- Email: [email protected]
EBSP observation of oriented textures in Y-based coated conductors
Physica C 463–465 (2007) 727–731 www.elsevier.com/locate/physc
EBSP observation of oriented textures in Y-based coated conductors S. Futami a, K. Matsumoto a
a,*
, A. Ibi b, Y. Yamada b, Y. Shiohara
c
Department of Materials Science and Engineering, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan b Superconductivity Research Laboratory, ISTEC, 2-4-1, Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan c Superconductivity Research Laboratory, ISTEC, 1-10-13, Shinonome, Koto-ku, Tokyo 135-0062, Japan Accepted 16 February 2007 Available online 6 June 2007
Abstract We investigated the microstructure of Y-based coated conductors by using electron back scatter diffraction pattern (EBSP). We prepared YBCO thin films on YSZ single crystal, RABiTS and IBAD substrates by using PLD. The EBSP observation showed that there was a big difference in two types of IBAD samples. There were many grain boundaries of misorientation angle >5 on the IBAD sample of Du = 7.6, while there were few grain boundaries of misorientation angle >5 on the IBAD sample of Du = 4.8. This indicates that the difference leads to the different behaviors of Jc–B properties. 2007 Elsevier B.V. All rights reserved. PACS: 74.72.Bk Keywords: REBCO; Coated conductors; EBSP
1. Introduction For the production of Y-based coated conductors (CC’s), highly textured YBCO films are required [1]. Ybased CC’s are mainly fabricated by means of IBAD and RABiTS methods [2,3]. The textures of the films on the substrates are basically studied by using X-ray diffraction (XRD) and transmission electron microscopy (TEM) [4,5]. However, information on the inclination between adjacent individual crystal grains, which is important for examining the current path, is not obtained by XRD. TEM analysis is carried out as a complementary approach to collect the detailed information on the textures of the films and the processing of the sample is needed. However, the field of view by TEM is small so that the available information is limited in the range to about lm. In contrast, the field of view by electron back scatter diffraction pattern (EBSP) is large and it is possible to observe the *
Corresponding author. Tel.: +81 75 753 5440; fax: +81 75 753 5486. E-mail address: [email protected] (K. Matsumoto). 0921-4534/$ - see front matter 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.physc.2007.02.057
sample in the range of many hundreds of lm and to characterize orientation of individual grain in the films by nondestructive way [6]. In this study, we prepared YBCO films on YSZ single crystal, IBAD and RABiTS substrates by pulsed laser deposition (PLD) and investigated the microstructure of these samples by using EBSP. 2. Experimental We prepared IBAD-GZO/Hastelloy substrates (Du = 4.8 for IBAD-GZO (IBAD-1) and Du = 7.6 for IBAD-GZO (IBAD-2)), the RABiTS Ni–Cr substrate, and the YSZ single crystal substrate. The buffer layers and the YBCO thin films were deposited on each substrate by using PLD. A Kr–F excimer laser (wavelength = 248 nm) was used to deposit films. Compositions of each sample were YBCO/CeO2/IBAD-GZO/Hastelloy (IBAD1, IBAD-2), YBCO/CeO2/YSZ/CeO2/Ni–Cr (RABiTS) and YBCO/CeO2/YSZ single crystal (YBCO on single crystal), respectively. On the IBAD substrate, the deposition temperature for YBCO was 800 C, the oxygen
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S. Futami et al. / Physica C 463–465 (2007) 727–731 Table 1 The compositions, Dx and Du of the samples Sample
Composition
Dx ()
Du()
IBAD-1
YBCO/CeO2/IBAD-GZO/ Hastelloy YBCO/CeO2/IBAD-GZO/ Hastelloy YBCO/CeO2/YSZ single crystal YBCO/CeO2/YSZ/CeO2/Ni– Cr
2.4
4.8
2.5
7.6
0.38
About 1.5 9.3
IBAD-2 YBCO on single crystal RABiTS
Fig. 1. X-ray h–2h diffraction patterns for two types of IBAD tapes, RABiTS tape and YBCO on single crystal.
pressure was 300 mTorr, and the substrate-target distance was 50 mm. On the RABiTS substrate and CeO2/YSZ single crystal, the deposition temperatures for YBCO were 780 C, the oxygen pressures were 200 mTorr, and the substrate-target distance was 67 mm. The thicknesses for YBCO thin films on the IBAD, the RABiTS and the single crystal substrates were about 0.3 lm, 0.12 lm and 0.2 lm. We used X-ray u scan, X-ray rocking curve (x scan) and X-ray h–2h diffraction to evaluate the crystalline orienta-
7.4
tion of the films. The surface morphologies of the films were examined by scanning electron microscopy (SEM). High-resolution EBSP was performed to determine the local crystal orientation in a JEOL JSM-6500F SEM with Orientation Imaging Microscopy provided by TexSem Lab., Inc. Accelerating voltage for EBSP measurement was 15 kV and 20 kV. The scanning step size was between 30 nm and 3 lm. 3. Results and discussion Fig. 1 shows X-ray h–2h diffraction patterns for IBAD1, IBAD-2, YBCO on single crystal and RABiTS. YBCO and buffer films in each sample are c-axis oriented. Fig. 2 shows YBCO (0 0 5) rocking curve and YBCO (1 0 3) u scan. The values of Dx for IBAD-1, IBAD-2, YBCO on
Fig. 2. XRD x scan and u scan dates for IBAD-1, IBAD-2 YBCO on single crystal and RABiTS. (a) YBCO (0 0 5) x scan, (b) YBCO (1 0 3) u scan.
Fig. 3. Surface SEM images of two types of IBAD tapes. (a) IBAD-1 (Du = 4.8) and (b) IBAD-2 (Du = 7.6).
S. Futami et al. / Physica C 463–465 (2007) 727–731
Fig. 4. EBSP analysis of two types of IBAD tapes. (a) YBCO (1 0 3) pole figure of IBAD-1 (Du = 4.8), (b) YBCO (1 0 3) pole figure of IBAD-2 (Du = 7.6).
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single crystal and RABiTS are 2.4, 2.5, 0.38 and 7.4. The values of Du for each sample are 4.8, 7.6, about 1.5 and 9.3, respectively. These are summarized in Table 1. Dx of IBAD-1 is as much as that of IBAD-2, while the values of Du of IBAD-1 and IBAD-2 are greatly different (Du = 4.8 for IBAD-1, Du = 7.6 for IBAD-2). Fig. 3 shows SEM surface images of YBCO films on IBAD-1 (Fig. 3a) and IBAD-2 (Fig. 3b). We show the results of EBSP analysis for IBAD-1 and IBAD-2 samples in Figs. 4–6. Accelerating voltage was 15 kV, scanning step size was 30 nm, and the observed area was 10.2 lm · 6.6 lm for these measurements. Fig. 4a and b is pole figures on which the azimuth of each measurement point is plotted. The difference of azimuth is related with
Fig. 5. EBSP analysis of two types of IBAD tapes. (a, b) Grain boundary map of IBAD-1 (Du = 4.8) and IBAD-2 (Du = 7.6). The black lines correspond to boundaries of misorientation angle >2. In the area of gray color, crystal orientation is not defined. (c) Misorientation profiles on the line of (i). The line of (A) is misorientation profile of adjoining point and the line of (B) is the profile of the crystal azimuth difference between each point and the point in the left end.
Fig. 6. EBSP analysis of two types of IBAD tapes. (a, b) Grain boundary map of IBAD-1 and IBAD-2. The black lines correspond to boundaries of misorientation angle >5. In the area of gray color, crystal orientation is not defined.
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S. Futami et al. / Physica C 463–465 (2007) 727–731
the results of X-ray u scan and X-ray x scan. Fig. 5a and b shows grain boundary maps. The black lines in the figure correspond to boundaries of misorientation angle >2. In the area of gray color, crystal orientation is not defined due to the surface asperity, deterioration of crystalline and so on. The diameters of grain are in the range of
100 nm to 1 lm. Fig. 5c shows misorientation profiles along the line of (i) in Fig. 5a. The line of (A) is misorientation profile of adjoining point. The line of (B) is the profile of the crystal azimuth difference between each point and the point in the left end. Along the line of (i), boundaries of misorientation angle >2 are not recognized. But
Fig. 7. Grain boundary maps of RABiTS tape of same area. (a) Rolled and annealed Ni–Cr tape, (b) YBCO film The fine lines correspond to boundaries of misorientation angle >2 and the bold lines correspond to boundaries of misorientation angle >5. In the area of gray color, crystal orientation is not defined.
b 2º 2º
Misorientation (degrees)
a
(iii) (iii) (i)
(ii) (ii)
1.4 1.2 1.0 0.8
(B)
0.6 0.4 0.2
(A)
0.0 2
4
6
8
10
Distance (μm)
d
0.7 0.6 0.5
(B)
0.4 0.3 0.2 0.1
(A)
0.0 2
4
6
8
Distance (μm)
10
Misorientation (degrees)
Misorientation (degrees)
c
0.7 0.6 0.5 0.4
(B)
0.3 0.2 0.1
(A)
0.0 2
4
6
Distance (μm)
8
10
Fig. 8. EBSP analysis of RABiTS tapes and YBCO on single crystal. (a) Grain boundary map of YBCO film. The black lines correspond to boundaries of misorientation angle >2. In the area of gray color, crystal orientation is not defined. (b–d) Misorientation profiles on the lines of (i), (ii), and (iii). The line of (A) is misorientation profile of adjoining point. The line of (B) is the profile of the crystal azimuth difference between each point and the point in the left end.
S. Futami et al. / Physica C 463–465 (2007) 727–731
misorientation distribution change with the interval of several hundred nm is observed, so there are boundaries of misorientation angle <2 on such a point. Grain boundary maps of IBAD-1 and IBAD-2 are shown in Fig. 6. The black lines in the figure correspond to boundaries of misorientation angle >5. This shows that there is great difference of current path in two types of IBAD samples. There are a lot of grain boundaries of misorientation angle >5 on IBAD-2, while there are few grain boundaries of misorientation angle >5 on IBAD-1. The length of boundaries of misorientation angle >5 in IBAD-1 is 12.2% for that in IBAD-2. Because a critical current density (Jc) in a magnetic field does not decrease at grain boundary of misorientation angle of 2 but slightly decreases at that of 5 [7,8], it is suggested that the Jc–B property of IBAD-1 is better than that of IBAD-2. It is expected that Jc–B property of IBAD-1 is similar to that of YBCO on single crystal because grain boundaries of misorientation angle >5 are few in both samples. Fig. 7 shows grain boundary maps of RABiTS ((a) NiCr substrate and (b) YBCO). The fine lines correspond to boundaries of misorientation angle >2 and the bold lines correspond to boundaries of misorientation angle >5. Scanning step size was 3 lm and measurement range was 600 lm · 600 lm. The diameters of grain of both samples are about 100 lm, and these grain sizes originate in rolling and annealing of Ni–Cr. The grain boundaries of YBCO thin film are almost originated from those of Ni–Cr substrate. Fig. 8a is the grain boundary map within an YBCO grain on the RABiTS. Misorientation profile along the line of (i) and the profile along the line of (ii) are shown in Fig. 8b and c. Scanning step size was 50 nm and measurement range was 20 lm · 27 lm for these measurements. Additionally, the typical profile of YBCO on single crystal with the scanning step size of 50 nm is shown in Fig. 8d. Fig. 8b suggests there are a few grains whose crystal orientation is different from surrounding area in the single YBCO grain because the bias of misorientation is observed in the profile. The area indicated by (iii) is such an area. In contrast, the profile in Fig. 8c is typical one observed at the area except (iii), and this profile is similar to that of YBCO on single crystal. It is thought that the inter-grain of YBCO on the single Ni–Cr grain is similar to that of single crystal. If the current path is taken into consideration, the grain size of YBCO on the RABiTS substrate should be small with a small inclination angle kept [9].
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4. Conclusion We investigated the microstructure of different biaxially textured YBCO films on IBAD, RABiTS and single crystal substrates by using EBSP. The difference of azimuth obtained by EBSP is related with the results of X-ray u scan and X-ray x scan. There are many grain boundaries of misorientation angle >5 on IBAD of Du = 7.6 (IBAD-2), while there are few grain boundaries of misorientation angle >5 on IBAD of Du = 4.8 (IBAD-1). The length of boundaries of misorientation angle >5 in IBAD-1 is 12.2% for that in IBAD-2. This indicated that Jc property in a magnetic field of IBAD-1 is better than that IBAD-2. It is expected that Jc in a magnetic field of IBAD-1 is similar to that of YBCO on single crystal because grain boundaries of misorientation angle >5 are few in both samples. In addition, it is suggested that the inter-grain of YBCO on single Ni–Cr grain in RABiTS sample is similar to that on single crystal. Acknowledgment A part of this study was performed commissioned by New Energy and Industrial Technology Development Organization through International Superconductivity Technology Center. References [1] D. Dimos, P. Chaudhari, J. Mannhart, Phys. Rev. B 41 (1990) 4038. [2] A. Goyal, D.P. Norton, J.D. Budai, M. Paranthaman, E.D. Specht, D.M. Kroeger, D.K. Christen, Q. He, B. Saffian, F.A. List, D.F. Lee, P.M. Martin, C.E. Klabunde, E. Hartfield, V.K. Sikka, Appl. Phys. Lett. 69 (1996) 1795. [3] K. Kakimoto, Y. Iijima, T. Saitoh, Physica C 392 (2003) 783. [4] E.Y. Sun, A. Goyal, D.P. Norton, C. Park, D.M. Kroeger, M. Paranthaman, D.K. Christen, Physica C 321 (1999) 29. [5] T. Kato, T. Muroga, Y. Iijima, T. Saitoh, T. Hirayama, I. Hirabayashi, Y. Yamada, T. Izumi, Y. Shiohara, Y. Ikuhara, Physica C 412 (2004) 813. [6] L. Ferna´ndez, B. Holzapfel, F. Schindler, B. de Boer, A. Attenberger, J. Ha¨nisch, L. Schultz, Phys. Rev. B 67 (2003) 52503. [7] T. Horide, K. Matsumoto, Y. Yoshida, M. Mukaida, A. Ichinose, S. Horii, Appl. Phys. Lett. 89 (2006) 172505. [8] D.T. Verebelyi, D.K. Christen, R. Feenstra, C. Cantoni, A. Goyal, D.F. Lee, M. Paranthaman, P.N. Arendt, R.F. DePaula, J.R. Groves, C. Prouteau, Appl. Phys. Lett. 76 (2000) 1755. [9] Y. Nakamura, T. Izumi, Y. Shiohara, Physica C 371 (2002) 275.
EBSP observation of oriented textures in Y-based coated conductors S. Futami a, K. Matsumoto a
a,*
, A. Ibi b, Y. Yamada b, Y. Shiohara
c
Department of Materials Science and Engineering, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan b Superconductivity Research Laboratory, ISTEC, 2-4-1, Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan c Superconductivity Research Laboratory, ISTEC, 1-10-13, Shinonome, Koto-ku, Tokyo 135-0062, Japan Accepted 16 February 2007 Available online 6 June 2007
Abstract We investigated the microstructure of Y-based coated conductors by using electron back scatter diffraction pattern (EBSP). We prepared YBCO thin films on YSZ single crystal, RABiTS and IBAD substrates by using PLD. The EBSP observation showed that there was a big difference in two types of IBAD samples. There were many grain boundaries of misorientation angle >5 on the IBAD sample of Du = 7.6, while there were few grain boundaries of misorientation angle >5 on the IBAD sample of Du = 4.8. This indicates that the difference leads to the different behaviors of Jc–B properties. 2007 Elsevier B.V. All rights reserved. PACS: 74.72.Bk Keywords: REBCO; Coated conductors; EBSP
1. Introduction For the production of Y-based coated conductors (CC’s), highly textured YBCO films are required [1]. Ybased CC’s are mainly fabricated by means of IBAD and RABiTS methods [2,3]. The textures of the films on the substrates are basically studied by using X-ray diffraction (XRD) and transmission electron microscopy (TEM) [4,5]. However, information on the inclination between adjacent individual crystal grains, which is important for examining the current path, is not obtained by XRD. TEM analysis is carried out as a complementary approach to collect the detailed information on the textures of the films and the processing of the sample is needed. However, the field of view by TEM is small so that the available information is limited in the range to about lm. In contrast, the field of view by electron back scatter diffraction pattern (EBSP) is large and it is possible to observe the *
Corresponding author. Tel.: +81 75 753 5440; fax: +81 75 753 5486. E-mail address: [email protected] (K. Matsumoto). 0921-4534/$ - see front matter 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.physc.2007.02.057
sample in the range of many hundreds of lm and to characterize orientation of individual grain in the films by nondestructive way [6]. In this study, we prepared YBCO films on YSZ single crystal, IBAD and RABiTS substrates by pulsed laser deposition (PLD) and investigated the microstructure of these samples by using EBSP. 2. Experimental We prepared IBAD-GZO/Hastelloy substrates (Du = 4.8 for IBAD-GZO (IBAD-1) and Du = 7.6 for IBAD-GZO (IBAD-2)), the RABiTS Ni–Cr substrate, and the YSZ single crystal substrate. The buffer layers and the YBCO thin films were deposited on each substrate by using PLD. A Kr–F excimer laser (wavelength = 248 nm) was used to deposit films. Compositions of each sample were YBCO/CeO2/IBAD-GZO/Hastelloy (IBAD1, IBAD-2), YBCO/CeO2/YSZ/CeO2/Ni–Cr (RABiTS) and YBCO/CeO2/YSZ single crystal (YBCO on single crystal), respectively. On the IBAD substrate, the deposition temperature for YBCO was 800 C, the oxygen
728
S. Futami et al. / Physica C 463–465 (2007) 727–731 Table 1 The compositions, Dx and Du of the samples Sample
Composition
Dx ()
Du()
IBAD-1
YBCO/CeO2/IBAD-GZO/ Hastelloy YBCO/CeO2/IBAD-GZO/ Hastelloy YBCO/CeO2/YSZ single crystal YBCO/CeO2/YSZ/CeO2/Ni– Cr
2.4
4.8
2.5
7.6
0.38
About 1.5 9.3
IBAD-2 YBCO on single crystal RABiTS
Fig. 1. X-ray h–2h diffraction patterns for two types of IBAD tapes, RABiTS tape and YBCO on single crystal.
pressure was 300 mTorr, and the substrate-target distance was 50 mm. On the RABiTS substrate and CeO2/YSZ single crystal, the deposition temperatures for YBCO were 780 C, the oxygen pressures were 200 mTorr, and the substrate-target distance was 67 mm. The thicknesses for YBCO thin films on the IBAD, the RABiTS and the single crystal substrates were about 0.3 lm, 0.12 lm and 0.2 lm. We used X-ray u scan, X-ray rocking curve (x scan) and X-ray h–2h diffraction to evaluate the crystalline orienta-
7.4
tion of the films. The surface morphologies of the films were examined by scanning electron microscopy (SEM). High-resolution EBSP was performed to determine the local crystal orientation in a JEOL JSM-6500F SEM with Orientation Imaging Microscopy provided by TexSem Lab., Inc. Accelerating voltage for EBSP measurement was 15 kV and 20 kV. The scanning step size was between 30 nm and 3 lm. 3. Results and discussion Fig. 1 shows X-ray h–2h diffraction patterns for IBAD1, IBAD-2, YBCO on single crystal and RABiTS. YBCO and buffer films in each sample are c-axis oriented. Fig. 2 shows YBCO (0 0 5) rocking curve and YBCO (1 0 3) u scan. The values of Dx for IBAD-1, IBAD-2, YBCO on
Fig. 2. XRD x scan and u scan dates for IBAD-1, IBAD-2 YBCO on single crystal and RABiTS. (a) YBCO (0 0 5) x scan, (b) YBCO (1 0 3) u scan.
Fig. 3. Surface SEM images of two types of IBAD tapes. (a) IBAD-1 (Du = 4.8) and (b) IBAD-2 (Du = 7.6).
S. Futami et al. / Physica C 463–465 (2007) 727–731
Fig. 4. EBSP analysis of two types of IBAD tapes. (a) YBCO (1 0 3) pole figure of IBAD-1 (Du = 4.8), (b) YBCO (1 0 3) pole figure of IBAD-2 (Du = 7.6).
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single crystal and RABiTS are 2.4, 2.5, 0.38 and 7.4. The values of Du for each sample are 4.8, 7.6, about 1.5 and 9.3, respectively. These are summarized in Table 1. Dx of IBAD-1 is as much as that of IBAD-2, while the values of Du of IBAD-1 and IBAD-2 are greatly different (Du = 4.8 for IBAD-1, Du = 7.6 for IBAD-2). Fig. 3 shows SEM surface images of YBCO films on IBAD-1 (Fig. 3a) and IBAD-2 (Fig. 3b). We show the results of EBSP analysis for IBAD-1 and IBAD-2 samples in Figs. 4–6. Accelerating voltage was 15 kV, scanning step size was 30 nm, and the observed area was 10.2 lm · 6.6 lm for these measurements. Fig. 4a and b is pole figures on which the azimuth of each measurement point is plotted. The difference of azimuth is related with
Fig. 5. EBSP analysis of two types of IBAD tapes. (a, b) Grain boundary map of IBAD-1 (Du = 4.8) and IBAD-2 (Du = 7.6). The black lines correspond to boundaries of misorientation angle >2. In the area of gray color, crystal orientation is not defined. (c) Misorientation profiles on the line of (i). The line of (A) is misorientation profile of adjoining point and the line of (B) is the profile of the crystal azimuth difference between each point and the point in the left end.
Fig. 6. EBSP analysis of two types of IBAD tapes. (a, b) Grain boundary map of IBAD-1 and IBAD-2. The black lines correspond to boundaries of misorientation angle >5. In the area of gray color, crystal orientation is not defined.
730
S. Futami et al. / Physica C 463–465 (2007) 727–731
the results of X-ray u scan and X-ray x scan. Fig. 5a and b shows grain boundary maps. The black lines in the figure correspond to boundaries of misorientation angle >2. In the area of gray color, crystal orientation is not defined due to the surface asperity, deterioration of crystalline and so on. The diameters of grain are in the range of
100 nm to 1 lm. Fig. 5c shows misorientation profiles along the line of (i) in Fig. 5a. The line of (A) is misorientation profile of adjoining point. The line of (B) is the profile of the crystal azimuth difference between each point and the point in the left end. Along the line of (i), boundaries of misorientation angle >2 are not recognized. But
Fig. 7. Grain boundary maps of RABiTS tape of same area. (a) Rolled and annealed Ni–Cr tape, (b) YBCO film The fine lines correspond to boundaries of misorientation angle >2 and the bold lines correspond to boundaries of misorientation angle >5. In the area of gray color, crystal orientation is not defined.
b 2º 2º
Misorientation (degrees)
a
(iii) (iii) (i)
(ii) (ii)
1.4 1.2 1.0 0.8
(B)
0.6 0.4 0.2
(A)
0.0 2
4
6
8
10
Distance (μm)
d
0.7 0.6 0.5
(B)
0.4 0.3 0.2 0.1
(A)
0.0 2
4
6
8
Distance (μm)
10
Misorientation (degrees)
Misorientation (degrees)
c
0.7 0.6 0.5 0.4
(B)
0.3 0.2 0.1
(A)
0.0 2
4
6
Distance (μm)
8
10
Fig. 8. EBSP analysis of RABiTS tapes and YBCO on single crystal. (a) Grain boundary map of YBCO film. The black lines correspond to boundaries of misorientation angle >2. In the area of gray color, crystal orientation is not defined. (b–d) Misorientation profiles on the lines of (i), (ii), and (iii). The line of (A) is misorientation profile of adjoining point. The line of (B) is the profile of the crystal azimuth difference between each point and the point in the left end.
S. Futami et al. / Physica C 463–465 (2007) 727–731
misorientation distribution change with the interval of several hundred nm is observed, so there are boundaries of misorientation angle <2 on such a point. Grain boundary maps of IBAD-1 and IBAD-2 are shown in Fig. 6. The black lines in the figure correspond to boundaries of misorientation angle >5. This shows that there is great difference of current path in two types of IBAD samples. There are a lot of grain boundaries of misorientation angle >5 on IBAD-2, while there are few grain boundaries of misorientation angle >5 on IBAD-1. The length of boundaries of misorientation angle >5 in IBAD-1 is 12.2% for that in IBAD-2. Because a critical current density (Jc) in a magnetic field does not decrease at grain boundary of misorientation angle of 2 but slightly decreases at that of 5 [7,8], it is suggested that the Jc–B property of IBAD-1 is better than that of IBAD-2. It is expected that Jc–B property of IBAD-1 is similar to that of YBCO on single crystal because grain boundaries of misorientation angle >5 are few in both samples. Fig. 7 shows grain boundary maps of RABiTS ((a) NiCr substrate and (b) YBCO). The fine lines correspond to boundaries of misorientation angle >2 and the bold lines correspond to boundaries of misorientation angle >5. Scanning step size was 3 lm and measurement range was 600 lm · 600 lm. The diameters of grain of both samples are about 100 lm, and these grain sizes originate in rolling and annealing of Ni–Cr. The grain boundaries of YBCO thin film are almost originated from those of Ni–Cr substrate. Fig. 8a is the grain boundary map within an YBCO grain on the RABiTS. Misorientation profile along the line of (i) and the profile along the line of (ii) are shown in Fig. 8b and c. Scanning step size was 50 nm and measurement range was 20 lm · 27 lm for these measurements. Additionally, the typical profile of YBCO on single crystal with the scanning step size of 50 nm is shown in Fig. 8d. Fig. 8b suggests there are a few grains whose crystal orientation is different from surrounding area in the single YBCO grain because the bias of misorientation is observed in the profile. The area indicated by (iii) is such an area. In contrast, the profile in Fig. 8c is typical one observed at the area except (iii), and this profile is similar to that of YBCO on single crystal. It is thought that the inter-grain of YBCO on the single Ni–Cr grain is similar to that of single crystal. If the current path is taken into consideration, the grain size of YBCO on the RABiTS substrate should be small with a small inclination angle kept [9].
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4. Conclusion We investigated the microstructure of different biaxially textured YBCO films on IBAD, RABiTS and single crystal substrates by using EBSP. The difference of azimuth obtained by EBSP is related with the results of X-ray u scan and X-ray x scan. There are many grain boundaries of misorientation angle >5 on IBAD of Du = 7.6 (IBAD-2), while there are few grain boundaries of misorientation angle >5 on IBAD of Du = 4.8 (IBAD-1). The length of boundaries of misorientation angle >5 in IBAD-1 is 12.2% for that in IBAD-2. This indicated that Jc property in a magnetic field of IBAD-1 is better than that IBAD-2. It is expected that Jc in a magnetic field of IBAD-1 is similar to that of YBCO on single crystal because grain boundaries of misorientation angle >5 are few in both samples. In addition, it is suggested that the inter-grain of YBCO on single Ni–Cr grain in RABiTS sample is similar to that on single crystal. Acknowledgment A part of this study was performed commissioned by New Energy and Industrial Technology Development Organization through International Superconductivity Technology Center. References [1] D. Dimos, P. Chaudhari, J. Mannhart, Phys. Rev. B 41 (1990) 4038. [2] A. Goyal, D.P. Norton, J.D. Budai, M. Paranthaman, E.D. Specht, D.M. Kroeger, D.K. Christen, Q. He, B. Saffian, F.A. List, D.F. Lee, P.M. Martin, C.E. Klabunde, E. Hartfield, V.K. Sikka, Appl. Phys. Lett. 69 (1996) 1795. [3] K. Kakimoto, Y. Iijima, T. Saitoh, Physica C 392 (2003) 783. [4] E.Y. Sun, A. Goyal, D.P. Norton, C. Park, D.M. Kroeger, M. Paranthaman, D.K. Christen, Physica C 321 (1999) 29. [5] T. Kato, T. Muroga, Y. Iijima, T. Saitoh, T. Hirayama, I. Hirabayashi, Y. Yamada, T. Izumi, Y. Shiohara, Y. Ikuhara, Physica C 412 (2004) 813. [6] L. Ferna´ndez, B. Holzapfel, F. Schindler, B. de Boer, A. Attenberger, J. Ha¨nisch, L. Schultz, Phys. Rev. B 67 (2003) 52503. [7] T. Horide, K. Matsumoto, Y. Yoshida, M. Mukaida, A. Ichinose, S. Horii, Appl. Phys. Lett. 89 (2006) 172505. [8] D.T. Verebelyi, D.K. Christen, R. Feenstra, C. Cantoni, A. Goyal, D.F. Lee, M. Paranthaman, P.N. Arendt, R.F. DePaula, J.R. Groves, C. Prouteau, Appl. Phys. Lett. 76 (2000) 1755. [9] Y. Nakamura, T. Izumi, Y. Shiohara, Physica C 371 (2002) 275.