Journal of the Korean Society for Nondestructive Testing (비파괴검사학회지)

The Korean Society for Nondestructive Testing (한국비파괴검사학회)
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A Femtosecond Laser Metrology on the Thermal Conductivity of a Nanoscale Superconductor Material

펨토초 레이저를 이용한 나노 스케일 초전도 재료의 열전도율 평가

  • Kim, Yun Young (Department of Mechanical Engineering, Dong-eui University)
  • 김윤영 (동의대학교 기계공학과)
  • Received : 2015.08.12
  • Accepted : 2015.10.12
  • Published : 2015.10.30
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Abstract

The present study investigates the thermal characteristics of a nanoscale superconductor material. A thin-film of $YBa_2Cu_3O_7-x$ was deposited on a $SrTiO_3$ substrate by using a pulsed-laser deposition technique and characterized using an ultrafast laser system. In order to extract a thermal conductivity value, a numerical solution for a transient one-dimensional heat conduction equation was obtained using a finite-difference method. The curve-fit shows a value 1.2 W/mK, which is relatively lower than those of bulk materials. This research provides a material property of superconductor thin-film required for the thermal design of micro or nanodevices.

본 연구에서는 펨토초의 펄스폭을 갖는 극초단 레이저를 이용하여 나노 스케일 초전도 재료의 열전도율을 측정하였다. 95 nm 두께의 이트륨바륨구리산화물($YBa_2Cu_3O_7-x$)을 티탄산스트론튬($SrTiO_3$) 기판 위에 펄스레이저 증착법으로 적층하여 시편을 제작하였으며, 유한차분법으로 1차원 과도 열전도 방정식의 해를 구하여 측정결과와 비교하였다. 곡선맞춤을 통하여 1.2 W/mK의 열전도율을 얻었으며, 이는 동일 재료의 벌크(bulk) 물성치에 비하여 낮은 값으로 확인된다. 본 연구는 마이크로/나노소자의 열설계를 위한 초전도 나노재료의 특성을 규명한다.

Keywords

References

  1. H. Takashima, K. Sasaki and T. Onishi, "Thermal stress analysis for the meander-shape YBCO fault current limiter," Physica C: Superconductivity and its Applications, Vol. 411, Issues 1-2, pp. 25-31 (2004) https://doi.org/10.1016/j.physc.2004.03.248
  2. N. Hu, K. Cao, D. Wang, M. Song, D. Miyagi, M. Tsuda and T. Hamajima, "Transient thermal analysis of a tri-axial HTS cable on fault current condition," Physica C: Superconductivity and its Applications, Vol. 494, pp. 276-279 (2013) https://doi.org/10.1016/j.physc.2013.05.012
  3. M. Song, Y. Tang, J. Li, Y. Zhou, L. Chen and L. Ren, "Thermal analysis of HTS air-core transformer used in voltage compensation type active SFCL," Physica C: Superconductivity and its Applications, Vol. 470, Issue 20, pp. 1657-1661 (2010) https://doi.org/10.1016/j.physc.2010.05.182
  4. Y. Shiohara, M. Yoshizumi, Y. Takagi and T. Izumi, "Future prospects of high Tc superconductors-coated conductors and their applications," Physica C: Superconductivity and its Applications, Vol. 484, pp. 1-5 (2013) https://doi.org/10.1016/j.physc.2012.03.058
  5. T. Nurgaliev, B. Blagoev, E. Mateev, L. Neshkov, V. Strbik, L. Uspenskaya, I. Nedkov and S. Chromik, "Investigation of DC current injection effect on the microwave characteristics of HTS YBCO microstrip resonators," Physica C: Superconductivity and its Applications, Vol. 498, pp. 1-4 (2014) https://doi.org/10.1016/j.physc.2013.12.002
  6. D. Golubev, F. Lombardi and T. Bauch, "Effect of heating on critical current of YBCO nanowires," Physica C: Superconductivity and its Applications, Vol. 506, pp. 174-177 (2014) https://doi.org/10.1016/j.physc.2014.06.013
  7. P. K. Wong, P. C. W. Fung, H. L. Tam and J. Gao, "Thermal-diffusivity measurements of an oriented superconducting-film-substrate composite using the mirage technique," Physical Review B, Vol. 51, Issue 1, pp. 523-533 (1995) https://doi.org/10.1103/PhysRevB.51.523
  8. T. Yagi, N. Taketoshi and H. Kato, "Distribution analysis of thermal effusivity for sub-micrometer YBCO thin films using thermal microscope," Physica C: Superconductivity and its Applications, Vol. 412-414, Part 2, pp. 1337-1342 (2004) https://doi.org/10.1016/j.physc.2003.12.087
  9. M. Aravind and P. C. W. Fung, "Thermal parameter measurements of bulk YBCO superconductor using PVDF transducer," Measurement Science and Technology, Vol. 10, No. 11, pp. 979-985 (1999) https://doi.org/10.1088/0957-0233/10/11/301
  10. Y. Y. Kim and S. Krishnaswamy, "Nondestructive evaluation of material properties of nanoscale thin-films using ultrafast optical pump-probe methods," Journal of the Korean Society for Nondestructive Testing, Vol. 32, No. 2, pp. 115-121 (2012) https://doi.org/10.7779/JKSNT.2012.32.2.115
  11. W. S. Capinski, H. J. Maris, E. Bauser, I. Silier, M. Asen-Palmer, T. Ruf, M. Cardona and E. Gmelin, "Thermal conductivity of isotopically enriched Si," Applied Physics Letters, Vol. 71, No. 15, pp. 2109-2111 (1997) https://doi.org/10.1063/1.119384
  12. C. A. Paddock and G. L. Eesley, "Transient thermoreflectance from thin metal films," Journal of Applied Physics, Vol. 60, No. 1, pp. 285-290 (1986) https://doi.org/10.1063/1.337642
  13. G. Grimvall, "Thermophysical Properties of Materials," North Holland, Amsterdam (1999)
  14. A. Knizhnik, G. E. Shter, G. S. Grader, G. M. Reisner and Y. Eckstein, "Interrelation of preparation conditions, morphology, chemical reactivity and homogeneity of ceramic YBCO," Physica C: Superconductivity and its Applications, Vol. 400, Issues 1-2, pp. 25-35 (2003) https://doi.org/10.1016/S0921-4534(03)01311-X
  15. T. Naito, H. Fujishiro, Y. Yamamura, K. Saito, H. Okamoto, H. Hayashi, Y. Gosho, T. Ohkuma and Y. Shiohara, "Specific heat and thermal diffusivity of YBCO coated conductors," Physica Procedia, Vol. 36, pp. 1609-1613 (2012) https://doi.org/10.1016/j.phpro.2012.06.316
  16. M. Ikebe, H. Fujishiro, T. Naito, K. Noto, S. Kohayashi and S. Yoshizawa, "Thermal conductivity of YBCO(123) and YBCO(211) mixed crystals prepared by MMTG," Cryogenics, Vol. 34, No. 1, pp. 57-61 (1994) https://doi.org/10.1016/0011-2275(94)90053-1
  17. S. J. Hagen, Z. Z. Wang and N. P. Ong, "Anisotropy of the thermal conductivity of $YBa_2Cu_3O_{7-y}$," Physical Review B, Vol. 40, No. 13, pp. 9389-9392 (1989) https://doi.org/10.1103/PhysRevB.40.9389
  18. T. Ikeda, T. Ando, Y. Taguchi and Y. Nagasaka, "Size effect of out-of-plane thermal conductivity of epitaxial $YBa_2Cu_3O_7$.$\delta$ thin films at room temperature measured by photothermal radiometry," Journal of Applied Physics, Vol. 113, Issue 18, p. 183517 (2013) https://doi.org/10.1063/1.4803885
  19. T. Yagi, N. Taketoshi and H. Kato, "Distribution analysis of thermal effusivity for sub-micrometer YBCO thin films using thermal microscope," Physica C: Superconductivity and its Applications, Vol. 412-414, pp. 1337-1342 (2004) https://doi.org/10.1016/j.physc.2003.12.087