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arXiv · 1608.01470

Bulk Superconductivity Induced by In-plane Chemical Pressure Effect in Eu0.5La0.5FBiS2-xSex

Gen Jinno·Rajveer Jha·Akira Yamada·Ryuji Higashinaka·Tatsuma D. Matsuda·Yuji Aoki·Masanori Nagao·Osuke Miura·Yoshikazu Mizuguchi
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Abstract

We have investigated Se substitution effect to superconductivity of an optimally-doped BiS2-based superconductor Eu0.5La0.5FBiS2. Eu0.5La0.5FBiS2-xSex samples with x = 0-1 were synthesized. With increasing x, in-plane chemical pressure is enhanced. For x = 0.6, 0.8, and 1, superconducting transitions with a large shielding volume fraction are observed in magnetic susceptibility measurements, and the highest Tc is 3.8 K for x = 0.8. From low-temperature electrical resistivity measurements, a zero-resistivity state is observed for all the samples, and the highest Tc is observed for x = 0.8. With increasing Se concentration, characteristics of electrical resistivity changes from semiconducting-like to metallic, suggesting that the emergence of bulk superconductivity is linked with the enhanced metallicity. A superconductivity phase diagram of the Eu0.5La0.5FBiS2-xSex superconductor is established. Temperature dependences of electrical resistivity show an anomalous two-step transition under high magnetic fields. Hence, the resistivity data are analyzed with assuming in-plane anisotropy of upper critical field.

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Gen Jinno, Rajveer Jha, Akira Yamada, Ryuji Higashinaka, Tatsuma D. Matsuda, Yuji Aoki, Masanori Nagao, Osuke Miura, Yoshikazu Mizuguchi. 2016-08-04. Bulk Superconductivity Induced by In-plane Chemical Pressure Effect in Eu0.5La0.5FBiS2-xSex. https://doi.org/10.7566/jpsj.85.124708

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