Disentangling Spin-Orbital Interactions - Extraction of far reaching exchange interactions in Cobalt Oxide

ORAL

Abstract

Cobalt oxide (CoO) is a classical example where the magnetic superexchange is sufficiently strong such that a significant molecular field induced mixing between single-ion spin-orbit manifolds occurs. This makes the extraction of all multi-neighbor exchange interactions and comparison with first principles theory nearly intractable. We disentangle these interactions via neutron spectroscopic measurements on the diluted structural analog Co0.03Mg0.97O, thereby switching off the magnetic-order-induced molecular field that is the origin of this strong admixture. By considering the prevalent `dimer' response, we extract 7 exchange constants out to the fourth coordination shell with a dominant antiferromagnetic next nearest neighbor 180o superexchange interaction, in agreement with Kanamori's original predictions. Other interactions appear in ferromagnetic/antiferromagnetic pairs, consistent with the Goodenough-Kanamori-Anderson rules and account for the Neel and Curie-Weiss temperatures obtained from thermodynamic measurements.

*We are grateful to the Carnegie Trust for the Universities of Scotland, the Royal Society, the STFC, the ERC and EPSRC for financial support.

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Presenters

  • Paul Sarte

    • Chemistry, University of Edinburgh

Authors

  • Paul Sarte

    • Chemistry, University of Edinburgh

  • Roger Cowley

    • Physics , University of Oxford

  • Efrain Rodriguez

    • University of Maryland
    • Department of Chemistry and Biochemistry, University of Maryland
    • Chemistry and Biochemistry , University of Maryland

  • Duc Le

    • ISIS Neutron Source

  • Victoria Garcia

    • ISIS Neutron and Muon Source
    • ISIS Neutron Source

  • Jon Taylor

    • ISIS Neutron Source

  • Christopher Frost

    • ISIS Neutron Source

  • Dharmalingam Prabhakaran

    • Condensed Matter Physics, University of Oxford
    • Physics Department, University of Oxford
    • Physics, University of Oxford
    • Physics , University of Oxford
    • University of Oxford
    • Physics, Oxford Univ

  • Chris MacEwen

    • Physics , The University of Edinburgh

  • Atsushi KITADA

    • Materials Science and Engineering, Kyoto University

  • Alexander Browne

    • Chemistry, University of Edinburgh

  • Elise Pachoud

    • Chemistry, University of Edinburgh

  • William Buyers

    • Chalk River Laboratories

  • Paul Attfield

    • Chemistry, University of Edinburgh

  • Chris Stock

    • University of Edinburgh
    • Univ of Edinburgh
    • University of Edingburgh
    • The University of Edinburgh
    • Physics , The University of Edinburgh