Resistivity and Magnetic Susceptibility Under Pressure (0–2.0 GPa) of Fe<sub>1+ε</sub>Te<sub>0.5</sub>Se<sub>0.5 </sub>and <i>R</i><sub>1-<i>x</i></sub>Ce<i><sub>x</sub></i>NiO<sub>3 </sub>[<i>R </i>= (La,Y), Pr]*
ORAL
Abstract
We report measurements of the ac magnetic susceptibility of the iron-based mixed-chalcogenide superconductor Fe1+εTe0.5Se0.5, and of the electrical resistivity of doped nickel-oxide compounds R1-xCexNiO3, with R = Pr or (La,Y), over the pressure range 0–20 kbar (0–2.0 GPa). Our iron-based material is optimized (ε ≈ 0.07) for bulk superconductivity, exhibiting an ambient-pressure superconducting transition at Tc ≈ 14 K, well above the transition of bulk FeSe (Tc = 9 K). With applied pressure, we observe an immense, nearly linear increase of Tc, with dTc /dP = +7.0±0.5 K/GPa. We have prepared bulk “113” doped nickelates using high-oxygen-pressure (150–200 bar), high-temperature (T ≈ 1000°C) synthesis. For undoped PrNiO3, the metal insulator transition temperature decreases with pressure, with reported dTMI/dP ≈ –42 to –76 K/GPa [1,2]. For Pr1-xCexNiO3 with x ≈ 0.0–0.2, we are exploring variations in dTMI/dP. We consider both steric (e.g., band-broadening, bond-straightening), electron-doping, and hole-filling contributions to this behavior.
[1] X. Obradors et al., Phys. Rev. B 47 12353 (1993); [2] P. C. Canfield et al., Phys. Rev. B 47 12357 (1993).
[1] X. Obradors et al., Phys. Rev. B 47 12353 (1993); [2] P. C. Canfield et al., Phys. Rev. B 47 12357 (1993).
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Presenters
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Rabia Husain
Department of Physics, University of Texas at Austin
Authors
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Zachary P. Kuklinski
Department of Physics, University of Texas at Austin
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Gregorio Ponti
Department of Physics, University of Texas at Austin
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Quinn D. B. Timmers
Department of Physics, University of Texas at Austin
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Rabia Husain
Department of Physics, University of Texas at Austin
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John T. Markert
Department of Physics, University of Texas at Austin, Department of Physics, The University of Texas at Austin