Anisotropic Band-Split Magnetism in CoFe2O4

Published

February 26, 2026

Author(s)

Harry Lane, Guratinder Kaur, Masahiro Kawamata, Yusuke Nambu, Lukas Keller, Russel Ewings, David Voneshen, Travis J. Williams, Helen Walker, Dwight Viehland, Peter Gehring, Christopher Stock

Abstract

Single crystal spinel CoFe2O4 exhibits the largest room-temperature saturation magnetostriction among non-rare-earth compounds and a high Curie temperature (Tc ∼ 780 K), properties that are critical to a wide range of industrial and medical applications. Neutron spectroscopy reveals a large band splitting (∼60 meV) between two ferrimagnetic magnon branches, which is driven by site mixing between Co2+ and Fe3+ cations, and a significantly weaker magnetocrystalline anisotropy (∼3 meV). Central to this behavior is the competition between vast mismatched molecular fields on the tetrahedral A-site and octahedral B-site sublattices and the single-ion anisotropy on the B-site. This creates a strong, energetic anisotropy that locks the magnetic moment within each structural domain in place. As a result of these differing energy scales, switching structural domains is energetically favored over a global spin reorientation under applied magnetic fields, and this is what amplifies the magnetostrictive nature of CoFe2O4.

Citation

Advanced Functional Materials

Volume

36

Issue

17

Pub Type

Journals

Download Paper

https://doi.org/10.1002/adfm.202516830

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Keywords

Magnetostriction, spin-lattice coupling, anisotropy, magnons, ferrimagnet, spinel, neutron scattering, x-ray diffraction

Citation

Lane, H. , Kaur, G. , Kawamata, M. , Nambu, Y. , Keller, L. , Ewings, R. , Voneshen, D. , Williams, T. , Walker, H. , Viehland, D. , Gehring, P. and Stock, C. (2026), Anisotropic Band-Split Magnetism in CoFe2O4, Advanced Functional Materials, [online], https://doi.org/10.1002/adfm.202516830, https://nps-ext.nist.gov/nps/nps_public_api/api/Publication/file/960400 (Accessed October 29, 2026)

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