resumo
A new Ca3Mn1.5Fe1.5O8 sample with a structure intermediate between the perovskite and brownmillerite, is synthesized by ceramic method. Rietveld refinement of powder X-ray diffraction data reveals that the compound crystallizes in the orthorhombic structure with Pm2a space group at room temperature. The crystal structure for this compound is formed by layers of Fe1O(4) tetrahedra, separated from each other by two layers of Fe2/Mn1O(6) octahedra. The Hirshfield surface analyses show that the intermolecular elec-trostatic interactions Mn1/Fe2...O, Ca1...O and Ca2...O are in short range, while the Fe1...O interaction is carried out long range. The electron density analysis proves that the structure is stabilized by covalent and ionic interactions. The orthorhombic phase is further supported by Raman and Fourier Transform In-frared spectroscopy (FTIR) analysis. The magnetic measurement indicated the existence of a paramagnetic (PM) behavior at high temperature and weak ferromagnetism with dominant antiferromagnetism at low temperature. (C) 2022 Elsevier B.V. All rights reserved.
palavras-chave
OXYGEN DEFECT
categoria
Chemistry
autores
Selmi, R; Cherif, W; Sarabando, AR; Ferreira, NM; Ktari, L
nossos autores
Artur Ricardo Mesquita Sarabando
bolseiro de investigaçãoGrupos
agradecimentos
This paper within the framework of collaboration is sup-ported by the Tunisian Ministry of Higher Education and Sci-entific Research and the Portuguese Ministry of Science, Tech-nology and Higher Education . The authors acknowledge the i3N (UID/CTM/50025/2020) and CICECO-Aveiro Institute of Materials (UID/CTM/50011/2020) , financed by FCT/MEC and FEDER under the PT2020 Partnership Agreement. This work is also funded by na-tional funds (OE) , through FCT - Funda??o para a Ci?ncia e a Tecnologia, I.P., in the scope of the framework contract for eseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19.