1. The self-annealing of irradiation induced defects in magnetite Fe3O4: Revealing reversible irradiation-induced disorder transformation through in situ TEM.
- Author
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Lopez Morales, Angelica M., Chen, Wei-Ying, and Kaoumi, Djamel
- Subjects
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METAL-insulator transitions , *TRANSMISSION electron microscopy , *LATTICE constants , *AMORPHIZATION , *HETEROSTRUCTURES - Abstract
This work reports heavy ion-irradiation effects in polycrystalline Fe3O4. For this matter, Fe/Fe3O4 heterostructures were irradiated in situ in a transmission electron microscopy with 1 MeV Kr ions at 50 K. Evidence of cubic to monoclinic transformation (a.k.a Verwey transition) was recorded in some magnetite grains upon cooling the sample (around 90 K); however, most of the oxide grains retain their cubic spinel structure. Irradiation effects were analyzed in the cubic phase up to a maximum dose of 38 dpa without the sign of amorphization. The extinction of first-order reflections was recorded at doses below 1 dpa, indicating the formation of a new (metastable) phase with half of the lattice parameters compared to the unirradiated Fe3O4 crystal. The formation of the new crystalline phase, which also presents a high resistance to amorphization, is related to the disordering of the cation lattice and the high mobility of the cation interstitials. The metastable phase readily recovers around 225 K during the natural warming of the sample from 50 K to room temperature. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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