Different Concentrations Of Nd Research Articles

The accumulation and effect of rare earth element neodymium on the root of rice seedlings.

Neodymium (Nd) potentially threatens ecological equilibrium for its wide usage in industries. In this study, the accumulation and effect of Nd on roots were investigated in the rice seedlings (Oryza sativa L.) exposed to different concentrations of Nd (0, 1, 10, 100, and 1000 μM). The toxic effect of Nd on rice growth was observed at the higher concentration, but the positive effects were found at the lower concentration. The accumulation of Nd was present in six different chemical forms, and the insoluble phosphate and oxalate Nd were the major forms of Nd in the roots. In addition, Nd was accumulated in the soluble fractions, organelles, and cell walls of rice seedlings, and the root cell wall was a major Nd sink site. The result of Fourier transform infrared spectrometer spectral analysis indicated that the functional groups of -OH and C-OH were the major binding sites of Nd in the cell wall of roots. Moreover, the level of reactive oxygen species (ROS) and the activity of catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) were significantly increased with the increase of Nd concentration. The enhanced antioxidant capacity also played an important role in Nd detoxification of rice seedlings. In all, the results indicated that forming of inactive oxalate or phosphate and efficient sequestration into the root cell wall was a key process in Nd accumulation and detoxification of rice seedlings.

Structural, optical and photoluminescence properties of alkaline-earth boro tellurite glasses doped with trivalent Neodymium for 1.06 μm optoelectronic devices

Abstract Alkaline-Earth Boro Tellurite (AEBT) glasses (AEBT) activated with trivalent neodymium (Nd3+) ions were made by employing conventional melt quenching technique to explore their structural details, optical and photoluminescence (PL) properties. Energy Dispersive X-ray spectroscopy (EDX), absorption, fluorescence and fluorescence decay were performed to identify their feasibility for photonic applications. Judd-Ofelt (J-O) studies used for the absorption spectral features reveals larger values for Ω2 and high radiative transition rates in AEBT glasses. The emission spectra of different concentrations of Nd3+ ions doped AEBT (AEBT: Nd3+) glasses show three transitions 4F3/2 → 4I9/2, 4F3/2 → 4I11/2 and 4F3/2 → 4I13/2 at the wavelengths 887 nm, 1064 nm, and 1334 nm respectively. Among the observed transitions, 4F3/2 → 4I11/2 is the intense one observed in near - infrared (NIR) and is useful for lasing action at 1064 nm. The optical absorption, fluorescence and decay spectral studies, reveals that one mol% of Nd3+ ions concentration is quite suitable in AEBT glasses (AEBTNd1.0) to generate lasing action at 1064 nm suitable for NIR photonic broadband amplification applications.

Laser emission at 0.89 µm in Nd3+-doped NaYF4 nanocrystalline glass ceramics

Nanocrystalline glass ceramics with different concentrations of Nd3+-doped NaYF4 are prepared by melt quenching. Different characterization methods show that the cubic NaYF4 crystalline phase has been formed. Based on the absorption and emission spectra of samples, the absorption (σabs) and emission (σsem) cross sections of Nd3+ (4I9/2 ↔ 4F3/2) in the NaYF4 nanocrystalline glass ceramics are analyzed. The absorption and emission spectra show typical absorption and emission peaks, suggesting the possibility of concentration quenching. The values of σabs and σsem reach 2.04 × 10−21 cm2 and 1.93 × 10−21 cm2, respectively, which are comparable to those of other glasses, and a positive value of the gain cross section (σg) for 0.89 µm is obtained when the population inversion is chosen as 0.2. The results show that the studied material has promising applications in waveguide lasers and optical amplifiers.

Charge compensation mechanisms in Nd-doped UO2 samples for stoichiometric and hypo-stoichiometric conditions: Lack of miscibility gap

The evolution of the crystal lattice of samples made of UO2 doped with different concentrations of Nd in stoichiometric and hypo-stoichiometric conditions has been systematically studied by X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS). The substitution of a trivalent cation for the U4+ initial position is responsible for creating local structural disorder and changes in the oxidation states. In this scenario, the lattice parameter is affected and the concentration of U5+ and formation of oxygen vacancies as well, since these are the mechanisms necessary to maintain the charge neutrality. The systematic oxidation of U4+ as predominant charge compensation mechanism over the formation of vacancies can be reduced by performing a thermal treatment under reducing conditions. This paper presents an experimental characterization of the uranium oxidation state mixture and local structure using XAS techniques in samples with chemical formula (U1-yNdy)O2-x, with y = 0.04, 0.17 and 0.25 (0<x < 0.038). In all cases, the deviation from the ideal oxygen stoichiometry of a perfect fluorite is small and the average long-range structure is not affected because also the cation substitution occurs randomly onto the metal sites of the ideal fluorite. However, the local distances of the first atomic shell depend on the actual local chemical composition. The atomic arrangement of the Nd neighbours differs from those of U, which is also sensitive to the overall concentration of Nd and the amount of vacancies.

Scintillation and TSL properties of Nd-doped TeO2–Al2O3-WO3 glasses

We evaluated photoluminescence (PL) and scintillation properties of TeO2–Al2O3-WO3 glasses with different concentrations of Nd (0, 0.1, 0.5 and 1.0 mol.%). The glass samples were fabricated by the conventional melt-quenching method. The Nd-doped samples showed sharp emission peaks due to the 4f-4f transitions of Nd3+ in PL and scintillation. The 0.5% and 1.0% Nd-doped samples showed high PL quantum efficiencies and scintillation intensities among the sample tested. Furthermore, the decay time constants for the Nd-doped samples in PL and scintillation were 140–206 and 110–123 μs, respectively. In addition, the undoped and Nd-doped samples showed thermally stimulated luminescence (TSL) with a weak glow peak approximately at 285 °C, and the detection limit of TSL (10 Gy) was much higher than that of common TSL materials.

Temperature-dependence on the lifetime of Nd3+-doped phosphate glass

The temperature dependence of the photoluminescence spectra and the lifetime of a phosphate glass (P2O5–Al2O3–Na2O–K2O) doped with different concentrations of Nd3+ ions was studied. The emission intensities of the (2S3/2, 4F7/2), (2H9/2,4F5/2),4F3/2 → 4I9/2 transitions were measured in a wide range of temperature from 80 up to 480 K. The changes in the emission band profiles were calibrated by means of the fluorescence intensity ratio method, and the results showed a small dependence on the Nd3+ ions concentration. Moreover, the 4F3/2 state lifetime shows a dependence on the Nd3+ ions concentration and temperature. The concentration quenching, Q, and the lifetime in the limit of zero concentration, τ0, were obtained as a function of temperature. In the limit of zero concentration, where the cross-relaxation process is negligible, the τ0 still showed a dependence on the temperature, where from 80 up to 200 K a thermal quenching occurs. For higher temperatures, its value keeps nearly constant at ~370 μs, in agreement with that previously found by Judd-Ofelt theory. This thermal quenching process is assigned to the population distribution between the two stark levels of the 4F3/2 state, presenting an energy difference of 77 cm−1, in accordance with the other Nd-doped materials.

Spectroscopic investigations of near-infrared emission from Nd3+-doped zinc-phosphate glasses: Judd-Ofelt evaluation

Zinc-phosphate glasses doped with different concentrations of Nd3+ ions have been prepared by the melt quenching technique and characterized the spectroscopic properties. The physical properties by means of density and molar volume are determined. The amorphous nature of the glasses has been confirmed by X–ray diffraction analysis. FTIR spectra exhibited the fundamental stretching vibrations modes of glass network. In order to study the spectroscopic properties of fabricated glasses, absorption and emission spectroscopy has been performed. Additionally, the spectroscopic properties of Nd3+ ions were analyzed using J–O theory. UV–Vis–NIR absorption spectra of glass samples divulged twelve significant peaks. Considerable enhancement of Ω2 values with increasing neodymium content indicated an improvement in the covalency and asymmetry of Nd3+ ions environment. Under the excitation of 808 nm laser diode, two near-infrared emission bands at around 890 and 1060 nm from 4F3/2 → 4I9/2 and 4I11/2 radiative transitions respectively were observed in the Nd3+ single doped glasses. The major intensity is observed for 1060 nm for such glass samples. Nd3+ ions dopant is found to augment the luminescence intensity by a factor as much as 2.23 times as the concentration of Nd3+ ions increase up to 1.5 mol%. The lifetimes of this level has been experimentally determined through decay profile studies. The developed glass possesses high fluorescence quantum efficiency (η = 96%). The results indicate that the prepared glass system could be a suitable candidate for using it as laser gain media around 1060 nm, solid-state lasers and fiber amplifiers.

Optical, Dielectric and Magnetic Properties of La1−xNdxFeO3 Powders and Ceramics

Nanocrystalline La1−xNdxFeO3 powders with different concentrations of Nd3+ have been synthesized using a modified Pechini method. Their structures were studied by X-ray powder diffraction (XRD). Furthermore, La1−xNdxFeO3 nanoceramics were prepared using a high pressure sintering technique. The luminescence spectra of the powders were investigated as a function of concentration of active dopant to check the possible energy transfers observed due to Nd3+ concentration changes. The electrical and magnetic properties of the powders and ceramics were investigated to determine the effect of Nd3+ doping on the dielectric permittivity and magnetization in the wide frequency range.

NIR photoluminescence and radioluminescence characteristics of Nd3+ doped BaTa2O6 phosphor

AbstractBarium tantalate phosphors activated with different concentrations of Nd3+ ion were synthesized via conventional solid state reaction method. The synthesized ceramic powders were characterized by X–ray diffraction (XRD), scanning electron microscopy‐energy dispersive spectroscopy (SEM‐EDS), laser diode (LD) excited near infrared (NIR) photoluminescence and X‐ray induced radioluminescence (RL) analyses. In XRD results, Nd3+ doped BaTa2O6 structure with tetragonal tungsten bronze (TTB) symmetry was observed to continue up to 10 mol%. In the examination of ceramic powders by SEM, grain size decreased with the increasing doping concentration. By using laser diode excited NIR photoluminescence of BaTa2O6:Nd3+ phosphor exhibited characteristic emissions at 877, 1080, and 1376 nm wavelengths due to 4F3/2 → 4I11/2, 4F3/2 → 4I11/2, and 4F3/2 → 4I11/2 band transitions respectively. Scintillation properties of Nd3+ doped samples from UV to near‐IR spectral region were carried out by the radioluminescence analysis. NIR and scintillation emissions initially increased by the doping concentration, and then decreased due to concentration quenching effect.

Spectroscopic investigations of neodymium doped barium bismuth fluoroborate glasses

A new series of neodymium doped barium bismuth fluoroborate glasses with the chemical composition of (70-x)H3BO3 + 5Bi2O3 + 10BaCO3 + 7.5CaF2 + 7.5ZnO + xNd2O3 (where x = 0.05, 0.1, 0.25, 0.5, 1, 2 (in wt.%) have been prepared by the conventional melt quenching method. The powder X-ray diffraction pattern confirms the amorphous nature of the prepared glasses. The Urbach energy reveals the minimum disorderness of the glass samples. Judd-Ofelt intensity parameters (Ωλ = 2, 4 and 6) were derived from the absorption spectrum and were used to calculate the emission properties. The near infrared emission spectra recorded with 808 nm laser diode excitation for different concentrations of Nd3+ ions and the emission for the 4F3/2 → 4I11/2 transition at 1060 nm found to be high intense. The measured decay curves for 4F3/2 fluorescent level exhibit single exponential nature with shortening of lifetime with increase in concentration. The laser parameters such as stimulated emission cross-section, branching ratios, gain band width and optical gain values are found to be high for BBFB:Nd3+ (0.5 wt%) glass. Hence, the results suggested that the present BBFB:Nd3+ (0.5 wt%) glass could be used as an efficient infrared laser source around 1.06 μm region.

Physical properties Nd3+ doped (SiO2–TiO2) monolithic glass for photoresistor applications

Silica–Titania glass monoliths were fabricated and doped with different concentrations of Nd3+ ions using the sol-gel method. The structure of the samples was characterized by x-ray diffraction (XRD) analysis and confirmed the amorphous structure of all the samples. The photocapacitance and photoresistance were measured at room temperature and different illumination intensities in the frequency range (20 Hz–3 MHz). The obtained results showed the vast potential of this class of materials for optoelectronic applications such as photoresistive and photocapacitive sensors.

Spectroscopic investigations of 1.06 µm emission and time resolved Z-scan studies in Nd3+-doped zinc tellurite based glasses

Zinc tellurite based glasses (TZNbTiNd: TeO2 + ZnO + Nb2O5 + TiO2) doped with various Nd3+ concentrations (0.01, 0.05, 0.1, 0.5, 1.0, 1.5 and 2.0mol% Nd2O3) were prepared and characterized through absorption, emission and decay rate measurements. Judd-Ofelt intensity parameters were derived from the absorption spectrum and used to calculate the radiative properties for the 4F3/2 → 4IJ/2 (where J = 9, 11 and 13) transitions of Nd3+ ions. Strong near infrared emission at 1.062µm (4F3/2 → 4I11/2) has been obtained for all the glasses upon 808nm diode laser excitation. The decay times from 4F3/2 level is found to be quite single exponential for different concentrations of Nd3+ ions with a shortening of lifetime with increasing concentration. In these measurements, the electronic refractive index variation is associated with the difference in the polarizabilities (Δαp) of the Nd3+ ion in its ground and excited states. The results indicate that in tellurite glasses, Δαp is relatively very high (4 × 10−25cm3) compared to other Nd3+-doped glasses. We also measured the imaginary part of the non-linear refractive index (n2′′) due to absorption saturation. Hence, the spectroscopic results indicate that the investigated glasses are potentially applicable as a 1062nm laser host as well as optical devices.

Studies of radiative and mechanical properties of Nd3+-doped lead fluorosilicate glasses for broadband amplification in a chirped pulse amplification based high power laser system

Lead fluorosilicate (SPbKNLFNd: SiO2 + PbF2 + K2O + Na2O + LiF + Nd2O3) glasses doped with different concentrations of Nd3+ ions have been prepared by the melt quenching technique and characterized the compositional, mechanical and spectroscopic properties. The elements present in the chemical composition of lead fluorosilicate glass were analyzed by X-ray fluorescence spectra (XRF). The structural analysis and OH- content has been evaluated from FTIR spectra. Judd–Ofelt (JO) theory has been applied to the absorption spectrum of 1.0mol% Nd3+-doped lead fluorosilicate glass to estimate the JO intensity parameters (Ωλ, λ=2, 4 and 6) which are in turn used to calculate the radiative properties of luminescent level of Nd3+ ions. The near infrared emission spectra recorded with 808nm laser diode excitation for different concentrations of Nd3+ ions show that the emission intensity is highest for the 4F3/2→4I11/2 transition at 1056nm. The measured decay times for the 4F3/2 level decreased with increasing Nd3+ ions concentration due to the concentration quenching. The laser parameters such as stimulated emission cross-section (σe =4.11×10–2°cm2) and Vickers's hardness (3.59GPa) were found to be higher for the 1.0mol% of Nd3+:SPbKNLF glass along with wider fluorescence bandwidth (∆λeff ~ 36nm) at ∆λp ~ 1056nm. The obtained values are strong evidence that the SPbKNLFNd glasses could be useful for broadband amplification in a chirped pulse amplification (CPA) based high power laser systems. The results obtained in the present study have been compared with similar results obtained for Nd3+:glasses.

Spectroscopic properties of Nd3+ ions in YAP nano-perovskites

Yttrium aluminium nano-perovskite doped with different concentrations of Nd3+(YAP: Nd3+) were successfully synthesized by the Pechini sol-gel method at 1200°C and 1550°C. X-ray powder diffraction patterns confirmed the monoclinic and orthorhombic structure space group P2/m and Pnma for the samples treated at 1200°C and 1550°C respectively. Yttrium aluminium garnet phase was detected in both treatments, being more noticeable at 1200°C treated samples. The non-equivalent center nature of these samples was observed performing site selection spectroscopy, confirming the presence of two different sites for the Nd3+ ions in the samples, associated with perovskite and garnet phases, previously detected in XRD measurements. The study of the luminescence dynamics of YAP: Nd3+ nano-perovskites treated at 1550°C for all concentrations was carried out, confirming the existence of the energy transfer between Nd3+ ions. Time resolved spectroscopy allowed to confirm that the thermal treatment at 1550°C was the proper one in order to obtain nano-perovskites.

Glass heating through submicron spots produced with silica microspheres

The emission spectra of phosphate glasses doped with different concentrations of Nd3+ ions have been measured and the dependence of the emission intensity on the concentration of doping ions has been explained using energy transfer models. Thus, the optimum concentration in order to obtain the maximum heating of the glass has been theoretically estimated. The glass sample doped with a Nd3+ concentration closest to the optimum was covered with silica transparent microspheres with different diameters (2, 7, and 25μm). The incident laser light at 532nm was focused through the microspheres producing submicron spots (known as photonic nanojets) that excite the doping ions in the glass and heat the matrix due to non-radiative processes. From this, the heating as a function of the microsphere diameter has been analysed.

Spectroscopic studies of Nd3+ doped lead tungsten tellurite glasses for the NIR emission at 1062 nm

Lead Tungsten Tellurite (LTT) glasses doped with different concentrations of Nd3+ ions were prepared by using the melt quenching technique to study the absorption, emission and decay spectral profiles with an aim to understand the lasing potentialities of these glasses. From the absorption spectra, the Judd–Ofelt (J–O) parameters are evaluated and in turn used to calculate the transition probability (AR), total transition probability (AT), radiative lifetime (τR) and branching ratios (βR) for prominent emission levels of Nd3+. The emission spectra recorded for LTT glasses gives three emission transitions 4F3/2→4I9/2, 4F3/2→4I11/2 and 4F3/2→4I13/2 for which effective band widths (ΔλP) and stimulated emission cross-sections (σse) are evaluated. Branching ratios (βR) measured for all the LTT glasses show that 4F3/2→4I11/2 transition is quite suitable for lasingapplications. The intensity of emission spectra increases with increase in the concentrations of Nd3+ up to 1.0mol% and beyond concentration quenching is observed. Relatively higher emission cross-sections and branching ratios observed for the present LTT glasses over the reported glasses suggests the feasibility of using LTT glasses for infrared laser applications. From the absorption, emission and decay spectral measurements, it was found that 1.0mol% of Nd3+ ion concentration is aptly suitable for LTT glasses to give a strong NIR laser emission at 1062nm.

Coherent manipulation of dipolar coupled spins in an anisotropic environment

We study coherent dynamics in a system of dipolar coupled spin qubits diluted in solid and subjected to a driving microwave field. In the case of rare earth ions, anisotropic crystal background results in anisotropic g tensor and thus modifies the dipolar coupling. We develop a microscopic theory of spin relaxation in transient regime for the frequently encountered case of axially symmetric crystal field. The calculated decoherence rate is nonlinear in Rabi frequency. We show that the direction of static magnetic field that corresponds to the highest spin g-factor is preferable in order to obtain higher number of coherent qubit operations. The results of calculations are in excellent agreement with our experimental data on Rabi oscillations recorded for a series of CaWO4 crystals with different concentrations of Nd3+ ions.

Investigation on 1.07 μm laser emission in Nd3+-doped sodium fluoroborate glasses

Spectroscopic and fluorescence properties of Nd3+ ions in sodium fluoroborate (SFB) glasses were prepared and characterized through optical absorption, emission and decay measurements. The energy level analysis was carried out using free-ion Hamiltonian model. Experimental oscillator strengths were determined by measuring the area encompassed by the absorption peaks recorded for 1.0 mol.% Nd3+- doped glasses. The Judd-Ofelt parameters (Ω2,4,6) were used to evaluate the laser characteristic parameters such as radiative transition probability (AR), radiative decay time (τR), fluorescence branching ratio (βR) and stimulated emission cross-section (σe) for the 4F3/2 metastable state. The fluorescence spectra for different concentrations of Nd3+ ions were recorded by exciting the samples at 514.5 nm Ar+ ion laser.

Fabrication and Luminescence Properties of Nd3+:Y2O3 Transparent Ceramics

Y2O3 nanoparticles doped with different concentrations of Nd3+ were prepared by the coprecipitation method, and the Nd3+:Y2O3 transparent ceramics were fabricated by vacuum sintering at 1700 degrees C, under 1 x 10(-3) Pa for 6 h. The structural, morphological, and luminescence properties of the samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and fluorescence analysis. The results show that the Nd3+:Y2O3 nanoparticles are homogeneous in size and nearly spherical, and the average diameter of the particles is in the range of 40-60 nm. There are no other phases except the Y2O3 cubic phase in the Nd3+:Y2O3 nanoparticles and transparent ceramics. Nd3+ dissolves completely in the Y2O3 cubic phase. The relative density of Nd3+:Y2O3 transparent ceramics is 99.7%, and the transmittance of the Nd3+:Y2O3 transparent ceramics exceeds 80% at the wavelength range.

Spectroscopic investigations of 1.06 μm emission in Nd 3+-doped alkali niobium zinc tellurite glasses

Thermal, structural and optical properties of Nd 3+ ions in tellurite glass (TeO 2–ZnO–Na 2O–Li 2O–Nb 2O 5) have been investigated. Differential thermal analysis revealed reasonably good forming tendency of the glass composition. FTIR spectra were used to analyze the functional groups present in the glass. Judd–Ofelt intensity parameters were derived from the absorption spectrum and used to calculate the radiative lifetime, branching ratio and stimulated emission cross-section of the 4F 3 /2 → 4I 9/2, 11 /2, 13/2 transitions. The quantum efficiency of the 4F 3 /2 level is comparable as well as higher than the typical value of the other tellurite based glasses. The decay from the 4F 3/2 level is found to be single exponential for different concentrations of Nd 3+ ions with a shortening of lifetime with increasing concentration. The experimental values of branching ratio and saturation intensity of 4F 3/2→ 4I 11/2 transition indicate the favourable lasing action with low threshold power.