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High temperature magnetism and charge ordering in multiferroic (LuFeO<sub>3</sub>)<sub>m</sub>/(LuFe<sub>2</sub>O<sub>4</sub>)<sub>1 </sub>(<i>m </i>= 3, 7, 9)

ORAL

Abstract

We combined optical spectroscopy, magnetic circular dichroism, and first principles calculations to uncover the microscopic origin of the high temperature magnetism in multiferroic superlattices (LuFeO3)m/(LuFe2O4)1, as well as the charge ordered state in the m = 3 case. Analysis of the dichroic spectra at characteristic energies reveals optical hysteresis loops of different Fe centers. Comparison between coercivity vs temperature curves indicates the bulk magnetization emanates mostly from the LuFe2O4 layer. Spectroscopic signature of the interface demonstrates that the larger Lu distortion only selectively increases the local magnetization of the Fe2+ and Fe3+ sites in the spin-up channel, which strengthens the exchange interaction, increases the total magnetization in the LuFe2O4 layer and enhances TC. Comparison between the calculated and measured dichroic spectra affirms a non-polar charge ordered state in the (3, 1) case. These findings provide a site specific technique to analyze the complex interactions in the materials with multiple magnetic centers, and also broaden the possibilities in the hunt for novel multiferroics with high TC and large magneto-electric coupling constant.

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Presenters

  • Shiyu Fan

    University of Tennessee, Physics, University of Tennessee, Knoxville, Physics and Astronomy, University of Tennessee, Knoxville

Authors

  • Shiyu Fan

    University of Tennessee, Physics, University of Tennessee, Knoxville, Physics and Astronomy, University of Tennessee, Knoxville

  • Hena Das

    Laboratory for Materials and Structures, Tokyo Institute of Technology, Midori-ku, 4259 Nagatesuta, Yokohama, Kanagawa 226-8503, Japan

  • Kevin Arthur Smith

    Chemistry, University of Tennessee, Knoxville, Department of Chemistry, University of Tennessee, Knoxville, Chemistry, University of Tennessee, Knoxville, Tennessee, 37996, USA

  • Alejandro R'ebola

    School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA

  • Julia Mundy

    School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA, Harvard University

  • Charles Brooks

    Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA, Harvard University

  • Megan Holtz

    School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA

  • Ramamoorthy Ramesh

    Department of Materials Science and Engineering, UC Berkeley, University of California, Berkeley, USA, University of California, Berkeley, Materials Science and Engineering, University of California, Berkeley, Department of Materials Science and Engineering, University of California, Berkeley, Department of Materials Science and Engineering,, University of California, Berkeley, California 94720, USA

  • David Anthony Muller

    Cornell University, School of Applied and Engineering Physics, Cornell University, Applied and Engineering Physics, Cornell University, School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA

  • Darrell Schlom

    Cornell University, Department of Materials Science and Engineering, Cornell University, Department of Materials Science and Engineering, Kavli Institute at Cornell for Nanoscale Science, Cornell University, Materials Science and Engineering, Cornell University, Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA, Platform for the Accelerated Realization, Analysis, & Discovery of Interface Materials (PARADIM), Cornell University

  • Craig J Fennie

    Cornell University, School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA

  • Stephen A McGill

    National High Magnetic Field Laboratory, NHMFL, Florida, Natl High Magnetic Field Lab, National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA, Physics, Florida State University, Florida State University, Tallahassee, FL 32310, USA, National High Magnetic Field Lab

  • Janice Lynn Musfeldt

    University of Tennessee, Department of Chemistry, University of Tennessee, Knoxville, Chemistry, University of Tennessee, Knoxville, University of Tennessee, Knoxville, Chemistry, University of Tennessee, Knoxville, Tennessee, 37996, USA