Andreev effect in GaMnAs/Nb microstructures for improved extraction of spin polarization

ORAL

Abstract

Point contact Andreev reflection is a powerful technique for extracting the spin polarization in a large variety of ferromagnetic materials. Yet, it produced conflicting data that proved difficult to model when studying spin polarization in GaMnAs, due in part to two main problems: the high resistivity of GaMnAs makes it difficult to isolate the interfacial conductance and characterize it properly and there can be a Schottky barrier at the GaMnAs/superconductor interface. We use photolithography to fabricate GaMnAs/Nb micro-structures that offer a direct way to extract the interface conductance and the spin polarization at the interface. Furthermore, our results show that the Schottky barrier can play a crucial role in determining the behavior of the interface conductance when varying the applied voltage.

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Authors

  • Justin Guenther

    Miami University

  • Oleg Popov

    Miami University, Chemistry Department, Penn State Univ., University Park, PA 16802, unaffiliated, Department of Materials Science and Engineering, Ohio State University Columbus, OH 43210, Department of Physics, Ohio State University, Columbus, OH 43210, Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201, Korea Institute of Science and Technology, University of Cincinnati, Miami University of Ohio, University of Michigan, University of Notre Dame, University of Nebraska-Lincoln, Wayne State University, University of Tennessee, National Technical University of Athens, The University of Tennessee, Kettering Univeristy, University of Michigan-Dearborn, FNAL, Harvard University, California State University, Department of Physics, Kettering University, Flint, Michigan, Department of Natural Sciences, University of Michigan-Dearborn, Applied Sciences Inc., Cedarville, Ohio, Oakland University, University of Stockholm, Arizona State University

  • Oleg Popov

    Miami University, Chemistry Department, Penn State Univ., University Park, PA 16802, unaffiliated, Department of Materials Science and Engineering, Ohio State University Columbus, OH 43210, Department of Physics, Ohio State University, Columbus, OH 43210, Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201, Korea Institute of Science and Technology, University of Cincinnati, Miami University of Ohio, University of Michigan, University of Notre Dame, University of Nebraska-Lincoln, Wayne State University, University of Tennessee, National Technical University of Athens, The University of Tennessee, Kettering Univeristy, University of Michigan-Dearborn, FNAL, Harvard University, California State University, Department of Physics, Kettering University, Flint, Michigan, Department of Natural Sciences, University of Michigan-Dearborn, Applied Sciences Inc., Cedarville, Ohio, Oakland University, University of Stockholm, Arizona State University

  • Oleg Popov

    Miami University, Chemistry Department, Penn State Univ., University Park, PA 16802, unaffiliated, Department of Materials Science and Engineering, Ohio State University Columbus, OH 43210, Department of Physics, Ohio State University, Columbus, OH 43210, Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201, Korea Institute of Science and Technology, University of Cincinnati, Miami University of Ohio, University of Michigan, University of Notre Dame, University of Nebraska-Lincoln, Wayne State University, University of Tennessee, National Technical University of Athens, The University of Tennessee, Kettering Univeristy, University of Michigan-Dearborn, FNAL, Harvard University, California State University, Department of Physics, Kettering University, Flint, Michigan, Department of Natural Sciences, University of Michigan-Dearborn, Applied Sciences Inc., Cedarville, Ohio, Oakland University, University of Stockholm, Arizona State University

  • Oleg Popov

    Miami University, Chemistry Department, Penn State Univ., University Park, PA 16802, unaffiliated, Department of Materials Science and Engineering, Ohio State University Columbus, OH 43210, Department of Physics, Ohio State University, Columbus, OH 43210, Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201, Korea Institute of Science and Technology, University of Cincinnati, Miami University of Ohio, University of Michigan, University of Notre Dame, University of Nebraska-Lincoln, Wayne State University, University of Tennessee, National Technical University of Athens, The University of Tennessee, Kettering Univeristy, University of Michigan-Dearborn, FNAL, Harvard University, California State University, Department of Physics, Kettering University, Flint, Michigan, Department of Natural Sciences, University of Michigan-Dearborn, Applied Sciences Inc., Cedarville, Ohio, Oakland University, University of Stockholm, Arizona State University

  • Oleg Popov

    Miami University, Chemistry Department, Penn State Univ., University Park, PA 16802, unaffiliated, Department of Materials Science and Engineering, Ohio State University Columbus, OH 43210, Department of Physics, Ohio State University, Columbus, OH 43210, Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201, Korea Institute of Science and Technology, University of Cincinnati, Miami University of Ohio, University of Michigan, University of Notre Dame, University of Nebraska-Lincoln, Wayne State University, University of Tennessee, National Technical University of Athens, The University of Tennessee, Kettering Univeristy, University of Michigan-Dearborn, FNAL, Harvard University, California State University, Department of Physics, Kettering University, Flint, Michigan, Department of Natural Sciences, University of Michigan-Dearborn, Applied Sciences Inc., Cedarville, Ohio, Oakland University, University of Stockholm, Arizona State University

  • Oleg Popov

    Miami University, Chemistry Department, Penn State Univ., University Park, PA 16802, unaffiliated, Department of Materials Science and Engineering, Ohio State University Columbus, OH 43210, Department of Physics, Ohio State University, Columbus, OH 43210, Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201, Korea Institute of Science and Technology, University of Cincinnati, Miami University of Ohio, University of Michigan, University of Notre Dame, University of Nebraska-Lincoln, Wayne State University, University of Tennessee, National Technical University of Athens, The University of Tennessee, Kettering Univeristy, University of Michigan-Dearborn, FNAL, Harvard University, California State University, Department of Physics, Kettering University, Flint, Michigan, Department of Natural Sciences, University of Michigan-Dearborn, Applied Sciences Inc., Cedarville, Ohio, Oakland University, University of Stockholm, Arizona State University

  • Khalid Eid

    Miami University