Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/17256
標題: 單晶鐵基超導材料Ca0.82Pr0.18Fe2As2之上臨界磁場分析
Upper Critical Field of Ca0.82Pr0.18Fe2As2 Superconducting Single Crystal
作者: 曾建璋
TSENG, CHIEN-CHANG
關鍵字: 超導
Superconductivity
鐵砷
半導體
122型
上臨界磁場
極小的下臨界磁場
熱擾動
電荷交換機制
尺度分析
Iron base
Semiconductor
upper critical field
Minimal lower critical magnetic field
Thermal fluctuation
Ginzburg critical region
Scaling law
charge exchange mechanism
出版社: 物理學系所
引用: [1] 科學月刊1987年12月216期高溫超導體研究與諾貝爾物理獎-古煥球、林雪蕙 [2] 超導物理新發展--鐵基超導體的興起-吳茂昆.....2 [3] High-temperature superconductivity in the iron pnictides , 2008 Michael R. Norman, Physics 1, 21 [4] S. Fujitsu, S. Matsuishi and H. Hosono, Published by Maney Publishing [5] S. Saha, N. Butch, T. Drye, J. Magill, S. Ziemak, K. Kir-shenbaum, P. Zavalij, J. Lynn, and J. Paglione, 2012 Phys. Rev. B 85, 024525 [6] B. Lv, L. Z. Deng, M. Gooch, F. Y. Wei, Y. Y. Sun, J. K. Meen, Y. Y. Xue, B. Lorenz, and C. W. Chu, 2011 PNAS 108,15705 [7] H. Kito, H. Eisaki, and A. Iyo, 2008 J. Phy. Soc. Jpn. 77, 063707 [8] J. Yang et al., 2008 Supercond. Sci. Tech. 21, 082001 [9] Kamihara Y, Watanabe T, Hirano M and Hosono H 2008 J. Am. Chem. Soc. 130 3296 [10] Long Ma, G. F. Ji, J. Dai, S. R. Saha, J. Paglione and Weiqiang Yu 2013 Chin. Phys. B 22 057401 [11] U. Stockert, N. Leps, L. Wang, G. Behr, S. Wurmehl, B. B uchner and R. Klingeler 2012 Phys. Rev. B , Volume 86.144407 [12] Yuen Yiu, V. Ovidiu Garlea, Michael A. McGuire, Ashfia Huq, David Mandrus, and Stephen E. Nagle 2012 Phys. Rev. B 86, 054111 [13] www.materialsnet.com.tw/AD/ADImages/.../EM/FE.../FE-SEM005.pdf‎ [14] Superconducting Quantum Interference Device Operation Manual, Quantum Design. [15] Closed cycle refrigerator systems Operation Manual, CRYO [16] Yan peng Qi, Zhao shun Gao, Lei Wang, Dong liang Wang, Xian ping Zhang, Chao Yao, Chunlei Wang, Cheng duo Wang and Yan wei Ma 2012 Supercond Sci. Technol. 25 045007 [17] S.-H. Baek, N. J. Curro, T. Klimczuk, E. D. Bauer, F. Ronning, and J. D. Thompson 2009 Phys. Rev. B 79, 052504 [18] F. Ronning et al., 2008 J. Phys.: Cond. Matt. 20, 322201 [19] R. Klingeler, N. Leps, I. Hellmann, A. Popa, U. Stockert, C. Hess, V. Kataev, H.-J. Grafe, F. Hammerath, G. Lang, et al., 2010 Phys. Rev. B 81, 024506. [20] H. Mukuda, N. Terasaki, N. Tamura, H. Kinouchi, M. Yashima, Y. Kitaoka, K. Miyazawa, P. Shirage, S. Suzuki, S. Miyasaka, et al., 2009 JPSJ 78, 084717. [21] Satoru Matsuishi, Atsushi Nakamura, Yoshinori Muraba and Hideo Hosono 2012 Supercond. Sci. Technol. 25 084017 [22] S. R. Saha, N. P. Butch, T. Drye, J. Magill, S. Ziemak, K. Kirshenbaum, P. Y. Zavalij, J. W. Lynn and J. Paglione 2012 Phys. Rev. B 85, 024525 [23] Rotter M, Tegel M and Johrendt D 2008 Phys. Rev. Lett. 101 107006. [24] Sasmal K, Lv B, Lorenz B, Guloy A, Chen F, Xue Y and Chu C W 2008 Phys. Rev. Lett. 101 107007 [25] Wu G, Chen H, Wu T, Xie Y. L, Yan Y. J, Liu R. H, Wang X. F, Ying J. J and Chen X. H 2008 J. Phys. Condens. Matter 20 422201 [26] Qi Y P, Gao Z S, Wang L, Wang D L, Zhang X P and Ma Y W 2008 New J. Phys. 10 123003 [27] M. D. Lan, J. Z. Liu, Y. X.Jia, Lu Zhang, Y. Nagata, P. Klavins, and R. N. Shelton 1993 Phys. Rev. B 47, 0111
摘要: 本論文主要研究單晶鐵基超導Ca0.82Pr0.18Fe2As2的製備與熱擾動在臨界區域對超導所造成的影響。我們成功地以自我助熔法製作單晶樣品,尺寸為5.5mm*5.5mm。由特徵峰判斷本樣品與四方晶系的ThCr2Si2結構相吻合,屬於I4/mmm。隨著Pr3+摻雜比例增加,沿c軸的晶格常數會變短。依能量光譜散射分析(EDS)確認樣品成分為Pr、Ca、Fe、As。以標準四點量測方式量測電阻,得知在無外加磁場下,自旋密度波(SDW)會被壓抑,並於49K時電阻明顯驟降,顯示超導特性。 以摻雜Pr3+的方式去調控晶格常數與載子濃度,引發超導特性的產生,探討超導轉變溫度與磁有序之間的關聯性。量測磁滯曲線的過程中,發現有趣的現象。本材料的下臨界磁場非常低,HC1~1 Oe,對於其他超導材料而言,這是非常奇特的。 實驗所得,磁場相依的熱擾動(Thermal Fluctuation) 所造成在臨界區域的變寬,引進尺度分析與電荷交換機制(charge-exchange mechanism),去探討上臨界磁場HC2(0),並借此推算出相干長度(coherence length)ξ、穿透深度(penetration depth)λ。
The research focuses on the growth of iron-based superconducting Ca0.82Pr0.18Fe2As2 single crystal and the influence of the thermal fluctuation on the superconductivity. The single crystal was grown by self-flux method. We confirm that the crystal has ThCr2Si2-type structure with I4/mmm space group. By using Energy Dispersive Spectroscopy we confirm the Pr、Ca、Fe、As elements in the specimen. A standard four-wire technique was used to measure the temperature dependence of resistivity. The transition region is broadened by the external magnetic fields. We observed a superconducting transition temperature of 49K under zero magnetic field. Extremely short lower critical field HC1 of ~ 1Oe is found in the initial stage of hysteresis loop measurement. The upper critical fields derived from the Thermal Fluctuation Scaling Analysis & charge-exchange mechanism is found to be 80 T for the applied field along the ab-plane and 35 T for the applied field along the c-axis. The anisotropic superconducting coherence lengthξand penetration depthλ are then discussed.
URI: http://hdl.handle.net/11455/17256
其他識別: U0005-0208201316085300
文章連結: http://www.airitilibrary.com/Publication/alDetailedMesh1?DocID=U0005-0208201316085300
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