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arXiv · 1112.0231

The doping dependence of superconductivity of (Ca1-xNax)Fe2As2

K. Zhao·Q. Q. Liu·X. C. Wang·Z. Deng·Y. X. Lv·J. L. Zhu·F. Y. Li·C. Q. Jin
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Abstract

Single crystalline CaFe2As2 and (Ca1-xNax)Fe2As2 polycrystals (0 < x < 0.66) are synthesized and characterized using structural, magnetic, electronic transport, and heat capacity measurements. These measurements show that the structural/magnetic phase transition in CaFe2As2 at 165 K is monotonically suppressed by the Na doping and that superconductivity can be realized over a wide doping region. For 0.3 < x < 0.36, the magnetic susceptibilities indicate the possible coexistence of the spin density wave (SDW) and superconductivity. Superconducting phases corresponding to the Na doping level in (Ca1-xNax)Fe2As2 for nominal x = 0.36, 0.4, 0.5, 0.6, and 0.66, with Tc = 17 K, 19 K, 22 K, 33 K, and 33 K, respectively, are identified. The effects of the magnetic field on the superconductivity transitions for x = 0.66 samples with high upper critical fields Hc2 \approx 103 T are studied, and a phase diagram of the SDW and superconductivity as a function of the doping level is thus presented.

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K. Zhao, Q. Q. Liu, X. C. Wang, Z. Deng, Y. X. Lv, J. L. Zhu, F. Y. Li, C. Q. Jin. 2011-12-01. The doping dependence of superconductivity of (Ca1-xNax)Fe2As2. https://arxiv.org/abs/1112.0231

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