Chlorine Insertion Promoting Iron Reduction in Ba-Fe Hexagonal Perovskites: Effect on the Structural and Magnetic Properties.
BaFeCl0.13(2)O2.48(2) has been synthesized and studied. A proper tuning of the synthetic route has been designed to stabilize this compound as a single phase. The thermal stability and evolution, along with the magnetic and structural properties are reported here. The crystal structure has been refined from neutron powder diffraction data, and it is of the type (hhchc)2-10H. It is stable up to a temperature of 900 °C, where the composition reads BaFeCl0.13(2)O2.34(2). The study by electron microscopy shows that the crystal structure suffers no changes in the whole BaFeCl0.13(1)O3-y (2.34 ≤ 3 - y ≤ 2.48) compositional range. Refinement of the magnetic structure shows that the Fe is antiferromagneticaly ordered, with the magnetic moment parallel to the ab plane of the hexagonal structure. At higher temperature, a nonreversible phase transition into a (hchc)-4H structure type takes place with overall composition BaFeCl0.13(1)O2.26(1). Microstructural characterization shows that, in some crystals, this phase intergrows with a seemingly cubic related phase. Differences between these two crystalline phases reside in the chlorine content, which keeps constant through the phase transition for the former and disappears for the latter.
Departamento de Química Inorgánica, Facultad de CC. Químicas, Universidad Complutense de Madrid , 28040 Madrid, Spain.
Laura
L
Serrador
Departamento de Química Inorgánica, Facultad de CC. Químicas, Universidad Complutense de Madrid , 28040 Madrid, Spain.
María
M
Hernando
Instituto de Ciencia de Materiales, CSIC , Cantoblanco 28049 Madrid, Spain.
José L
JL
Martínez
Departamento de Química Inorgánica, Facultad de CC. Químicas, Universidad Complutense de Madrid , 28040 Madrid, Spain.|Centro Nacional de Microscopía Electrónica CNME , 28040 Madrid, Spain.
José M
JM
González-Calbet
Departamento de Química Inorgánica, Facultad de CC. Químicas, Universidad Complutense de Madrid , 28040 Madrid, Spain.
Aurea
A
Varela
Centro Nacional de Microscopía Electrónica CNME , 28040 Madrid, Spain.
F Javier
FJ
García-García
Departamento de Química Inorgánica, Facultad de CC. Químicas, Universidad Complutense de Madrid , 28040 Madrid, Spain.
Marina
M
Parras