Evolution of the Phase Diagram of LaFeP$_{1-x}$As$_{x}$O$_{1-y}$F$_{y}$ ($y$ = 0 -- 0.1)

K. T. Lai; A. Takemori; S. Miyasaka; F. Engetsu; H. Mukuda; S. Tajima

doi:10.1103/physrevb.90.064504

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arXiv · 1408.0584

Evolution of the Phase Diagram of LaFeP$_{1-x}$As$_{x}$O$_{1-y}$F$_{y}$ ($y$ = 0 -- 0.1)

K. T. Lai·A. Takemori·S. Miyasaka·F. Engetsu·H. Mukuda·S. Tajima

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Abstract

P/As-substitution effects on the transport properties of polycrystalline LaFeP$_{1-x}$As$_{x}$O$_{1-y}$F$_{y}$ with $x$ = 0 -- 1.0 and $y$ = 0 -- 0.1 have been studied. In the F-free samples ($y$ = 0), a new superconducting (SC) dome with a maximum $T_{c}$ of 12 K is observed around $x$ = 0 -- 0.3. This is separated from another SC dome with $T_{c}$ $\sim$10 K at $x$ = 0.6 -- 0.8 by an antiferromagnetic region ($x$ = 0.3 -- 0.6), giving a two-dome feature in the $T_{c}-x$ phase diagram. As $y$ increases, the two SC domes merge together, changing to a double peak structure at $y$ = 0.05 and a single dome at $y$ = 0.1. This proves the presence of two different Fermi surface states in this system.

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K. T. Lai, A. Takemori, S. Miyasaka, F. Engetsu, H. Mukuda, S. Tajima. 2014-08-04. Evolution of the Phase Diagram of LaFeP$_{1-x}$As$_{x}$O$_{1-y}$F$_{y}$ ($y$ = 0 -- 0.1). https://doi.org/10.1103/physrevb.90.064504

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