Source data for Figures 2, 3 and 4 of the article entitled "Phase stability of iron oxides epitaxial thin films under O₂, CO₂ and H₂O environmental conditions", J. Mater. Chem. C, 2025.

[Description of data collection methods] In-situ Grazing Incidence X-ray Diffraction (GIXRD) was performed at the BM25-SpLine beamline at the ESRF. Measurements were carried out during annealing under O₂, CO₂, H₂O and UHV, with temperature ranging from RT to 1100°C and pressures from 10⁻⁹ mbar to 1 bar. Films were epitaxially grown on SrTiO₃(001) substrates.