Magnetic transformations in the Sr0.78Y0.22Co1 − x Fe x O3 − γ system with a perovskite structure

Effects of partial Co replacement by Fe in Sr0.775Y0.225CoO3-δ on its magnetic property, oxygen deficiency and crystal structure

“…4a and Fig. 5a that the Sr 0.775 Y 0.225 CoO 3−δ compound exhibits ferromagnetic ordering at the clearly discernable onset temperature of 335 K, in agreement with those reported by Kobayashi et al [19], Balamurugan [22], and Troyanchuk et al [27,28] for the oxygen deficient samples at the same yttrium doping level. Upon 10 % Fe replacement of Co, the measured M-T curve presented in Fig.…”

“…Upon 10 % Fe replacement of Co, the measured M-T curve presented in Fig. 4b shows the relatively less rapid rise of the ZFC magnetization around 335 K and its splitting from the FC magnetization curve remains clearly observable at a slightly higher temperature, similar to the result reported for the sample with 12 % Fe-doping [27,28] and the 25 % Ga replacement of Co [26]. As shown in Fig.…”

“…The result presented in Fig. 4b is notably different from the magnetization curves reported for the 50 % Co substitution by Fe, which shows the complete suppression of FM ordering [26,27]. The cusp-like anomaly occurring at the temperature about 325 K on the ZFC curve is understood to signify the antiferromagnetic contribution [27,28].…”

“…4b is notably different from the magnetization curves reported for the 50 % Co substitution by Fe, which shows the complete suppression of FM ordering [26,27]. The cusp-like anomaly occurring at the temperature about 325 K on the ZFC curve is understood to signify the antiferromagnetic contribution [27,28]. For the two compounds, there is no sign for the existence of spin glass state as found in the SrCo 1−x M x O 3−δ (M = Nb, Ru) system [31], in agreement with the previous report [16].…”

“…Indeed, the two cases were shown to be related to different induced changes in oxygen content and the perovskite structure. Specifically, suppression of FM order shown in the compound with 50 % Co replacement by Fe is accompanied with a large reduction of oxygen deficiency by 0.076, and significant changes in the crystal structure, whereas δ ∼ = 0 and relatively small changes in the crystal structure were found in the sample of 25 % Co substitution by Ga. Interestingly, more recent studies [27,28], while confirming the suppression of FM ordering and 0.045 reduction of oxygen deficiency upon 50 % Fe doping of the same compound have also shown that the compound with 12 % Fe doping still exhibits a small residual FM signal somewhat similar to what was found in 25 % Ga doped sample, while undergoing unequally smaller reduction of oxygen deficiency of about 0.020. In view of the scarcity of reports in this doping range, it is desirable to verify or confirm the dopant induced changes particularly at the low level Co replacement by Fe.…”