@article {MANOUSOU2025180081,
	title = {Phase Evolution in Low Fe Concentration V1-xFexO2 Compounds: Phase diagram and Annealing Effects},
	journal = {Journal of Alloys and Compounds},
	year = {2025},
	pages = {180081},
	abstract = {We present a comprehensive investigation into the synthesis, phase evolution and valence state of vanadium (V) in V1-xFexO2 (x = 0 \%, 0.5 \%, 0.75 \%, 1.0 \%) compounds. Polycrystalline samples have been synthesized with solid-state reaction method, followed by thermal annealing. X-Ray Powder Diffraction (XRPD) analyzed by Le Bail method revealed the transformation from monoclinic (M1) phase (space group: P21/c) to triclinic (T) one with increasing Fe concentration. Additionally, a monoclinic (M2) phase (space group: C2/m) emerged at 1.0 \% Fe doping. Temperature-dependent XRPD and diffuse reflectance measurements elucidated the phase transitions during heating cycles, showing the impact of Fe doping on the system{\textquoteright}s behavior. The construction of a complete phase diagram for the V1-xFexO2 system (x <= 1.0 \%) was achieved, addressing ambiguities in the low-Fe concentration region. X-ray Photoelectron Spectroscopy (XPS) further confirmed the influence of Fe doping on the vanadium valence states, indicating an increase of V5+ sites and therefore a lattice distortion and stabilization of the triclinic phase. The metal-insulator transition temperature (TMIT) appears to be almost constant. Post-annealing led to the reinstatement of the M1 phase in all samples, and a modified phase diagram was constructed. The accompanied decrease of V5+ ions contributed to the destabilization of the T and M2 phases, favoring the thermodynamically stable M1 phase. The findings provide valuable insights into the complex phase behavior of V1-xFexO2 compounds, showcasing a significant interplay between charge redistribution, the vanadium valence state, and the oxygen defects of the system.},
	keywords = {Annealing effects, Fe-doped VO, MIT, Phase diagram, SPT, XPS, XRPD},
	issn = {0925-8388},
	doi = {https://doi.org/10.1016/j.jallcom.2025.180081},
	url = {https://www.sciencedirect.com/science/article/pii/S0925838825016391},
	author = {Dimitra K. Manousou and Stefanos B. Atata and Yoo Jung Sohn and Tsipas, Polychronis and Andrzej Grzechnik and Maria Calamiotou and Karen Friese and Spiros Gardelis}
}
