Irradiation-Induced Grain Growth of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si28.svg"> <mml:mrow> <mml:mrow> <mml:mi mathvariant="bold-italic">γ</mml:mi> <mml:mi mathvariant="bold-italic">F</mml:mi> </mml:mrow> <mml:msub> <mm

This work reports the first observations of grain growth under irradiation of Fe oxides, specifically maghemite (γ-Fe 2 O 3 ) and magnetite (Fe 3 O 4 ). The Fe oxide thin films were grown by Pulsed Laser Deposition and irradiated in-situ in a Transmission Electron Microscope at − 223 ∘ C using 1 MeV Kr 2+ ions up to 8.75 x 10 19 ions / m 2 to study grain growth kinetics under irradiation. Grain growth at such low temperatures appears to follow kinetics that can be accounted for by the thermal spike model developed for metals in the literature. The corresponding activation energies were calculated and compared with other oxides. The results demonstrate that γ-Fe 2 O 3 , despite its larger initial grain size, exhibits surprisingly fast grain growth in comparison with Fe 3 O 4 , likely due to the presence of iron vacancies in the crystal structure that facilitate faster atomic diffusion under irradiation.