2026-06-29T02:06:14Zhttps://docta.ucm.es/rest/oai/request

oai:docta.ucm.es:20.500.14352/1172832025-03-18T14:57:40Zcom_20.500.14352_14col_20.500.14352_15

00925njm 22002777a 4500 dc Gutiérrez Martín, Daniel author Hernando González, María author Parras Vázquez, Marina Marta author Torres Pardo, María De La Almudena author Fernández Díaz , Mª Teresa author Savvin, S author Rodrigues, Joao author González Calbet , Jose Mª author Silva Jr , Romualdo author Martínez, Jose Luis author Varela Losada, María Áurea author 2025-01-27 This work provides a comprehensive examination of the structural and magnetic properties of 6H-BaFeO2.96 over a wide temperature range (10 K < T < 300 K) using neutron and synchrotron X-ray diffraction. Additionally, the local oxidation state of iron is examined using electron energy loss spectroscopy. No structural changes that could indicate a charge-order transition are observed in spite of a reported possible charge disproportionation of Fe4+ into Fe(4+δ)+ and Fe(4-δ)+ phenomenon at low temperature. According to the magnetic characterization, BaFeO2.96 orders antiferromagnetically at TN=156 K. The application of external magnetic fields strongly influences the magnetic behavior; the transition temperature shifts to lower values with the applied magnetic field and the long-range magnetic order melts with an applied field of 14 T. The magnetocaloric effect clearly shows at TN a change from negative to positive magnetic entropy. The Rietveld refinement of the neutron powder diffraction data collected at 10 K, gives a magnetic ordering with propagation vector [0, 0, ½] and three magnetically distinct sites for the Fe atoms. This magnetic structure consists of ferromagnetic Fe-sheets perpendicular to the c-axis with the magnetic moments along the [110] direction coupled both ferromagnetic and antiferromagnetically along the c-axis. The magnetic moment values of the three Fe ions are very differentevidencing a delicate equilibrium of competing magnetic interactions. Gutiérrez-Martín, D., et al. «Unveiling the Magnetic Structure of BaFeO3-y: Shedding Light on the Elusive Magnetic Behavior». Journal of Alloys and Compounds, vol. 1010, enero de 2025, p. 177081. DOI.org (Crossref), https://doi.org/10.1016/j.jallcom.2024.177081. 10.1016/j.jallcom.2024.177081 https://hdl.handle.net/20.500.14352/117283 https://doi.org/10.1016/j.jallcom.2024.177081 Unveiling the magnetic structure of BaFeO3-y: Shedding light on the elusive magnetic behavior