Neodymium Substitution Research Articles

Enhancing SrBi₂Nb₂O₉ ceramics: The role of neodymium substitution in structural, dielectric, and ferroelectric properties

This study investigates the impact of neodymium substitution for bismuth in SrBi2Nb2O9 (SBN) ceramics, a potential lead-free alternative for ferroelectric applications. X-ray diffraction analysis reveals a decrease in lattice parameters and volume with increasing Nd content. Scanning electron microscopy examines the influence of neodymium on grain morphology, showing a transition from characteristic SBN plate-like grains to a mix of plates and micro-spheres. Dielectric properties are evaluated, showing an increase in room-temperature permittivity for Nd-doped samples compared to the undoped counterparts. Additionally, the influence of Nd doping on relaxor ferroelectric behavior is studied. The Curie temperature (Tc) increases with Nd concentration, while the temperature dependence of relaxation time weakens. Ferroelectric properties exhibit significant changes due to Nd doping. Inverse permittivity versus temperature (ϵr−1 vs. T) measurements suggest an unconventional response, potentially due to lattice strain induced by the larger ionic radius of Nd. The potential influence of doping concentration on the order of the ferroelectric transition is also explored. Overall, neodymium substitution in SBN ceramics enhances their ferroelectric properties, making them promising for advanced electronic applications.

Microwave absorption properties of β-type ferrites: Influence of Nd-loading percentage on structural, spectral, elemental, and electrical features

Hexagonal ferrites have drawn significant attention due to a broad range of telecommunication and stealth technology applications. β-Type hexagonal ferrites are rarely used in various technological applications. In the current work, Nd3+ substituted polycrystalline β-type hexagonal ferries with composition LiFe11-x NdxO17 (x = 0.0–0.04, ∇ x = 0.01) were prepared using the sol-gel method. All prepared samples were sintered at 1000 °C for 4 h. The influence of Neodymium (Nd3+) on its structural, electrical, and dielectric properties was investigated. Lattice parameters (a, c) and Vcell increased with varying Neodymium substitution levels. The crystallite size was measured in the range of 38–42 nm. Fourier Transform IR (Infrared) spectroscopy exposed the presence of two spectral bands at 416 to 449 cm−1 and 449 to 489 cm−1. XPS (x-ray photoelectron spectroscopy) analysis verified the presence of metal ions and their chemical states in all prepared samples. The dielectric constant, loss, tan δ, and σac (ac-conductivity) decreased by increasing Nd3+ content. Jonscher's power law explains the conduction mechanism of charge carriers in all fabricated samples. The influence of relaxation time and grain boundaries on the electrical characteristics of prepared nanomaterials was investigated by impedance analysis. SEM (scanning electron microscopy) confirms the successful formation of β-hexaferrite nanomaterials. A minimum reflection loss of −32.08 dB was observed at 1.5 GHz for the x = 0.04 sample. This minimum reflection loss evidenced the novelty of the research and suggested their usefulness in high-frequency microwave applications. All samples investigated in this research work are suitable for high-frequency applications, multilayer chip inductors, and EM interference shielding.

Impact of Neodymium substitution on electrical properties in mixed phase of Bismuth containing pyrochlore (Bi2Sn2O7 and Bi2O3–SnO2)

Impact of Neodymium substitution on electrical properties in mixed phase of Bismuth containing pyrochlore (Bi2Sn2O7 and Bi2O3–SnO2)

Effect of substitution of aluminium and neodymium on structural and magnetic properties of yttrium iron garnet studied using 57Fe internal field NMR

The structural and magnetic properties of non-magnetic aluminium and magnetic neodymium substituted yttrium iron garnet samples (Y3-xAlxFe5O12 and Y3-nNdnFe5O12) were investigated. Powder samples were synthesized using auto combustion route. The Rietveld refinement analysis of the samples confirmed the presence of the garnet phase and showed presence of minimal impurity phases, specifically perovskite and hematite. Substitution on Y3Fe5O12 with Al resulted in a linear decrease in saturation magnetization, while Nd substitution showed a non-linear change. In accordance with this the Internal Field Nuclear Magnetic Resonance (IFNMR) spectrum exhibited a downward shift in peak frequency when Al was substituted, and a significant reduction in intensity with Nd substitution in yttrium iron garnet samples. Aluminium ions take up either tetrahedral or octahedral positions in the lattice, apart from the dodecahedral site, because of their smaller ionic radii. This causes a decrease in the hyperfine field that originates from Fe3+ ions in tetrahedral and octahedral sites. On the other hand, neodymium ions occupy dodecahedral sites and are expected not to affect Fe ions. Concurrently, an observable peak shift was not observed in the IFNMR spectrum for Nd substitution. However, Nd substitution introduced strain in the lattice due to their larger ionic radii compared to yttrium, which they replace. This strain causes disorder in tetrahedral and octahedral sites and affects 57Fe signal intensity. The magnetic properties observed from VSM analysis is also interpreted in view of observed changes in the 57Fe IFNMR spectrum. X-ray Photoelectron spectroscopy (XPS) was employed mainly to explore spin orbit splitting of Fe 2p state in the samples.

Structural and electrical properties of potassium and neodymium substituted SrBi4Ti4O15 ceramics

Sr1-2xKxNdxBi4Ti4O15 (x = 0.0 and 0.1) ceramics are synthesized by solid-state sintering method. The phase formation confirmation and structural parameters are obtained from X-ray diffraction analysis. The effect of potassium and Neodymium substitution on microstructure, dielectric and piezoelectric properties of ceramics are investigated. The Curie temperature is found to be decreased and the piezoelectric coefficient (d33), electromechanical coupling factor (kp) are found to be increased.

Preparation and Basic Properties of Praseodymium-Neodymium-Chromium Containing Imitation Gemstone Glass.

Imitation gemstone glass has numerous characteristics, including low cost, rich colour, stable colouring, and the formation of colour-changing effects that can meet the jewellery market demand for beautiful gemstones of middle and low grades. In this study, four types of gem-imitating glass were prepared by the elemental substitution of praseodymium, neodymium and chromium elements based on rare earth glass and examined by combining refractive index, density, spectral characteristics and colour parameters. Sample 1 contained only Pr6O11 and showed a golden-yellow colour like chrysoberyl. Sample 2 contained only Nd2O3 and showed a blue-purple colour like amethyst. Sample 3 contained Pr6O11 and Nd2O3 and appeared green under D65 light source and red under A light source, with a colour-change effect like alexandrite. Sample 4 contained Pr6O11, Nd2O3 and Cr2O3 and showed a highly saturated green colour like emerald because of the strong colouring effect of Cr3+ in the glass. The findings revealed that all four samples are transparent, with a refractive index greater than 1.5 and a density higher than 2.6 g/cm3. The comprehensive performance of the four imitation gemstone glasses can be found in the corresponding natural gemstones, which has a certain practical value.

Role of neodymium substitution on the structural, magnetic and microwave absorbing properties of nickel ferrites

The neodymium substituted nickel ferrites with a nominal composition of NiNdxFe(2-x)O4 (with x = 0.00; 0.01; 0.03; 0.05; 0.06; 0.08 and 0.10) were successfully synthesized by milling technique. The NiO, Nd2O3 and Fe2O3 powders were used as raw materials and were prepared in a mole ratio. The characterization of the samples was done by X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) and vector network analyzer (VNA). In this study, the PXRD showed and verified that all Nd3+ ion successfully substituted the NiFe2O4 samples with a single cubic spinel phase. Infrared spectra showed two strong absorption bands in the frequency range of 405–420 cm−1 and 595–610 cm−1, which were respectively attributed to tetrahedral and octahedral sites of the spinel ferrites. The SEM revealed homogenous morphology on all NiNdxFe(2-x)O4 but still not uniform powders. The particle size of the powder ranged from 150 to 700 nm. The magnetic properties of all of the samples showed a ferrimagnetic behavior. The Ms value was decreased when the Hc increased with increases in the Nd3+ substitution value. The ability to absorb the microwave measured by VNA shows the enhancement of the microwave attenuation where the Nd3+ substitution increased. The microwave attenuation changes increased from 91.25% to 98.32%. It can be seen that the composition of x at 0.05 promises to be new material for microwave absorption.

Effect of Nd3+ ions on structural, spectral, magnetic, and dielectric properties of Co–Zn soft ferrites synthesized via sol-gel technique

The substitution of Neodymium (Nd) in the cobalt - zinc (Co–Zn) ferrite was analyzed. The sol-gel technique was used to synthesize these ceramic samples. The crystalline structural, molecular characterizations, and magnetic properties were analyzed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) experiments, and vibrating sample magnetometer (VSM) respectively. XRD patterns revealed the single-phase cubic spinel structure of the samples. Lattice parameter varied from 8.41 to 8.38 Å with the inclusion of Nd concentration. The existence of two characteristic frequency bands in the range of 400–1400 cm−1 was confirmed by FTIR spectra. VSM measurements showed the magnetic behaviour at room temperature. The saturation magnetization was noted to decrease from 81 to 66 emu/g with increasing the Nd concentration. The sample having step size x = 0.025 revealed the highest coercivity and retentivity. Dielectric properties were studied and showed variation in dielectric constant, dielectric loss, ac conductivity, and energy dissipation (tangent loss) in the prepared materials.

Phase equilibria in the Nd2O3–BaO–Fe2O3 system: Crystal structure, oxygen content, and properties of intermediate oxides

AbstractThe phase equilibria in the ½Nd2O3–BaO–½Fe2O3 system were systematically studied at 1373 K in air and presented in the form of a phase diagram. By X‐ray diffraction (XRD) analysis of quenched samples, the homogeneity ranges and crystal structure were determined for the following intermediate oxides: Nd1‐xBaxFeO3‐δ with 0.0 ≤ x ≤ 0.05 (space group (SG) Pnma) and with 0.6 ≤ x ≤ 0.7 (SG Pm‐3m), Ba6+yNd2‐yFe4O15‐δ with 0.0 ≤ y ≤ 0.4 (SG P63mc), and Ba1.1Nd1.9Fe2O7‐δ (SG P42/mnm). The structural parameters of single‐phase oxides were refined by the Rietveld method. The changes in oxygen content for Nd1‐xBaxFeO3‐δ (0.6 ≤ x ≤ 0.7), Ba6Nd2Fe4O15‐δ, and Ba1.1Nd1.9Fe2O7‐δ versus temperature in air were determined by thermogravimetric analysis. Gradual substitution of neodymium by barium in the Nd1‐xBaxFeO3‐δ (0.6 ≤ x ≤ 0.7) oxides leads to a decrease of oxygen content. Partial ordering via formation of separate domains with ap × ap × 5ap superstructure in Nd0.4Ba0.6FeO3‐δ, which cannot be detected by XRD, noticeably influence its thermal expansion and electrical conductivity.

Role of Neodymium Substitution on the Structural, Magnetic and Microwave Absorbing Properties of Nickel Ferrites

Role of Neodymium Substitution on the Structural, Magnetic and Microwave Absorbing Properties of Nickel Ferrites

STRUCTURAL, MORPHOLOGICAL STUDY OF NEODYMIUM SUBSTITUTED COBALT ZINC FERRITES NANOPARTICLES SYNTHESIZED VIA CO-PRECIPITATION METHOD

Neodymium (Nd) doped cobalt, zincferrite nanoparticles, i.e; Co0.5Zn0.5Fe2-xNdxO4, were synthesized using co-precipitation method. The compositional characterization was done by Fourier transmission infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and XRD. To understand the structural and magnetic properties of cation dispersal has been proposed and found to be in agreement with experimental observations. The XRD analysis confirmed that the prepared material is single phase spinel cubic. XRD analysis gave average crystallite size in the range 29.9-31.4 nm. There was a slight increase in crystallite size with the Neodymium substitution. The average value of lattice parameter came as 8.095-8.26 Å. The absorption bands observed through FTIR analysis were in the expected range for the single phase spinel cubic. SEM analysis showed that the irregular grains were formed in the micrometer range.

Optical, magnetic and magneto-transport properties of Nd 1-xAxMn0.5Fe0.5O3-δ (A=Ca, Sr, Ba; x=0, 0.25)

The effect of A-site doping by alkaline earth metals (A = Ca, Sr and Ba) on optical, magnetic, and electrical properties of Nd1-xAxMn0.5Fe0·5O3-δ (x = 0, 0.25) has been investigated. The UV–vis absorption spectra show that the A-site doping decreases the absorption. Two values of optical band-gap energy (Eg) can be estimated for each studied sample: the higher Eg value is associated with the charge transfer involving iron cations and the lower Eg value – with the charge transfer via manganese cations. Partial substitution of neodymium by alkaline earth metals decreases the Néel temperature (TN) and induces significant irreversibility between the zero-field cooled (ZFC) and field-cooled (FC) data below TN. The field-dependent magnetization at 3 K indicates antiferromagnetic ordering with a spin canting. Temperature dependencies of resistivity demonstrate the change from metallic to semiconductor-type conduction (with increasing temperature) at T = Tp < TN. The Tp temperature significantly decreases with doping. The introduction of alkaline earth metals in Nd1-xAxMn0.5Fe0·5O3-δ noticeably reduces the resistivity in the semiconducting region. The small polaron hopping (SPH) mechanism of conduction is suggested at T > TN. Within the range of Tp < T < TN, the resistivity data are interpreted by the variable range hopping (VRH) mechanism. A significant value of magnetoresistance (∼44%) is observed only for Nd0.75Sr0·25Mn0·5Fe0·5O3-δ at 120 K.

Effect of neodymium stimulation on the dielectric, magnetic and humidity sensing properties of iron oxide nanoparticles

Neodymium-doped iron oxide (Nd–Fe2O3) nanoparticles (NPs), synthesized via chemical co-precipitation method where particle size is reduced due to the neodymium doping. The addition of neodymium doping, the applied thermal energy of Fe2O3 changes the dielectric constant and loss. At this juncture, the dielectric constant increases due to the elevation of neodymium concentration and thermal energy which eventually reduces the dielectric value. On comparison of dielectric performance, the pristine Fe2O3 endows a high dielectric constant and loss in comparison to Nd–Fe2O3. Neodymium induces the transition from antiferromagnetic to superparamagnetic. The as-fabricated sensors confirm humidity sensing at different ranges. Fascinatingly, the sensitivity of the sensor has increased owing to the increase of neodymium substitution and decrease of particle size while the response time is decreased. The sensors confirm outstanding performance in corrosive environment and their response and sensitivity time values are respectively 5s and 85%.

Effect of neodymium on barium-based spinel ferrites

In the present work, the effect of neodymium on the barium-based spinel ferrites has been investigated. A series of spinel ferrites with compositions BaNdyFe2-yO4 (y = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10) was synthesized by the sol–gel technique. These spinel ferrites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), electrical properties, and magnetic properties. X-ray analysis ascertained the formation of single-phase cubic spinel structure for all samples, while some traces of second phase recognized as orthorhombic phase NdrFeO3 in the last two samples. There was an overall increase in the lattice parameter as neodymium (Nd) contents were substituted. There was a regular increase in bulk density and X-ray density with the increase in neodymium concentration. Electrical measurements demonstrate that resistivity and activation energy increase with the neodymium substitution, while dc resistivity decreases with the rise of temperature showing the semiconductor nature of the synthesized ferrites. Curie temperature dropped with the substitution of neodymium concentration. Magnetic properties of the synthesized materials were studied between applied magnetic field range − 2 KOe and + 2 KOe and corresponding M–H loops were obtained. The saturation magnetization and remanence decreased on the substitution of Nd while coercivity (Hc) values enhanced. The smaller values of anisotropic constant exhibited the isotropic nature of these ferrites. The prepared spinel ferrites might be suitable for high-frequency multilayer chip inductors.

Recycling and substitution of light rare earth elements, cerium, lanthanum, neodymium, and praseodymium from end-of-life applications - A review

The light rare earth elements (LREEs) lanthanum, cerium, neodymium and praseodymium are increasingly used in renewable energy technology and are applicable in portable electronic devices, such as phosphors in lightning applications and in catalysis. The extraction of REEs from virgin ores causes environmental degradation. LREEs are considered as critical metals. To overcome the environmental and criticality challenges of LREEs, recycling presents means by which they can be obtained from secondary sources. Presently, the recycling rate of LREEs is still very low. Substitutes of LREEs in most cases are either inferior or still undiscovered. This study investigates the criticality challenges and environmental impacts of producing LREEs from virgin ores. It focuses on LREEs obtainable in selected end-of-life products considered to have significant recycling potential; these include NdFeB magnets, Ni-MH batteries, phosphors in lighting and catalysts. Current recycling technologies, including representative methods and current recycling challenges are also reviewed. Although current recycling technologies have recorded growth, there is still a need for further improvements. The article highlights current LREEs substitution advances and the faced challenges in finding suitable LREEs substitutes. Furthermore, future ways to promote sustainability of LREEs recycling, to improve substitution, and to tackle the criticality challenges of LREEs are proposed.

Sintering and ionic conduction of neodymium-bearing fluorobritholites

Abstract The present work describes the sintering and ionic conductivity of rare-earth-based fluorobritholite (Sr8La2-xNdx(PO4)4(SiO4)2F2 with 0 ≤ x ≤ 2). The materials were prepared via conventional solid state reactions. The analysis and characterization of the synthesized powders were carried out using several techniques. The samples’ ionic conductivity σ was measured via a complex impedance spectroscopy. The results showed that the substitution of lanthanum and/or neodymium by strontium and silicates by phosphorus in fluorapatite has been established and well-crystallized single-phase apatites were consequently obtained as a result. The neodymium-lanthanum substitution was total according to the small dimensional differences between the two cations. Next, the powders were after that compacted into pellets and then pressurelessly sintered at a 1250–1450 °C temperature range. The relative densities of the sintered bodies were found to depend on sintering temperature as well as on Nd content. The 90% relative density was obtained with x = 2 sample sintered at 1250 °C. The microstructures of the densest bodies were characterized by a closed porosity. The measured ionic conductivity σ of the samples was found to depend simultaneously on both the Nd content and the heating temperatures, while the maximum value of 2.73 10−6 S cm−1 was obtained at 780 °C for x = 2. A correlation between material structures and densification ratios with the ionic conductivity σ was detailed.

Combination of structural and microstructural effects in the multiferroic response of Nd and Ti co-doped BiFeO3 bulk ceramics

Different dopant strategies are currently under investigation in order to overcome the many problems that limit the commercial viability of BiFeO3-based ceramic devices. Neodymium substitution onto the A site of the perovskite lattice provokes significant changes in the crystal structure of the parent material which can derive in enhanced multiferroic properties, but the conductivity in the bulk system is still too high. Titanium doping on the other hand generates a distinctive micro-nanostructure in the consolidated ceramics which can largely increase the dc resistivity of the whole material. A combination of these two effects is here attempted in a co-doping approach which evidences that the microstructural effect caused upon Ti-doping, provoking a reduction of the leakage currents, eventually allows the co-doped material to capitalize on the unique piezoelectric and magnetic properties structurally triggered by the Nd-doping.

Self-Organized Growth of Clustered Structures in La0.6–xNd x Sr0.3Mn1.1O3–δ Doped Perovskites

Our results on the atomic order in La0.6–xNd x Sr0.3Mn1.1O3–δ manganites with partial Nd substitution for La (x = 0–0.4) demonstrate that all of the materials consist of differently sized groups: microcrystalline groups with long-range atomic order, D = 300–600 A in size; clustered groups with mesoscopic atomic order and D = 100–200 A; amorphous clustered groups with D = 20–30 A; and a disordered material with short-range atomic order, on a length scale of two or three interatomic distances (D ~ 10 A). It has been shown that, in the case of partial Nd substitution for La (x = 0.1–0.2) in the manganite, clusters 100–200 A in size, as well as those of the rhombohedral phase 20–50 A in size, initiate an FM → AFM magnetic phase transition in the range 200–250 K. Neodymium substitution for half of the lanthanum (in La0.3Nd0.3Sr0.3Mn1.1O3–δ) has been found to result in the development of self-organization processes, with a reduction in cluster size fluctuations in the range ΔD ≈ ±50 A in the orthorhombic ferromagnetic and rhombohedral antiferromagnetic phases.

Effect of neodymium substitution on crystalline orientation, microstructure and electric properties of sol-gel derived PZT thin films

Pb(NdxZr0.52Ti0.48)O3 (PNZT) (x = 0%, 1%, 2%, 3%, 4%, 5%) thin films were prepared by sol-gel process to investigate the effects of neodymium substitution on crystalline orientation, microstructure and electric properties of lead zirconate titanate (PZT) films. X-ray diffraction (XRD) and scanning electron microscope (SEM) analysis showed that PNZT films with Nd doping concentration below 3% exhibited dense perovskite structure with (100) preferred orientation. The average grain size of PNZT films decreased as the Nd substitution increased. The maximum dielectric constant, remnant polarization and minimum coercive field were obtained in 2% Nd-doped PZT films. Fatigue resistance was also improved significantly with 2% Nd dopant.

Improved dielectric resonator through Nd substitution in SrLa 4 Ti 4 O 15 ceramics at microwave frequencies

Abstract The effects of neodymium substitution on the sintering temperature and microwave dielectric properties of SrLa 4 Ti 4 O 15 were investigated. A single-phase solid solution with a hexagonal structure was formed in Sr(La 1−x Nd x ) 4 Ti 4 O 15 (x = 0.01–0.1) ceramics. By increasing x from 0.01 to 0.07, the dielectric constant and Q×f value of the sample increased at a sintering temperature of 1590 °C and thereafter decreased. In addition, the increase in the dielectric constant and Q×f value with increasing sintering temperature was in agreement with the increase in density in the composition range of 0.01–0.1. The zero temperature coefficient of resonant frequency of the Sr(La 1−x Nd x ) 4 Ti 4 O 15 (x = 0.01–0.1) ceramics also improved with increasing Nd content. Nd substitution resulted in excellent microwave dielectric properties, obtaining e r = 47.5, Q×f = 49,900 GHz, and τ f = 0.54 ppm/°C for the x = 0.07 composition.