Tailoring Oxygen Content on PrBaCo2O5+ä Layered Cobaltites

C. FRONTERA; A. CANEIRO; A.E. CARRILLO; J. ORÓ SOLÉ; J.L. GARCÍA MUÑOZ

CHEMISTRY OF MATERIALS

AMER CHEMICAL SOC

Lugar: Washington; Año: 2005 vol. 17 p. 5439 - 5445

0897-4756

The LnBaCo2O5+ä cobaltites with ordered A-site cations exhibit a very rich phase diagram as a functionof the oxygen content, which determines the doping of CoO2 planes. By means of thermogravimetryanalysis (TGA), we study the appropriate way to tailor oxygen contents in PrBaCo2O5+ä compounds.Starting from an air-synthesized sample, we study the evolution of ä during different heat treatmentswith “in situ” TGA measurements. We find that ä can be tailored from ä = 0.2 to ä = 0.9.Thermogravimetry measurements also show that oxygen ions can flow through (0 0 1) PrOä planes atrelatively low temperatures (200 °C, this temperature increases in compounds with smaller rare earths).By means of neutron powder diffraction at room temperature, we determine the structural details andstudy the eventual order of oxygen vacancies for different values of ä.