Phase equilibria, crystal structure, oxygen nonstoichiometry and thermal expansion of complex oxides in the Nd 2 O 3 – SrO – Fe 2 O 3 system

Crystal structure and properties of novel oxide Sm0.9Ca1.1Fe0.7Co0.3O4-d

“…In contrast with previously reported SmCaCoO 4-δ [10] and LnSrFeO 4-δ (Ln=La [16], Nd [17,18], Gd [19], Sm [13]), we have failed to synthesize samarium-calcium ferrite with an equimolar Sm / Ca-ratio at 1100 °C in air. It is known that the homogeneity range limits for such solid solu-tions depend significantly on temperature, ionic radius of dopants and oxygen partial pressure.…”

Phase equilibria, structure, oxygen nonstoichiometry, and thermal expansion of oxides in the 1/2Y2O3–SrO–1/2Fe2O3 system

“…A comparison of the 1/2Ln 2 O 3 –SrO–1/2Fe 2 O 3 phase diagrams for the La‐, Nd‐ and Y‐containing systems shows that the width of homogeneity ranges for the Ln x Sr 1− x FeO 3−δ solid solutions in the case of Ln = Y is the smallest on both sides (on the side of LnFeO 3 , and on the side of the cubic phase enriched with Sr). This can be explained by the larger size difference between Sr 2+ and Y 3+ ions ( =1.44−1.075 = 0.365 Å) compared to that for La ( = 1.44−1.36 = 0.08 Å) and Nd ( = 1.44−1.27 = 0.17 Å) .…”

“…The information concerning small‐sized rare earth‐ or yttrium‐based ferrites is limited, although undoped strontium ferrite and yttrium ferrite have been the objects of wide‐ranging studies as magnetic and membrane materials in the last few decades . The wide variety of specific features of phase formation in the related systems and significant differences in the phase diagrams of these systems require detailed study of each system, in particular Y 2 O 3 –SrO–Fe 2 O 3 .…”

“…Summarizing the aforementioned data, one can conclude that the phase equilibria in the Y 2 O 3 –SrO–Fe 2 O 3 system are unclear, and the available information about the homogeneity range in a Sr x Y 1− x FeO 3−δ solid solution is contradictory (the values of x = 0.25 and 0.5 obtained in [] lie outside of the range 0.71 ≤ x ≤ 0.91 reported in []). Therefore, the aims of present work are: (a) the determination of homogeneity ranges and the crystal structure of the solid solutions formed in the 1/2Y 2 O 3 –SrO–1/2Fe 2 O 3 system; (b) the characterization of oxygen content in the obtained solid solutions and determination of its changes with temperature; (c) the determination of thermal expansion for the obtained solid solutions; (d) establishing the phase equilibria in the 1/2Y 2 O 3 –SrO–1/2Fe 2 O 3 system and a comparison of the obtained phase diagram with the related 1/2Ln 2 O 3 –SrO–1/2Fe 2 O 3 (Ln = Nd, La) and 1/2Y 2 O 3 –MO–1/2Fe 2 O 3 (M = Ca, Ba) systems.…”

Flintstone as a nanocomposite material for photonics

“…A large number of papers, both on the subject of analysis of the activation temperature in sintering and inelastic deformation of materials [139,140] and on that of the analysis of solidphase reaction mechanisms [141][142][143][144][145][146][147][148][149][150][151], show that all these solid-phase processes start in the systems only after the nonautonomous phase has transitioned to a liquid-like state, i.e., they are liquid-phase reactions in a sense, as stated in [75,78]. As another example, we can compare the findings from the study of Ruddlesden-Popper phase formation kinetics from different reagents [151][152][153][154][155][156][157][158][159][160][161][162][163][164][165][166][167][168] with data on the values of some temperature transformations in the Ln 2 O 3 -SrO-Al 2 O 3 system [169][170][171][172][173], in which the compounds are formed that are promising for the production of functional and structural high-temperature materials [174][175][176][177]…”