Search

A series of Y3+xAl5O12 (−0.12 ≤ x ≤ 0.12) ceramics were prepared via a solid-state reaction under a vacuum sintering environment to investigate the impact of variations in different cation composition on the phase composition, microstructure, and microwave dielectric properties of yttrium aluminum garnet (Y3Al5O12; YAG) ceramics. X-ray diffraction analyses revealed that Al2O3 precipitates in the Al-excess samples. In contrast, the YAlO3 secondary phase appeared in the Y-excess samples, and variations in the content of both contributed to an increase in lattice parameters. The Rietveld refinement results showed that the lattice parameters and unit cell volume increased as the |x| value increased. The secondary phases of granular Al2O3 and YAlO3 crystallized at the extended grain boundaries in samples with excess Al and Y were visible in the scanning electron microscopy images. The electron diffraction patterns confirmed that a small amount of Y2O3 promoted continuous phase boundaries and facilitated the release of internal stresses. Ultimately, after sintering at 1750 °C for 12 h and at x = 0.03, the microwave dielectric properties of the non-stoichiometric YAG ceramic sample were er = 11.18, Q×f = 236936 GHz, and τf = −35.9 ppm/℃.

Fluoride ion (F−) is one of the most hazardous elements in potable water. Over intake of F− can give rise to dental fluorosis, kidney failure, or DNA damage. As a result, developing affordable, equipment-free and credible approaches for F− detection is an important task. In this work, a new three dimensional rare earth cluster-based metal-organic framework assembled from lanthanide Y(III) ion, and a linear multifunctional ligand 3-nitro-4,4′-biphenyldicarboxylic acid, formulated as {[Y(μ3-OH)]4[Y(μ3-OH)(μ2-H2O)0.25(H2O)0.5]4[μ4-nba]8}n (1), where H2nba = 3-nitro-4,4′-biphenyldicarboxylic acid, has been hydrothermally synthesized and characterized through infrared spectroscopy (IR), elemental and thermal analysis (EA), power X-ray diffraction (PXRD), and single-crystal X-ray diffraction (SCXRD) analyses. X-ray diffraction structural analysis revealed that 1 crystallizes in tetragonal system with P4¯21m space group, and features a 3D framework with 1D square 18.07(3)2 Å2 channels running along the [0,0,1] or c-axis direction. The structure of 1 is built up of unusual eight-membered rings formed by two types of {Y4O4} clusters connected to each other via 12 μ4-nba2− and 4 μ3-OH− ligands. Three crystallographic independent Y3+ ions display two coordinated configurations with a seven-coordinated distorted monocapped trigonal-prism (YO7) and an eight-coordinated approximately bicapped trigonal-prism (YO8). 1 is further stabilized through O-H⋯O, O-H⋯N, C-H⋯O, and π⋯π interactions. Topologically, MOF 1 can be simplified as a 12-connected 2-nodal Au4Ho topology with a Schläfli symbol {420·628·818}{43}4 or a 6-connected uninodal pcu topology with a Schläfli symbol {412·63}. The fluorescent sensing application of 1 was investigated to cations and anions in H2O. 1 exhibits good luminescence probing turn-on recognition ability toward F− and with a limit detection concentration of F− down to 14.2 μM in aqueous solution (Kec = 11403 M−1, R2 = 0.99289, σ = 0.0539). The findings here provide a feasible detection platform of LnMOFs for highly sensitive discrimination of F− in aqueous media.

The increasing demand for high-purity rare earths and their compounds induced the separation technology of rare earths promotion. In this work, the mixtures of sec-nonylphenoxy acetic acid (CA100) and alkylated phosphine oxides (Cyanex923 and Cyanex925) were used as extractants instead of single CA100 for high-efficiency extraction of rare earths from chloride medium. Compared with single CA100 system, the mixtures of CA100 and Cyanex923/Cyanex925 could improve the extraction selectivity of Yttrium (Y) from the lanthanoids based on their separation factors. The evident synergistic effects on lanthanum (III) with CA100 and Cyanex923 were investigated by using the methods of slope analysis and constant mole to determine the extraction reaction. The reaction product, equilibrium constants, formation constants, and the thermodynamic functions were determined. The synergistic extraction of lanthanum (III) with CA100 and Cyanex923 was proved to be endothermically driven.

The growth of high-quality and large-size cerium-doped lutetium yttrium orthosilicate (Ce:(LuY)2SiO5, Ce:LYSO) crystals with lower cost has great influence on their applications in various physical devices. According to the chemical bonding theory of single crystal growth, the fast thermodynamic growth direction of Ce:LYSO is [010] direction. In this work, the maximum pulling rate of 3.5 mm/h is obtained along [010] direction of Ce:LYSO via the Czochralski (Cz) method. Finally, Ce:LYSO bulk single crystals with diameter of 64 mm and length of 220 mm and mass of 4.2 kg are grown. The luminescence performance of low-doped Ce:LYSO for nuclear irradiation (22Na) detector device was studied. Light yield of 26193 ph/MeV and decay time of 38 ns were obtained. The present work provides a promising fast growth approach to achieving large size functional bulk crystal via both thermodynamic and kinetic controls.

Undoped and Y-doped CuSe with different dopant concentration (0.01–0.04 mol%) have been successfully synthesized using selenium (IV) oxide (SeO2), copper (II) sulfate pentahydrate (CuSO4⋅5H2O), and yttrium as sources of Cu2+, Se2−, and Y3+ ions, respectively, on glass slides via spray pyrolysis method. The impact of yttrium doping on the structural, compositional, morphological, electrical, and optical properties of CuSe were studied using X-ray diffractormeter, Scanning electron microscopy-SEM, Energy dispersive X-ray spectroscopy-EDX, four-point probe, and 756S UV–Visible spectrophotometer accordingly. The XRD result reveals that the deposited thin materials exhibited a polycrystalline cubic structure with preferred orientation along (200), while the EDX result affirms the existence of the fundamental elements deposited. The electrical studies result supported the fact that the thin films are semiconductors. The optical results revealed high absorbance, low transmittance, and narrowed energy band gap of CuSe films after adding yttrium dopant. Undoped CuSe recorded an energy band gap value of 3.0 eV which experienced a declined range from 2.81 to 2.50 eV upon Y doping. Addition of Y dopant was seen to improve the crystallinity of the films and narrowed the energy band gap of undoped CuSe, thereby boosting the performance of YCuSe for use as photovoltaic material and also a more reliable material for absorber layer in solar energy collection.

The saturated and unsaturated vapor pressures of tris(2,2,6,6-tetramethylheptane-3,5-dionato)yttrium(III), Y(thd)3, were measured by the static method with a membrane null-manometer in wide ranges of temperature (179.5–418°C) and pressure (300–5220 Pa). The average molecular weight of the compound in unsaturated vapor calculated from the obtained data unambiguously indicates that the gas phase above the liquid compound consists of the Y2(thd)6 dimer molecules. It follows from the temperature dependence of the molecular weight that in the unsaturated vapor the dimer dissociates into the monomers Y(thd)3, and at a higher temperature, the monomer dissociates to form Y(thd)2. Thermodynamic characteristics of the dissociation processes were calculated, and the thermodynamic parameters of the Y(thd)3 evaporation were refined to give the results, which agree well with the mass spectrometry and electron diffraction data for the Y(thd)3 vapor.

Rare earths (REs) play a key role in distorting spinel structure by creating some defects at the lattice sites and make them suitable for magnetodielectric applications. In the present study, the nanoferrites of CuRE0.02Fe1.98O4 where REs = Y3+, Yb3+, Gd3+, were prepared using one step sol–gel method. The prepared samples are represented as copper ferrite (CFO), yttrium doped copper ferrite (Y-CFO), ytterbium doped copper ferrite (Yb-CFO) and gadolinium doped copper ferrite (Gd-CFO), respectively. The single-phase structure of all the REs doped nanoferrites was determined by X-ray diffraction (XRD) analysis. The porosity, agglomerations and grain size of the REs doped copper ferrite were examined using field emission scanning electron microscopy (FESEM) analysis. Fourier transform infrared spectroscopy (FTIR) elaborates the phase formation and environmental effects on the REs doped nanoparticles (NPs). The recorded room temperature M−H loops from a vibrating sample magnetometer (VSM) elucidate the magnetic properties of the REs doped spinel nanoferrites. The magnetic saturation (Ms) was calculated in the range of 23.08 to 51.78 emu/g. The calculated coercivity values (272.6 to 705.60 Oe) confirm the soft magnetic behavior of REs doped copper ferrites. Furthermore, the electromagnetic and dielectric properties were assessed using a Vector network analyzer (VNA) from 1 to 6 GHz. The permeability, permittivity, dielectric tangent loss and electric modulus of the REs doped spinel ferrites illustrate that the prepared NPs may be suitable for microwave and high frequency applications.

The separation of zirconium and hafnium isotopes from the early actinides and rare earth elements (REE) with Eichrom’s Pb resin has been studied. Batch studies were performed to characterize the behavior of actinium, thorium, zirconium, hafnium, lutetium, and yttrium on Pb resin from HCl solutions (0.001 M to 11 M). The early actinides and REE had no affinity for the resin at any concentration of HCl, but zirconium and hafnium showed a moderate uptake at high concentrations of HCl with a maximum extraction at 11 M HCl. Several column separations were tested, including with only tracer isotopes and with mass. Rapid, simple separations of zirconium from actinium, thorium, protactinium, and the REE with high yields and low elution volumes are presented with applications for tracer isotope production and fission product separations. The resin is less suitable for hafnium separations as hafnium tends to bleed off the resin even at high concentrations of HCl.

Barium yttrium phosphate (BYP) phosphor doped with trivalent praseodymium ions (BaY(1-x) (PO4 )3 :Pr3+ (x = 0, 0.01, 0.05, 0.1, 0.15, and 0.2 wt%) was synthesized using a high temperature solid-state reaction method. Structural properties were analyzed through X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. XRD patterns confirmed the structure of the synthesized phosphor and average crystalline size was estimated (approximately 63.8 A). Vibrational functional groups were identified using FTIR spectroscopy. The emission spectrum was recorded under an 444 nm excitation wavelength, which showed various emission transitions of Pr3+ ions. Commission Internationale de l'eclairage coordinates, colour purity, and colour correlated temperature values were calculated for the BYP:Pr3+ phosphors and these coordinate values fell in the yellow region of the visible spectrum.

The electrocatalytically active films based on nanodispersed titanium dioxide modified by Y3+ ions and synthesized by the sol-gel method were characterized by the X-ray diffraction (XRD) and ultraviolet-visible photocurrent spectra. Electrocatalytic properties of the TiO2 and Y–TiO2 electrodes were investigated during the process of oxygen electroreduction.The XRD results indicated that the TiO2 and Y–TiO2 powders with the yttrium content of 0.5–5 mol % calcined at 500°C had an anatase crystal structure, with the crystallite size of 10–12 nm. The electrodes based on the Y–TiO2 films were photosensitive in a wavelength range of 250–400 nm. For all investigated samples with the Y(III) content of ≤ 5 mol %, both an increase in the photocurrent quantum yield and a shift of spectra towards longer wavelengths vs. those of the undoped TiO2 were observed. The photocurrent quantum yield for the Y–TiO2 samples first increased and then decreased with increasing the Y(III) content, and reached its maximum with 2% Y–TiO2 films. It was found that doping of the TiO2 films by Y(III) improves the catalytic activity of the Y–TiO2 electrodes in the reaction of oxygen electroreduction. A correlation between photo- and electrocatalytic properties and structural changes occurring in the TiO2 films upon yttrium doping has been revealed.

The colored non-toxic near-infrared (NIR) reflective and infrared radiative pigments are desired in reducing the energy consumption of buildings. In this work, yttrium ferrite (YFeO3) pigments with controllable crystalline structure were successfully synthesized via the method of solid-state reaction at low-heating temperature. The effects of the crystalline structure and microstructure, especially charge state distribution, on the bandgap, chromatic properties, infrared reflection and radiation performance of YFeO3 pigments were investigated for the first time. With the calcining temperature increased, the structure of obtained pigments changed from hexagonal to orthorhombic, and the bandgap was obviously widened. The black hexagonal YFeO3 pigments possessed small particle size, and their intensive optical absorption in the NIR range was related to the noticeable multiple reflections induced by the grain boundary. While, the brown orthorhombic YFeO3 powdered pigments, as well as the corresponding pigmented coatings, possessed good NIR reflection characteristics, and the high solar reflectance values clearly highlight the potential of these pigments as cool pigments. In addition, the obtained YFeO3 pigmented coatings showed high emissivity in 8–14 μm waveband (atmospheric window), indicating their potential applications in energy saving of buildings by combining NIR shielding and space cooling. The larger amount of Fe2+-Fe3+ ions pairs in the orthorhombic pigments led to the enhancement of free carrier absorption, which enhanced infrared emission and contributed to the slightly decreased NIR reflectance.

Nanopowders of the compositions BaHf1 – xYbxO3 – δ (x = 0.04, 0.08, 0.10) and BaCe0.9 – xZrxY0.1O3 – δ (x = 0, 0.5, 0.6, 0.7, 0.8) were synthesized by the combined crystallization of nitric acid salts and the citrate-nitrate method. Those nanopowders were used to produce ceramic materials with a cubic crystal structure of the perovskite type, with a grain size of ~20–70 nm. The study of electrophysical properties revealed that they have a proton type of conductivity in the temperature range of 500–700°C; σ = 10–2–10–5 S/cm. The type and mechanism of electrical conductivity of ceramics of the composition BaHf1 – xYbxO3 – δ (x = 0.04, 0.08, 0.10) were studied both experimentally and using theoretical calculations by computer modeling using the electron density functional method; the results are in good agreement. The research shows the prospects of using the obtained ceramic materials as proton-conducting electrolytes for solid oxide fuel cells.

In this study, a series of glass systems with a composition of (49 − x)H3BO3–35TeO2–15PbO–1.0Nd2O3–xY2O3 (x = 0.0, 0.5, 1.0, 1.5, 2.0, and 2.5 mol%) was prepared via melt-quench technique. The effect of Y2O3 content on the density, molar volume, oxygen packing density, elastic, and structural properties were investigated. The density and molar volume were found to vary concerning Y2O3 content. Ultrasonic non-destructive testing was employed at room temperature for measuring the elastic properties of the prepared glass samples. The density data, ultrasonic velocities, and measured elastic moduli were found to be composition dependent with Y2O3 content. The Y2O3 modifier was expected to change the physical properties of neodymium-doped lead borotellurite glasses. The structure analyzed using X-ray diffraction was confirmed the amorphous nature of the prepared glasses. Fourier Transform Infrared Spectroscopy has been carried out and reveals that the inclusion of Y2O3 into the glass system tends to increase the number of bridging oxygen atoms. All element study of the glass sample was proved by energy dispersive X-ray analysis.

The crystallization kinetics of erbium-substituted yttrium aluminum garnet (Er:YAG) from the amorphous phase was studied depending on the degree of substitution of yttrium by erbium: (Y1-xErx)3Al5O12, x = 0 – 0.9. The corresponding series of nanopowders were synthesized using the sol-gel method with binary sols as the starting materials. Crystallized single-phase Er:YAG powders were obtained at temperatures as low as 1370 K through the formation of intermediate phases. The crystallization kinetics of the Er:YAG precursors was analyzed using non-isothermal differential scanning calorimetry and X-ray diffraction analysis. The proposed unified crystallization model, based on which the kinetic parameters of the crystallization process of the Er:YAG from the amorphous phase were determined, depending on the content of erbium oxide. Time-temperature-transformation curves were developed from the obtained data to determine the optimal modes in the heat treatment and sintering of optical ceramics. Er:YAG transparent ceramics were obtained by vacuum sintering of sol-gel powders.

(Y1–xPrx)2O2Se solid solutions with х = 0.004, 0.008, 0.010, 0.012, and 0.020 have been prepared from oxides by ampule synthesis. We have measured their excitation spectra at λem = 514 nm and their photoluminescence and quantum yield spectra at λex = 463 nm (T = 300 K). Comparing their emission intensities at wavelengths of 514 (3P0 → 3H4 transition) and 670 nm (3P0 → 3F2 transition), we have determined the optimal dopant concentration (x = 0.01), at which the quantum yield has a maximum, reaching 3%.

The effects of Cr2O3 and/or NiO addition to Y2O3-doped Bi-based high-voltage ZnO varistors were investigated, including crystal structure and interface states analysis. Incorporating 0.35 mol% Cr2O3 in Y-doped varistors increased the single-grain varistor voltage VNNGB from 2.6 to 3.3 V and decreased the leakage current density by a factor of 40, from 2 × 10−5 to 5 × 10-7 A/cm2. The nonlinearity index α before and after degradation increased from 21 to 35. 1.2 mol% NiO increased VNNGB to 4 V. Highest varistor voltage was 1500 V for 0.3 mol% NiO. Resistance to electrical degradation improved with optimal amounts of Cr or Ni by reduction of grain boundary oxygen vacancies. Though the donor density was changed prominently by addition of Cr and/or Ni, changes in the barrier height were suppressed by the change in interface state density. As a result, the change in VNNGB was related mainly to the empty interface state under no bias.

The spectroscopic properties of a series of Dy3+ single-doped and Dy3+/Nd3+, Dy3+/Tb3+, and Dy3+/Tm3+ co-doped YAlO3 (yttrium aluminum perovskite, YAP) phosphors were investigated and compared through the measurements of optical absorption, emission spectra, and fluorescence decay curves. For the Dy3+ ion single-doped samples, the intensity of each absorption band increases with an increment in Dy3+ ion doping concentration, and the identified strong absorption peak at 447 nm indicates that Dy3+:YAP phosphors are suitable to be pumped by a blue laser diode (LD). For all co-doped samples, absorption peaks of Dy3+ ion along with some of the absorption bands of Nd3+, Tb3+, and Tm3+ ions are observed. Under 351 and 447 nm excitation, a prominent emission peak at 572 nm was obtained in all the samples, corresponding to Dy3+: 4F9/2 → 6H13/2 transition. Here, 2 at% Dy3+:YAP phosphor exhibits the highest yellow emission intensity under 447 nm pumping. Among the three kinds of Dy3+ co-doped phosphors, Dy3+/Tb3+:YAP phosphor possesses the dominant yellow emission. The fluorescence decay curves show exponential behaviour and are fitted well. The Commission International de L'Eclairage (CIE) chromaticity coordinates were calculated following the respective emission spectra, and it is found that all the coordinates locate in the yellow region. The energy transfer (ET) processes were investigated and the concentration quenching mechanism was discussed. The obtained results suggest that Dy3+-activated YAP phosphors are good candidates for yellow LED applications.

Polycrystalline ceramic samples of Mn substituted Yttrium ortho-ferrite have been synthesized using the conventional high temperature solid-state reaction method. X-ray diffraction analysis confirmed the formation of the polycrystalline compound. Rietveld analysis of X-ray diffraction patterns revealed the monophasic orthorhombic structure with space group Pnma. Average crystallite size has been calculated which is showing the decreasing trend with increase of Mn content. The three-dimensional crystal structures have been generated using the Vesta software and different structural parameters have been calculated using these structures. The dielectric measurement as a function of frequency and temperature indicates that the relative permittivity and loss factors are increasing with the increase in substitution concentration. Similarly, the impedance has been measured as a function of frequency and temperature which reflects overall decreasing trend. In all cases the AC conductivity is showing the increasing trend with temperature. Further, the DC conductivity has also been measured and the material constant (B) has been calculated which reflect the NTCR (negative temperature coefficient of resistance) effect for these materials. The I–V characteristic curves recorded at 573 K and 673 K show the enhancement in current and linearity with temperature as well as with substitution concentration.

Cerium-doped yttrium aluminum garnet (Y3Al5O12:Ce, YAG:Ce) was prepared using a sol-gel method and then fired for CO2 laser post-treatments. Phase transformations and formation of impurities were not observed in YAG:Ce after CO2 laser sintering. The shift of the diffraction peak and the appearance of another Raman peak indicate a more homogeneous distribution of Ce activators and enhanced crystallinity in laser-sintered YAG hosts. Larger spheres (100–200 μm) with tiny crystallites (

Neodymium-doped yttrium aluminum garnet (YAG:Nd) powder was prepared by solution-combustion synthesis using aluminum nitrate, yttrium nitrate, neodymium nitrate, urea, and glycine as starting materials. The characteristic near-IR emission of Nd3+ at 1067 nm was found to maximize at a Nd3+ concentration of 1 mol %. The impact of Si4+ co-doping on the crystal structure, morphology, and photoluminescence has also been studied. In the presence of the dopant, the emission intensity enhanced by 21% at an optimal Si4+ content of YAG:Nd3+ phosphor, which can be attributed to improvement in crystallinity, formation of pure phase, and creation of color centers due to mismatch in ionic radii between parent and doped ions.

Double- and triple-decker lanthanide phthalocyaninates exhibit unique physical-chemical properties, particularly single-molecule magnetism. Among other factors, the magnetic properties of these sandwiches depend on their conformational state, which is determined via the skew angle of the phthalocyanine ligands. Thus, in the present work we report the comprehensive conformational study of substituted terbium(III) and yttrium(III) trisphthalocyaninates in solution depending on the substituents at the periphery of molecules, redox-states and nature of solvents. Conjunction of UV-vis-NIR spectroscopy and quantum-chemical calculations within simplified time-dependent DFT in Tamm–Dancoff approximation provided the spectroscopic signatures of staggered and gauche conformations of trisphthalocyaninates. Altogether, it allowed us to demonstrate that the butoxy-substituted complex behaves as a molecular switcher with controllable conformational state, while the crown-substituted triple-decker complex maintains a staggered conformation regardless of external factors. The analysis of noncovalent interactions within the reduced density gradient approach allowed to shed light on the nature of factors stabilizing certain conformers.

The influence of Nd3+ ion-reinforced yttrium lead borotellurite glasses based on (49-x)B2O3-35TeO2-15PbO-1.0Y2O3-xNd2O3 (where x = 0.0, 0.5, 1.0, 1.5, 2.0, and 2.5% mol) was investigated in terms of their optical (linear and nonlinear) and gamma-ray attenuation properties. The values of the nlinear were varied from 2.482 (S1 sample) to 2.421 (S6 sample). Our findings showed that Rmolar (19.134–17.259 cm3/mol) and αmolar (7.593–6.848) × 10–24 cm3 have direct relationship on studied glasses. The Rloss (0.1811–0.1725) and Toptical (0.6932–0.7057) were in inverse behavior with the increasing Nd3+ ions in glasses. Our findings also showed that Mcriterion was varied from 0.2793 to 0.2914, while the eoptical was varied from 6.160 to 5.861. Moreover, the highest mass attenuation coefficients values were reported for S6 glass sample with the highest Nd2O3 additive (i.e., 2.5 mol%) in terms of gamma-ray attenuation competencies of studied glasses. The minimum EBF and EABF values were reported for the S6 sample, while S1 sample was reported with its maximum EBF and EABF values. Results revealed that S glasses have suitable properties for optical applications. It can be concluded that S6 sample has superior gamma-ray attenuation properties among the investigated glasses.

(HDEHP + Hexa)/SiO2-P, a silica-based adsorbent, was prepared and used to separate Y(III) from a mixed solution of Sr(II) and Y(III). The adsorption behavior of the adsorbent was investigated using batch tests. The adsorbent exhibited high adsorption performance for Y(III) in low nitric acid concentrations and weak adsorption performance for Y(III) at higher concentrations. In contrast, Sr(II) was not adsorbed in either acid concentration range. The same tendency was observed under hydrochloric acid conditions. Y(III) separation from a mixed solution of Sr(II) and Y(III) was verified by a column test. Overall, the (HDEHP + Hexa)/SiO2-P adsorbent can separate Y(III) from Sr(II).

Laboratory experiments were performed to study the transient evolution of inclusions in Si–Mn-killed stainless steels with additions of 60 and 360 ppm yttrium using low- and high-oxygen yttrium-containing ferroalloys. With the increase of the yttrium content in the steel, the evolution path of inclusions was CaO–Al2O3–SiO2–MnO → Y2O3–Al2O3–SiO2(–CaO–MnO) → Y2O3 and YS → Y2O3. The YS inclusion was generated as a transient product in the steel with 360 ppm yttrium addition using high-oxygen yttrium-containing ferroalloys. With the addition of 60 ppm yttrium, initial larger CaO–Al2O3–SiO2–MnO inclusions were modified to smaller liquid Y2O3–Al2O3–SiO2(–CaO–MnO) inclusions, resulting in a smaller diameter of inclusions. After the addition of 360 ppm yttrium, initial liquid CaO–Al2O3–SiO2–MnO inclusions were modified to small solid Y2O3-rich inclusions, lowering the average diameter of inclusions. Then, the size of inclusions in the steel increased due to the collision of solid inclusions.

This work aims to fully analyze the luminescence spectra and time response properties of LYSO:Ce (Lu2-2xY2xSiO5:Ce) scintillation crystals with different Y contents. The photoluminescence excitation (PLE) and emission (PL) spectra of Ce1 and Ce2 luminescence centers in LYSO:Ce crystals with different Y contents have been systematically examined. The shape of photoluminescence emission spectra and the contribution of the energy transfer process between Ce1 and Ce2 have been varied with the yttrium content in the crystal. Based on the photoluminescence and scintillation decay time measurements, a table has been shown to provide the relationship between the decay time and Y content in the crystal. Meanwhile, the afterglow measurements demonstrate the relationship between long-lived delay recombination processes and the free carrier traps existing in the bandgap, and the source of afterglow has been analyzed.

Hafnium zirconium oxide (HZO) is promising for applications in future memory devices and energy storage and harvesting. While many studies have focused upon the dielectric and structural properties of HZO, much less investigated are their thermal properties, particularly in thin-film form. We present the first report on the thermal conductivity of plasma-enhanced atomic layer deposited (PEALD) HZO thin films. Steady-state thermoreflectance measures the effective thermal conductivity of undoped and yttrium-doped HZO films and their interfaces. The effective thermal conductivity of the undoped film is found to be 0.75 W m–1 K–1, which is comparable to those reported previously for thermal ALD HZO films with similar composition. With increasing yttrium doping level, the effective thermal conductivity slightly decreases down to 0.67 W m–1 K–1 owing to dopant scattering of phonons. Our PEALD HZO films are nanocrystalline as observed by grazing-incidence X-ray diffraction and transmission electron microscopy.

Orange-red emitting praseodymium (Pr3+) activated yttrium molybdenum oxide (Y2MoO6) nanophosphors (NPs) were synthesized via low-temperature solution combustion method using Aloe vera gel as a surfactant and fuel. The synthesized NPs were subjected to structural, morphological, optical, and electrical studies. The powder X-ray diffraction (PXRD) study reveals that the Y2MoO6 composite consists of a monoclinic crystal phase. Peak shift to the left side was observed with increase in the doping concentration of Pr3+ ions into the crystal system, which is attributed to the strain. Foamy type morphology was revealed from scanning electron microscope studies, whereas the nanostructural features of the samples were confirmed by both transmission electron microscope and PXRD. From the diffused reflectance spectroscopy study, the optical band gap was estimated to be in the range of 3.36–3.48 eV. Fourier transforms infrared spectroscopy was used to identify the metal oxygen bonds along with the other types of bonds if any. The AC conductivity and dielectric properties were measured in the frequency range of 100 Hz–5 MHz. The photoluminescence (PL) studies revealed the characteristic of emission peaks of Pr3+ ions. The Commission International de l'Eclairage (CIE) coordinates were located in orange-red color. The average correlated color temperature analysis indicates that the Y2MoO6:Pr3+ NPs can be useful for use in warm light sources. The Y2MoO6: Pr3+ (5 mol%) NPs were used for the design of anti-counterfeiting ink in security applications. The tunable properties of the prepared Y2MoO6:Pr3+ NPs make them suitable for multifunctional applications.

Molybdenum trioxide (MoO3) micro-belts were successfully synthesized via the sol–gel coprecipitation method. The synthesized material was, then, doped with different concentrations of yttrium element, Y. The influence of the doping concertation on crystallographic, microstructural, optical, and photocatalytic properties has been studied. Good thermal stability has been revealed by thermogravimetric analysis. The X-ray diffraction analysis identified the orthorhombic phase. The peaks were shifted toward the lower 2θ angle position after doping, confirming the Y3+ substitution in the MoO3 crystal structure. Scanning electron microscope measurements revealed a belt-like shape with a decreasing size when increasing the Y3+ ions concentration. SEM clearly showed a non-homogeneous distribution of second-phase particles, depending on the concentration of yttrium doping, which could be attributed to the Y2Mo4O15 secondary phase. The band-gap energy was shifted to the lower-energies of an amount of 0.61 eV when going from 0 to 10% of yttrium. The photocatalytic performances were monitored through photodegradation of methylene blue under different radiations. It was observed that Y-dopant significantly improved the photocatalytic activity of MoO3, the longer the wavelength the better the removal efficiency. This enhancement could be associated with the doping-induced modification of the band-gap or to the microstructure evolution.

The rates of chemical expansion for 20 at % yttrium-doped barium zirconate upon hydration at 100–900 °C under water partial pressures of 0.008 and 0.023 atm have been studied using combined thermog...

The present research describes the results of Raman spectroscopic study of undoped and Y-doped SrZrO3 having a great potential for application in proton-conducting fuel cells. Effects of yttrium doping and strontium nonstoichiometry on the local environment of cations and vibrational properties of strontium zirconate were investigated. Ceramic samples SryZr1-xYxO3-δ (x = 0, 0.02, 0.05; y = 0.94, 0.98, 1.00) were synthesized via a chemical solution method and sintered at 1650 °C. Microstructure, phase and chemical composition of the samples were characterized by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Analysis of Raman spectra peculiarities upon changes in Sr- and Y- concentrations has shown that yttrium ions can be partitioned over both A- and B-sites in the strontium-deficient zirconates with the dopant concentrations more than 2 at%.

In this study, YAlO3 (YAP) was produced at low temperatures by a powder sintering process. Al2O3–Y2O3 powder mixtures were subjected to heat treatment at different temperatures. The relationship between the sintering temperature and the emergence of new phases was investigated via X-ray diffraction, and supported by energy dispersive X-ray spectroscopy. The crystallization of the monoclinic yttrium aluminum oxide (Y4Al2O9) occurred at 1 000 °C, whereas the yttrium aluminum perovskite (YAlO3) crystallization occurred at 1 100°C. Energy dispersive X-ray spectroscopy analysis showed yttrium content in the sample containing Al2O3–YAlO3 powder sintered at 1100 °C, associated with the YAlO3 phase formed at this temperature. Brunauer–Emmett–Teller surface analysis showed a significant decrease in the pore volume of the sample sintered at 1 100°C.

Sol–gel technique is utilized to produce the series of ferrite having chemical formula BaYyFe2-yO4 (y = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10). The cubic structure of all the samples have been revealed through X-ray diffraction data. The inclusion of yttrium content among the ferrites beyond 0.06, it will result into development of YFeO3 secondary phase. The lattice parameter of samples upsurges with the substitution of yttrium ions (Y3+). Jump lengths on A & B sites, bond lengths and ionic radii have direct relation with yttrium concentration. The evaluation of electrical parameters reveal that the resistivity, activation energy and bond length increased with the growth of yttrium. Below the Curie temperature, the movement of electrons and holes is main cause of conduction mechanism. But above this temperature, the polaron hopping handle the conduction process. With the addition of yttrium, the saturation magnetization value decreased. Coercivity of samples enlarged with the substitution of yttrium ions. The involvement of yttrium ion in barium ferrite system makes it appropriate for high frequency appliances.

A wide range of applications of nano cobalt ferrite as a magnetic ceramic in material and biological science and technology suggests a need to optimize its structural and magnetic features. Chemical composition and the size of cobalt ferrite particles with its substituent ions are the determining factors in exploring its properties. For this purpose, yttrium-doped cobalt–zinc nano sized ferrite with the chemical formula Co0.8Fe2-xZn0.2YxO4 and with x ranging from 0.00 to 0.03 in step of 0.01 were synthesized by the combustion method and then analyzed to know their structural and magnetic parameters. The spinel phase formation was confirmed by using x-ray diffractometry. The samples contained 15-nm sized particles as confirmed from scanning electron micrographs. Hysteresis shows decline in magnetic parameters with increase in rare earth doping and is attributed to the 3d-4f orbital coupling and their magnetic interactions. Magnetostriction measurements were measured using strain gauge sensor. As against our expectation, the yttrium substitution decreased the magnetostriction values. However, the derivative of strain with respect to magnetic field showed a rise with yttrium doping. This suggests an application in transducers.

The structural and magnetic properties of La 0.6 − x Y x Sr 0.4 MnO 3 (x = 0–0.3) manganite synthesized by the sol-gel method was systematically investigated. The structural properties of the samples were investigated using X-ray diffraction (XRD) patterns and confirmed by Rietveld refinement analysis. Using the energy dispersive X-ray (EDX) analysis, the atomic percentage of the elements in the samples was confirmed. To investigate the surface morphology of the specimens, a field emission scanning electron microscopy (FESEM) analysis of the specimens was performed. The effect of yttrium substitution on the magnetic properties of the samples was also investigated. The Curie constant, magnetic moment, blocking temperature, and Curie temperature (Tc) were calculated using the Curie-Weiss law and the magnetic susceptibility of the samples.

The thermal properties of individual precursors, zirconium(IV) and yttrium(III) dipivaloylmethanates, and of their mixtures [Zr(thd)4–Y(thd)3, Hthd = 2,2,6,6-tetramethylheptane-3,5-dione] used for preparing mixed oxide films by chemical vapor deposition were studied in the condensed and gas phases. In the condensed phase, the vaporization rate of both individual compounds and their mixtures considerably exceeds the decomposition rate. The vaporization, thermal stability of the vapors, and thermal decomposition of the compounds in a vacuum and in the presence of oxygen were studied using mass-spectrometric monitoring of the gas phase composition. Comparison of the thermal behavior of individual Zr(thd)4 and Y(thd)3, heated in separate vaporizers of the mass spectrometer inlet system, and of their mixtures with different Zr(thd)4 to Y(thd)3 ratios reveals no chemical interaction between the precursors in the examined temperature interval.

The possibility of rare earth elements (REE) separation by ion interaction chromatography (IIC) employing their complexes with diglycolic acid (ODA) in anion exchange mode has been studied theoretically and experimentally. Calculations, assuming that only trivalent complex is significantly uptaken by the stationary phase, indicated that at at pH 4–6, the retention in the lanthanide series should increase from La to the Tb–Dy–Ho region with yttrium showing apparent atomic number (App.At.No.) of 67½ and then decrease with further increase of atomic number. Chromatographic experiments in the system: Column: Eternity C18—mobile phase 5 mM ODA/8.6 mM TBAOH/0.6 mM HNO3; pH 4.60 confirmed theoretically predictions. It was found that scandium at pH ≥ 4.0 elutes in front of the whole REE group but at low pH enters the region of light lanthanides. The non-monotonical change of affinity of the REE with the increase of atomic number results in quite unusual order of elution of REE namely: Sc

The chemical separation of zirconium from lanthanides by liquid–liquid extraction is challenging but critical for medical and technological applications. Using the example of 89Zr, we optimize the liquid–liquid-extraction process by means of the radiotracer technique. We produced 89Zr by proton irradiation of a metallic yttrium target at a cyclotron. The purification of the radionuclide was performed by a UTEVA resin. 89Zr was separated in no-carrier-added form in a sulfuric acid solution. 89Zr was successfully used in solvent extraction tests with calixarenes for the separation of zirconium from lanthanides. This reaction is suitable for the efficient extraction and purification of lanthanides.

By means of X-ray phase analysis and energy-dispersive X-ray analysis, the effect of yttrium on the structural-phase state of the hypoeutectic Mo–15.3 V–10.5 Si alloy is investigated. It is established that the main phases of the Мо–(15.4–14.3) V–(10.6–9.8) Si–(0.3–5.3) Y alloys obtained under the conditions of nonequilibrium solidification are the (Mo1 – xVx)ss metal solid solution (matrix), (Mo1 – xVx)3Si silicide solid solution, and Y5Si3 silicide. In alloys doped with yttrium up to 1.0 at %, the space between dendrites of the (Mo1 – xVx)ss metal phase is filled with the (Mo1 – xVx)3Si solid solution, and at the boundaries of the metal solid solution, Y5Si3 is located. At the yttrium concentration of alloys higher than 3.0 at %, space between the (Mo1 – xVx)ss dendrites is filled with Y5Si3 silicide, inside which (Mo1 – xVx)3Si grains are formed. No ternary and quaternary yttrium-containing compounds are detected. The elemental composition of phases of the Мо–(15.4–14.3) V–(10.6–9.8) Si–(0.3–5.3) Y alloys is almost identical and is characterized by silicon nonstoichiometry. The silicon content of the (Mo1 – xVx)ss and (Mo1 – xVx)3Si phases lies within the accepted limits of the homogeneity region, and the silicon concentration of Y5Si3 (≈35.4 at %) goes beyond the defined limits. Doping the Мо–15.3 V–10.5 Si alloy with yttrium increases the degree of dispersion of the structure. Particles of the main structural constituents become close in size. At the same time, the volumetric ratio of the metal phase to the silicide phase increases as the yttrium content of the alloys is raised. The density of the alloys varies within 8.7 and 9.0 g/cm3.

Sn-substituted yttrium iron garnet samples, Y3Fe5-xSnxO12 (x = 0–0.1, step 0.02) were prepared using a citrate sol–gel method and followed by a sintering process. Synchrotron X-ray diffraction (SXRD), X-ray absorption near edge structure (XANES), scanning electron microscope (SEM) and Fourier infrared spectroscopy (FTIR) measurements were used to investigate the structure parameters, valence state of Fe, oxygen vacancies and lattice distortion in the samples. The magnetic properties of the samples were measured with the SQUID and VSM equipments. The Sn substitution and oxygen vacancies cause the transformation of Fe3+ to Fe2+ which leads to the decrease of Curie temperature and slight increase of saturation magnetization. Temperature dependence of the resistivity in the range of 300–573 K was investigated to elucidate the conduction mechanism in the samples. The resistivity of the sol-gel derived samples was found to be nine orders of magnitudes lower than the value for the bulk sample prepared by flux-grown method. The effects of Fe2+ centers, lattice dislocation, porosity and grain boundary on the resistivity are discussed. This study indicates that Sn-substituted yttrium iron garnets are good candidates for sensor elements which operate based on electrical signals.

Yttrium stabilized zirconia (YSZ) ceramics doped with Eu3+ ions have been successfully fabricated by Spark Plasma Sintering (SPS) technique. The influence of the europium concentration and post-annealing process on the structural, optical, and luminescent properties of the ceramics has been studied. It is shown that an increase in the europium concentration from 0.1 to 3 wt% does not lead to significant changes in the transmission spectra. However, annealing in air atmosphere at temperature from 700 °C to 1300 °C significantly affects the transmission spectrum, as a possible consequenceofthe formation of oxygen vacancy defects. The analysis of the photoexcitation and photoluminescence spectra showed that the main excitation bands are determined by direct excitation of the 7F0 ground state of Eu3+ions to the higher 4f energy levels with further radiation transitionsfrom these states. Moreover, the europium ion in the obtained ceramics occupy low-symmetry sites without inversion center.The luminescence decay kineticsare described by a doubleexponential function with decay time τ1 ~ 20 ns and τ2~ 90 ns for intrinsic emission centers and millisecond (τ ~ 1.4 ms) for Eu3+emission, for all investigated ceramics. The luminescence spectra in nanosecond time region are characteristic for yttrium-stabilized zirconia and are caused by oxygen vacancies in the presence of heavy cations (Y3+ and Eu3+).

The cathode in the magnetron should have good secondary emission property and a certain thermionic property. In this article, ZrH2 was added as an activator to obtain rare earth-doped tungsten matrix impregnated cathode to improve the emission property. Cathodes with ZrH2 (Y15-411-Zr cathode) or without ZrH2 (Y15-411 cathode) were prepared by a spray drying method combined with high-temperature sintering in dry hydrogen atmosphere. The emission properties and emission mechanism have been studied. The results showed that thermionic emission performance and secondary emission performance of Y15-411-Zr cathode are 3.4 times and 1.2 times higher than those of Y15-411 cathode, respectively. With the addition of ZrH2, yttrium was produced during activating process, which contributed to the better emission properties of Y15-411-Zr cathode. Furthermore, the work function of barium and oxygen adsorbed on yttrium oxide and yttrium surface was calculated using the first principle. The results showed that the lowest work function of Ba-O absorbed on Y2O3 and Y is 1.9 and 1.6 eV, respectively.

In this work, the efficiencies of three organometallic yttrium precursors used to produce YSZ coatings by plasma-enhanced chemical vapor deposition were studied. Yttrium (III) acetylacetonate, Y (acac)3, yttrium (III) hexafluoroacetylacetonate, Y (acacF6)3, and yttrium (III) tris(2,2,6,6-tetramethyl-3,5-heptanedionate), Y (tmhd)3, were used to stabilize the cubic phase in zirconia deposited at temperatures from 500 to 800 °C. Our results showed that at temperatures between 500 and 600 °C, Y (tmhd)3 appeared to be the most efficient dopant as it introduced the highest concentration of yttria (1–2.7 mol%) with only 6.4–5.6 at.% carbon. However, at 700 and 800 °C, Y (acac)3 introduced twice as much yttria (8–15 mol%) as Y (tmhd)3 with almost the same amount of carbon (5.4–3 at.%). Conversely, Y (acacF6)3 was the least efficient as it maintained a low concentration of yttria of around 0.7–1.8 mol% with 3.6–8.2 at.% carbon for all the deposition temperatures. Among these precursors, only Y (acac)3 surpassed 8 mol% yttria and achieved a fully stabilized cubic phase at 800 °C, with the remaining samples stabilizing only the tetragonal phase. The tetragonal phase was stabilized due to the formation of crystallites of around 10 nm. The observed difference in the efficiency of the three precursors was correlated to important differences in their decomposition behavior as observed by mass spectrometry and thermogravimetry/differential scanning calorimetry.

In this study, ZnO99.5-x/Ag0.5/Yx (where 0≤ x ≤ 10) nanopowders were synthesized by using the hydrothermal method. The structural, optical and thermoluminescence properties of the prepared nanopowders were experimentally examined. Moreover, the effect of yttrium (Y) dopant ratio on the studied properties was discussed in details. The structural, morphological, optical properties of the prepared TL material were investigated using X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and ultraviolet–visible (UV–Vis) respectively. The pellets of the nanopowders were exposed to X-ray doses of up to 4 Gy to investigate their thermoluminescence response, sensitivity and reproducibility. The glow curve for the ZnO/Ag/Y sample was observed at yttrium dopant ratio of 7% mol and the main peak corresponding to 165 °C. The heating rate of 7 °C/s was found to be consistent with the highest TL intensity at a low standard deviation. The best TL response with minimum standard deviation was observed at 300 °C. The optimum annealing time corresponding to the highest TL response was 30 min. The study demonstrated a linear dose response with a strong correlation coefficient equal to 0.999. The sensitivity of the co-doped ZnO/Ag/Y nanopowders (pellets) was found to be 0.28, which is lower than that of TLD-100 chips by 3.5 times. The results demonstrated the suitability of the novel synthesized TL material for electronic and dosimetry applications.

The effect of cadmium sulfide (CdS) nanoparticles synthesized by hydrothermal method on the structural properties and on the excess conductivity of yttrium-based compound (YBa2Cu3Oy) and bismuth-based compound ((Bi,Pb)2Sr2Ca2Cu3Oδ) was reported. The electrical resistivity versus temperature, $$\rho (T)$$ , in the paraconductive region, was analyzed using the Aslamazov–Larkin model. Different fluctuation regions indicated by the short-wave region, mean-field region, and critical region were identified. The coherence length $${\xi }_{c}(0)$$ , the effective layer thickness $$d$$ , the penetration depth $${\lambda }_{c}(0)$$ , the lower and upper critical magnetic fields, $${B}_{c1}\left(0\right)$$ and $${B}_{c2}\left(0\right)$$ , the critical current densities $${J}_{c}\left(0\right)$$ , and numerous other superconducting parameters are determined. It was found that the intrinsic properties are much more improved in the CdS-added samples, which suggests that the addition of CdS nanoparticles in the superconducting matrix leads to the enhancement of the grain connectivity, the formation of strong pinning centers contributing to the reduction of magnetic vortex motion and therefore, the improvement of the conduction properties in the yttrium- and bismuth-based materials.

Drastic reduction in commercialization has favored the interest in lateritic and other minerals as rare earth elements source. In this study, inductively coupled plasma optical emission spectrometr...