Rare Earth Tb Research Articles

The Effect of Grain Size on the Diffusion Efficiency and Microstructure of Sintered Nd-Fe-B Magnets by Tb Grain Boundary Diffusion.

The grain boundary diffusion process (GBDP) of heavy rare earth Tb is an effective method to improve the coercivity of Nd-Fe-B magnets, and the matrix grain size has a crucial effect on the diffusion efficiency and depth of the Tb element. In this work, magnets with different grain sizes have been fabricated using powder metallurgy to investigate the effect of grain size on Tb diffusion efficiency and the microstructure of Nd-Fe-B-type magnets. After the Tb diffusion process, the coercivity increment of the magnet with 4.9 μm large grain is 8.60 kOe, which is much higher than that of the magnet with 3.0 μm small grain (~5.90 kOe), which clearly demonstrates that the coercivity increment decreases as the grain size decreases. Microstructure analysis suggested that grain refinement significantly increases the total surface area, resulting in narrowing and discontinuity of the grain boundary phase (GBP). Therefore, as the channel for diffusion, the narrowing and discontinuity of the GBP are unfavorable for diffusion, resulting in a decrease in diffusion efficiency.

Magnetism and spin transport at permalloy/Cu1−xTbx interfaces

The significance of spin transport over an interface in energy-efficient spintronic devices has stimulated interest in the spintronic society during the last few decades. Here, interfaces of $\text{permalloy}/{\mathrm{Cu}}_{1\ensuremath{-}x}{\mathrm{Tb}}_{x}$ (Py/Cu-Tb) were investigated in depth. As the Cu-Tb thickness increases, we found that the saturation magnetization of the bilayers falls and then plateaus. Element-specific x-ray magnetic circular dichroism studies suggest that the Tb moment aligns opposite to the Fe and Ni moments, forming a self-assembled antiferromagnetic interface. As a result, the Cu-Tb adjacent layer to Py and the interface have a significant impact on spin transport. Relevant parameters, such as spin mixing conductance, spin diffusion length, and damping, can be tuned by inserting a thin Cu layer between Py and Tb or varying the compositions of Cu-Tb alloys. Using rare-earth Tb, we provide an effective method for controlling the spin transport and magnetism of ferromagnet/normal-metal interfaces. This approach is expected to have a great deal of potential in spintronic applications.

Rapid detection of lamotrigine by a water stable fluorescent lanthanide metal–organic framework sensor

Lamotrigine (LTG) is an antiepileptic drug, but excessive use of LTG can cause life-threatening skin rashes. Herein, a new type of Tb-MOF with two emitting centers for LTG detection was designed and synthesized. The unique crystal structure is derived from a hexacarboxylic acid ligand and lanthanide Tb3+ ion. The application of ratiometric fluorescence sensing improves the accuracy for detecting LTG. The Tb-MOF also displays excellent sensitivity with fast response within 40 s, low detection limit of 1.66 μM and high recyclability. This research provides important significance for using lanthanide metal–organic framework (Ln-MOF) as the platform for fluorescent sensing.

Preparation of non-polluting Tb-doped mesoporous carbon nitridephotocatalyst and study on the efficacy and mechanism of degradation of antibiotics in water.

Given that the biological treatment of antibiotic wastewater can easily induce resistant bacteria, the photocatalytic degradation of antibiotics is considered as a better method for treating antibiotic wastewater. Therefore, the ability to remove Tylosin (TYL) and Tetracycline (TC) in aqueous solution using rare earth element Tb-doped g-C3N4 under simulated natural solar radiation was investigated. A series of rare earth Tb3+ doped mesoporous g-C3N4 were successfully prepared by nitric acid treatment and Tb(NO3)3·5H2O samples showed significantly higher degradation efficiency for TYL and TC than pure g-C3N4. Leaching toxicity experiments were carried out on the catalyst using chard seeds and demonstrated negligible toxicity of the leachate from the catalyst. The structure, elemental state, optical properties, morphology, and photogenerated carrier separation of the prepared xTCN catalysts were characterized by XRD, XPS, UV-Vis DRS, TEM, and PL. The results show that Tb doping enhanced the photocatalytic activity of the g-C3N4 catalyst by narrowing the band gap while improving the light-trapping ability; The separation and transport rate of photogenerated carriers were significantly increased after Tb doping. Finally, a simple, efficient, and non-polluting Tb-doped carbon nitride photocatalyst is successfully developed in this paper.

Understanding the Role of Element Grain Boundary Diffusion Mechanism in Nd–Fe–B Magnets

AbstractGrain boundary diffusion (GBD) of multiple rare earths has proven effective in enhancing the performance of permanent magnets, whereas the diffusion behaviors are still unclear due to their intricate interactions. In this work, the synergistic effects of three rare earths (Tb, Ce, and La) on the grain boundaries diffusion process are investigated, achieving a high‐performance diffused Nd–Fe–B magnet with the high coercivity of 1822 kA m−1 and thermal stability of −0.447% K−1. This promotion originates from the improved diffusion depth of Tb at specific regions, induced by the coordination effects of Ce and La, as evidenced via electron probe microanalysis and the first‐principles calculations. It thus results in the uniform formation of Tb‐diffused magnetic harden grains, associated with the strongly pinned domain walls, which is further observed directly by in situ Lorentz transmission electron microscopy and reconstructed by micromagnetic simulations. The study provides insight into the role of element GBD mechanism and has promising potential to explore other element systems as diffusion sources for permanent magnets.

Special features of the Faraday effect in rare earth orthoaluminate TbAlO3

The luminescence excitation spectra (LES) and luminescence (fluorescence) spectra of terbium orthoaluminate TbAlO3 have been studied within the wavelength range 150–350 nm and 450–700 nm, respectively, and within the temperature range 25–300 K. Based on the results of studying the LES within the wavelength range 220–260 nm, it has been concluded that in the same range there is an intense optical absorption band due to the allowed (in the electric dipole approximation) transition 4f(8)(F76)→4f(7)5d(eg). While measuring the Faraday effect (FE) in TbAlO3 the spectral dependence of the rotation angle θ of the major axis of the polarization ellipse has been investigated for temperature 300 K over the visible and near ultraviolet (UV) spectral range 250–400 nm. From the analysis of the data of magneto-optical studies, the frequency dependence of the Verde constant of TbAlO3 in the UV spectral range has been restored. The behavior of the FE frequency dependence for the absorption band of the 220–260 wavelength indicates that there is a “paramagnetic” contribution to the Verdet constant caused by allowed (in the electric dipole approximation) transitions occurring from the Stark sublevels of the ground 7F6 multiplet to the states of the mixed excited configuration 4f(7)5d of the rare-earth Tb3+ ion in orthoaluminate.

One-step fabrication of dual functional Tb3+ coordinated polymeric micro/nano-structures for Cr(VI) adsorption and detection

Hexavalent chromium Cr(VI) has been considered as one of the most hazardous heavy metals because of its strong and persistent toxicity to the ecosystem and human beings. Herein, we have synthesized a double hydrophilic block co-polyarylene ether nitriles (abbreviated as dhPEN) bearing aromatic backbone as well as pendent carboxyl and sulfonate groups. Afterward, the synthesized dhPEN has been co-assembled with the lanthanide Tb3+ via a one-step solvent exchange protocol, leading to generation of Tb3+ coordinated dhPEN (Tb-dhPEN) micro/nano-structures that exhibit good adsorption capacity and detection sensitivity towards Cr(VI). More specifically, the direct self-assembly of dhPEN and Tb3+ in mixed H2O/DMF solvents resulted to Tb-dhPEN microparticles with lamellar structures, which exhibited a high Cr(VI) adsorption capacity approaching to 402 mg/g. The detailed characterization confirm that Cr(VI) is adsorbed and partially reduced to Cr(III) by the Tb-dhPEN microparticles via chemical interaction. Furthermore, the self-assembly of dhPEN with Tb3+ in the H2O/DMF mixed solvents containing NaOH contributed to the generation of spherical nanoparticles showing green emission at 545 nm, which can be selectively quenched by the Cr(VI), leading to the specific detection of trace concentration of Cr(VI) down to 0.12 nM as well as reliable determination of Cr(VI) presented in real environmental samples.

Selective incorporation of rare earth elements by seaweeds from Cape Mondego, western Portuguese coast

This study examined the mechanism of incorporation of the rare earth elements (REEs), La, Ce, Nd, Eu, Gd, Tb, Yb, into green (Codium tomentosum, Ulva rigida), red (Gracilaria gracilis, Osmundea pinnatifida, Porphyra sp), and brown seaweeds (Saccorhiza polyschides, Undaria pinnatifida) collected from a single site near the coastline of the Cape Mondego, western Portugal. The concentrations of REEs, Mg, Ca, Al, Fe, Zn, and Cu in the biomasses were determined by inductively-coupled plasma mass spectrometry (ICP-MS). The species showed differences in their incorporation and fractionation of REEs from the same environment: the sum of REEs was higher in U. rigida, C. tomentosum, G. gracilis, and O. pinnatifida (0.7–1.7 μg g−1) than in Porphyra sp., S. polyschides, and U. pinnatifida (0.1–0.2 μg g−1). Ratios of Ce/Yb ranged from 13 (in S. polyschides) to 103 (in U. rigida), indicating different proportions of light and heavy REEs among species. Good correlations were found between Al and Fe (R2 = 0.98), and between these elements and La, Ce, Nd, Gd (R2 = 0.88–0.97) and Yb (R2 = 0.66–0.71) for all species except C. tomentosum and G. gracilis. Profiles of REE values normalised to average upper-continental crust composition indicated positive anomalies of Eu and Tb that reinforced the singularity of these elements in the REE group. Correlations between the REEs and Al or Fe suggest that detrital terrigenous particles, adhered to seaweed walls, may be an important mechanism for the incorporation of REEs by seaweeds. Different patterns for C. tomentosum and G. gracilis may also be indicative of the higher influence of cell wall composition on REE incorporation.

Rare-Earth Doping Graphitic Carbon Nitride Endows Distinctive Multiple Emissions with Large Stokes Shifts

Rare-Earth Doping Graphitic Carbon Nitride Endows Distinctive Multiple Emissions with Large Stokes Shifts

Novel phosphonate-functionalized composite sorbent for the recovery of lanthanum(III) and terbium(III) from synthetic solutions and ore leachate

A new process of phosphorylation of algal/polyethyleneimine composite beads allows to dramatically increase the sorption of rare earth elements (La(III) and Tb(III), as light and heavy REE elements, respectively). Sorption proceeds through interactions with several functional groups (phosphonate, but also amine, and carboxylate groups). The sorption capacity at optimum pH (pH0 : 5, pHeq : 4–4.2) reaches 1.44 mmol La g−1 and 1.02 mmol Tb g−1 (increased by 4.5 to 6.7 compared with raw beads). Sorption isotherms are fitted by the Langmuir equation, while fast uptake kinetics (equilibrium within 20–30 min) is described by the pseudo-first order rate equation. Bound metal ions are quantitatively desorbed using a 0.2 M HCl/0.5 M CaCl2 solution; the recycling of the sorbent for five cycles of sorption and desorption shows high stability of sorption (loss of sorption capacity < 9%) and desorption (efficiency > 99%). The sorbent exhibits a remarkable preference for REEs against Si(IV), Ca(II), and Mg(II). The sorbent is used efficiently for the recovery of REEs from acidic leachates of a sedimentary ore. A global process is designed including acidic leaching, pre-treatment of leachates by U(VI) sorption on quaternary ammonium (QA) resin (about 94% of U content). The outlet solution of QA resin is treated at different pH values: the best results are obtained at pH0 5 (pHeq : ~4.5). The REEs are selectively recovered from the eluates by precipitation with oxalic acid: the REE-oxalate precipitate retains 70–76% of its content in the acidic leachates. After precipitation of Al(III) and Fe(III) at pH 5, residual uranium is recovered by precipitation at pH 9 (4.3% of metal leached from the ore).

Impact of terbium inclusion on the photodetection performance of ZnO thin films

Terbium (Tb)-doped ZnO thin films were fabricated using the successive ionic layer adsorption and reaction route. Their structural, morphological, optical, and ultraviolet photosensing properties were studied and compared with those of pure ZnO thin films. The x-ray diffraction results illustrate that the pure and Tb-doped ZnO films reveal hexagonal structures with the P63mc space group. The 1% Tb-doped ZnO film shows an increase in the absorption and a decrease in bandgap value from 3.24 eV to 3.15 eV compared to pure ZnO. The photoluminescence results reveal the existence of emission centers at 388, 414, 441, and 477 nm in the fabricated thin films. By increasing the rare earth (Tb) element, the near band edge emission was decreased and correspondingly increased the blue emission due to its 4f orbital energy transition. The photosensing parameters, such as responsivity, external quantum efficiency, and specific detectivity values of the 1% Tb-doped ZnO detector, are 2.21 × 10−1 A W−1, 75%, and 1.84 × 1010 Jones, respectively, which are higher compared to the other fabricated devices due to their better optoelectronic properties. For the 5% Tb-doped ZnO detector, the I–V characteristic curve shows a non-linear behavior, which indicates that a small Schottky barrier is formed in the detector due to widening of the potential barrier and depletion region by Tb. We also investigated the possible energy band diagram of both linear and non-linear (Schottky barrier) behaviors for Tb-doped ZnO detectors.

Study of Solidification Thermal Analysis, Microstructure and Mechanical Characteristics of A384 Cast Alloy Treated with Rare Earth (Sm, Tb, Ce and La) Elements

This article investigates the refining and modification response of cast A384 aluminium alloy induced by the addition of rare earth elements and the impact on microstructural and mechanical performance. Thermal analysis technique is used to develop cooling curves, and the first and second derivatives were obtained for each solidification cooling curve and used to identify the sequence of reactions and phase crystallization during solidification without and with Sm and/or Tb or La and/or Ce additions. Microstructural characteristics, hardness, strength, wear and corrosion resistance are evaluated. Optical and SEM observations in addition to EDS analysis provided more details regarding the intermetallic precipitates formed, which revealed the presence of intermetallic phases rich in Sm and/or Tb as well as Ce and/or La. It is observed that the added rare earth metals Sm plus Tb to A384 alloy improved the alloy strength and hardness due to their refining and modification effect. Furthermore, enhancement of both wear and corrosion resistance is achieved through the addition of 1.0 wt.% Samarium (Sm) to A384 samples.

Pressure-induced structural transition and antiferromagnetism in elemental terbium

Structural and magnetic properties of rare-earth Tb metal have been studied by means of neutron powder diffraction at pressures up to 9 GPa in the temperature range 7--290 K. A structural phase transition from the initial hexagonal close-packed (hcp) to the Sm-type rhombohedral phase develops gradually at high pressures above 4 GPa. The initial ferromagnetic state in the hcp phase is suppressed and an antiferromagnetic state is developed in the pressure-induced phase. In the Sm-type structure and the temperature range below ${T}_{\mathrm{MO}}=110\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ (at 9 GPa) down to 50 K, long-range order of Tb magnetic moments located in the layers resembling hexagonal close-packing type is formed with a propagation vector ${k}_{\mathrm{AF}1}=(0\phantom{\rule{0.16em}{0ex}}0\phantom{\rule{0.16em}{0ex}}\frac{1}{2})$, while the layers resembling cubic close-packing type remain disordered. This partial disorder disappears at temperatures below 50 K when magnetic order, including the moments in the latter layers, develops with a propagation vector ${k}_{\mathrm{AF}2}=(\frac{1}{2}\phantom{\rule{0.16em}{0ex}}0\phantom{\rule{0.16em}{0ex}}\frac{1}{2})$. The relative stability of the hcp and Sm-type structures under pressure was examined by density functional theory calculations, providing significant support to the experimental findings. The calculated bulk moduli of the hcp and Sm-type phases are close to the experimentally determined ones and the estimate ${P}_{0}\ensuremath{\approx}4\phantom{\rule{0.16em}{0ex}}\mathrm{GPa}$ obtained for the equilibrium transition pressure is close to the onset pressure found in real material. The volume collapse at the hcp to Sm-type transition was evaluated to amount to $0.4\phantom{\rule{0.16em}{0ex}}{\AA{}}^{3}$ per atom.

Effect of terbium doping on the optical, electrical and magnetic properties of nanocrystalline nickel ferrite

The present study focuses on the preparation and the characterization of a series of rare-earth terbium (Tb3+) ion-doped nickel ferrite (NFO) nanoparticles [(NiTbxFe2−xO4, x = 0.10, 0.15, 0.20)]. These samples were synthesized using sol–gel method. Rare-earth Tb was doped to tune the structural, optical, dielectric and magnetic features of the spinel nickel ferrite nanoparticles. Therefore, the systematic impact of Tb3+ on the structural, optical, electrical and magnetic studies were carried out. X-ray diffraction (XRD) profile reveals the presence of a single spinel ferrite phase for small doping while in moderately doped NFO NPs, an additional orthorhombic phase along with the spinel phase exists. The strain is increased in Tb-doped NFO lattice. X-ray photoelectron spectroscopy (XPS) study also confirms the presence of Tb ions at the tetrahedral site of Tb-NFO nanoparticles. In absorption spectroscopy, the shift of absorption towards the visible region is significantly increased with the increase in doping amount of trivalent Tb ion. The empirical variable range hopping (VRH) model is introduced to evaluate the density of states and the hopping range, respectively. The electrical properties of Tb-doped NFO compounds exhibit high values of dielectric constant at room temperature with Tb doping. Electric modulus study confirms the presence of non-Debye type of relaxation behaviour in the samples. Two relaxation peaks are observed at higher doping concentration. Room temperature magnetization study confers hysteresis behaviour in Tb-doped nickel ferrite nanoparticle at high frequencies. Different magnetic parameters are evaluated from the magnetic hysteresis loops. There is a significant decrease in magnetization with Tb doping due to the lower magnetic ordering of rare-earth ions.

Influence of rare earth element terbium doping on microstructure and magnetostrictive properties of Fe81Al19 alloy

Fe81Al19Tbx (x=0, 0.05, 0.1, 0.2, 0.3, 0.4) alloys were prepared by a non-consumable vacuum arc melting technique under an inert argon gas atmosphere. The microstructures of the alloys were studied by X-ray diffraction (XRD) and scanning electron microscopy combined with an energy dispersive spectroscopy (SEM/EDS). The magnetic properties and magnetostriction coefficients of the alloys were measured by a vibrating sample magnetometer (VSM) and adifferential resistive strain sensor, respectively. The results show that the Fe81Al19 alloy consists of a single A2 phase with bcc structure, whereas the Tb doped Fe81Al19 alloys are composed of the A2 phase and a small amount of rare earth-rich phase. The doping of the rare earth element Tb makes the Fe81Al19 alloy preferentially oriented along with the <100> crystal direction. With the increase of Tb content, the magnetostriction coefficient of the alloy first increases and then decreases. When x=0.1, the magnetostriction coefficient reaches the maximum, which is 146 × 10−6. Compared with the as-cast Fe81Al19 alloy (27 × 10−6), it increases by 441%. The enhanced magnetostrictive properties are mainly attributed to the preferred orientation along <100> of A2 phase of the Tb doped Fe81Al19 alloys and lattice distortion caused by the small amount of rare earth atoms entering the Fe–Al alloy lattice.

Electrochemical Recovery and Behaviors of Rare Earth (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb) Ions on Ni Sheets.

The electrochemical behaviors of rare earth (RE) ions have extensively been studied because of their high potential applications to the reprocessing of used nuclear fuels and RE-containing materials. In the present study, we fully investigated the electrochemical behaviors of RE(III) (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb) ions over a Ni sheet electrode in 0.1 M NaClO4 electrolyte solution by cyclic voltammetry between +0.5 and −1.5 V (vs. Ag/AgCl). Amperometry electrodeposition experiments were performed between −1.2 and −0.9 V to recover RE elements over the Ni sheet. The successfully RE-recovered Ni sheets were fully characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and photoluminescence spectroscopy. The newly reported recovery data for RE(III) ions over a metal electrode provide valuable information on the development of the treatment methods of RE elements.

Synthesis, characterization and spectroscopic properties of some rare earth activated LiAlO2 phosphor

The current paper comprises the synthesis of LiAlO 2 phosphor doped with rare-earth elements Tb 3+ , Eu 3+ , and Dy 3+ by microwave-assisted solution combustion synthesis method (SCS) and the spectroscopic properties were examined. The phosphors samples were identified and characterized by XRD, FT-IR, thermo-gravimetric analysis TG-DTA and SEM. All the prepared phosphors show polycrystalline nature with a grain size of about 49 nm as confirmed from XRD and SEM. Photoluminescence excitation and emission spectrum of Tb 3+ , Eu 3+ , and Dy 3+ doped LiAlO 2 with different sintering temperature and concentration of dopants were investigated. The Dy 3+ shows the strongest blue emission peak at 484 nm corresponding to the transition 4 F 9/2 to 6 H 15/2 under UV excitation of 358 nm. The Eu 3+ doped LiAlO 2 phosphor shows emission peak 591 nm to 615 nm for UV excitation of 238 nm which arise due to 5 D 0 to 7 F 1 electric dipole transitions. The Tb 3+ doped phosphor shows a broad excitation peak centered at 238 nm whereas it exhibits an emission peak at 544 nm corresponding to the peak transition 5 D 4 - 7 F 6 under the UV excitation at 238 nm.

Sensing application of novel nanocomposite based on lanthanide functionalized nanoporous material and polymer matrix

Recently, lanthanide hybrid material has aroused great interest because of its wide range application in lighting material, bio-imaging, chemical/biological sensing and so on. Here, a binary lanthanide terbium/mesoporous silica hybrid material (Tb@MCM-41), and a ternary lanthanide terbium/mesoporous silica/polyurethane hybrid material (Tb@MCM-41@PU) are reported. Typically, the lanthanide Tb3+ ions were connected onto the surface of mesoporous MCM-41 via the molecular bridge built by the synergy of silane coupling agent (APTEOS) and chelating reagent (DTPA), and then the resulted Tb@MCM-41 was encapsulated into a commercial polymer matrix (PU) to form Tb@MCM-41@PU composite film. The sensing experiments conducted in solution had proven that Tb@MCM-41 has good selective sensing ability to the dopamine molecular. And further experiments also indicated the Tb@MCM-41@PU composite film can be used as a very convenient sensor tool towards dopamine.

Enhanced oxygen reduction reaction performance of ReOx/NC (Re = La, Ce, Pr, Sm, Eu, Tb, Er, Tm and Yb)-especially Pr6O11/NC via accommodating oxygen vacancies and its application for Zn-air battery

Rare earth metals have been widely investigated for oxygen reduction reaction (ORR) owing to their special 4f shell electronic configurations. However, the systematic comparisons of ORR activity with different rare earth have yet rarely studied. Herein, a series of rare earth (La, Ce, Pr, Sm, Eu, Tb, Er, Tm and Yb) oxides electrocatalysts were prepared with ketjin black EC300J as carbon support, in which the addition of rare earth is optimized. The ORR activities of different rare earth were evaluated by rotating disk electrode technology. The ORR performance of rare earth oxides composited carbon catalysts can be enhanced through accommodating oxygen vacancies. Then, the rare earth composite catalyst with the best ORR activities was chosen to detailed exploration. For practical application, the performance of rechargeable Zn-air battery was also researched. We believe that our work lay a good foundation to further explore rare earth based ORR catalyst with higher ORR performance.

Functionalization of 1D In2O3 nanotubes with abundant oxygen vacancies by rare earth dopant for ultra-high sensitive ethanol detection

Herein, pristine indium oxide (In2O3) and rare earth (Ce, Tm, Eu, Er, and Tb)-doped In2O3 nanotubes were synthesized by a facile one-step electrospinning method. Rare-earth (RE) doping increases the number of active sites on the surface, which enhances the electrical response and gas-sensing performance of In2O3, with different RE elements causing different enhancement effects. Transmission electron microscopy elemental mapping shows a homogeneous distribution of RE elements on the whole nanotube. Analysis of the gas-sensing mechanism shows that RE doping modifies the oxygen species adsorbed on the sensor surface. Our findings promote the development of new dopant-based metal oxide semiconductors for high-performance gas sensing.