TY - JOUR
T1 - High-pressure synthesis and physical properties of new iron (nickel)-based superconductors
AU - Shirage, P. M.
AU - Miyazawa, K.
AU - Ishikado, M.
AU - Kihou, K.
AU - Lee, C. H.
AU - Takeshita, N.
AU - Matsuhata, H.
AU - Kumai, R.
AU - Tomioka, Y.
AU - Ito, T.
AU - Kito, H.
AU - Eisaki, H.
AU - Shamoto, S.
AU - Iyo, A.
N1 - Funding Information:
The authors are grateful to S. Ishida, M. Nakajima, S. Uchida, Y. Tanaka for transport properties measurements and helpful discussion. P.M.S. is grateful to the Japan Society for the Promotion of Science (JSPS) for the JSPS postdoctoral fellowship (2006–2008). This work was supported by Grant-in-Aid for Specially promoted Research (20001004 and 17001001) from The Ministry of Education, Culture, Sports, Science and Technology (MEXT), the Mitsubishi Foundation and JST, Transformative Research-Project on Iron Pnictides (TRIP).
PY - 2009
Y1 - 2009
N2 - We have utilized a high-pressure (HP) technique to synthesize a series of newly-discovered iron (nickel)-based superconductors. For the LnFeAsO-based superconductors (Ln = lanthanide), we show that the introduction of oxygen (O)-deficiency in the LnO layers, which is achievable only through HP process, is an effective way to dope electron carriers into the system, which results in yielding the superconducting transition temperature (Tc) comparable with those for F-substituted counterpart. The effect of O-deficiency, variation of Ln ions, and the external pressure on Tc are examined. All the experimental data indicate strong correlation between the crystal structure and the superconductivity of the oxypnictide superconductors. Upper critical field measurement on single crystalline sample of PrFeAsO1-y shows the superconducting anisotropy of 5, which is smaller than cuprates. We also demonstrate that HP technique is applicable for the so-called '122' systems, by showing the results on polycrystalline (Ca, Na)Fe2As2, (Ba, K)Fe2As2, as well as single crystal BaNi2P2 samples.
AB - We have utilized a high-pressure (HP) technique to synthesize a series of newly-discovered iron (nickel)-based superconductors. For the LnFeAsO-based superconductors (Ln = lanthanide), we show that the introduction of oxygen (O)-deficiency in the LnO layers, which is achievable only through HP process, is an effective way to dope electron carriers into the system, which results in yielding the superconducting transition temperature (Tc) comparable with those for F-substituted counterpart. The effect of O-deficiency, variation of Ln ions, and the external pressure on Tc are examined. All the experimental data indicate strong correlation between the crystal structure and the superconductivity of the oxypnictide superconductors. Upper critical field measurement on single crystalline sample of PrFeAsO1-y shows the superconducting anisotropy of 5, which is smaller than cuprates. We also demonstrate that HP technique is applicable for the so-called '122' systems, by showing the results on polycrystalline (Ca, Na)Fe2As2, (Ba, K)Fe2As2, as well as single crystal BaNi2P2 samples.
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U2 - 10.1016/j.physc.2009.03.027
DO - 10.1016/j.physc.2009.03.027
M3 - Article
AN - SCOPUS:65649093036
SN - 0921-4534
VL - 469
SP - 355
EP - 369
JO - Physica C: Superconductivity and its applications
JF - Physica C: Superconductivity and its applications
IS - 9-12
ER -