The effects of the substitution of alkaline earths or Y for La on the structure and electrical properties of LaSrFeO4 with K2NiF4 structure have been investigated. EDTA titration confirmed that Fe3+ was oxidized to Fe4+ in an amount corresponding to that of divalent alkaline earth ions substituted for La3+. The change in the lattice constants was interpreted in terms of the ionic radius of the substituted ions and the Jahn-Teller distortion of the Fe(IV)O6 octahedra having d4 electronic configuration. All the substituted LaSrFeO4 samples were semiconducting over the temperature range from 100 to 300 K. The measurement of the Seebeck coefficient revealed that the conduction carriers of LaSrFeO4 were holes and the carrier concentration increased with increasing amount of Fe4+. La1-xAxSrFeO4 exhibited a monotonic decrease in resistivity and activation energy for conduction with increasing Fe4+ abundance. The activation energy for conduction did not change by changing the lattice constant where the Fe4+ abundance did not change with various substituents.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry