2025/12/17 by Lane, Harry, Kaur, Guratinder, Kawamata, Masahiro +9
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Strongly Correlated Electrons (cond-mat.str-el)
paper · doi:10.48550/arxiv.2512.15683
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 extremely large 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.