Structure and magnetism in deficient La0.7−x□xSr0.3CoO3 (0≤x≤0.2) perovskite cobaltites

Synthesis, and measurement of structural and magnetic properties, of La1−xCdxCoO3 perovskite ceramic oxides

“…The structural parameters obtained for the parent compound are consistent with the literature [29]. The parent compound exhibits a spin-glass behavior at low temperature which originates due to the competition between the ferromagnetic (Co 3+ −O−Co 4+ ) and the antiferromagnetic (Co 3+ −O−Co 3+ and Co 3+ −O− Co 4+ ) interactions [28]. Chemical titrations showed the portion of Co 4+ increased from 3.5% at 0% doping to 14.9% at 20% Cd doping.…”

“….In addition, a combination of a) and b) is also possible, as demonstrated in SrFeO 3−x materials synthesized in air [27]. Authors of literature on La 0.7−x □ x Sr 0.3 CoO 3 materials showed that, in general, the samples are oxygen substoichiometric, and the portion of substoichiometric O 2 increases with increasing La-deficiency and creation of vacancies at La sites, leading to a gradual decrease of the unit cell volume and accounts for the observed spin-glass to paramagnetic and ferromagnetic magnetic behavior as a result of the progressive increase in deficiency [28]. The observed magnetic properties in our samples (S=3/2), attributed to the effective spins of a vacancy created at the La 3+ site, are consistent with such observations.…”

Synthesis and measurement of structural and magnetic properties of K-doped LaCoO3 perovskite materials

“…Characterization results showed that the samples are oxygen stoichiometric, the portion of substoichiometric O 2 increases with increasing La deficiency, and the creation of vacancies at La sites leads to a gradual decrease of the unit cell volume. Based on the magnetic studies, the observed spin-glass to paramagnetic behavior was attributed to the progressive increase in oxygen deficiency [36]. The observed magnetic properties in our sample (S = 3/2) strongly suggests the creation of vacancies created at the La 3+ site.…”

“…The observed behavior of mixed-valency and oxygen vacancy could account for the cobaltates compound exhibiting a spin-glass behavior at low temperature due to the competition between ferromagnetic (Co 3+ -O-Co 4+ ) and the antiferromagnetic (Co 4+ -O-Co 4+ ) interactions [36]. Thus, it indicates that partial substitution of La 3+ site by monovalent K + results in the creation of oxygen vacancy at the La site, which causes the introduction of effective spins and Curie-like behavior at lower temperature.…”

“…Studies on Sr-doped LaCoO 3 by Ben Amor et al showed that doping created vacancies at the La 3+ site, resulting in the stoichiometry La 0.7−x x Sr 0.3 CoO 3 [36]. Characterization results showed that the samples are oxygen stoichiometric, the portion of substoichiometric O 2 increases with increasing La deficiency, and the creation of vacancies at La sites leads to a gradual decrease of the unit cell volume.…”