Magnetic excitation spectrum and the hierarchy of the magnetic interactions in ErFeO 3

Physical review. B./Physical review. B, vol. 114

Abstract

We report a comprehensive investigation of the excitation spectrum of ErFeO 3 orthoferrite by means of time-of-flight neutron spectroscopy. The spectrum consists of two distinct components: strongly dispersive spin wave excitations of the Fe 3 + sublattice spanning ≈ 9 –65 meV, and crystal electric field (CEF) excitations of Er 3 + ions below 36 meV. The observed spin wave dispersions and spectral weight are well captured within linear spin wave theory, enabling extraction of the key Fe-Fe exchange parameters. Low-energy incident neutrons with their enhanced energy resolution, further revealed the dispersive character and splitting of Kramers-degenerate CEF levels. We show that the dispersion is caused by the exchange coupling between Er 3 + ions, while the degeneracy is lifted by interactions between the Er 3 + and Fe 3 + sublattices. We further explore the influence of dipolar and antisymmetric exchange interactions with the focus on the magnetic ground state of ErFeO 3 , with particular attention to the low-temperature spin arrangement. Taken together, our results provide a detailed account of the spin dynamics in ErFeO 3 and reveal a hierarchy of interactions scales characteristic for orthoferrites.

Authors 6

1. Anonymous

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich

2. Piotr Fabrykiewicz Aachen

   RWTH Aachen University · Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich

   RWTH Aachen University

3. Devashibhai Thakarshibhai Adroja

   University of Johannesburg · Rutherford Appleton Laboratory

   Affiliation as printed

   Rutherford Appleton Laboratory

   University of Johannesburg

4. Martin Meven Aachen

   RWTH Aachen University · Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich

   RWTH Aachen University

5. A. Schneidewind

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich

6. Michał Stękiel

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich