Abstract
In this project four oxide systems have been studied with focus on synthesis and characterization; LaxSr4-xFeO10-δ(0.00 ≤ x ≤ 1.00), LaSr3Fe3-yMnyO10-δ (0.50 ≤ y ≤ 1.50), Sr4Fe3--z(CO3)zO10-4z-δ (0.00 ≤ z ≤ 1.00) and SrFeO2.0. The RP 3 series of the La-Sr-Fe-O system, LaxSr4-xFe3O10-δ, have been investigated by means of phase purity and extension of the solid solution region. Samples have been synthesized by three different synthesis routes, two complexation routes and the ceramic route. All samples have been characterized by PXRD, and Rietveld refinements have been conducted on selected samples to confirm crystal structure and to extract unit cell dimensions. To evaluate the possible incorporation of carbonate into the cationic lattice of the oxide, ATR FT-IR has been conducted on selected LaxSr4-xFe3O10-δ samples. Oxygen content of as-synthesized La1.0Sr3.0Fe3O10-δ and oxygen vacancy concentration (δ) versus temperature is determined by cerimetric titration and TGA, respectively. Selected compositions in the RP 3 like oxycarbonate series Sr4Fe3-z(CO3)zO10-4z-δ (0.00 ≤ z ≤ 1.00) were synthesized by several different methods for different z values. All samples have been characterized by PXRD, and the phase pure z = 1.00 also by NPD, PSXRD, ATR FT-IR and TGA. The existence of z = 0.00 member of Sr4Fe3-z(CO3)zO10-4z-δ or the x = 0.00 member of LaxSr4-xFe3O10-δ is evaluated and discussed. An initial screening study with respect to synthesis conditions is reported for the LaSr3Fe3-yMnyO10-δ (0.50 ≤ y ≤ 1.50) RP 3 series. Syntheses were performed by a complexation route and characterization was done by PXRD and phase identification by Rietveld refinements. SrFeO2.0 has been tried prepared by topotactic reduction SrFeO2.8 using different reducing agents/oxygen getters. Samples have been characterized by PXRD and cerimetric titration.