6 of the Energy Frontier Research Center (EFRC), Cen- ter for Emergent Superconductivity (CES). A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by NSF Cooper- ative Agreement No. DMR-0084173, by the State of Florida, and by the U.S. Department of Energy. $^{∗}$Present address: Ames Laboratory US DOE and De- partment of Physics and Astronomy, Iowa State Univer- sity, Ames, IA 50011, USA. We thank T. P. Murphy for useful discussions and ex- periment support in NHMFL. This work was carried out at the Brookhaven National Laboratory, which is oper- ated for the U.S. Department of Energy by Brookhaven Science Associates DE-Ac02-98CH10886. This work was in part supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences as part VI. ACKNOWLEDGEMENTS Phys. Rev. B 80 , 144512 (2009). 20 H. Q. Yuan, J. Singleton, F. F. Balakirev, S. A. Baily, G. F. Chen, J. L. Luo, and N. L. Wang, Nature 457 , 565 (2009). 1 Y. Kamihara, T. Watanabe, M. Hirano, and H. Hosono, J. Am. Chem. Soc. 130 , 3296 (2008). 2 X. H. Chen, T. Wu, G. Wu, R. H. Liu, H. Chen, and D. F. Fang, Nature 453 , 761 (2008). 3 G. F. Chen, Z. Li, D. Wu, G. Li, W. Z. Hu, J. Dong, P. Zheng, J. L. Luo, and N. L.Wang, Phys. Rev. Lett. 100 , 247002 (2008). 21 S. A. Baily, Y. Kohama, H. Hiramatsu, B. Maiorov, F. F. Balakirev, M. Hirano, and H. Hosono, Phys. Rev. Lett. 102 , 117004 (2009). 22 M. M. Altarawneh, K. Collar, C. H. Mielke, N. Ni, S. L. Bud’ko, and P. C. Canfield, Phys. Rev. B 78 , 220505(R) (2008). 4 Z. A. Ren, J. Yang, W. Lu, Y. Wei, X. L. Shen, Z. C. Li, G. C. Che, X. L. Dong, L. L. Sun, F. Zhou, and Z. X. Zhao, EPL 82 , 57002 (2008). 23 M. Kano, Y. Kohama, D. Graf, F. Balakirev, A. S. Sefat, M. A. Mcguire, B. C. Sales, D. Mandrus, and S. W. Tozer, J. Phys. Soc. Jpn 78 , 084719 (2009). 24 T. Terashima, M. Kimata, H. Satsukawa, A. Harada, K. Hazama, S, Uji, H. Harima, G.-F. Chen, J.-L Luo, and N.-L. Wang, J. Phys. Soc. Jpn 78 , 063702 (2009). 5 H.-H. Wen, G. Mu, L. Fang, H. Yang, and X. Y. Zhu, EPL 82 , 17009 (2008). 6 M. Rotter, M. Tegel, and D. Johrendt, Phys. Rev. Lett. 101 , 107006 (2008). 25 T. Kida, T. Matsunaga, M. Hagiwara, Y. Mizuguchi, Y. Takano, and K. Kindo, J. Phys. Soc. Jpn 78 , 113701 (2009). 7 G. F. Chen, Z. Li, G. Li, W. Z. Hu, J. Dong, X. D. Zhang, P. Zheng, N. L. Wang, and J. L. Luo, Chin. Phys. Lett. 25 , 3403 (2008). 26 B. Hunter, ”Rietica-A visual Rietveld program”, In- ternational Union of Crystallography Commission on Powder Diffraction Newsletter No. 20 , (Summer) http://www.rietica.org (1998). 8 X. C. Wang, Q. Q. Liu, Y. X. Lv, W. B. Gao, L. X. Yang, R. C. Yu, F. Y. Li, and C. Q. Jin, Solid State Commun. 148 , 538 (2008). 9 H. Ogino, Y. Matsumura, Y. Katsura, K. Ushiyama, S. Horii, K. Kishio, and J. Shimoyama, Supercond. Sci. Tech- nol. 22 , 075008 (2009). 27 R. W. Hu, E. S. Bozin, J. B. Warren, and C. Petrovic, Phys. Rev. B 80 , 214514 (2009). 10 X. Y. Zhu, F. Han, G. Mu, P. Cheng, B. Shen, B. Zeng, and H.-H. Wen, Phys. Rev. B 79 , 220512(R) (2009). 11 F. C. Hsu, J. Y. Luo, K. W. Yeh, T. K. Chen, T. W. Huang, P. M. Wu, Y. C. Lee, Y. L. Huang, Y. Y. Chu, D. C. Yan, and M. K. Wu, Proc. Natl. Acad. Sci. U.S.A. 105 , 14262 (2008). 28 G. F. Chen, Z. G. Chen, J. Dong, W. Z. Hu, G. Li, X. D. Zhang, P. Zheng, J. L. Luo, and N. L. Wang, Phys. Rev. B 79 , 140509(R) (2009). 29 Z.-S. Wang, H.-Q. Luo, C. Ren, and H.-H. Wen, Phys. Rev. B 78 , 140501(R) (2008). 30 Z. Bukowski, S. Weyeneth, R. Puzniak, P. Moll, S. Ka- trych, N. D. Zhigadlo, J. Karpinski, H. Keller, and B. Bat- logg, Phys. Rev. B 79 , 104521 (2009). 12 K.-W. Yeh, T. W. Huang, Y. L. Huang, T. K. Chen, F. C. Hsu, P. M. Wu, Y. C. Lee, Y. Y. Chu, C. L. Chen, J. Y. Luo, D. C. Yan, and M. K. Wu, EPL 84 , 37002 (2008). 13 Y. Mizuguchi, F. Tomioka, S. Tsuda, T. Yamaguchi, and Y. Takano, Appl. Phys. Lett. 94 , 012503 (2009). 14 A. Subedi, L. Zhang, D. J. Singh, and M. H. Du, Phys. Rev. B 78 , 134514 (2008) . 31 J. Karpinski, N. D. Zhigadlo, S. Katrych, Z. Bukowski, P. Moll, S. Weyeneth, H. Keller, R. Puzniak, M. Tortello, D. Daghero, R. Gonnelli, I. Maggio-Aprile, Y. Fasano, Ø. Fischer, K. Rogacki, and B. Batlogg, Physica C 469 , 370 (2009). 32 W. K. Kwok, S. Fleshler, U. Welp, V. M. Vinokur, J. Downey, and G. W. Crabtree, and M. M. Miller, Phys. Rev. Lett. 69 , 3370 (1992). 15 Y. Mizuguchi, F. Tomioka, S. Tsuda, T. Yamaguchi, and Y. Takano, Appl. Phys. Lett. 93 , 152505 (2008). 16 L. J. Zhang, D. J. Singh, and M. H. Du, Phys. Rev. B 79 , 012506 (2009). 33 W. K. Kwok, J. Fendrich, S. Fleshler, U. Welp, J. Downey, and G. W. Crabtree, Phys. Rev. Lett. 72 , 1092 (1994). 34 H. Safar, P. L. Gammel, D. A. Huse, D. J. Bishop, J. P. Rice, and D. M. Ginsberg, Phys. Rev. Lett. 69 , 824 (1992). 35 G. Blatter, M. V. Feigel’man, V. B. Geshkenbein, A. I. Larkin, and V. M. Vinokur, Rev. Mod. Phys. 66 , 1125 (1994). 17 J. Jaroszynski, F. Hunte, L. Balicas, Y.-J. Jo, I. Raiˇcevi´c, A. Gurevich, D. C. Larbalestier, F. F. Balakirev, L. Fang, P. Cheng, Y. Jia, and H. H. Wen, Phys. Rev. B 78 , 174523 (2008). 18 F. Hunte, J. Jaroszynski, A. Gurevich, D. C. Larbalestier, R. Jin, A. S. Sefat, M. A. McGuire, B. C. Sales, D. K. Christen, and D. Mandrus, Nature 453 , 903 (2008). 19 H.-S. Lee, M. Bartkowiak, J.-H. Park, J.-Y. Lee, J.-Y. Kim, N.-H. S., B. K. Cho, C.-U. Jung, J. S. Kim, and H.-J. Lee, 36 Z. Pribulova, T. Klein, J. Kacmarcik, C. Marcenat, M.