Spin dynamics study and experimental realization of tunable single-ion anisotropy in multiferroic Ba2CoGe2O7 under external magnetic fields

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

Abstract

We report a spin-wave study on multiferroic ${\mathrm{Ba}}_{2}{\mathrm{CoGe}}_{2}{\mathrm{O}}_{7}$ under magnetic fields up to 12 T using low-energy inelastic neutron scattering. In-plane transverse $({T}_{1})$ spin-wave modes are highly dispersive along $(h00)$ and rather flat but strong in intensity along $(30l)$. In addition, two dispersive electromagnon modes have been observed around 3.5 meV. Dispersion of the out-of-plane transverse modes $({T}_{2})$ under fields reveals that the single-ion anisotropy constant decreases with increasing magnetic field, which is consistent with the linear spin-wave theory. Our results imply that the field-dependent single-ion anisotropy plays a crucial role in determining the characteristics of ${T}_{2}$ and electromagnon modes in the three-dimensional anisotropic spin-wave spectrum.

Authors 9

1. Rajesh Dutta Aachen Institut für Kristallographie

   Forschungszentrum Jülich · Heinz Maier-Leibnitz Zentrum · RWTH Aachen University

   Affiliation as printed

   Institut für Kristallographie, RWTH Aachen Universität, 52066 Aachen, Germany

   Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, 85747 Garching, Germany

   Jülich Centre for Neutron Science (JCNS), Forschungszentrum Jülich GmbH at Heinz Maier-Leibnitz Zentrum (MLZ)

   RWTH - Rheinisch-Westfälische Technische Hochschule Aachen University (RWTH Aachen Templergraben 55 52062 Aachen (Hausanschrift) 52056 Aachen (Postanschrift) - Germany)

2. Henrik Thoma Aachen Institut für Kristallographie

   Forschungszentrum Jülich · Heinz Maier-Leibnitz Zentrum · RWTH Aachen University

   Affiliation as printed

   Institut für Kristallographie, RWTH Aachen Universität, 52066 Aachen, Germany

   Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, 85747 Garching, Germany

   Jülich Centre for Neutron Science (JCNS), Forschungszentrum Jülich GmbH at Heinz Maier-Leibnitz Zentrum (MLZ)

   RWTH - Rheinisch-Westfälische Technische Hochschule Aachen University (RWTH Aachen Templergraben 55 52062 Aachen (Hausanschrift) 52056 Aachen (Postanschrift) - Germany)

3. I. Radelytskyi

   Forschungszentrum Jülich · Heinz Maier-Leibnitz Zentrum

   Affiliation as printed

   Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, 85747 Garching, Germany

   Jülich Centre for Neutron Science (JCNS), Forschungszentrum Jülich GmbH at Heinz Maier-Leibnitz Zentrum (MLZ)

4. A. Schneidewind

   Forschungszentrum Jülich · Heinz Maier-Leibnitz Zentrum

   Affiliation as printed

   Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, 85747 Garching, Germany

   Jülich Centre for Neutron Science (JCNS), Forschungszentrum Jülich GmbH at Heinz Maier-Leibnitz Zentrum (MLZ)

5. Vilmos Kocsis

   Budapest University of Technology and Economics · Leibniz Institute for Solid State and Materials Research · RIKEN Center for Emergent Matter Science

   Affiliation as printed

   Department of Physics, Budapest University of Technology and Economics, and MTA-BME Lendület Magneto-optical Spectroscopy Research Group, 1111 Budapest, Hungary

   RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan

   CEMS - RIKEN Center for Emergent Matter Science (CEMS) (Hirosawa 2-1, Wako, Saitama 351-0198 - Japan)

   Department of Physics [Budapest] (Budafoki ut 8, 1111 Budapest - Hungary)

   IFW Dresden - Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden (Helmholtzstraße 20, D-01069 Dresden - Germany)

6. Y. Tokunaga

   Chiba University · RIKEN Center for Emergent Matter Science · The University of Tokyo

   Affiliation as printed

   Department of Advanced Materials Science, University of Tokyo, Kashiwa 277-8561, Japan

   RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan

   CEMS - RIKEN Center for Emergent Matter Science (CEMS) (Hirosawa 2-1, Wako, Saitama 351-0198 - Japan)

   Chiba University (Japan)

7. Y. Taguchi

   RIKEN Center for Emergent Matter Science

   Affiliation as printed

   RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan

   CEMS - RIKEN Center for Emergent Matter Science (CEMS) (Hirosawa 2-1, Wako, Saitama 351-0198 - Japan)

8. Yoshinori Tokura

   RIKEN Center for Emergent Matter Science · The University of Tokyo

   Affiliation as printed

   Department of Applied Physics, University of Tokyo, Hongo, Tokyo 113-8656, Japan

   Quantum-Phase Electronics Center, Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan

   RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan

   CEMS - RIKEN Center for Emergent Matter Science (CEMS) (Hirosawa 2-1, Wako, Saitama 351-0198 - Japan)

   Department of Applied Physics, The University of Tokyo (Department of Applied Physics, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan - Japan)

   Department of Applied Physics, University of Tokyo, Kongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

9. Vladimir M. Hutanu Aachen Institut für Kristallographie

   Forschungszentrum Jülich · Heinz Maier-Leibnitz Zentrum · RWTH Aachen University

   Affiliation as printed

   Institut für Kristallographie, RWTH Aachen Universität, 52066 Aachen, Germany

   Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, 85747 Garching, Germany

   Jülich Centre for Neutron Science (JCNS), Forschungszentrum Jülich GmbH at Heinz Maier-Leibnitz Zentrum (MLZ)

   RWTH - Rheinisch-Westfälische Technische Hochschule Aachen University (RWTH Aachen Templergraben 55 52062 Aachen (Hausanschrift) 52056 Aachen (Postanschrift) - Germany)