Short- and long-range order in La1−xSrxCoO3 and La1−xBaxCoO3

Chemical and electronic characterization of cobalt in a lanthanum perovskite. Effects of strontium substitution

“…In fact, the structural data included also in the scheme, obtained from XRD (10) show a higher Co-Co distance in the Sr-substituted perovskite, compatible with a small expansion of the cell. This distance is closer to twice the Co-O distance in the [CoO 6 ] octahedron, showing that, as recognized recently by other authors [13], the Co-O-Co bond angle has increased, approaching the ideal 1801 in cubic structures. As a result, almost no distortion occurs in the rhombohedrical structure of the La 0.5 Sr 0.5 CoO 3À d substituted perovskite.…”

“…They are also interesting for their catalytic properties in the oxidation of hydrocarbon and soots, and the decomposition of nitrogen oxides [10]. Moreover, some authors have found that the low spin configuration of the LaCoO 3 perovskite at room temperature changes to a higher spin configuration by increasing the temperature or introducing Sr(II) atoms, also associated with changes in magnetic and conducting properties [11][12][13][14][15]. In spite of that, there is no general agreement about the origin of these relevant characteristics.…”

Ferromagnetic state of La1−xBaxCoOFita1, Szymczak2, Puźniak3 et al. 2011Phys. Rev. B261190View full textAdd to dashboardCite

“…8) and the average value ω ≈ 5 • reported for Sr-and Ba-doped cobaltites, 30 we have evaluated that dT C /dP changes sign at cf /W ≈ 0.38. That is to say, dT C /dP >0 when the bandwidth W is large enough as compared to the e g -t 2g energy so that the t 2g level lies within the bandwidth of the e g electrons; therefore the population of the higher spin state does not decrease under pressure despite increasing cf .…”

Emerging Strategies for Developing High-Performance Perovskite-Based Materials for Electrochemical Water Splitting

“…Specifically, the best reported perovskite OER electrocatalysts suffer a minimum theoretical overpotential of 300–400 mV that originates from the scaling relationship . The lattice-oxygen mechanism (LOM), in which surface oxygen is activated as a highly active site for the OER, can subtly circumvent the redox switching of 3d transition-metal sites. ,, Furthermore, the LOM is closely related to the metal–oxygen covalency. ,, For example, LaCoO 3 is quite stable under OER conditions and follows the traditional AEM. However, the scaling relationship between *OOH and *OH can be broken for La 0.6 Sr 0.4 CoO 3 .…”