Unveiling the magnetic structure of BaFeO3-y: Shedding light on the elusive magnetic behavior

Gutiérrez-Martín, D. ; Hernando, M. ; Parras, M. ; Torres-Pardo, A. ; Fernández-Díaz, M.T. ; Savvin, S. ; González-Calbet, J.M. ; Rodrigues, J.E. ; Silva Jr, R.S. ; Martínez, J.L. ; Varela, A.

Resumen: 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 different evidencing a delicate equilibrium of competing magnetic interactions.

Idioma: Inglés

DOI: 10.1016/j.jallcom.2024.177081

Año: 2025

Publicado en: JOURNAL OF ALLOYS AND COMPOUNDS 1010 (2025), 177081 [12 pp.]
ISSN: 0925-8388

Financiación: info:eu-repo/grantAgreement/ES/MICIU/PID2020–113753RB-I00
Financiación: info:eu-repo/grantAgreement/ES/MICIU/TED2021–129254B-C22

Tipo y forma: Article (Published version)