Chemical disorder of La and Sr ions in the block layer of LaSrFeO4

57Fe Mössbauer spectroscopic studies were carried out on the single layered perovskite, LaSrFeO4, in the temperature range 15–380 K. The observed line width asymmetries in the line shapes of the spectra were understood to arise from a chemical disorder of La3+ and Sr2+ ions in the block layer of the perovskite structure. The temperature dependence of the hyperfine magnetic field, quadrupole interaction, and isomer shift observed for the system was also analyzed in terms of the local environment of Fe atoms in this structure.