Effect Of Gd3 Research Articles

Effect of Gd3+ doping on microstructure and magnetic properties of Ni–Zn–Co ferrite

Effect of Gd3+ doping on microstructure and magnetic properties of Ni–Zn–Co ferrite

Impact of Gd-doping on structural and electrical properties of 0.4CaBi2Nb2O9-0.6Na0.5Bi2.5Nb2O9 piezoelectric ceramics

This paper focuses on improving the electrical properties of 0.4CaBi2Nb2O9-0.6Na0.5Bi2.5Nb2O9 piezoelectric ceramics through Gd doping. The effect of Gd3+ replacing Ca2+ and Na+ on the 0.4CaBi2Nb2O9-0.6Na0.5Bi2.5Nb2O9 (0.4CBN-0.6NBN) piezoelectric ceramics was subjected to a comprehensive examination. The introduction of Gd3+ has led to the development of a pseudo-tetragonal phase, enhancing the polarization and strengthening the piezoelectric effect. Among the 0.4CBN-0.6NBN-xGd (x = 0.00–0.05) ceramic samples, the sample at x = 0.03 that exhibits the best piezoelectric properties demonstrates a high Curie temperature of 849.7 °C, low dielectric loss (tanδ) of 1.295 % (at 550 °C), high DC resistivity (ρDC) of 1.58 × 108 Ω‧cm (at 500 °C), and a high d33 value of 17.3 pC/N. Following annealing at 800 °C, its d33 retains 94.2 % of its initial value. The improved electrical performances indicate that the Gd-doped 0.4CBN-0.6NBN ceramics hold a great deal of promise for high-temperature piezoelectric applications.

Effect of Gd3+ ion on silver zinc borate glasses

The conventional melt quenching technique approach has been used to create glasses with the composition of ZnO-B2O3-Gd2O3-Ag2O.Using the X-ray diffraction technique, the synthesized glasses have been characterized. Using the Archimedes method, the density and molar volume were calculated. To record the absorption spectra, a UV–visible spectrometer was employed, the energy band gap has been evaluated using Tauc's plots. The variation of band gap energies related to Gd2O3 concentration has been discussed. FTIR spectra are examined to determine the sample's structure and functional group. When the Gd3+ ion is added to the doped glass, the photo luminescence spectra produces a consistent orange-red emission, as evidenced by the colour coordinates obtained from the CIE diagram.

Spectrum regulation of LuAG:Ce phosphor ceramic with Gd doping for high-brightness and high-power yellow-emitting LEDs applications

To realize the high-brightness of yellow light-emitting diodes (LEDs), the yellow-emitting phosphor ceramics with high luminous efficiency (LE) are urgently explored. Based on the idea of spectrum regulation, the Lu3-x-yGdyAl5O12:xCe3+ (LuGdAG:Ce) phosphor ceramics were prepared via vacuum solid-state sintering. The effect of Gd3+ and Ce3+ content on the structure, luminescence and thermal properties of LuAG:Ce ceramics were investigated. The distortion ratio (D) of CeO8 and bandgap were effectively modified via Gd3+ doping, resulting in massive red-shifting of Ce3+ emission (513→561 nm). The LEDs lighting encapsulated by LuGdAG:Ce ceramics changes from green to yellow. Importantly, the yellow LEDs with a LE up to 139.0 lm/W@180 W and a warm correlated color temperature (CCT) of 3620 K were achieved based ceramic Ce07Gd9. The LuGdAG:Ce phosphor ceramic has the best of luminescence performance in phosphor-converted yellow LEDs lighting so far, which is considered to be the highly promising color converter.

Effect of Gd3+ ion doping on structural, optical, magnetic and dielectric properties on superparamagnetic Mg0.5Zn0.5Fe2−xGdxO4 (0 ≤ x ≤ 1) nanoparticles synthesized via oleic acid assisted chemical co-precipitation method

In the present study, different compositions having general formula Mg0.5Zn0.5GdxFe2−xO4, (x = 0, 0.025, 0.050, 0.075, 0.1) were synthesized using chemical co-precipitation method. The substitution of Gd3+ ions have exhibited profound impacts on the structural, morphological, magnetic, and optical parameters of Mg-Zn ferrites. Single-phase cubic spinel structure has been substantiated by X-ray diffractometer (X-ray diffraction, XRD) analysis for all compositions without any contamination peak. The values of the lattice constant and X-ray density both show an increasing trend when the Gd3+ ion concentration increases. (Fourier transformed infrared spectroscopy) FTIR spectra recorded in the mid-infrared region (4000–400 cm−1) exhibit two main absorption bands associated with the Oh and Td sites within the frequency range of 400–600 cm−1. Morphological studies using (High-resolution transmission electron microscopy) HR-TEM analysis reveal agglomeration of nanoparticles and the average particle size lies between 8 and 9 nm. Maximum magnetization displays an erratic trend with increasing Gd3+ ion concentration, although both retentivity and coercivity decreases. The hysteresis curve for samples of differing ratios of Gd3+ ions demonstrated the superparamagnetic nature. Tauc’s plot was employed to calculate the energy bandgap (Eg) of synthesized nanoparticles and Eg value were observed to decline from 3.563 eV to 3.521 eV with an increasing Gd3+ ion concentration. Impedance analyzer was used in the frequency range of 100 Hz–100 MHz to study dielectric properties at room temperature. The dielectric parameters declined as the frequency values increased. Due to lower values of dielectric parameters in Gd3+ ion doped Mg–Zn nano-ferrite, these materials are suitable in the fabrication of devices that need to operate at high frequencies such as switching memory storage devices. Moreover, these materials are appropriate for application in ferrofluids and medicinal treatments such as magnetic hyperthermia because of their low coercive field value.

Partial substitution-induced luminescent improvement in Dy3+-activated tellurooxyphosphate phosphor

A series of Dy3+-doped tellurooxyphosphate-based phosphors: Na3Ca4-x(TeO3)(PO4)3:xDy3+ and Na3Ca3.91-yGdy(TeO3)(PO4)3:0.09Dy3+ were obtained by a microwave-assisted synthesis, aiming to develop photoluminescent materials suitable for phosphor-converted white light-emitting diodes (pc-wLED). The effect of Gd3+ partial substitution on the luminescent enhancement of Na3Ca3.91-yGdy(TeO3)(PO4)3:0.09Dy3+ phosphor was investigated in detail. When the substitution amount of Gd3+ is 0.06, the luminescence intensity is significantly enhanced. Simultaneously, the partial substitution of Gd3+ induces the increase of the structural rigidity, leading to higher thermostability and better resistance to chromaticity shifting. The study provides a potential yellow-emitting material for pc-wLED.

Rare earth Gd3+ substituted on cobalt ferrites: Structural and dielectric studies by citrate gel autocombustion method

Gadolinium-doped cobalt ferrite (CoGdxFe2-xO4; X = 0–0.025 in a 0.005 interval) was synthesised using citrate gel autocombustion. The effect of Gd3+ ions on structural, dielectric, and magnetic characteristics has been investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, ultraviolet visible spectroscopy (UV), an impedance (dielectric) analyzer, and a vibrating sample magnetometer (VSM) were used to characterise the as-synthesised materials. X-ray diffraction powder patterns were used to confirm phase identification and spinel structure, and the Williamson-Hall plot was used to investigate the crystalline size and lattice strain on the peak broadening of each sample, with crystalline size ranging from 13 to 48 nm. The scanning electron microscopy (SEM) micrographs demonstrate particle agglomeration, while energy dispersive spectroscopy (EDAX) pictures indicate the purity and existence of all elements in the created material samples. The frequency-dependent dielectric constant, dielectric loss, and AC electrical conductivity in the frequency range 50 Hz–1 MHz. The behaviour of dielectric properties has been studied using the Maxwell-Wagner model and Koop's theory. Because of this, higher frequencies show less dielectric loss, making them appropriate for use in high-frequency device applications.

The structural, morphological and optical studies on BaAl2O4/MgAl2O4/MgO:x% Gd3+ (0 ≤ x ≤ 1.1) mixed phases synthesized by sol-gel method

In this study, BaAl2O4/MgAl2O4/MgO:x% Gd3+ (BMM:x% Gd3+) (0 ≤ x ≤ 1.1) mixed phases nanophosphors were prepared for the first-time using sol-gel method. The effect of Gd3+ concentration on the morphology, structure, and optical characteristics were examined. X-ray diffraction (XRD) confirmed the presence of hexagonal (BaAl2O4), cubic (MgAl2O4 and MgO) phases. Varying the Gd3+ concentration has no significant influence on the prepared nanophosphors morphology. Energy dispersive X-ray spectroscopy (EDS) confirmed the presence of the anticipated elementary compositions. Photoluminescence (PL) results showed three emissions peaks located around 312, 616 and 730 nm. The emission peak at 312 nm was ascribed to 6P7/2 → 6S7/2 transition in Gd3+ whereas other emission peaks originated from other impurities such as Cr3+.

Effect of Gd3+/Nd3+- dual doped borate glasses on the physical and spectroscopic properties for the NIR emission at 1.069 µm

Near-infrared luminescence properties of dual doped Gd3+/Nd3+-incorporated glasses were manufactured using the melt-quenching technique and characterized by several techniques. The modification in glass structure may be seen in the differences in density, molar volume, and refractive index that occur when the amount of lanthanide oxide in the glass increases. The spectroscopic properties of Nd3+ in these glasses are quite well understood, and the observed optical characteristics may be used to process and eventually determine laser properties. According to the results of XANES, the Nd oxidation state remains the predominant peak for Nd3+ in all of the samples. The transition from 4I9/2 to 4G5/2 +2G7/2 is important for the strongest band in the absorption spectra, which can be seen at 584 nm. The luminescence spectra show peaks caused by 4F3/2→4IJ (J=11/2, 13/2) at three excitation wavelengths of 526, 574 and 805 nm. After the processing, we created glass samples for the study of photoluminescence with various amounts of Nd2O3 incorporated into the best host, 25Li2O-5Al2O3-2.5Gd2O3-(67.5-X)B2O3-XNd2O3. Based on luminescence intensity, it is determined that 1.0 mol% of Nd2O3 is the concentration quenching in the studied glasses. The 4F3/2 →4I11/2 transition at 1069 nm, excited by 526, 578 and 803 nm, has the highest emission intensity. The combined findings of the glasses demonstrate that near-infrared luminescence may be successfully used with them. All of the analysis shows that the dual doped Gd3+/Nd3+ borate glass would be a potential solid-state laser candidate.

Effect of Gd3+ doping on the luminescence and up-conversion of Pr3+ activated Ca2(Lu0.99-xGdxPr0.01)Hf2Al3O12

In this work, the optical properties including the up-conversion of Pr3+ doped Ca2(Lu,Gd) Hf2Al3O12 are presented. The change in optical properties of trivalent praseodymium as a function of the gadolinium concentration was investigated by gradually replacing the lutetium cations by Gd3+. The presence of single-phase samples was proven by PXRD. Additionally, reflection spectroscopy, as well as excitation and emission measurements under X-ray and VUV excitation were recorded. Finally, decay curves were taken to determine the dependence of the decay constants from the chemical composition.

Effect of Gd3+, La3+, Lu3+ Co-Doping on the Morphology and Luminescent Properties of NaYF4:Sm3+ Phosphors

The series of luminescent NaYF4:Sm3+ nano- and microcrystalline materials co-doped by La3+, Gd3+, and Lu3+ ions were synthesized by hydrothermal method using rare earth chlorides as the precursors and citric acid as a stabilizing agent. The phase composition of synthesized compounds was studied by PXRD. All synthesized materials except ones with high La3+ content (where LaF3 is formed) have a β-NaYF4 crystalline phase. SEM images demonstrate that all particles have shape of hexagonal prisms. The type and content of doping REE significantly effect on the particle size. Upon 400 nm excitation, phosphors exhibit distinct emission peaks in visible part of the spectrum attributed to 4G5/2→6HJ transitions (J = 5/2-11/2) of Sm3+ ion. Increasing the samarium (III) content results in concentration quenching by dipole-dipole interactions, the optimum Sm3+concentration is found to be of 2%. Co-doping by non-luminescent La3+, Gd3+ and Lu3+ ions leads to an increase in emission intensity. This effect was explained from the Sm3+ local symmetry point of view.

Effect of Gd3+ doping on structural, vibrational, dielectric, and ferroelectric properties of Bi0.5Na0.5TiO3 ceramic

The effect of adding Gadolinium on bismuth sodium titanate ceramics on structure and electrical characteristics with the chemical formula (Bi 1-x Gd x ) 0.5 Na 0.5 TiO 3 (x = 0.00, 0.02, 0.04, 0.06,0.08 and 0.10) (BGNT) were examined using a solid-state reaction approach. The pure perovskite rhombohedral phase is visible without any secondary phase for all of the compositions in the X-ray diffraction pattern. A comprehensive investigation of Raman spectra revealed the vibrational and phonon modes of the molecular structure. The dielectric investigation of sintered samples in temperature and frequency dependence revealed two dielectric peaks attributable to factors generated by phase transitions from ferroelectric to antiferroelectric and antiferroelectric to paraelectric. With a low remanent polarization ( Pr = 0.65 µC/cm 2 ) and a coercive field ( Ec = 8.62 kV/cm), the polarisation hysteresis (P–E) loop demonstrated optimal electrical performances.

Suppression of intrinsic thermal conductivity in Sr1-x Gd x TiO3 ceramics via phonon-point defect scattering for enhanced thermoelectric application.

A substantial reduction in the thermal conductivity for strontium titanate (ABO3) perovskite structure was realized for the A-site substitution of gadolinium (rare earth element) in SrTiO3 ceramics. The effect of Gd3+ substitution on the structure, composition, and thermoelectric properties of SrTiO3 was investigated. The substitution of Gd3+ in the SrTiO3 matrix resulted in the minimalization of thermal conductivity. The thermal conductivity followed a similar trend as that of thermal diffusivity, but specific heat capacity exhibited a non-monotonic trend. The thermal conductivity is reduced to 1.05 W m-1 K-1 for the minimal substitutional composition (Sr0.99Gd0.01TiO3) which is 30% less than that of SrTiO3 at 303 K. The variation in the ionic radii and atomic mass of the heavier rare earth Gd3+ substituted over Sr2+ resulted in the reduction of thermal conductivity of SGTO ceramics caused by the corresponding boundary scattering at low temperatures and temperature-independent phonon-impurity scattering at high temperatures.

Atomic scale network structure of a barium aluminosilicate glass doped with different concentrations of rare-earth ions explored by molecular dynamics simulations

Molecular dynamics (MD) simulation is employed for exploring the coordination of atoms in peralkaline BaO-Al2O3-SiO2 glasses of variable Gd3+ doping concentrations between 1 and 3.8 mol% Gd2O3. For this the MD simulation procedure of inherent structure sampling was used which provides statistically robust information on the local atomic surrounding of the doped rare earth ions. Distributions of Si/Al/Ba/Gd cations in the first, second and third coordination spheres are investigated. Special focus is laid on the effect of Gd3+ doping concentration on the local surrounding of the Gd3+ ions, i. e. rare earth clustering, and general glass structure. The simulations show that SiOAl bonds are preferred in comparison to SiOSi and AlOAl connections with respect to the random model predictions. Deviations from a statistical Si/Al distribution around the BaOp and GdOq polyhedra are observed. The network modifier ions are preferably surrounded by other network modifier ions, rather than by network formers. It is shown that the incorporation of Gd does not affect radial distribution functions, cumulative radial distribution function curves and the coordination sphere of Gd for Gd2O3 doping concentrations of up to 3.8 mol%, i.e. no rare earth clustering is observed. However, increasing Gd2O3 concentrations decrease the number of bridging oxygen and increase the number of non-bridging oxygen (NBO) species in the glass structure. Charge compensation of the additional non-bridging oxygen species is achieved by increasing NBO coordination numbers with Ba2+.

Effect of Gd3+/Ti4+ heterovalent substitution on the crystal structure, morphology, optical properties, and phase transition behavior of bismuth layer-structured SrBi2Nb2O9

The double-layer Aurivillius compounds Sr1-xGdxBi2Nb2-xTixO9 (x ​= ​0, 0.2, 0.4, 0.6, 0.8, and 1), which have the potential to be developed as a ferroelectric material, have been synthesized using the molten salt method. This study aims to investigate the effect of the simultaneous substitution of Gd3+ and Ti4+ ions in SrBi2Nb2O9 on the phase formation, crystal structure, morphology, and ferroelectric properties. The single-phase product with A21am orthorhombic structure was obtained for all samples by X-ray diffraction analysis. The unit cell becomes more orthorhombic with increasing x as the degree of tetragonality increases. SEM micrographs demonstrate the plate-like grain morphology with an anisotropic growth direction, and the grain is smaller in size with increasing x. FTIR spectra indicate that cation substitution was successful, especially Ti4+ ions at the B-site. With increasing x, the ferroelectric transition temperature (Tc) increases, which has been explained in terms of a reduction in the tetragonality. The open hysteresis loops provide evidence of ferroelectric properties which is consistent with the trend of room-temperature dielectric constant. The optical bandgap value is proportional to the trend of the dielectric characteristics of the samples.

Upconversion enhanced photocatalytic conversion of lignin biomass into valuable product over CeVO4/palygorskite nanocomposite: Effect of Gd3+ incorporation

Photocatalysis has great potential on converting lignin biomass to value-added chemicals. Herein, dendritic-like CeVO4 in situ grew on the phosphoric acid-activated palygorskite (P-Pal) nanorod surface and 5% incorporation of Gd3+ ions achieved the strongest up-conversion property, which converted near infrared (NIR) light into UV and visible light boosting the absorption range of solar energy. Under optimized 6 h sunlight irradiation, the highest conversion rate of sodium lignosulfonate (SLS) can reach 73.2%, and the vanillin yield can reach 4.5 mg/gSLS. Gd3+: CeVO4 and P-Pal formed well-defined Z-scheme heterojunction which retained strong redox ability of charge carriers, and·O2- acted as the main reactive species for the photocatalytic conversion of SLS to valuable products. Notably, abundant Lewis acid sites and Brønsted acid sites induced by phosphoric acid acted as active sites boosting the cleavage of C-C bonds in SLS. Present work offers an alternative for mineral-based catalysts toward photocatalytic conversion of biomass.

Improved linear and nonlinear optical properties of PbS thin films synthesized by spray pyrolysis technique for optoelectronics: An effect of Gd3+ doping concentrations

In the present article, the pure PbS and different concentrations of Gd doped PbS (Gd:PbS) films were developed using the spray pyrolysis route by growing thin films on the glass substrate. The estimated crystallite sizes were found from 15.5 to 20.8 nm for as-deposited films. The spherical shape morphology of grains was observed by FESEM. The obtained average grain sizes varied from 52.8 to 108.2 nm were obtained from the grain size distributions for 0.0, 0.5, 1.5, and 2.5 wt % Gd: PbS films, respectively. Extinction coefficients of as-deposited films were measured from 0.04 to 0.12 in the range of wavelength 200–2500 nm. Refractive indices of films were obtained from 5.4 to 1.22 in range of 200–2500 nm wavelength. The band gaps of 2.75, 2.64, 2.45, and 3.10 eV for 0.0, 0.5, 1.0 and 2.5 wt % Gd thin films were estimated using Tauc's relation respectively. The values of the dielectric constant, dielectric loss, and optical conductivity were recorded in the range of 1.32–29.6, 0.30–0.61, and 2.34 × 1014–3.08 × 1013 between 200 and 2500 nm wavelengths for as-deposited thin films respectively. The optimum values of linear susceptibility, non-linear susceptibility and refractive index were recorded in the range of 1.23–2.93, 5.21 × 10−10 - 120 × 10−10, 3.54 × 10−9 – 74.2 × 10−9 (esu) between 1.46 and 0.52 eV respectively for as-deposited thin films. The Gd: PbS thin films improve the physical properties and therefore, it becomes suitable candidature for the applications in optoelectronic devices.

Effect of Gd3+-Sm3+ Energy Transfer on the Luminescence Properties of Ba-Na-B Glasses

In this work, Sm3+-doped Ba-Na-B glasses with the varying of Gd3+ concentration from 0 to 10 mol% were prepared by melt-quenching technique. The absorption spectra show the highest peak at 402 nm (in UV-Vis region) and at 1227 nm (in NIR region). The emission spectra, excited by 402 nm excitation wavelength, show the emission peaks centered at 563, 600, 646 and 706 nm. The glass sample with 2.5 mol% of Gd3+ ions show the highest light yield. The emission spectra, excited by 275 nm for investigation of Gd3+ to Sm3+ energy transfer, also highest emission peaks observed at 311 and 622 nm for Gd3+ ions. The emission peaks observed at 563, 600, 646 and 706 nm for Sm3+ ions. The glass sample with 7.5 mol% of Gd3+ ions show the highest light yield because of the better energy transfer from Gd3+ to Sm3+ ions. The color of the emission from these glass samples are located in orange emission region when excited with 402 nm and located in reddish-orange emission region when excited with 275 nm.

Effect of Gd3+ substituted Cadmium silicate nanophosphor for dosimetric applications

The Gd3+ substituted CdSiO3 nanophosphors (1–9 mol %) have been synthesized by using solution combustion (SC) method. Phosphors have been well reported by powder X-ray diffraction (PXRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR) and UV–Visible spectroscopy. PXRD patterns reveal monoclinic CdSiO3 phase which can be obtained for calcining the samples at 800 °C for 2 h and average size of the samples is (22–42) nm as calculated by Scherer's formula and W–H plots. SEM micrographs show that crystallites are of agglomerated and irregular in shape. The band gap was evaluated by Wod and Tauc method is in the range of (5.18–5.35) eV. A fine determined single Thermoluminescence (TL) glow peak at 138 °C was verified for all the UV exposed models. So prepared nanomaterial's can used in nano-radiation dosimeters.

Effect of Gd3+ Doping on Sol-Gel Prepared Y₂O₃ Films as Gate Insulators for Oxide Thin Film Transistors.

The relationships between the microstructure and the dielectric properties of sol-gel prepared Y₂O₃ films with various Gd3+ doping were systematically investigated. Robust solution processed lanthanide films, (Y1-xGdx)₂O₃ (0 < x ≤ 0.5), are demonstrated as high-k gate insulators for low voltage-driven oxide thin film transistors and their optimized composition is presented. With the proper amount of Gd3+ doping, the corresponding thin film insulators exhibit low leakage current with increased dielectric constant. The resultant Zn-Sn-O/(Y, Gd)₂O₃ TFT exhibits enhanced performance, by a factor of 10.7 compared with TFTs using a SiO2 insulator, with a field-effect mobility of ~3.15 cm²V-1s-1 and an exceptionally low operating voltage <15 V.