Enhanced grain connectivity in K-doped ferropnictide Ba-122 bulks and wires with high transport critical current density

ORAL

Abstract

We present very much improved properties of (Ba$_{0.6}$K$_{0.4})$Fe$_{2}$As$_{2}$ (Ba-122) made as round wires in which transport critical current densities J$_{c}$ (4.2 K, SF) in excess of 0.12 MAcm$^{-2}$, which is approximately 5 times higher than any other ferropnictide wire, have been obtained. Careful low-temperature synthesis was used to eradicate extrinsic current-blocking phases and cracks, which also had the effect of producing fine grain size ($<$200nm) and a high grain boundary density. Very high magnetic field evaluations showed that the upper critical field H$_{c2}$ was well above 50 T and H$_{c2}$ anisotropy was significantly less than 2. This low anisotropy suggests that high vortex stiffness and perhaps less suppression of the grain boundary (GB) order parameter occur in this compound compared to the planar GBs of Co-doped Ba-122 used for bicrystal experiments, which showed weak link behavior that limits critical current across GBs like in other high-temperature superconductors.

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Authors

  • Jeremy Weiss

    National High Magnetic Field Laboratory Applied Superconductivity Center

  • Chris Neu

    Florida State University, NHMFL, Institut Neel, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China, Florida State University, Department of Physics, Florida State University, Tallahassee, FL, Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, Florida State University, National High Magnetic Field Laboratory, Institute of Physics, Chinese Academy of Sciences, China, Austin Peay State University, University of Pardubice, Davidson College, Covenant College, Lookout Mtn, GA 30750, Russian Academy of Sciences, Moscow, RU, University of Tennessee Space Institute, Tullahoma, TN, USA, Sandia National Laboratories,* Albuquerque, NM, Arkansas State University, Jonesboro, AK, None, Mississippi State University, Mississippi State University Department of Physics and Astronomy, Florida State University and the National High Magnetic Field Laboratory, Faculte des Sciences et Techniques and Universite Aix-Marseille, MIT Haystack Observatory, Departments of Chemistry and Physics, University of Tennessee of Chattanooga, Departments of Chemistry and Physics, University of Tennessee at Chattanooga, Western Kentucky University, Thomas Jefferson National Accelerator Facility, Newport News, VA, Fermilab, University of Virginia and Fermilab, Indiana University Bloomington, Indiana University Health Proton Therapy Center, University of North Florida, National Superconducting Cyclotron Laboratory, Michigan State University, Flordia State University, Louisiana State University, Washington University, Argonne National Laboratory, Lawrence Berkeley National Laboratory, Department of Physics, Florida State University., JINR, Tsinghua University, LBNL, LBNL/Vanderbilt University, Vanderbilt University, Florida A\&M University, Georgia Institute of Technology, Department of Physics, Virginia Tech, Gatton Academy, Exeter University, Florida International University, Office of Research, University of North Florida, Physics Department, University of North Florida, NSCL, Michigan State University, Physics Department, Florida State University, University of Tennessee-Knoxville, Neel Institut, Kazan Federal University, Bielefeld University, Ben Gurion University, LCIB - CEA, University of Georgia, Lawrence Livermore National Laboratory, Livermore, CA 94550, NHMFL, Tallahassee, USA, Department of Chemistry, University of Waterloo, Ontario, Canada, NHMFL, Tallahassee FL 32310 USA, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany, Wigner Research Center for Physics, Budapest, Hungary, Experimental physics II, University of Augsburg, Germany, Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, National High Magnetic Field Laboratory Florida State University, Tallahassee, Florida 32310, IM2NP-CNRS (UMR 7334) and Universite Aix-Marseille, National High Magnetic Field Laboratory Applied Superconductivity Center, Heifei National Lab for Physical Science at Microscale, USTC, Institute of Physics, Chinese Academy of Sciences, Department of Electrical Engineering, Rice University, National High Magnetic Field Laboratory, National High Magnetic Field Laboratory/FSU, University of Virginia

  • Chris Neu

    Florida State University, NHMFL, Institut Neel, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China, Florida State University, Department of Physics, Florida State University, Tallahassee, FL, Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, Florida State University, National High Magnetic Field Laboratory, Institute of Physics, Chinese Academy of Sciences, China, Austin Peay State University, University of Pardubice, Davidson College, Covenant College, Lookout Mtn, GA 30750, Russian Academy of Sciences, Moscow, RU, University of Tennessee Space Institute, Tullahoma, TN, USA, Sandia National Laboratories,* Albuquerque, NM, Arkansas State University, Jonesboro, AK, None, Mississippi State University, Mississippi State University Department of Physics and Astronomy, Florida State University and the National High Magnetic Field Laboratory, Faculte des Sciences et Techniques and Universite Aix-Marseille, MIT Haystack Observatory, Departments of Chemistry and Physics, University of Tennessee of Chattanooga, Departments of Chemistry and Physics, University of Tennessee at Chattanooga, Western Kentucky University, Thomas Jefferson National Accelerator Facility, Newport News, VA, Fermilab, University of Virginia and Fermilab, Indiana University Bloomington, Indiana University Health Proton Therapy Center, University of North Florida, National Superconducting Cyclotron Laboratory, Michigan State University, Flordia State University, Louisiana State University, Washington University, Argonne National Laboratory, Lawrence Berkeley National Laboratory, Department of Physics, Florida State University., JINR, Tsinghua University, LBNL, LBNL/Vanderbilt University, Vanderbilt University, Florida A\&M University, Georgia Institute of Technology, Department of Physics, Virginia Tech, Gatton Academy, Exeter University, Florida International University, Office of Research, University of North Florida, Physics Department, University of North Florida, NSCL, Michigan State University, Physics Department, Florida State University, University of Tennessee-Knoxville, Neel Institut, Kazan Federal University, Bielefeld University, Ben Gurion University, LCIB - CEA, University of Georgia, Lawrence Livermore National Laboratory, Livermore, CA 94550, NHMFL, Tallahassee, USA, Department of Chemistry, University of Waterloo, Ontario, Canada, NHMFL, Tallahassee FL 32310 USA, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany, Wigner Research Center for Physics, Budapest, Hungary, Experimental physics II, University of Augsburg, Germany, Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, National High Magnetic Field Laboratory Florida State University, Tallahassee, Florida 32310, IM2NP-CNRS (UMR 7334) and Universite Aix-Marseille, National High Magnetic Field Laboratory Applied Superconductivity Center, Heifei National Lab for Physical Science at Microscale, USTC, Institute of Physics, Chinese Academy of Sciences, Department of Electrical Engineering, Rice University, National High Magnetic Field Laboratory, National High Magnetic Field Laboratory/FSU, University of Virginia

  • Chris Neu

    Florida State University, NHMFL, Institut Neel, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China, Florida State University, Department of Physics, Florida State University, Tallahassee, FL, Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, Florida State University, National High Magnetic Field Laboratory, Institute of Physics, Chinese Academy of Sciences, China, Austin Peay State University, University of Pardubice, Davidson College, Covenant College, Lookout Mtn, GA 30750, Russian Academy of Sciences, Moscow, RU, University of Tennessee Space Institute, Tullahoma, TN, USA, Sandia National Laboratories,* Albuquerque, NM, Arkansas State University, Jonesboro, AK, None, Mississippi State University, Mississippi State University Department of Physics and Astronomy, Florida State University and the National High Magnetic Field Laboratory, Faculte des Sciences et Techniques and Universite Aix-Marseille, MIT Haystack Observatory, Departments of Chemistry and Physics, University of Tennessee of Chattanooga, Departments of Chemistry and Physics, University of Tennessee at Chattanooga, Western Kentucky University, Thomas Jefferson National Accelerator Facility, Newport News, VA, Fermilab, University of Virginia and Fermilab, Indiana University Bloomington, Indiana University Health Proton Therapy Center, University of North Florida, National Superconducting Cyclotron Laboratory, Michigan State University, Flordia State University, Louisiana State University, Washington University, Argonne National Laboratory, Lawrence Berkeley National Laboratory, Department of Physics, Florida State University., JINR, Tsinghua University, LBNL, LBNL/Vanderbilt University, Vanderbilt University, Florida A\&M University, Georgia Institute of Technology, Department of Physics, Virginia Tech, Gatton Academy, Exeter University, Florida International University, Office of Research, University of North Florida, Physics Department, University of North Florida, NSCL, Michigan State University, Physics Department, Florida State University, University of Tennessee-Knoxville, Neel Institut, Kazan Federal University, Bielefeld University, Ben Gurion University, LCIB - CEA, University of Georgia, Lawrence Livermore National Laboratory, Livermore, CA 94550, NHMFL, Tallahassee, USA, Department of Chemistry, University of Waterloo, Ontario, Canada, NHMFL, Tallahassee FL 32310 USA, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany, Wigner Research Center for Physics, Budapest, Hungary, Experimental physics II, University of Augsburg, Germany, Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, National High Magnetic Field Laboratory Florida State University, Tallahassee, Florida 32310, IM2NP-CNRS (UMR 7334) and Universite Aix-Marseille, National High Magnetic Field Laboratory Applied Superconductivity Center, Heifei National Lab for Physical Science at Microscale, USTC, Institute of Physics, Chinese Academy of Sciences, Department of Electrical Engineering, Rice University, National High Magnetic Field Laboratory, National High Magnetic Field Laboratory/FSU, University of Virginia

  • Chris Neu

    Florida State University, NHMFL, Institut Neel, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China, Florida State University, Department of Physics, Florida State University, Tallahassee, FL, Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, Florida State University, National High Magnetic Field Laboratory, Institute of Physics, Chinese Academy of Sciences, China, Austin Peay State University, University of Pardubice, Davidson College, Covenant College, Lookout Mtn, GA 30750, Russian Academy of Sciences, Moscow, RU, University of Tennessee Space Institute, Tullahoma, TN, USA, Sandia National Laboratories,* Albuquerque, NM, Arkansas State University, Jonesboro, AK, None, Mississippi State University, Mississippi State University Department of Physics and Astronomy, Florida State University and the National High Magnetic Field Laboratory, Faculte des Sciences et Techniques and Universite Aix-Marseille, MIT Haystack Observatory, Departments of Chemistry and Physics, University of Tennessee of Chattanooga, Departments of Chemistry and Physics, University of Tennessee at Chattanooga, Western Kentucky University, Thomas Jefferson National Accelerator Facility, Newport News, VA, Fermilab, University of Virginia and Fermilab, Indiana University Bloomington, Indiana University Health Proton Therapy Center, University of North Florida, National Superconducting Cyclotron Laboratory, Michigan State University, Flordia State University, Louisiana State University, Washington University, Argonne National Laboratory, Lawrence Berkeley National Laboratory, Department of Physics, Florida State University., JINR, Tsinghua University, LBNL, LBNL/Vanderbilt University, Vanderbilt University, Florida A\&M University, Georgia Institute of Technology, Department of Physics, Virginia Tech, Gatton Academy, Exeter University, Florida International University, Office of Research, University of North Florida, Physics Department, University of North Florida, NSCL, Michigan State University, Physics Department, Florida State University, University of Tennessee-Knoxville, Neel Institut, Kazan Federal University, Bielefeld University, Ben Gurion University, LCIB - CEA, University of Georgia, Lawrence Livermore National Laboratory, Livermore, CA 94550, NHMFL, Tallahassee, USA, Department of Chemistry, University of Waterloo, Ontario, Canada, NHMFL, Tallahassee FL 32310 USA, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany, Wigner Research Center for Physics, Budapest, Hungary, Experimental physics II, University of Augsburg, Germany, Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, National High Magnetic Field Laboratory Florida State University, Tallahassee, Florida 32310, IM2NP-CNRS (UMR 7334) and Universite Aix-Marseille, National High Magnetic Field Laboratory Applied Superconductivity Center, Heifei National Lab for Physical Science at Microscale, USTC, Institute of Physics, Chinese Academy of Sciences, Department of Electrical Engineering, Rice University, National High Magnetic Field Laboratory, National High Magnetic Field Laboratory/FSU, University of Virginia

  • Chris Neu

    Florida State University, NHMFL, Institut Neel, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China, Florida State University, Department of Physics, Florida State University, Tallahassee, FL, Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, Florida State University, National High Magnetic Field Laboratory, Institute of Physics, Chinese Academy of Sciences, China, Austin Peay State University, University of Pardubice, Davidson College, Covenant College, Lookout Mtn, GA 30750, Russian Academy of Sciences, Moscow, RU, University of Tennessee Space Institute, Tullahoma, TN, USA, Sandia National Laboratories,* Albuquerque, NM, Arkansas State University, Jonesboro, AK, None, Mississippi State University, Mississippi State University Department of Physics and Astronomy, Florida State University and the National High Magnetic Field Laboratory, Faculte des Sciences et Techniques and Universite Aix-Marseille, MIT Haystack Observatory, Departments of Chemistry and Physics, University of Tennessee of Chattanooga, Departments of Chemistry and Physics, University of Tennessee at Chattanooga, Western Kentucky University, Thomas Jefferson National Accelerator Facility, Newport News, VA, Fermilab, University of Virginia and Fermilab, Indiana University Bloomington, Indiana University Health Proton Therapy Center, University of North Florida, National Superconducting Cyclotron Laboratory, Michigan State University, Flordia State University, Louisiana State University, Washington University, Argonne National Laboratory, Lawrence Berkeley National Laboratory, Department of Physics, Florida State University., JINR, Tsinghua University, LBNL, LBNL/Vanderbilt University, Vanderbilt University, Florida A\&M University, Georgia Institute of Technology, Department of Physics, Virginia Tech, Gatton Academy, Exeter University, Florida International University, Office of Research, University of North Florida, Physics Department, University of North Florida, NSCL, Michigan State University, Physics Department, Florida State University, University of Tennessee-Knoxville, Neel Institut, Kazan Federal University, Bielefeld University, Ben Gurion University, LCIB - CEA, University of Georgia, Lawrence Livermore National Laboratory, Livermore, CA 94550, NHMFL, Tallahassee, USA, Department of Chemistry, University of Waterloo, Ontario, Canada, NHMFL, Tallahassee FL 32310 USA, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany, Wigner Research Center for Physics, Budapest, Hungary, Experimental physics II, University of Augsburg, Germany, Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, National High Magnetic Field Laboratory Florida State University, Tallahassee, Florida 32310, IM2NP-CNRS (UMR 7334) and Universite Aix-Marseille, National High Magnetic Field Laboratory Applied Superconductivity Center, Heifei National Lab for Physical Science at Microscale, USTC, Institute of Physics, Chinese Academy of Sciences, Department of Electrical Engineering, Rice University, National High Magnetic Field Laboratory, National High Magnetic Field Laboratory/FSU, University of Virginia

  • Chris Neu

    Florida State University, NHMFL, Institut Neel, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China, Florida State University, Department of Physics, Florida State University, Tallahassee, FL, Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, Florida State University, National High Magnetic Field Laboratory, Institute of Physics, Chinese Academy of Sciences, China, Austin Peay State University, University of Pardubice, Davidson College, Covenant College, Lookout Mtn, GA 30750, Russian Academy of Sciences, Moscow, RU, University of Tennessee Space Institute, Tullahoma, TN, USA, Sandia National Laboratories,* Albuquerque, NM, Arkansas State University, Jonesboro, AK, None, Mississippi State University, Mississippi State University Department of Physics and Astronomy, Florida State University and the National High Magnetic Field Laboratory, Faculte des Sciences et Techniques and Universite Aix-Marseille, MIT Haystack Observatory, Departments of Chemistry and Physics, University of Tennessee of Chattanooga, Departments of Chemistry and Physics, University of Tennessee at Chattanooga, Western Kentucky University, Thomas Jefferson National Accelerator Facility, Newport News, VA, Fermilab, University of Virginia and Fermilab, Indiana University Bloomington, Indiana University Health Proton Therapy Center, University of North Florida, National Superconducting Cyclotron Laboratory, Michigan State University, Flordia State University, Louisiana State University, Washington University, Argonne National Laboratory, Lawrence Berkeley National Laboratory, Department of Physics, Florida State University., JINR, Tsinghua University, LBNL, LBNL/Vanderbilt University, Vanderbilt University, Florida A\&M University, Georgia Institute of Technology, Department of Physics, Virginia Tech, Gatton Academy, Exeter University, Florida International University, Office of Research, University of North Florida, Physics Department, University of North Florida, NSCL, Michigan State University, Physics Department, Florida State University, University of Tennessee-Knoxville, Neel Institut, Kazan Federal University, Bielefeld University, Ben Gurion University, LCIB - CEA, University of Georgia, Lawrence Livermore National Laboratory, Livermore, CA 94550, NHMFL, Tallahassee, USA, Department of Chemistry, University of Waterloo, Ontario, Canada, NHMFL, Tallahassee FL 32310 USA, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany, Wigner Research Center for Physics, Budapest, Hungary, Experimental physics II, University of Augsburg, Germany, Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, National High Magnetic Field Laboratory Florida State University, Tallahassee, Florida 32310, IM2NP-CNRS (UMR 7334) and Universite Aix-Marseille, National High Magnetic Field Laboratory Applied Superconductivity Center, Heifei National Lab for Physical Science at Microscale, USTC, Institute of Physics, Chinese Academy of Sciences, Department of Electrical Engineering, Rice University, National High Magnetic Field Laboratory, National High Magnetic Field Laboratory/FSU, University of Virginia