Temperature-pressure-composition phase diagram for Ba(Fe$_{1-x}$Ru$_{x})_{2}$As$_{2}$ (x$\le $0.285 and P$\le $84kbar)

ORAL

Abstract

BaFe$_{2}$As$_{2}$ shows a structural/magnetic (SM) phase transition near T$_{SM}$=134K, which is suppressed upon partial substitutions at the Ba (K), Fe (Cr, Mn, Co, Ni, Cu, Ru, Rh, Pd, Ir) or As (P) sites, and also by adding pressure (P), most times leading to the emergence of superconductivity (SC) at low T. Here, we report on the P-dependence of the electrical resistivity in under- to near-optimally doped Ba(Fe$_{1-x}$Ru$_{x})_{2}$As$_{2}$ (0$\le $x$\le $0.285) for P$\le $84kbar. Pressure suppresses the SM transition at a rate that increases with Ru content, e.g. for x=0.092, 0.161, and 0.210, dT$_{SM}$/dP $\sim $-0.2, -0.4, and -0.6K/kbar, respectively. Although the x=0.092 and x=0.161 compositions are not SC at P=0, SC is seen when T$_{SM}$ is sufficiently reduced by P. For x=0.161, T$_{c}$ at first increases to a maximum near 25K at $\sim $20kbar, after which it decreases at a rate of $\sim $-0.4K/kbar. Likewise, the T$_{c}$ values for the higher dopings peak $\sim $20kbar and decrease at higher P at similar rates. We find that the application of pressure on Ba(Fe$_{1-x}$Ru$_{x})_{2}$As$_{2}$ enhances T$_{c}$ beyond that which was achieved with only doping, seen before in Ba(Fe$_{1-x}$Co$_{x})_{2}$As$_{2}$. -- Supported by U.S. DOE (DE-AC02-07CH11358), AFOSR-MURI (FA9550-09-1-0603), and NSF (DMR-0805335).

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Authors

  • S.K. Kim

    Iowa State University and Ames Lab

  • M.S. Torikachvili

    Iowa State University, Ames Lab. and San Diego State University

  • Alexander Thaler

    Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University, Iowa State University and Ames Lab., Iowa State University/Ames Lab, Department of Physics and Astronomy, Iowa State University and Ames Laboratory, Ames, IA

  • E.C. Colombier

    Iowa State University and Ames Lab.

  • Sergey Bud'ko

    Ames Laboratory, Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University, Iowa State University, Iowa State University and Ames Lab., Iowa State University/Ames Lab, Iowa State University and Ames Laboratory US DOE, Ames Laboratory and Iowa State University, IA, USA, Ames Laboratory, Iowa State University

  • Paul Canfield

    Ames Laboratory and Dept. of Physics and Astronomy, Iowa State University, Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University, Iowa State University, Iowa State University and Ames Lab., Iowa State University/Ames Lab, Iowa State University, Ames Laboratory, Ames Laboratory and Iowa State University, IA, USA, Ames Laboratory, Ames, IA 50011, U.S.A., Ames Laboratory, Iowa State University