Multiple field-induced phases in the frustrated triangular magnet Cs3Fe2Br9

Physical review. B./Physical review. B, vol. 104

Abstract

The recently discovered material ${\mathrm{Cs}}_{3}{\mathrm{Fe}}_{2}{\mathrm{Br}}_{9}$ contains ${\mathrm{Fe}}_{2}{\mathrm{Br}}_{9}$ bi-octahedra forming triangular layers with hexagonal stacking along the $c$ axis. In contrast to isostructural Cr-based compounds, the zero-field ground state is not a nonmagnetic $S=0$ singlet-dimer state. Instead, the ${\mathrm{Fe}}_{2}{\mathrm{Br}}_{9}$ bi-octahedra host semiclassical $S=\frac{5}{2}\phantom{\rule{4pt}{0ex}}{\mathrm{Fe}}^{3+}$ spins with a pronounced easy-axis anisotropy along $c$, and interestingly, the intradimer spins are ordered ferromagnetically. The high degree of magnetic frustration due to (various) competing intradimer and interdimer couplings leads to a surprisingly rich magnetic phase diagram. The zero-field ground state is already reached via an intermediate phase, and the high-field magnetization and thermal expansion data for $H\ensuremath{\parallel}c$ identify 10 different ordered phases. Among them are phases with constant magnetization of $\frac{1}{3}$, respectively $\frac{1}{2}$, of the saturation value, and several transitions are strongly hysteretic with pronounced length changes, reflecting strong magnetoelastic coupling.

Authors 16

1. Daniel Brüning

   University of Cologne

   Affiliation as printed

   II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany

2. T. Fröhlich

   University of Cologne

   Affiliation as printed

   II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany

3. D. Gorkov

   University of Cologne · Heinz Maier-Leibnitz Zentrum · Technical University of Munich

   Affiliation as printed

   Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstraße 1, 85748 Garching, Germany

   II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany

4. Ivana Cı́sařová

   Charles University

   Affiliation as printed

   Department of Inorganic Chemistry, Charles University in Prague, Hlavova 2030/8, 128 43 Prague 2, Czech Republic

5. Y. Skourski

   Helmholtz-Zentrum Dresden-Rossendorf · Dresden High Magnetic Field Laboratory

   Affiliation as printed

   Hochfeld-Magnetlabor Dresden (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden, Germany

6. L. Rossi

   Radboud University Nijmegen

   Affiliation as printed

   High Field Magnet Laboratory (HFML-EMFL) and Institute for Molecules and Materials, Radboud University, 6525 ED Nijmegen, The Netherlands

7. B. Bryant

   Radboud University Nijmegen

   Affiliation as printed

   High Field Magnet Laboratory (HFML-EMFL) and Institute for Molecules and Materials, Radboud University, 6525 ED Nijmegen, The Netherlands

8. S. Wiedmann

   Radboud University Nijmegen

   Affiliation as printed

   High Field Magnet Laboratory (HFML-EMFL) and Institute for Molecules and Materials, Radboud University, 6525 ED Nijmegen, The Netherlands

9. Martin Meven Aachen Institut für Kristallographie

   Heinz Maier-Leibnitz Zentrum · RWTH Aachen University

   Affiliation as printed

   Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), 85747 Garching, Germany

   RWTH Aachen University, Institut für Kristallographie, 52056 Aachen, Germany

10. Alexey V. Ushakov

    Russian Academy of Sciences · M.N. Mikheev Institute of Metal Physics

    Affiliation as printed

    M.N. Mikheev Institute of Metal Physics, Ural Branch, Russian Academy of Sciences, 620137 Ekaterinburg, Russia

11. Sergey V Streltsov

    Ural Federal University · Russian Academy of Sciences · M.N. Mikheev Institute of Metal Physics

    Affiliation as printed

    M.N. Mikheev Institute of Metal Physics, Ural Branch, Russian Academy of Sciences, 620137 Ekaterinburg, Russia

    Ural Federal University, Mira St. 19, 620002 Ekaterinburg, Russia

12. Daniel I. Khomskii

    University of Cologne

    Affiliation as printed

    II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany

13. P. Becker

    University of Cologne

    Affiliation as printed

    Abteilung Kristallographie, Institut für Geologie und Mineralogie, Universität zu Köln, Zülpicher Straße 49b, 50674 Köln, Germany

14. L. Bohatý

    University of Cologne

    Affiliation as printed

    Abteilung Kristallographie, Institut für Geologie und Mineralogie, Universität zu Köln, Zülpicher Straße 49b, 50674 Köln, Germany

15. M. Braden

    University of Cologne

    Affiliation as printed

    II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany

16. T. Lorenz

    University of Cologne

    Affiliation as printed

    II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany