Charge and structural ordering in the brownmillerite phases: La1-xSrxMnO2.5 (0.2 < x < 0.4)
- Casey, PS
- Barker, D
- Hayward, MA
Publication date
May 2006
DOI Publisher
Elsevier BV Journal
Journal of Solid State ChemistryAbstract
The topotactic reduction of La1-xSrxMnO3 (0.2<x<0.4) perovskite phases to the corresponding La1-xSrxMnO2.5 brownmillerite phases with NaH is described. Neutron and electron diffraction data show the x = 0.25 and 0.2 phases adopt structures with an unusual ordered L-R-L-R alternation of twisted chains of Mn(II) tetrahedra within each anion-deficient layer. This is accompanied by Mn(II)/(III) charge ordering within the remaining MnO6 octahedral layers. In contrast, the x = 0.4 phase adopts a structure in which the twisted chains of tetrahedra are disordered. © 2006 Elsevier Inc. All rights reserved
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