Coherent intergrowth of simple cubic and quintuple tetragonal perovskites in the system Nd2−Ba3+(Fe,Co)5O15−

Phase equilibria in the Nd2O3–BaO–Fe2O3 system: Crystal structure, oxygen content, and properties of intermediate oxides

“…The obtained results are in good agreement within the experimental error with the data measured earlier. 52,55 Using TGA data for Nd 1-x Ba x FeO 3-δ (x = 0.6 and 0.7) taken from our earlier works 52,55 and the absolute (3 -δ) values at room temperature from the present work, the mean oxidation state of iron ions was calculated (Figure 2). One can see that the average oxidation state of iron ions decreases with increasing temperature gradually approaching 3+ value due to…”

“…However, earlier a transmission electron microscopy examination of Nd 0.4 Ba 0.6 FeO 3-δ revealed a presence of separate domains with a p × a p × 5a p superstructure, where a p is the parameter of basic perovskite, distributed in the matrix of A-site disordered perovskite. 52 These domains adopt the tetragonal structure which forms due to the ordering of Nd and Ba cation along c-axis in the quite regular sequence "Nd-Ba-(Nd,Ba)-(Nd,Ba)-Ba-Nd", where pure Ba and pure Nd layers alternate with mixed (Nd,Ba) layers. This type of superstructure, first found in SmFeO 3-δ -BaFeO 3-δ system and presented by formula Sm 2-ε Ba 3+ε Fe 5 O 15-δ , 53 is very sensitive to a number of factors, such as size difference and ratio of A-site cations (Ln/Ba), cobalt substitution in B-site sublattice, oxygen content.…”

Introducing Barium in Transition Metal Oxide Frameworks: Impact upon Superconductivity, Magnetism, Multiferroism and Oxygen Diffusion and Storage

“…In fact this quintuple perovskite was shown from a combined HREM and energy electron loss spectroscopy (EELS) study to exhibit a unique nanoscale ordering of the Ba and Sm layers according to the five‐fold sequence “Ba−Ln‐Ba‐A−A‐Ba”, where A is a mixed layer containing ∼ 50 % Ba/ 50 % Sm, with together nanoscale chemical twinning, forming 90° oriented nanodomains (Figure ). This layered perovskite structure was also shown to exhibit significant oxygen deficiency (δ ∼ 0.75) and could be extended to other lanthanides Ln= Eu, Nd by stabilizing the structure with cobalt in the octahedral sites, according to the formulation Ln 2 Ba 3 Fe 5‐X Co x O 15‐δ …”

Synthesis, Crystal Structure, and Properties of NdNi0.5Mn0.5O3−

“…The temperature dependence of oxygen non-stoichiometry for NdNi 0.5 Mn 0.5 O 3− was obtained by thermogravimetric analysis (TGA) using a Netzsch STA 409 PC instrument in the temperature interval of 25-1100 ∘ C. The absolute value of oxygen content at room temperature was calculated from the results of iodometric titration performed with Akvilon (АTP-02) as described previously [7]. The total conductivity and Seebeck coefficient measurements were carried out simultaneously using the standard 4-probe DC technique with Pt wire leads.…”