Critical magnetic fluctuations in the layered ruthenates Ca<sub>2</sub>RuO<sub>4</sub> and Ca<sub>3</sub>Ru<sub>2</sub>O<sub>7</sub> studied by neutron spectroscopy

ORAL

Abstract

The unconventional magnetic and electronic properties of ruthenates and other transition metal oxides with 4d valence electrons often arise from a complex interplay between spin-orbit coupling, crystal field effects, and Hund's coupling. In single-layer Ca2RuO4 recent neutron spectroscopy experiments revealed a novel type of soft-magnetism with strong single-ion anisotropy and ‘Higgs’ amplitude fluctuations in the spin-wave spectrum. On the other hand, bilayer Ca3Ru2O7 exhibits competing antiferromagnetic (AFM) Mott-insulating and AFM-metallic phases, and even minute doping by non-magnetic Ti-ions can alter the magnetic correlations significantly. Here we report on high-resolution neutron triple-axis spectroscopy measurements of critical AFM fluctuations in proximity to the Néel temperatures of Ca2RuO4, Ca3Ru2O7, and 1% Ti-doped Ca3Ru2O7. Such fluctuations are fundamentally related to the nature of the magnetic correlations and can provide new insights into the complex magnetism of single and bilayer ruthenates.

–

Presenters

  • Heiko Trepka

    • Max Planck Institute for Solid State Research, Stuttgart, Germany

Authors

  • Heiko Trepka

    • Max Planck Institute for Solid State Research, Stuttgart, Germany

  • Thomas Keller

    • Max Planck Institute for Solid State Research, Stuttgart, Germany

  • Maximilian Krautloher

    • Max Planck Institute for Solid State Research, Stuttgart, Germany

  • Joel Bertinshaw

    • Max Planck Institute for Solid State Research, Stuttgart, Germany

  • Juan P Porras

    • Max Planck Institute for Solid State Research, Stuttgart, Germany

  • Jianhui Xu

    • Heinz Maier-Leibnitz Zentrum, Garching, Germany

  • Klaus Habicht

    • Helmholtz-Zentrum für Materialien und Energie, Berlin, Germany

  • Martin Boehm

    • Institut Laue-Langevin
    • Institut Laue-Langevin, Grenoble, France

  • Karin Schmalzl

    • Jülich Centre for Neutron Science, Jülich, Germany

  • Bernhard Keimer

    • Max Planck Inst for Solid State Research
    • Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
    • Max Planck Institute for Solid State Physics
    • Max Planck Institute for Solid State Research
    • Solid State spectroscopy, Max Planck Institute for Solid State Research
    • Max Planck Institute for Solid State Research, Stuttgart, Germany

  • Matthias Hepting

    • Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
    • Max Planck Institute for Solid State Physics
    • Max Planck Institute for Solid State Research, Stuttgart, Germany