Distribution coefficients in (YSmLuCa)3(FeGe)5O12 film growth

The composition of bubble garnet films has been analyzed by Inductively Coupled Plasma Emission Spectroscopy (ICP) to determine the distribution coefficients for different growth conditions. Under typical growth conditions, the distribution coefficients, k, of each element are as follows: k^Y = 2.15, k^Sm = 1.56, k^Lu = 1.32, k^Ca = 0.45, k^Fe = 0.98, k^Ge = 1.10. As the supercooling temperature (growth rate) increases, k^Ca, which is the smallest and deviates most from 1.0, changes in the direction approaching 1.0. For charge compensation, k^Ge also increases, consequently, k^Fe must decrease. Also k^Y, which is the largest, $\text{k}{}^{\mathrm{Sm}}\text{k}{}^{\mathrm{Y}}$ and $\text{k}{}^{\mathrm{Lu}}\text{k}{}^{\mathrm{Y}}$ change in the direction approaching 1.0. On the other hand, as the melt parameter R₁ (≡ $\text{Fe}{}_2\text{O}{}_3\text{Σ}\text{Ln}{}_2\text{O}{}_3$) increases, k^Fe decreases, and k^Y, k^Sm and k^Lu increase, whereas $\text{k}{}^{\mathrm{Sm}}\text{k}{}^{\mathrm{Y}}$ and $\text{k}{}^{\mathrm{Lu}}\text{k}{}^{\mathrm{Y}}$ remain constant at 0.73 and 0.61, respectively.     

Growth and mobility measurements of (YLuCa)3(FeTiGe)5O12 films for magnetic bubble application

The liquid phase epitaxial growth conditions and properties of garnet films of nominal composition Y_1.8 Lu_0.2Ca_1.0Fe_4.0Ti_0.3Ge_0.7O₁₂ are described. Ca+Ge reduces the lattice parameter when substituted into yttrium-lutetium iron garnet. On the other hand, Ca+Ti increases it. Ca+Ti+Ge additions to the garnet make it easy to match the lattice parameter with the GGG substrate and to obtain stable bubbles. This material has low ferrimagnetic resonance damping loss and high mobility bubbles. The bubble mobility, estimated from the damping parameter and other static bubble properties, is 5626 cm/sec-Oe. This value approximately agrees with that measured by translational field gradient techniques. The bubble translation bias margin at 310 kHz and temperature coefficient of the static bubble properties are reported briefly.     

Shaped single crystal growth and scintillating application of Yb:(Gd,Lu)3(Ga,Al)5O12 solid solutions

Shaped single crystals of (Yb_0.05Lu_xGd_0.95−x)Ga₅O₁₂ (0.0x0.9) and Yb_0.15Gd_0.15Lu_2.7(Al_xGa_1−x)O₁₂ (0.0x1.0) were grown by the modified micro-pulling-down method. Continuous solid solutions with garnet structure and a linear compositional dependency of crystal lattice parameter in the system Yb:(Gd,Lu)₃(Ga,Al)₅O₁₂ are formed. Measured optical absorption spectra of the samples show 4f–4f transitions related to Gd³⁺ ion at 275 and 310 nm, and also an onset of charge transfer transitions from oxygen ligands to Gd³⁺ or Yb³⁺ cations below 240 nm. A complete absence of Yb³⁺ charge transfer luminescence under X-ray excitation in any of the investigated samples was explained by the overlapping of charge transfer absorption of Yb³⁺ by that of Gd³⁺ ions. For specific composition of Lu_1.5Gd_1.5Ga₅O₁₂ an intense defect––host lattice-related emission, which achieve of about 40% integrated intensity compared with Bi₄Ge₃O₁₂, was found.     

The origin of the uniaxial anisotropy in thin films of (YLaPb)3 (FeGa)5O12 and its variation along the growth direction

The uniaxial anisotropy of La, Ga: YIG films grown by liquid phase epitaxy has been measured using spin-wave resonance techniques. The results show that in films produced at growth temperatures above 840°C on [111] Gd₃Ga₅O₁₂ substrates the uniaxial anisotropy is stress induced. At lower growth temperatures the Pb incorporation gives rise to a positive growth-induced anisotropy of 4×10⁴ erg/cm³ per Pb atom per formula unit. Around the growth temperature of 840°C, where the Pb and La effects cancel, homogeneous films can be grown. Variations of anisotropy within the filmsthickness will be shown to be due to variations of local growth rates which in turn cause composition changes.     

Time-resolved spectroscopy of intrinsic luminescence of Y3Ga5O12 and (LaLu)3Lu2Ga3O12 single crystals

The nature of intrinsic luminescence of Y₃Ga₅O₁₂ (YGG) and (LaLu)₃Lu₂Ga₃O₁₂ (LLGG) single crystals grown from a melt was determined. In the case of a YGG single crystal containing Y_Ga antisite defects with a concentration of 0.25–0.275 at.% the intrinsic luminescence was considered as a superposition of luminescence of self-trapped excitons (STE), luminescence of excitons localized near antisite defects (LE(AD) centers) and luminescence caused by a recombination of an electron with a hole captured at Y_Ga antisite defects. Due to a large (2–3%) concentration of Lu_La antisite defects in LLGG single crystals the intrinsic luminescence was a superposition mainly of the LE(AD) center emission and the recombination luminescence of Lu_La antisite defects. The energy structure of the mentioned centers in YGG and LGGG hosts was determined from the excitation spectra of their luminescence under excitation by synchrotron radiation in the range of the fundamental absorption edge of these garnets.     

Etude du systeme KPO3-LaP3O9. Donnees cristal lographiques sur K2La(PO3)5 et (NH4)2La(PO3)5

The system KPO₃-LaP₃O₉ has been studied for the first time by differential thermal analysis and X ray diffraction. The system shows two compounds KLa(PO₃)₄ and K₂La(PO₃)₅ which melt in a peritectic decomposition at 880°C and 770°C respectively. An eutectic point appears at 705°C; The eutectic point corresponds to a concentration of 10% molar LaP₃O₉.Infra Red absorption spectra are typical of chain phosphates.The new compound K₂La(PO₃₅ is isotypic whith (NH₄)₂La(PO₃)₅ which has been synthetized for the first time. They belong to the triclinic system whith space group P1 and Z = 2. The parameters of the unit cell are: $\text{a = 7.309(4)}\text{A}\text{?}$$\text{b = 13.35(2)}\text{A}\text{?}$$\text{c = 7.155(7)}\text{A}\text{?}$α = 90°3(1) β = 109°17(7) γ = 89°90(4) for K₂La(PO₃)₅ and: $\text{a = 7.174(8)}\text{A}\text{?}$$\text{b = 13.38(2)}\text{A}\text{?}$$\text{c = 7.35(2)}\text{A}\text{?}$α = 90°6(2) β = 107°4(1) γ = 89°82(7) for (NH₄)₂La(PO₃)₅.     

Synthesis and structural characterization of (Bi2O3)1?x (Y2O3)x and (Bi2O3)1?x (Gd2O3)x solid solutions

Solid solution series, (Bi₂O₃)_1−x (Y₂O₃)_x and (Bi₂O₃)_1−x (Gd₂O₃)_x, forx = 0.10, 0.20, 0.30 and 0.40 were synthesized by standard ceramic technique. The structural phase characterization was carried out using X-ray powder diffraction technique. It was found that the solid solution containing 20–40 mole% of Y₂O₃ had face-centred cubic structure. All samples of the solid solution series, (Bi₂O₃)_1−x (Gd₂O₃)_x, had rhombohedral single phase in the concentration range 0.10 ≤x ≤ 0.40. Lattice parameters offcc phase of Y₂O₃ doped samples were calculated from the X-ray diffraction data. The lattice constant ‘a’ gradually decreases with increasing content of dopant concentration (x) for the Y₂O₃ doped system and obeys Vegard’s rule. The unit cell parameters for the (Bi₂O₃)_1−x (Gd₂O₃)_x doped samples showing rhombohedral phase were obtained on hexagonal setting.     

Crystal Structure of (H3O)6[(UO2)5(SeO4)8(H2O)5](H2O)5

Crystals of (H₃O)₆[(UO₂)₅(SeO₄)₈(H₂O)₅](H₂O)₅ were prepared from aqueous solutions by evaporation. The crystal structure [monoclinic system, space group P2₁/m, a = 13.835(2), b = 13.4374(16), c = 14.310(3) Å, β = 108.004(14)°, V = 2530.1(7) Å ³] was solved by the direct method and refined to R ₁ = 0.090 for 4409 reflections with |F _hkl ≥ 4σ|F _hkl |. The structure is based on [(UO₂)₅(SeO₄)₈(H₂O)₅]⁶⁻ layers arranged parallel to the (101) plane; these layers have a unique topological structure. The U(1)O₆(H₂O) and U(3)O₆(H₂O) linked through selenate groups form chains running along [ [`1]\bar 1 01] direction. The chains are combined in layers by U(2)O₆(H₂O) bipyramids. The layers are linked with each other by hydrogen bonds through the H₂O and H₃O⁺ groups located between the layers.     

Synthesis of Nanotubular Mg3Si2O5(OH)4-Ni3Si2O5(OH)4 Silicates at Elevated Temperatures and Pressures

Mg₃Si₂O₅(OH)₄-Ni₃Si₂O₅(OH)₄ nanotubes with the chrysotile structure and MgO : NiO molar ratios of 1 : 2 and 2 : 1 are synthesized by hydrothermal reactions at temperatures from 250 to 450°C and pressures from 30 to 100 MPa. The reaction path and kinetics, as well as the dimensions and morphology of the resulting nanotubes, are shown to depend on the nature of the starting reagents, chemical composition of the reaction system, and hydrothermal synthesis conditions. At higher nickel concentrations in the hydrous silicates, nanotube formation requires higher temperatures, longer hydrothermal treatment times, and higher NaOH concentrations in the reaction system.__________Translated from Neorganicheskie Materialy, Vol. 41, No. 7, 2005, pp. 849–855.Original Russian Text Copyright © 2005 by Korytkova, Maslov, Pivovarova, Polegotchenkova, Povinich, Gusarov.     

Growth reproducibility of the bubble properties of (YSmLuCa)3 (FeGe)5 O12 films

Reproducibility of CaGe garnet films grown by LPE is discussed in comparison with that of Ga garnet films. The influence of growth temperature deviation on the properties of CaGe garnet films is not compensated by the adjustment of the substrate rotation rate, although it is effective for Ga garnet film growth. On the other hand, the bubble collapse field of CaGe garnet films is less sensitive to the growth temperature than that of Ga garnet films. Therefore by determining the growth time accurately the bubble collapse field of as-grown films has been controlled within ±1%, even if the growth temperature deviates from the desired value by ±1°C.     

Magnetic anisotropy of V3O5

The magnetic anisotropy of V₃O₅ was investigated by magneto-torque measurements in the temperature range from 4.2 to 300 K. It has been confirmed that the Néel temperature is about 75 K and that two of the three principal axes vary with temperature in both the paramagnetic and antiferromagnetic states. The results are explained on a simplified four-sublattice model.     

Growth and magnetooptical properties of thin garnets films in the system (Pr Gd Yb)3-xBix(Fe Al)5O12

Growth from liquid phase epitaxy and magnetooptical properties of single crystal garnet films in (Pr Gd Yb)_3-xBi_x(Fe Al)₅O₁₂ system are reported. The dependences of the distribution coefficient and the Bi content of the films on the growth temperature are analyzed. The influence of the growth condition on the magnetic and magneto-optical properties of the materials are described and discussed in order to obtain in planemagnetization films having large Faraday rotation (> 1 800 degr./cm) and figure of merit (50 – 80 degr./dB) suitable for integrated magnetooptics application.     

Comparison of Bi3Fe5O12 film giant Faraday rotators grown on (111) and (001) Gd3Ga5O12 single crystals

Bismuth iron garnet (Bi₃Fe₅O₁₂, BIG) epitaxial thin films were grown on single crystal (Gd₃Ga₅O₁₂, GGG) (111) and (001) substrates by rf-magnetron sputtering technique. Processing parameters have been optimized to obtain high deposition rate (2.74 μm/h) and the surface rms roughness less than 10 nm. X-ray diffraction reveals films epitaxial quality: exclusive (111) or (001) orientation with narrow rocking curves and strong in-plane texture. Films possess low optical loss and magneto-optical Faraday rotation (FR) as high as 5 deg/μm at 677 nm wavelength. Comparative analysis of films grown on (111) and (001) substrates clearly shows significant superiority of BIG/GGG(001) film. For this film, the coercive field ∼100 Oe appears to be 2.5 times lower while the optical transmission to be 10% higher than that for BIG/GGG(111) film. Enhanced magneto-optical performance of BIG/GGG(001) films relies upon better accommodation of the film-to-substrate mismatch strain through the tetragonal BIG lattice distortions compared to the rhombohedral one in BIG/GGG(111) films.     

Solvothermal synthesis of In(OH)3 nanorods and their conversion to In2O3

In this work, we demonstrate that monodisperse indium hydroxide (In(OH)₃) nanorods constructed with parallel wire-like subunits have been fabricated via a acrylamide-assisted synthesis route without any template. NH₃ from the hydrolysis of acrylamide acts as the OH⁻ provider. The structure and morphology of as-prepared products have been characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and thermogravimetric analysis (TG). A detailed mechanism has been proposed on the basis of time-dependent experimental results. Furthermore, by annealing In(OH)₃ precursors at 500 °C for 3 h in air, In₂O₃ samples were obtained with the designed morphology.     

Control of properties during the growth of a large number of (Y,Sm)3(Ga,Fe)5O12 films from the same melt

For the growth of a large number of (Y, Sm)₃(Ga, Fe)₅O₁₂ films from the same melt, we describe the drift and methods to control the drift in film properties, so that the films are suitable for making magnetic bubble memory devices. The melt was based on PbO-B₂O₃ flux. The film thickness h and the characteristic length l were kept at around 5.4 μm and 0.54 μm respectively. The desired h was achieved by adjusting the growth time. The desired values for l were achieved by adjusting the growth temperature and by periodically adding small amounts of Ga₂O₃. The lattice constant was kept within the specified limits by periodic additions of Y₂O₃. Using these techniques we were able to grow more than a hundred films, out of which ～ 85% were acceptable for device fabrication. Based on the deduced values for the composition of our films, we have calculated the melt depletion resulting from the growth of a single film. We find that the experimentally determined additions of Ga₂O₃ and Y₂O₃ that gave us good control over film properties are almost equal to the calculated depletions for these two oxides.     

Solid-state field-assisted silver diffusion in (TeO2)0.6(WO3)0.25(La2O3)0.05(Na2O)0.1 glass

Silver-doped layers have been produced in (TeO₂)_0.6(WO₃)_0.25(La₂O₃)_0.05(Na₂O)_0.1 (TWLN) glass by solid-state field-assisted diffusion. The silver concentration profile in the glass has been determined by secondary ion mass spectrometry (SIMS) and Rutherford backscattering spectrometry (RBS). The Matano-Boltzmann method applied to thermally activated diffusion indicates that the silver diffusion coefficient in the glass is a weak function of silver concentration. We carried out modeling of silver concentration profiles in the doped layer of the TWLN glass after solid-state field-assisted diffusion. Good agreement of the theoretical fit and experimental data suggests that the model chosen can be used to describe solid-state field-assisted diffusion of silver ions in TWLN glasses. Using RBS data, we have quantitatively estimated the surface density of silver atoms after field-assisted diffusion. Combining SIMS and RBS, we were able to assess the absolute silver concentration depth profile. Our results demonstrate that field-assisted diffusion, a simple and effective procedure for doping optical glasses, can be used to produce planar waveguide structures based on the tellurite glass studied here.     

Crystal growth and characterization of Yb-doped Gd3Ga5O12

Single crystals of (Yb_xGd_1−x)₃Ga₅O₁₂ (0.0 ≤ x ≤ 1.0) have been grown by the micro-pulling-down method. Formation of continuous solid solutions with a garnet structure was confirmed. Composition dependence of the lattice constant, thermal diffusivity, specific heat capacity and thermal conductivity was investigated. Assignment of the Yb³⁺-energy levels in Gd₃Ga₅O₁₂-host lattice has been performed by using absorption, emission and Raman spectroscopy measurements at both, room temperature and at 12 K.     

Larger Ba(NO3)2/Sr(NO3)2 crystal growth and solubility determination

The solubility of Ba(NO₃)₂ and Sr(NO₃)₂ crystals in aqueous solution from 25 to 65 °C has been determined by both an optical interferometer and a weight technique. A Mach-Zehnder interferometer was used for measuring the concentration distribution of Ba(NO₃)₂ and Sr(NO₃)₂ near the solid/liquid interface during crystal growth and dissolution. A fringe carrier technique was introduced to visualize more clearly the boundary layer and to solve the concentration distribution. Crystals were successfully grown with sizes larger than  mm by a temperature cooling method. The Ba_xSr_1−x(NO₃)₂ crystal was also nucleated and grown. The Raman spectra of Ba_xSr_1−x(NO₃)₂ indicate that the barium ions probably degrade the properties of Sr(NO₃)₂.     

Fex（In2O3）1—x磁性颗粒膜的结构及光学性质

用射频溅射法制备了金属／半导体Fex(In2O3)1-x颗粒膜。实验结果表明：纳米尺度的Fe颗粒比较均匀地分布在非晶态母体In2O3中。退火可使In2O3晶化。该样品在室温下表现出超顺磁驰豫,符合Langevin方程。光学测量表明：嵌Fe的磁性颗粒膜,其电子的带间跃迁由In2O3的直接跃迁变为间接跃迁,基本吸收边红移;随磁性增强,局域态尾变宽,带隙变窄。