MAGNETIC-PROPERTIES OF THE CANFE2TIN-2O3N-1 PEROVSKITE RELATED SERIES - AN EPR STUDY

We report here an EPR study of the perovskite-like family CanFe2Tin-2O3n-1, where Ti4+ non-magnetic ions substitute for Fe3+ in the brownmillerite structure (n = 2). For terms n = 3 and 4, intense EPR spectra above ≈ 330 K associated with the resonance of paramagnetic Fe3+ ions are observed. The integrated intensity of the EPR line presents a maximum at T0 = T(Imax) ≈ 330 K in both cases, becoming negligible for T < 275(5)K. Dc magnetic susceptibility measurements present a pronounced break in the slope of χdc (T) vs T at 283(3) K in both compounds. These anomalies are taken as indications of the establishment of magnetic ordering in the materials. The depression of the ordering temperature found for the terms n = 3 and 4 of the series, as compared to the case of n = 2, is discussed in terms of the possible cationic order in these compounds. A reduction of the dimensionality of the magnetic behavior is suggested in going from n = 2 to n = 3 and 4. © 1992.