Jahn-Teller distortion driven magnetic polarons in magnetite

Abstract

The first known magnetic mineral, magnetite (Fe${}_3$O${}_4$), has unusual properties which have fascinated mankind for centuries; it undergoes the Verwey transition at $T_{\mathrm{V}}$ $\sim$120 K with an abrupt change in structure and electrical conductivity. The mechanism of the Verwey transition however remains contentious. Here we use resonant inelastic X-ray scattering (RIXS) over a wide temperature range across the Verwey transition to identify and separate out the magnetic excitations derived from nominal Fe${}^{2+}$ and Fe${}^{3+}$ states. Comparison of the RIXS results with crystal-field multiplet calculations shows that the spin-orbital $dd$ excitons of the Fe${}^{2+}$ sites arise from a tetragonal Jahn-Teller active polaronic distortion of the Fe${}^{2+}$O${}_6$ octahedra. These low-energy excitations, which get weakened for temperatures above 350 K but persist at least up to 550 K, are distinct from optical excitations and best explained as magnetic polarons.

References in corpus (7)

• Mechanism of the Verwey transition in magnetite
• Resonant X-ray diffraction studies on the charge ordering in magnetite
• High-energy photoemission on Fe3O4: Small polaron physics and the Verwey transition
• Zener double exchange from local valence fluctuations in magnetite
• Local electronic structure of Fe${}^{2+}$ impurities in MgO thin films: Temperature-dependent soft x-ray absorption spectroscopy study
• Raman and fluorescence characteristics of resonant inelastic X-ray scattering from doped superconducting cuprates
• Investigation of the presence of charge order in magnetite by measurement of the spin wave spectrum

Cited by in corpus (15)

• Local orbital degeneracy lifting as a precursor to an orbital-selective Peierls transition
• Development of the Soft X-ray AGM-AGS RIXS Beamline at Taiwan Photon Source
• Discovery of the soft electronic modes of the trimeron order in magnetite
• Vacancy-driven non-cubic local structure and magnetic anisotropy tailoring in Fe${}_x$O-Fe${}_{3-\delta }$O${}_4$ nanocrystals
• Giant thermal hysteresis in Verwey transition of single domain Fe3O4 nanoparticles
• Trimeron-phonon coupling in magnetite
• Oxidation State Dynamics and Emerging Patterns in Magnetite
• Dual Orbital Degeneracy Lifting in a Strongly Correlated Electron System
• Ultrafast generation of hidden phases via energy-tuned electronic photoexcitation in magnetite
• Pressure driven re-entrant magnetoelectric transition in honeycomb $F{e}_{4}N{b}_2{O}_9$
• Response of the Verwey transition in magnetite to a controlled point-like disorder induced by 2.5 MeV electron irradiation
• Dual-stage structural response to quenching charge order in magnetite
• Trimeron ordering, bandgap and polaron hopping in magnetite
• Bimagnon dispersion of La2CuO4 probed by resonant inelastic X-ray scattering
• Direct observation of Jahn-Teller critical dynamics at a charge-order Verwey transition