[1] Kamihara, Y., Watanabe, T., Hirano, M. and Hosono, H., Iron-Based Layered Superconductor La[O1-xFx]FeAs (x = 0.05−0.12) with Tc = 26 K, J. Am. Chem. Soc., 130, 3296-3297 (2008).
[2] Rotter, M., Tegel, M. and Johrendt, D., Superconductivity at 38 K in the Iron Arsenide (Ba1-xKx)Fe2As2, Phys. Rev. Lett., 101, 107006 (2008).
[3] Hosono, H., Yamamoto, A., Hiramatsu, H. and Ma, Y., Recent advances in iron-based superconductors toward applications, Materials today, 21, 278-302 (2018).
[4] Altarawneh, M. M., Collar, K., Mielke, C, H., Ni, N., Bud’ko, S. L. and Canfield, P. C., Determination of anisotropic Hc2 up to 60 T in Ba0.55K0.45Fe2As2 single crystals, Phys. Rev. B, 78, 220505(R) (2008).
[5] Yamamoto, A, Jaroszynski, J., Tarantini, C., Balicas, L., Jiang, J., Gurevich, A., Larbalestier, D. C., Jin, R., Sefat, A. S., McGuire, M. A., Sales, B. C., Christen, D. K. and Mandrus, D., Small anisotropy, weak thermal fluctuations, and high field superconductivity in Co-doped iron pnictide Ba(Fe1−xCox)2As2, Appl. Phys. Lett., 94, 062511 (2009).
[6] Farrell, D. E., Rice, J. P., Ginsberg, D. M. and Liu, J. Z., Experimental Evidence of a Dimensional Crossover in Y1Ba2Cu3O7−δ, Phys. Rev. Lett.,64, 1573 (1990).
[7] Weiss, J. D., Tarantini, C., Jiang, J., Kametani, F., Polyanskii, A. A., Larbalestier, D. C. and Hellstrom, E. E., High intergrain critical current density in fine-grain (Ba0.6K0.4)Fe2As2 wires and bulks, Nat. Mater., 11, 682-685 (2012).
[8] Togano, K., Gao, Z., Taira, H., Ishida, S., Kihou, K., Iyo, A., Eisaki, H., Matsumoto, A. and Kumakura, H., Enhanced high-field transport critical current densities observed for ex situ PIT processed Ag/(Ba, K)Fe2As2 thin tapes, Supercond. Sci. Technol., 26, 065003 (2013).
[9] Ma, Y. W., Yao, C., Zhang, X. P., Lin, H., Wang, D. L., Matsumoto, A., Kumakura, H., Tsuchiya, Y., Sun, Y. and Tamegai, T., Large transport critical currents and magneto-optical imaging of textured Sr1−xKxFe2As2 superconducting tapes, Supercond. Sci. Technol., 26, 035011 (2013).
[10] Pak, C., Su, Y. F., Collantes, Y., Tarantini, C., Hellstrom, E. E., Larbalestier, D. C. and Kametani, F., Synthesis Routes to Eliminate Oxide Impurity Segregation and Their Influence on Intergrain Connectivity in K-doped BaFe2As2 Polycrystalline Bulks, Supercond. Sci. Technol. 33, 084010 (2020).
[11] Lee, S., Jiang, J., Zhang, Y., Bark, C.W., Weiss, J. D., Tarantini, C., Nelson, C. T., Jang, H.W., Folkman, C. M., Baek, S. H., Polyanskii, A., Abraimov, D., Yamamoto, A., Park, J. W., Pan, X. Q., Hellstrom, E. E., Larbalestier, D. C. and Eom, C. B., Template engineering of Co-doped BaFe2As2 single-crystal thin films, Nat. Mater., 9, 397-402 (2010).
[12] Kurth, F., Tarantini, C., Grinenko, V., Hänisch, J., Jaroszynski, J., Reich, E., Mori, Y., Sakagami, A., Kawaguchi, T., Engelmann, J., Schultz, L., Holzapfel, B., Ikuta, H., Hühne, R. and Iida, K., Unusually high critical current of clean P-doped BaFe2As2 single crystalline thin film, Appl. Phys. Lett., 106, 072602 (2015).
[13] Iida, K., Sato, H., Tarantini, C., Hänisch, J., Jaroszynski, J., Hiramatsu, H., Holzapfel, B. and Hosono, H., High-field transport properties of a P-doped BaFe2As2 film on technical substrate, Sci. Rep., 7, srep39951 (2017).
[14] Tarantini, C., Kametani, F., Lee, S., Jiang, J., Weiss, J. D., Jaroszynski, J., Hellstrom, E. E., Eom, C. B. and Larbalestier, D. C., Development of very high Jc in Ba (Fe1-xCox)2As2 thin films grown on CaF2, Sci. Rep., 4, 7305 (2014).
[15] Mikheenko, P., Mart ́ınez, E., Bevan, A., Abell, J. S. and MacManus-Driscoll, J. L., Grain boundaries and pinning in bulk MgB2, Supercond. Sci. Technol., 20, S264-S270 (2007).
[16] Zerweck, G., On pinning of superconducting flux lines by grain boundaries, J. Low Temp. Phys., 42, 1-9 (1981).
[17] Dimos, D., Chaudhari, P., Mannhart, J., Superconducting transport properties of grain boundaries in YBa2Cu3O7 bicrystals, Phys. Rev. B, 41, 4038–4049 (1990).
[18] MacManus-Driscoll, J. L., Foltyn, S. R., Jia, Q. X., Wang, H., Serquis, A., Civale, L., Maiorov, B., Hawley, M. E., Maley, M. P. and Peterson, D. E., Strongly enhanced current densities in superconducting coated conductors of YBa2Cu3O7–x + BaZrO3, Nat. Mater., 3, 439-443 (2004).
[19] Ayai, N., Kikuchi, M., Yamazaki, K., Kobayashi, S., Yamade, S., Ueno, E., Fujikami, J., Kato, T., Hayashi, K., Sato, K., Hata, R., Iihara, J., Yamaguchi, K. and Shimoyama, J., The Bi-2223 Superconducting Wires With 200A-Class Critical Current, IEEE Trans. Appl. Supercond., 17, 3075-3078 (2007).
[20] Kametani, F., Li, P., Abraimov, D., Polyanskii, A. A., Yamamoto, A., Jiang, J., Hellstrom, E. E., Gurevich, A., Larbalestier, D. C., Ren, Z. A., Yang, J., Dong, X. L., Lu, W. and Zhao, Z. X., Intergrain current flow in a randomly oriented polycrystalline SmFeAsO0.85 oxypnictide, Appl. Phys. Lett., 95, 142502 (2009).
[21] Lee, S., Jiang, J., Weiss, J. D., Folkman, C. M., Bark, C. W., Tarantini, C., Xu, A., Abraimov, D., Polyanskii, A., Nelson, C. T., Zhang, Y., Baek, S. H., Jang, H. W., Yamamoto, A., Kametani, F., Pan, X. Q., Hellstrom, E. E., Gurevich, A., Eom, C. B. and Larbalestier, D. C., Weak-link behavior of grain boundaries in superconducting Ba (Fe1-xCox)2As2 bicrystals, Appl. Phys. Lett., 95, 212505 (2009).
[22] Katase, T., Ishimaru, Y., Tsukamoto, A., Hiramatsu, H., Kamiya, T., Tanabe, K. and Hosono, H., Advantageous grain boundaries in iron pnictide superconductors, Nat. Commun., 2, 409 (2011).
[23] Si, W., Zhang, C., Shi, X., Ozaki, T., Jaroszynsski, J. and Li, Q., Grain boundary junctions of FeSe0.5Te0.5 thin films on SrTiO3 bi-crystal substrates, Appl. Phys. Lett., 106, 032602 (2015).
[24] Sarnelli, E., Nappi, C., Camerlingo, C., Enrico, E., Bellingeri, E., Kawale, S., Braccini, V., Leveratto, A. and Ferdeghini, C., Properties of Fe (Se, Te) Bicrystal Grain Boundary Junctions, SQUIDs, and Nanostrips, IEEE Trans. Appl. Supercond., 27, 7400104 (2017).
[25] Iida, K., Omura, T., Matsumoto, T., Hatano, T. and Ikuta, H., Grain boundary characteristics of oxypnictide NdFeAs(O, F) superconductors, Supercond. Sci. Technol., 32, 074003 (2019).
[26] Shimada, Y., Yamamoto, A., Hayashi, Y., Kishio, K., Shimoyama, J., Hata, S. and Konno, T. J, The formation of defects and their influence on inter- and intra-granular current in sintered polycrystalline 122 phase Fe-based superconductors, Supercond. Sci. Technol., 32, 084003 (2019).
[27] Hecher, J., Baumgartner, T., Weiss, J. D., Tarantini, C., Yamamoto, A., Jiang, J., Hellstrom, E. E., Larbalestier, D. C. and Eisterer, M., Small grains: a key to high-field applications of granular Ba-122 superconductors?, Supercond. Sci. Technol., 29, 025004 (2016).
[28] Hara, T., Tsuchiya, K., Tsuzaki, K., Man, X., Asahata, T. and Uemoto, A., Application of orthogonally arranged FIB–SEM for precise microstructure analysis of materials, J. Alloys Compd., 577, S717-S721 (2013).
[29] Fernández, M. P., Witte, F. and Tozzi, G., Applications of X-ray computed tomography for the evaluation of biomaterial-mediated bone regeneration in critical-sized defects, J. Microsc., 277, 179-196 (2020).
[30] Inoue, K., Takamizawa, H., Kitamoto, K., Kato, J., Miyagi, T., Nakagawa, Y., Kawasaki, N., Sugiyama, N., Hashimoto, H., Shimizu, Y., Toyama, T., Nagai, Y. and Karen, A., Three-Dimensional Elemental Analysis of Commercial 45 nm Node Device with High-k/Metal Gate Stack by Atom Probe Tomography, Appl. Phys. Express, 4, 116601 (2011).
[31] Matsushita, T., Kiuchi, M., Yamamoto, A., Shimoyama, J. and Kishio, K., Essential factors for the critical current density in superconducting MgB2: connectivity and flux pinning by grain boundaries, Supercond. Sci. Technol., 21, 015008 (2008).
[32] Tokuta, S. and Yamamoto, A., Thermal response of the iron-based Ba122 superconductor to in situ and ex situ processes, Supercond. Sci. Technol., 34, 034004 (2021).
[33] Tarantini, C., Pak, C., Su, Y., Hellstrom, E. E., Larbalestier, D. C. and Kametani, F., Effect of heat treatments on superconducting properties and connectivity in K‑doped BaFe2As2, Sci. Rep., 11, 3143 (2021).
[34] Tokuta, S., Shimada, Y. and Yamamoto, A., Evolution of intergranular microstructure and critical current properties of polycrystalline Co-doped BaFe2As2 through high-energy milling, Supercond. Sci. Technol., 33, 094010 (2020).