Synthesis, magnetic and luminescent properties of Nd[1–x]La[x]GaO[3] (0.7 ≤ х ≤ 1.0) solid solutions

Nd[1–x]La[x]GaO[3] (0.7 < х < 1.0) solid solutions were synthesized by the ceramic method, their crystal structure, magnetic and luminescent properties were investigated. The solid solutions investigated behave as paramagnetics in temperature region of 5–300 K. Calculated values of Nd{3+} ion effective magnetic moment in solid solutions investigated are lower than theoretical. There probably exists „partial freezing” of orbital moment of Nd{3+} ions by the crystal field of the orthorhombically distorted perovskite structure of Nd[1–x]La[x]GaO[3] gallates. It is shown that Nd[0.1]La[0.9]GaO[3] is an efficient phosphor with IR-emission, so it is prospective for use in IR-LEDs

Crystal structure and magnetic properties of highly-coercive Sr[1–x]Gd[x]Fe[12–x]Zn[x]O[19] ferrites

High-coercivity ferrite samples Sr[1–x]Gd[x]Fe[12–x]Zn[x]O]19] (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) with magnetoplumbite structure were prepared from oxides Fe[2]O[3], Gd[2]O[3], ZnO and carbonate SrCO[3] by solid-state ceramic method, the dependence of the unit cell parameters aand con the value of xwas determined. XRD showed that the samples with x >0.1 were not single-phase, and the samples with x > 0.2 contained not only bases phase with the structure of magnetplumbite, but also the a-Fe[2]O[3] and Gd[3]Fe[5]O[12] phases. It was found that increase of the xvalue leads to a slight decrease in the Curie temperature (from 727 K for the basic ferrite SrFe[12]O[19] to 714 K for Sr[1–x]Gd[x]Fe[12–x]Zn[x]O[19] solid solution with x = 0.5). It has been found that at 300 K values of spontaneous magnetization (no) and coercive force (?Hc) of solid solution Sr[0.9]Gd[0.1]Fe[11.9]Zn[0.1]O[19] are respectively 1.3 and 2.3% higher than for the base ferrite SrFe[12]O[19], and values of samples with x > 0.1 of these magnetic properties decreases gradually

ПОСЛЕДОВАТЕЛЬНОСТЬ ФАЗОВЫХ ПРЕВРАЩЕНИЙ ПРИ КРИСТАЛЛИЗАЦИИ МАТЕРИАЛА СОСТАВА Sr2FeMoO6-δ ИЗ ПРЕКУРСОРОВ

The sequence of phase transformations during Sr2FeMoO6-d crystallization by solid phase method was studied for powders synthesized from the stoichiometric mixture of SrFeO3- x and SrMoO4 precursors. It was found that the synthesis of strontium ferromolybdate solid solution proceeds through a series of parallel chemical reactions. Reveals that at the beginning stage of interaction the initially formed Sr2FeMoO6-δ powder is enriched with iron. During the annealing process, the composition of strontium ferromolybdate changes and the molybdenum content increases upon further heating. It was found that the use of precursors reduces the annealing temperature.Исследована последовательность фазовых превращений в процессе кристаллизации материала состава Sr2FeMoO6-d твердофазным методом из стехиометрической смеси прекурсоров SrFeO3-х и SrMoO4. Установлено, что синтез материала состава Sr2FeMoO6-d протекает через ряд последовательно-параллельных стадий. Причем на начальном этапе взаимодействия образующийся материал состава Sr2FeMoO6-d обогащен железом и его состав в ходе реакции изменяется в сторону увеличения содержания молибдена. Показано, что использование прекурсоров способствует уменьшению температуры отжига

Crystal structure and magnetic properties of highly-coercive Sr[1–x]Gd[x]Fe[12–x]Zn[x]O[19] ferrites

High-coercivity ferrite samples Sr[1–x]Gd[x]Fe[12–x]Zn[x]O]19] (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) with magnetoplumbite structure were prepared from oxides Fe[2]O[3], Gd[2]O[3], ZnO and carbonate SrCO[3] by solid-state ceramic method, the dependence of the unit cell parameters aand con the value of xwas determined. XRD showed that the samples with x >0.1 were not single-phase, and the samples with x > 0.2 contained not only bases phase with the structure of magnetplumbite, but also the a-Fe[2]O[3] and Gd[3]Fe[5]O[12] phases. It was found that increase of the xvalue leads to a slight decrease in the Curie temperature (from 727 K for the basic ferrite SrFe[12]O[19] to 714 K for Sr[1–x]Gd[x]Fe[12–x]Zn[x]O[19] solid solution with x = 0.5). It has been found that at 300 K values of spontaneous magnetization (no) and coercive force (?Hc) of solid solution Sr[0.9]Gd[0.1]Fe[11.9]Zn[0.1]O[19] are respectively 1.3 and 2.3% higher than for the base ferrite SrFe[12]O[19], and values of samples with x > 0.1 of these magnetic properties decreases gradually

Synthesis, magnetic and luminescent properties of Nd[1–x]La[x]GaO[3] (0.7 ≤ х ≤ 1.0) solid solutions

Nd[1–x]La[x]GaO[3] (0.7 < х < 1.0) solid solutions were synthesized by the ceramic method, their crystal structure, magnetic and luminescent properties were investigated. The solid solutions investigated behave as paramagnetics in temperature region of 5–300 K. Calculated values of Nd{3+} ion effective magnetic moment in solid solutions investigated are lower than theoretical. There probably exists „partial freezing” of orbital moment of Nd{3+} ions by the crystal field of the orthorhombically distorted perovskite structure of Nd[1–x]La[x]GaO[3] gallates. It is shown that Nd[0.1]La[0.9]GaO[3] is an efficient phosphor with IR-emission, so it is prospective for use in IR-LEDs

THE SEQUENCE OF PHASE TRANSFORMATIONS DURING THE CRYSTALLIZATION MATERIAL WITH COMPOSITION Sr₂FeMoO_6-_δ FROM PRECURSORS

The sequence of phase transformations during Sr2FeMoO6-d crystallization by solid phase method was studied for powders synthesized from the stoichiometric mixture of SrFeO3- x and SrMoO4 precursors. It was found that the synthesis of strontium ferromolybdate solid solution proceeds through a series of parallel chemical reactions. Reveals that at the beginning stage of interaction the initially formed Sr2FeMoO6-δ powder is enriched with iron. During the annealing process, the composition of strontium ferromolybdate changes and the molybdenum content increases upon further heating. It was found that the use of precursors reduces the annealing temperature