Abstract
The brownmillerite phase LaSrCoFeO5 has been prepared by partially reducing the parent perovskite material LaSrCoFeO6 in 10% H-2/N-2. The material crystallizes in the Icmm space group with the transition metal ions randomly distributed over the octahedral and tetrahedral sites of the structure. The material shows G-type antiferromagnetic order at room temperature which is consistent with the presence of high spin Co2+ and Fe3+. The perovskite phases LaSrCoFeO5F and LaSrCoFeO5.58 are synthesized by fluorination and room temperature air oxidation of LaSrCoFeO5, respectively. LaSrCoFeO5.56 could be prepared by quenching the sample from 1300 degrees C into liquid nitrogen. Neutron powder diffraction data, Mossbauer spectroscopy and magnetic susceptibility measurements suggest a G-type antiferromagnetism in these materials at room temperature due to the presence of Co3+ in the high spin state, which is not common in this type of materials.
Original language | English |
---|---|
Pages (from-to) | 3253-3259 |
Number of pages | 7 |
Journal | Journal of Materials Chemistry |
Volume | 20 |
Issue number | 16 |
DOIs | |
Publication status | Published - 1 Jan 2010 |