Oxygen content analysis of functional perovskite-derived cobalt oxides

Oxygen and cation ordered perovskite, Ba2Y2Mn4O11

“…It is seen that the weight loss occurs in a single sharp step around 550 -650 o C. Attempts to obtain samples with 0.5 < δ < 1 by means of N 2 annealing at temperatures between 550 and 650 o C all ended up with depletion of oxygen down to the δ ≈ 0.5 level. This is in drastic contrast to the case of the BaRECo 2 O 5+δ double perovskites [13] for which continuous tuning of oxygen nonstoichiometry within 0 < δ < 0.7 is possible by selecting a proper temperature for the N 2 annealing in the temperature range of 300 -1000 o C, i.e. Among these, the first [9,20] and the last [17,22] are close to those reported in Ref.…”

“…For copper, the maximum B-site occupation so far reached is x = 0.7 in (Ba,La)Y(Cu x Fe 1-x ) 2 O 5+δ by means of ultra-high-pressure high-temperature treatment [11]. Of BaREB 2 O 5+δ (B = Co, Fe and Mn), the phases with B = Co are easiest to synthesize: they form in air, O 2 and N 2 atmospheres with most of the REs and exhibit wide and tunable ranges of excess oxygen in the REO δ layer [12,13]. The B = Fe phases require strongly reduced oxygen pressures to form, but allow continuous tuning of the oxygen nonstoichiometry [5,10].…”

Enhancement of giant magnetoresistance effect in the Ruddlesden–Popper phase Sr3Fe2−xCoxO7−δ: predominant role of oxygen nonstoichiometry and magnetic phase separation

“…The oxygen content, 7-δ, was determined by the cerimetric titration technique. Note that the iodometric titration, which has been generally applied for various oxide materials, does not give accurate results due to a small difference in the equilibrium potential between Fe 3+ /Fe 2+ (E 0 = 0.77 V) and 2I -/I 2 (0.54 V) redox couples [13]. The oxidation states of iron were determined from Mössbauer spectroscopy.…”

Room-temperature ferromagnetism inSr1−xYxCoO3−δKobayashi1, Ishiwata2, Terasaki3 et al. 2005Phys. Rev. BSelf Cite9214780View full textAdd to dashboardCite

“…That the resultant oxygen content of the sample represented an equilibrium value (in air) was confirmed by means of thermogravimetric annealing experiments. The oxygen content was determined through iodometric titration [18]. A powdered sample of 20-40 mg was dissolved in 1 M HCl solution (ca.…”