Mössbauer Effect in the System BaFeO2.5–3.0

Abstract

Mössbauer spectra were measured at 298°, 78°, and 4°K for a number of samples in the system barium ferrate(III)—barium ferrate(IV). The composition with highest iron(IV) content (BaFeO2.95) has an isomer shift, at 298°K, of =0.29 mm/sec relative to Cu(57Co). At 78°K, the absorption is magnetically split having an isomer shift of =0.31 mm/sec and a hyperfine field of 227 kOe. Barium ferrate(III) is similar to the strontium analog and YIG in that there are equal numbers of octahedral and tetrahedral iron sites. The Mössbauer spectrum at 78°K indicates isomer shifts of 0.29 and 0.10 mm/sec and hyperfine splittings of 536 and 459 kOe for the octahedral and tetrahedral sites, respectively. Spectra of intermediate compositions are more complex. Results of this system are compared with those previously determined for the analogous strontium system.