Possible evidence for a spin-state crossover in the Verwey state inFe3O4thin films

In epitaxial thin films of magnetite a large change in magnetization across the Verwey transition has been observed. In the Verwey state, the sample magnetization appeared to be strongly reduced, in some samples even close to zero. Using superconducting quantum interference magnetometry, x-ray absorption near edge spectroscopy, and polarized neutron reflectometry, a simple rotation of the magnetization vector due to a change in magnetocrystalline anisotropy was excluded. The experimental data rather suggest an intrinsic loss of magnetic moment due to a possible transition into a low or intermediate spin state of ${\mathrm{Fe}}²⁺$. This observation discloses a different aspect of the Verwey transition.