T. I. Chupakhina

Synthesis and magnetic properties of a new layered oxide La1.5Sr1.5Mn1.25Ni0.75O6.67

A new oxide phase La1.5Sr1.5 Mn1.25Ni0.75O6.67 ± 0.05, a member of the An + 1 BnO3n+1(n=2) Rad-dlesden—Popper homologue series, was synthesized, and its structure and magnetic properties characterized. Magnetic anomalies associated with the competition between antiferromagnetic and ferromagnetic orders are observed in the range of the temperatures studied (2-400 K). The ESR spectra of the compound feature the constriction of a magnetic signal and a shift toward g(Mn4+).

New ways to synthesize multifunctional ceramics La2 - x Sr x NiO4

A study was made of specific features of the formation of multifunctional ceramics La2 - xSrxNiO4 in thermal decomposition of carboxylate precursor complexes of several types. Pyrolysis of organics–salt composites is initiated by catalytic decarboxylation under the action of a d-element (Ni) to form metal oxides in the active state. It was shown that the synthesis of solid solutions La2 - xSrxNiO4 from carboxylate precursors occurs by single-stage thermolysis using any carboxylic acid or its salt.

Synthesis, crystal and electronic structures, and thermodynamic characteristics of BaCe1 − xInxO3 − x/2 solid solutions

New perovskite oxide phases BaCe1 − xInxO3 − x/2 (x = 0.1–0.8) (space group Pbnm) have been synthesized. The unit cell volume of the resulting solid solutions monotonically decreases with an increase in the degree of substitution of indium for cerium due to the contraction of octahedra in perovskite blocks. The thermodynamic stability of the compound BaCe0.75In0.25O2.875 was studied by the solution calorimetry method, and barium cerates were shown to be thermodynamically stable with respect to binary oxides at room temperature. The structure of occupied and vacant states in BaCe1 − xInxO3 − x/2 was determined on the basis of X-ray emission, absorption, and photoelectron spectra, and the energy gap was estimated at ∼2 eV.

Synthesis and magnetic properties of the complex oxide La1.5Sr1.5CuMnO6.67

A new oxide phase, La1.5Sr1.5CuMnO6.67, related to the Ruddlesden-Popper homologous series An + 1BnO3n + 1 (n = 2) was synthesized. The magnetic susceptibility of the obtained compound obeys the Curie-Weiss law above 114 K. At 14 K, a magnetic anomaly related to the transition to the spin-glass state was detected.

La 1.8 Sr 0.2 Ni 0.8 M 0.2 O 4 (M = Fe, Co, or Cu) Complex Oxides: Synthesis, Structural Characterization, and Dielectric Properties

New solid solutions La1.8Sr0.2Ni0.8M0.2O4 (M = Fe, Co, or Cu) have been prepared, and their crystal- chemical characteristics and electric properties studied. The studied materials have been shown to have activation-time conductivity. Structural distortions have been found to affect the dielectric properties of ceramic samples. La1.8Sr0.2Ni0.8M0.2O4 is observed to have the greatest distortion of АО9 coordination polyhedra and a higher dielectric constant.

Phase formation features and magnetic properties of complex oxides in the systems Sr-Co-M-O (M = Zn, Cu)

It was shown that, in the systems Sr-Co-M-O (M=Zn, Cu), the first stage of the crystallization of solid solutions Sr3Co2 − xMxO6 with a tetragonal structure of the Ruddlesden-Popper type is the formation of quasi-one-dimensional oxides of the family A3m+3nAn′B3m+nO9m+6n. The magnetic properties of new compounds, Sr3Co1.35Cu0.65O6 and Sr14Co8.4Cu2.6O33, were measured, and a relationship between the structure and the existence of magnetic ordering at low temperatures was established.