure c-axis oriented grains and (b) a-axis oriented grains.
Fig. 2. I–V curves of REBCO films with different thickness.
80–100 lm. And 50 lm thick C-276 tape was used for IBAD-MgO process. On RABiTS tapes, all of CeO2 seed layer, YSZ barrier layer, CeO2 cap layer and REBCO superconducting layer were grown in a reel-to-reel research PLD system which could fabricate several hundred meters long tapes. On IBAD-MgO tapes, kilometer-long class CeO2 cap layers were deposited by reactive sputtering and REBCO superconducting layer were grown by PLD in pilot line. The width of RABiTS tape and IBAD-MgO tape was 1.0 cm. Superconducting properties of REBCO tapes were measured by TapeStar system and four-probe method (77 K, self-field). 3. Results and discussion 3.1. REBCO coated conductor based on RABiTS tapes On RABiTS tapes, during superconducting layer optimization, it was found that pure (0 0 1) oriented YSZ layer, CeO2 cap layer could be easily grown by PLD process. Thinner REBCO layers had pure
Fig. 4. XRD Phi scan pattern of a kilometer long class CeO2 cap layer coated IBADMgO tape.
c-axis orientation and high critical current density with over 4 106 A/cm2. But as REBCO layer thickness increased over 2 lm, it can be seen from Fig. 1 that REBCO layers had a-axis and c-axis mixed orientations. Since the average grain size of Ni–W tapes was just several tens of micrometers, it was concluded that the formation of a-axis oriented grains did not resulted from the heater temperature homogeneity deviation. The substantial variability of the YBCO orientation from grain to grain was previously reported by other group [6]. The source of the variation was due to a difference in crystallographic orientation of the underlying substrate grains. The YBCO grains inherit the orientation of the underlying Ni–W grains. Ni–W grain with different out-plane tilt had different density of YBCO nuclei. Large distances between the nuclei allowed the formation of secondary phases between the YBCO grains, thus degrading the overall structural integrity of the YBCO layer, which was supported by the study by Coll et al. [7]. Under optimized
Fig. 3. SEM images of REBCO films with different thickness, (a) 0.4 lm and (b) 2.0 lm thickness.
Please cite this article in press as: Y. Li et al., Fabrication of long REBCO coated conductors by PLD process in China, Physica C (2015), http://dx.doi.org/ 10.1016/j.physc.2015.03.020
Y. Li et al. / Physica C xxx (2015) xxx–xxx
3
Fig. 5. Longitudinal Ic profile of a 100 m long class REBCO tape measured by TapeStar.
conditions, hundred meter long class REBCO tapes had 300 A end-to-end superconducting critical current (77 K, self-field). It was difficult to improve superconducting performance further on RABiTS tapes by PLD process. 3.2. REBCO thick film deposition on IBAD-MgO tapes In order to fabricate long REBCO coated conductors with high Ic performance, it is necessary to fully understand the epitaxial growth mechanism of thick REBCO films on metal tape substrates. For REBCO thick film deposition, the most difficult thing is how to avoid Jc degradation. Fig. 2 shows the relationship between superconducting critical current Ic values and REBCO layer thickness. As shown in Fig. 2, under optimized conditions, for less than 0.8 lm REBCO films, Jc was 5 106 A/cm2. With increasing the thickness from 1.0 lm to 1.4 lm, Jc decreased from 4.5 106 A/cm2 to 3.6 106 A/cm2. When REBCO thickness increased to 2.0 lm, Ic was 680 A and still nearly linearly increasing with thickness. To understand the Jc degradation of thick REBCO films, the samples with different thickness were analyzed by SEM and XRD. It was found that all the samples had only (0 0 l) peaks and no (l 0 0) peaks from XRD results. The SEM images of thin and thick REBCO films were shown in Fig. 3. For thinner REBCO film, the surface was very flat and showed layer-by-layer growth mode. But for thicker film, the surface became rougher and REBCO grain became larger. So the Jc of the sample was not only dependant on the orientation, but also the REBCO growth mode and grain size. The key elements to maintain high Jc value was to control REBCO grain size in submicrometer range and keep layer-by-layer epitaxial growth mode. Once REBCO top layer changed from layer-by-layer growth mode to island growth mode, REBCO grains subsequently became large particles, and Jc rapidly decreased below 4 106 A/cm2. So far, we have achieved highest Ic value of 780 A at 2.8 lm thickness. This result is close to achieve the final goal of 1000 A/cm at 3.0 lm thickness. Further research work on increasing REBCO layer thickness is ongoing.
processes, except for PLD, already reached kilometer long range at a deposition tape speed of over 100 m/h speed. PLD YBCO process is currently developed in 100 m long range. Fig. 5 shows a longitudinal Ic profile of a 100 m long class REBCO tape measured by TapeStar. The lowest Ic value measured by four probe method from the end part of the tape was 500 A. As shown in Fig. 5, the Ic profile along longitudinal direction is quite uniform. 4. Conclusions REBCO deposition processes by PLD have been systematically investigated on RABiTS and IBAD-MgO tapes. On RABiTS tapes, although thin REBCO layer showed high Jc of >4 106 A/cm2, over 2.0 lm thick films showed lower Jc of <3 106 A/cm2 due to mixed a/c axis orientations. On IMAD-MgO tapes, REBCO films deposited by PLD showed layer-by-layer growth mode. When REBCO thickness increased to 2.0 lm, Ic was still nearly linearly increasing with thickness. Short sample at 2.8 lm thickness had Ic value of 780 A. This is very close to the final goal of 1000 A/cm at 3.0 lm thickness. On pilot PLD line, hundred meter long class REBCO tapes with 500 A (at 77 K, self-field) had been successfully fabricated. Currently, the process optimization for kilometer long coated conductor tapes is underway. Acknowledgements This work was supported by Shanghai Science and Technology Committee (Grant Nos. 11DZ1100402, 11DZ1100401, 11DZ1100400, and 13DZ0500100), the Ministry of Science and Technology of China (Grant No. 2014AA032702), the National Natural Science Foundation of China (Grant No. 51372150), the Natural Science Foundation of China for Youths (Grant No. 11204174), the China’s domestic International Thermonuclear Experimental Reactor (ITER) Plan matched project (Grant No. 2011GB113004). References
3.3. REBCO long tape fabrication In 2013, a pilot REBCO long tape fabrication line was set up at Shanghai Superconductor Technology Corporation Ltd. Since then, the laboratory developed process parameters which have been transferred to pilot line. On pilot line, to reduce the cost, a simplified buffer architecture was used, i.e. a single sputter-deposited CeO2 on IBAD-MgO tapes for YBCO depositions. The in-plane texture of sputter deposited CeO2 cap layer was less than 5 degree, as shown in Fig. 4. The in-plane phi scan full width at half maximum, FWHM, DU, was 4.89° and the out-plane omega scan, Dx, was 1.65°. The best in plane texture result was 2.9°. So far, all
[1] J.G. Bednorz, K.A. Muller, Z. Phys. B 64 (1986) 89. [2] M. Igarashi, K. Kakimoto, S. Hanyu, R. Kikutake, Y. Sutoh, R. Suzuki, M. Daibo, H. Fuji, H. Kutami, Y. Iijima, M. Itoh, T. Saitoh, Phys. Procedia 36 (2012) 1412. [3] Jae-Hun Lee, Hunju Lee, Jung-Woo Lee, Soon-Mi Choi, Sang-Im Yoo, Seung-Hyun Moon, Supercond. Sci. Technol. 7 (2014) 1. [4] V. Selvamanickam, Y. Chen, X. Xiong, Y. Xie, M. Martchevski, A. Rar, Y. Qiao, R.M. Schmidt, A. Knoll, K.P. Lenseth, C. Weber, IEEE Trans. Appl. Supercond. 19 (2009) 3225. [5] Y. Li, Z. Zhao, L. Liu, Q. Ye, H. Zheng, IEEE Trans. Appl. Supercond. 19 (2009) 3295. [6] V.F. Solovyov, D. Abraimov, D. Miller, Q. Li, H. Wiesmann, J. Appl. Phys. 105 (2009) 113927. [7] M. Coll, J. Gàzquez, R. Hühne, B. Holzapfel, Y. Morilla, J. García-López, A. Pomar, F. Sandiumenge, T. Puig, X. Obradors, J. Mater. Res. 24 (2009) 1446.
Please cite this article in press as: Y. Li et al., Fabrication of long REBCO coated conductors by PLD process in China, Physica C (2015), http://dx.doi.org/ 10.1016/j.physc.2015.03.020