Flux Pinning Mechanism in BaSnO3-Added GdBa2Cu3O7-x Films with Different Thickness
- 300 Downloads
Types of flux pinning mechanism in pure and BaSnO3 (BSO)-added GdBa2Cu3O7-x (GdBCO) superconducting films have been determined by using the Dew-Hughes model. We have found that as the BSO content increases up to 4 wt%, dominant pinning mechanism of GdBCO films has changed from normal surface pinning due to intrinsic linear defects to normal point pinning by BSO addition. Careful analysis on the scaling of the flux pinning for the 4 wt% BSO-doped GdBCO films with various film thicknesses revealed that the pinning mechanism came from the hybrid pinning of two kinds of pinning types. In addition to the normal point pinning by BSO addition, another type of Δκ-pinning was observed to be prominent in the thinner films in low magnetic field region as normal point pinning was deteriorated. Through the EXAFS analysis, it was found that the Δκ-pinning is possibly originated from the oxygen deficiency in localized position. These results suggested that film thickness directly affects the flux pinning mechanism of the BSO-doped GdBCO films, and in the application point of view, an optimization of the film thickness may be crucial to operate normal point pinning induced by BSO addition.
KeywordsGdBCO BSO Flux pinning mechanism EXAFS
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (NRF-2018R1A2B6004784).
- 7.Aytug, T., Paranthaman, M., Gapud, A.A., Kang, S., Christen, H.M., Leonard, K.J., Martin, P.M., Thompson, J.R., Christen, D.K., Meng, R., Rusakova, I., Chu, C.W., Johansen, T.H.: Enhancement of flux pinning and critical currents in YBa2Cu3O7-δ films by nanoscale iridium pretreatment of substrate surfaces. J. Appl. Phys. 98, 114309 (2005)ADSCrossRefGoogle Scholar
- 8.Huijbregtse, J. M., Klaassen, F. C., Szepielow, A., Rector, J. H., Dam, B., Griessen, R., Kooi, B. J., de Hosson, J. Th. M.: Vortex pinning by natural defects in thin films of YBa2Cu3O7- δ. Supercond. Sci. Technol. 15, 395–404 (2002)Google Scholar
- 12.Goyal, A., Kang, S., Leonard, K.J., Martin, P.M., Gapud, A.A., Varela, M., Paranthaman, M., Ijaduola, A.O., Specht, E.D., Thompson, J.R.: Irradiation-free, columnar defects comprised of self-assembled nanodots and nanorods resulting in strongly enhanced flux-pinning in YBa2Cu3O7- δ films. Supercond. Sci. Technol. 18, 1533–1538 (2005)ADSCrossRefGoogle Scholar
- 14.Matsushita, T., Nagamizu, H., Tanabe, K., Kiuchi, M., Otabe, E.S., Tobita, H., Yoshizumi, M., Izumi, T., Shiohara, Y., Yokoe, D.: Improvement of flux pinning performance at high magnetic fields in GdBa2Cu3Oy coated conductors with BHO nano-rods through enhancement of Bc2. Supercond. Sci. Technol. 25, 125003 (2012)CrossRefGoogle Scholar
- 15.Tobita, H., Notoh, K., Higashikawa, K., Inoue, M., Kiss, T., Kato, T., Hirayama, T., Yoshizumi, M., Izumi, T., Shiohara, Y.: Fabrication of BaHfO3 doped Gd1Ba2Cu3O7- δ coated conductors with the high I c of 85A/cm-w under 3 T at liquid nitrogen temperature 77 K. Supercond. Sci. Technol. 25, 062002 (2012)ADSCrossRefGoogle Scholar
- 24.Wang, X.L., Li, A.H., Yu, S., Ooi, S., Hirata, K., Lin, C.T., Collings, E.W., Sumption, M.D., Bhatia, M., Ding, S.Y., Dou, S.X.: Thermally assisted flux flow and individual vortex pinning in Bi2Sr2Ca2Cu3O10 single crystals grown by the traveling solvent floating zone technique. J. Appl. Phys. 97, 10B114 (2005)CrossRefGoogle Scholar
- 32.Prins, R., Koningsberger, D.C. (eds.): X-ray absorption: principles, applications, techniques of EXAFS, SEXAFS. XANES. Wiley, New York (1988)Google Scholar