The study of defects observed in substrates with gadolinium gallium garnet (GGG) with orientations (110), (100) and (111) and in epitaxial films grown of iron-yttrium garnet (YIG) were investigation. It is shown that the line width ferromagnetic resonance strongly depends on the presence of defects in YIG films. It was established that the highest quality and minimal magnetic losses have YIG films with a thickness of 2...8 mm grown on GGG defect-free substrates with orientation (111), which were grinding and polishing the surface to 14 grade purity.
Comparative NGR study of the parameters of the magnetic hyperfine structure of epitaxial films grown on single-crystal substrates of orientations of (100) and (111) by liquid phase epitaxy (LPE) and chemical transport reactions (CTR) is conducted. It is established that in the films obtained by the method of CTR, there is a significant number of ions of bivalent iron, which is in phase magnetite . After heat treatment of these films in air at T = 1273 K, the magnetite becomes the oxide. In the films of , grown by the LPE method the divalent iron was not detected.
As shown by calculations, the vector direction of the magnetization of films obtained by the method of LPE, lies in the film plane regardless of the orientation (100) or (111) substrates. In films obtained by the CTR method, it forms with the substrate 41 - 450.
Alloys with the general formula TiCo2-хSn were produced by way of sintering primary components – pure metals in an argon atmosphere. The alloys were homogenized by annealing in the evacuated quartz vessel at T=1070 K during 500 h. X-ray diffraction analysis confirmed single-phase condition of all samples. Nuclear gamma resonance (NGR) analysis was made at T=295 and 80 K using radiation source BaSn119Sn. It was established, that Sn atoms in samples with x=0.6 and 1.0 are in two crystallographic positions, pyramids (1) and tetrahedrons (2) to which isomer shifts correspond (relative to SnO2 1.52-1.65 mm/s for Sn(1) and 2.99 mm/s for Sn(2). Zeeman splitting for Sn(1) in TiCo2Sn takes place at T=295 and 80 K, and for compositions with x=0.3-1.0 at T=80 K only. For Sn(2) it is noted only in alloy TiCoSn at T=80 K. The conclusion has been made on the reason of formation of effective magnetic fields on non-magnetic tin atoms nuclei.
In article present the results of low-temperature Mossbauer studies of iron (III) oxide/hydroxide nanocomposite synthesized by the method of deposition. Based on these studies, the composition of the synthesized composite was revealed. The nanodispersed composite with a specific surface 280 m2/g is a hematite in the weakly disordered crystalline state (CSR 10 nm), and a lepidocrocite in the X-ray amorphous state (particles size 3-4 nm). The relative integral intensity of the Zeeman sextet, which corresponds to the magnetically ordered phase of hematite, is practically unchanged and is about 17%. The tendency to divide the magnetically ordered component into two sextets, which differ in quadrupole splitting QS= –0.21 mm/s and QS= 0.21 mm/s, respectively, is observed starting from a temperature of 190 K. As a result of annealing of the synthesized material at a temperature of 200°C, a slight redistribution (≈ 5%) of the content of paramagnetic and magnetically ordered components was recorded, which indicates the structural stability of the nanoparticles of the lepidocrocite γ-FeOOH phase at this temperature. Increase of annealing temperatures to 500oC leads to the predicted course of the phase transition γ-FеООH ® α-Fе2О3. The mechanism of growth of hematite crystallites during sintering due to fixation side faces of larger α-Fe2O3 phase of nanoparticles of the γ-FeOOH phase with simultaneous transformation of their crystal structure to side faces of larger α-Fe2O3 phase particles is presented.
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