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Influence of pressure on the superconducting critical temperature of explosively precompressed metastable A15 Nb3Si

ORAL

Abstract

Diamond anvil cell pressure measurements up to 88 GPa were performed on explosively compressed A15 Nb3Si material to trace Tc as a function of pressure. Tc is suppressed to ~ 5.2 K at 88 GPa. Using these Tc (P) data for A15 Nb3Si, applying pressures up to 120 GPa at room temperature on tetragonal Nb3Si and measuring superconductivity present via resistivity gave no indication of any transition to the A15 structure. This is in contrast to the explosive compression (up to P ~ 110 GPa) of tetragonal Nb3Si, which produced 50-70% A15 material and Tc = 18 K at ambient pressure in a 1981 Los Alamos National Laboratory experiment. We believe that, despite theoretical calculations that A15 Nb3Si has an enthalpy vs the tetragonal structure that is 0.07 eV/atom smaller at 100 GPa, it is the accompanying high temperature (1000 oC) caused by explosive compression that is necessary to successfully drive the reaction kinetics of the tetragonal to A15 Nb3Si structural transformation. We performed annealing experiments on the A15 explosively compressed material that are consistent with this viewpoint.

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Presenters

  • James Hamlin

    Department of Physics, University of Florida, University of Florida

Authors

  • James Hamlin

    Department of Physics, University of Florida, University of Florida

  • Jinhyuk Lim

    Department of Physics, University of Florida

  • Jungsoo Kim

    University of Florida, Department of Physics, University of Florida

  • Ajinkya Hire

    Department of Materials Science and Engineering, University of Florida

  • Yundi Quan

    Department of Physics, University of Florida

  • Richard Hennig

    University of Florida, Department of Materials Science and Engineering, University of Florida, Materials Science and Engineering, University of Florida

  • Peter Hirschfeld

    University of Florida, Department of Physics, University of Florida, Physics, University of Florida, univ of Florida

  • Gregory Randall Stewart

    University of Florida, Department of Physics, University of Florida

  • Bart Olinger

    Los Alamos National Laboratory