About the nature of Ni3+ magnetic centres in the LaSrAl1−xNixO4 ceramics

LaSrAl_1?x Ni _x 0₄ (x≤0.11) ceramics werer studied by EPR. It was established that Ni³⁺ ions in this compound may be in two states: a low spin one with t _2g ⁶ e _g ¹ electron configuration and high spin state with t _2g ⁵ e _g ² electron configuration. It was shown that the random distribution of La³⁺ and Sr²⁺ ions in the heavy metal sublattice leads to two kinds for each type of these centres with different degree of tetragonal distortions. The total concentration of NiO₆ isolated centres in these ceramics does not exceed 5–10 % of a total number of nickel ions at a givenx. A model, explaining these peculiarities observed in an experiment by the enhanced tendency of Ni³⁺ ions to clusterization, was proposed. It appears that even at small concentrations Ni³⁺ ions form clusters and conglomerates, whose structural characteristics of the oxygen octahedra are comparable with those in LaSrNiO₄.     

State of atoms of transition elements in dilute solid solutions based on LiMO2 (M = Sc, Ga, Al): I. Magnetic properties of LiFe x Sc1? x O2

Magnetic properties of solid solutions of the double oxide LiFeO₂ in a diamagnetic solvent LiScO₂ were studied. The observed anomalies in the magnetic parameters can be accounted for by the formation of nanoclusters of iron, oxygen, and lithium atoms. Original Russian Text ? N.P. Bobrysheva, A.A. Selyutin, 2007, published in Zhurnal Obshchei Khimii, 2007, Vol. 77, No. 6, pp. 890–894.     

Thermal stability and features of the synthesis of mixed ceramic oxides La2−x Sr x CoO4

Thermal behavior of the mixed oxides La_2?x Sr _x CoO₄ (0.1 < x < 1.5) in the temperature range 1200–1700 K was studied. The use of the ceramic synthesis method makes it possible to obtain homogeneous samples at the calcination temperature of 1673 K. It was found by the high-temperature mass-spectrometry method that a charge can be depleted of cobalt oxide during the high-temperature synthesis.