Properties Of Nd Research Articles

Hydrothermal Synthesis and Spectroscopic Properties of a New Glaserite Material, K3RE(VO4)2 (RE = Sc, Y, Dy, Ho, Er, Yb, Lu, or Tm) with Potential Lasing and Optical Properties

A new series of materials of the glaserite family with the general formula K(3)RE(VO(4))(2)(RE = Sc, Y, Dy, Ho, Er, Tm, Yb, and Lu) have been hydrothermally synthesized using 10 M K(2)CO(3) at 560 °C and characterized by single crystal X-ray diffraction (XRD), powder XRD, differential thermal analysis/thermogravimetric analysis (DTA/TGA), energy-dispersion X-ray (EDX), Raman, infrared, and absorption spectroscopy. All the compounds crystallize in the trigonal P3̅m1 space group (No. 164), and their structures contain VO(4) tetrahedra, REO(6) octahedra, and two different K(1)O(10) and K(2)O(12) polyhedra. The spectroscopic properties of Nd(3+), Yb(3+), or Er(3+) doped K(3)RE(VO(4))(2) (RE = Y or Lu) are also reported, and the results obtained show that these compounds have promising potential as new laser host materials.

Preparation and properties of Nd,Yb:GGG polycrystalline nanopowders

Gadolinium gallium garnet (GGG) polycrystalline powders doped with Nd,Yb were prepared by co-precipitation method. The structure, phase and properties of powders were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and fluorescence spectroscopy. XRD analysis indicated that the crystallization of Nd,Yb:GGG powders occur at 900 °C. SEM analysis showed that the morphology of the powders was irregular and the average radius is 68.74 nm. FTIR analysis manifested that pure Nd,Yb:GGG powders were formed at 900 °C. The fluorescence spectrum revealed that the most strong emission of Nd,Yb:GGG powders was 1030 nm, which was attributed to 2F5/2→2F7/2 of Yb3+. The possible formation mechanism of Nd,Yb:GGG powders were preliminarily discussed.

Influence of doping with various cations on electrical conductivity of apatite-type neodymium silicates

Abstract Apatite-type neodymium silicates doped with various cations at the Si site, Nd 10 Si 5 B O 27− δ ( B =Mg, Al, Fe, Si), were synthesized via the high-temperature solid state reaction process. X-ray diffraction and complex impedance analysis were used to investigate the microstructure and electrical properties of Nd 10 Si 5 B O 27− δ ceramics. All Nd 10 Si 5 B O 27− δ ceramics consist of a hexagonal apatite structure with a space group P 63/ m and a small amount of second phase Nd 2 SiO 5 . Neodymium silicates doped with Mg 2+ or Al 3+ cations at the Si site have an enhanced total conductivity as contrasted with undoped Nd 10 Si 6 O 27 ceramic at all temperature levels. However, doping with Fe 3+ cations at the Si site has a little effect on improving the total conductivity above 873 K. The enhanced oxide-ion conductivity in a hexagonal apatite-type structure depends upon the diffusion of interstitial oxide-ion through oxygen vacancies induced by the Mg 2+ or Al 3+ substitution to the Si 4+ site and through the channels between the SiO 4 tetrahedron and Nd 3+ cations. At 773 K, the highest total conductivity is 4.19×10 −5 S cm −1 for Nd 10 Si 5 MgO 26 ceramic. At 1073 K, Nd 10 Si 5 AlO 26.5 silicate has a total conductivity of 1.55×10 −3 S cm −1 , which is two orders of magnitude higher than that of undoped Nd 10 Si 6 O 27 .

High-field magnetic properties in Nd–Fe intermetallic compound

On the basis of the molecular field theory, an improved two-sublattice model is applied to analyze the magnetic properties in Nd2Fe17Hx (x=0, 3 and 4.9) under high magnetic fields. As is known, two types of magnetic ions exist in Nd–Fe intermetallic compound. Here, the exchange interactions of Nd–Nd, Nd–Fe and Fe–Fe are taken into account. And, as to the ferromagnetic compounds, we define the effective exchange field Hex=νχeffHe, where ν the molecular field coefficient, χeff the effective magnetic susceptibility, and He the external magnetic field. Meanwhile, the field-dependence characteristics of magnetization at different temperatures are discussed. Also, the parameters αA and αB, associated with v and χeff, are defined, and the field-dependence, temperature-dependence characteristics are analyzed. Additionally, it is confirmed that the hydrogen content shows great influence on the magnetic properties in Nd2Fe17Hx compound.

Ultrasonic, Transport, and Magnetic Properties of Nd0.5Sr0.5Mn1−x Cr x O3 Perovskites

The resistivity, magnetization and longitudinal ultrasonic velocity (V l) have been measured in single-phase polycrystalline Nd0.5Sr0.5Mn1−x Cr x O3 (x=0, 0.02, 0.05, 0.1) to clarify the Cr doping effect on the metal-insulator and charge ordering transitions. For x=0 sample, the V l shows two large stiffening just below the metal-insulator transition temperature T MI and the charge ordering temperature T CO, respectively. It is suggested that the former ultrasonic anomaly may originate from the spin-lattice effect and the dynamic Jahn-Teller effect, and the latter is due to the electron-lattice effect arising from the static Jahn-Teller effect of Mn3+. With the Cr doping, the T MI shifts to lower temperature, the maximum of magnetization becomes smaller and the resistivity remains metallic type. Furthermore, only one stiffening of ultrasonic velocity is observed below T MI in these doping samples. The analysis suggests that the Cr doping enhances the double exchange between Mn3+ and Mn4+, and thoroughly destroys the charge ordering state.

Laser action in Nd^3+-doped lanthanum oxysulfide powders

We have investigated the stimulated emission properties of Nd(3+) doped La(2)O(2)S powders at room temperature as a function of pumping energy density, excitation wavelength, and Nd(3+) ion concentration. The absolute stimulated emission energy has been measured. Expressions for the slope efficiencies and lasing thresholds as a function of rare earth concentration and pumping wavelengths, which qualitatively agree with experimental observations, are discussed.

VUV Luminescence With Nd Doped KCaF$_{3}$ Under X-Ray Excitation

Radioluminescence properties of Nd doped KCaF3 single crystals were studied. X-ray excited luminescence spectra were measured in the vacuum ultraviolet (VUV) region by using a custom-made device filled with nitrogen atmosphere. As a result, VUV luminescence was observed at 190 nm. Radioluminescence intensity due to the core-valence luminescence (CVL) of KCaF3 decreased with increasing of Nd3+ concentration.

Pressure-induced tuning of a magnetic phase separation in Nd0.53Sr0.47MnO3

X-ray magnetic circular dichroism and neutron diffraction measurements were conducted in situ at high pressure and low temperature to investigate the evolution of the magnetic properties of Nd${}_{0.53}$Sr${}_{0.47}$MnO${}_{3}$ (NSMO47). The neutron diffraction data provide the experimental evidence for the presence of antiferromagnetic domains within the conducting ferromagnetic host at ambient pressure. The antiferromagnetic phase becomes dominant above 3 GPa with a concomitant reduction of the FM phase. Those findings indicate that the magnetic ground state of NSMO47 is more complex than previously reported, confirming the coexistence of competing phases over the doping range in which colossal magnetoresistance is observed. We also find that magnetic phase separation in the form of domains appears to be an intrinsic phenomenon at high pressure.

Float zone growth and anisotropic spectral properties of Nd:LaVO4 single crystals

Nd:LaVO4 single crystals were successfully grown by the floating zone method and their optical properties along each optic elasticity axis were investigated. The crystals grown at 10mm/h in air did not contain any macroscopic defects for Nd-concentrations upto 5at%. The optic elasticity axes were determined by the conoscopic figures with a polarizing microscope. The absorption cross-section along the Z-axis was 2.6×10−20cm2 near 800nm and the FWHM was 20nm. The absorption cross-sections along other directions were much the same as that along the Z-axis. The fluorescence lifetime of the 5at%-doped crystal was approximately 80μs. All the polarized fluorescence spectra of the Nd:LaVO4 single crystal had a broadened band around 1060nm with FWHMs of 7–10nm, which are wide enough to generate femtosecond order pulses.

Effect of Sr substitution on microwave dielectric properties of Nd(Mg0.5Sn0.5)O3 ceramics

The microwave dielectric properties of Nd(1−2x/3)Srx(Mg0.5Sn0.5)O3 ceramics were examined with a view to their exploitation in mobile communication. The Nd(1−2x/3)Srx(Mg0.5Sn0.5)O3 ceramics were prepared by the conventional solid-state method with various sintering temperatures. The X-ray diffraction patterns of the Nd2.94/3Sr0.03(Mg0.5Sn0.5)O3 ceramics revealed no significant variation of phase with sintering temperatures. A density of 6.88g/cm3, a dielectric constant (εr) of 19.3, a quality factor (Q×f) of 91,200GHz, and a temperature coefficient of resonant frequency (τf) of −65ppm/°C were obtained for Nd2.94/3Sr0.03(Mg0.5Sn0.5)O3 ceramics that were sintered at 1550°C for 4h.

Growth, Structure and Spectroscopic Characterization of Nd3+-Doped KBaGd(WO4)3 Crystal with a Disordered Structure

The undoped and the Nd3+:KBaGd(WO4)3 crystals were grown by the top seeded solution growth (TSSG) method from a flux of K2W2O7. The structure of the pure crystal was determined by the single-crystal X-ray diffraction method. It crystallizes in the monoclinic symmetry with space group C2/c. In the structure, K+ and Ba2+ ions share the same 8f site with occupancy of 0.464 and 0.536, respectively. The investigation of spectral properties of Nd3+:KBaGd(WO4)3 crystal indicates that it exhibits broad absorption and emission bands, which are attributed to locally disordered environments around the Nd3+ centers. The broad absorption band is suitable for diode laser pumping.

Structure and dielectric properties of Nd x Sr1−x TiO3 ceramics for energy storage application

Structure and dielectric properties of Nd x Sr1−x TiO3 ceramics for energy storage application

Low-temperature sintering and microwave dielectric properties of Nd(Co1/2Ti1/2)O3 ceramics using glass addition of oxides

The microstructures and microwave dielectric characteristics of complex perovskite Nd(Co1/2Ti1/2)O3 ceramics with 60P2O5–15ZnO–5La2O3–5Al2O3–5Na2O–5MgO–5Yb2O3 (PZLANMY) additions (1–4wt%) prepared through the conventional solid-state route were investigated. It was found that Nd(Co1/2Ti1/2)O3 ceramics can be sintered at 1210°C owing to the sintering aid of PZLANMY-glass addition. At 1300°C, Nd(Co1/2Ti1/2)O3 ceramics with 1wt% of PZLANMY-glass addition possess a dielectric constant (εr) of 27, a Q×f value of 64,000GHz and a temperature coefficient of resonant frequency (τf) of −29ppm/°C. The PZLANMY-glass doped Nd(Co1/2Ti1/2)O3 ceramics can find applications in microwave devices that require low sintering temperature.

The Influence of Powder Particle Size on Behavior of Hot Plastic Deformation, Structure and Magnetic Properties of Nd-Fe-B Die-Upset Magnets

The influence of powder particle size on behaviour of hot plastic deformation, structure and magnetic properties of Nd–Fe–B die-upset magnets have been examined. It was found, that powder particle size strongly affected plastic properties of material during hot deformation process. Precursors made of powder with the smallest particles (d < 32 μm) shown bigger plastic resistance than those made of powder with the larger ones (32 – 88 or 88 – 350 μm). For the same pressing force and temperature, applied within hot plastic deformation process, precursors made of the smallest particle powder allowed to obtain only 56 % deformation, while the another, made of larger particle powder: 65% deformation.

Magnetic Properties of Nd<sub>0.6</sub>Dy<sub>0.4</sub>Fe<sub>3</sub>(Bo<sub>3</sub>)<sub>4</sub>

The magnetic properties of trigonal Nd0.6Dy0.4Fe3(BO3)4 substituted compound with the competitive Nd-Fe and Dy-Fe exchange interactions have been investigated. It has been shown that in Nd0.6Dy0.4Fe3(BO3)4 a spontaneous spin-reorientation transition from an ease-axis state to an easy-plane occurs near 31 K. Anomalies of the magnetization curves are observed in a spin-flop transition induced by the magnetic field B||c. The calculations were performed using a molecular-field approximation and a crystal-field model for the rare-earth subsystem. Extensive experimental data on the magnetic properties of Nd0.6Dy0.4Fe3(BO3)4 have been interpreted and good agreement between theory and experiment has been achieved using the obtained theoretical dependences.

Magnetic order and the electronic ground state in the pyrochlore iridate Nd2Ir2O7

We report a muon spin relaxation/rotation, bulk magnetization, neutron scattering, and transport study of the electronic properties of Nd${}_{2}$Ir${}_{2}$O${}_{7}$. We observe the onset of strongly hysteretic behavior in the temperature-dependent magnetization below 120 K, and an abrupt increase in the temperature-dependent resistivity below 8 K. Muon spin relaxation measurements show that the hysteretic magnetization is driven by a transition to a magnetically disordered state, and below 8 K a magnetically ordered ground state sets in, as evidenced by the onset of spontaneous muon precession. Our measurements point toward the absence of a true metal-to-insulator phase transition in this material and suggest that Nd${}_{2}$Ir${}_{2}$O${}_{7}$ may lie within or on the metallic side of the boundary of the Dirac semimetal regime within its topological phase diagram.

Microwave Dielectric Properties of Nd(Zn1/2Ti1/2)O3 Ceramics with V2O5 Additives

The microwave dielectric properties and the microstructures of V2O5-doped Nd(Zn1/2Ti1/2)O3 ceramics prepared by conventional solid-state route have been studied. Doping with V2O5 (up to 6 wt.%) can effectively promote the densification of Nd(Zn1/2Ti1/2)O3 ceramics with low sintering temperature. At 1300 °C, Nd(Zn1/2Ti1/2)O3 ceramic when added with 6 wt.% V2O5 possesses a dielectric constant of 29.9, a quality factor (Q × f) value of 105000 GHz (at 8 GHz), and a temperature coefficient of resonant frequency of −45 ppm/°C. These V2O5-doped Nd(Zn1/2Ti1/2)O3 ceramics can be used in microwave devices.

Optical pressure and temperature sensor based on the luminescence properties of Nd^3+ ion in a gadolinium scandium gallium garnet crystal

Hypersensitivity to pressure and temperature is observed in the near-infrared emission lines of the Nd(3+) ion in a Cr(3+),Nd(3+):Gd(3)Sc(2)Ga(3)O(12) crystal, associated to the R(1,2)((4)F(3/2))→Z(5)((4)I(9/2)) and R(1,2)((4)F(3/2))→Z(1)((4)I(9/2)) transitions. The former emissions show large linear pressure coefficients of -11.3 cm(-1)/GPa and -8.8 cm(-1)/GPa, while the latter show high thermal sensitivity in the low temperature range. Thus this garnet crystal can be considered a potential optical pressure and/or temperature sensor in high pressure and temperature experiments up to 12 GPa and below room temperature, used in diamond anvil cells and excited with different UV and visible commercial laser due to the multiple Cr(3+) and Nd(3+) absorption bands.

Synthesis and characterization of nanocrystalline Nd3+-doped gadolinium scandium aluminum garnet powders by a gel-combustion method

Nd3+-doped gadolinium scandium aluminum garnet (Nd:GSAG) precursor was synthesized by a gel combustion method using metal nitrates and citric acid as raw materials. The structure and morphology of the precursor and the sintered powders were studied by means of X-ray diffraction (XRD), infrared spectroscopy (IR) and transmission electron microscopy (TEM). The results showed that the precursor transformed into pure GSAG polycrystalline phase at about 800°C, and the powders sintered at 800–1000°C were well-dispersed with average particle sizes in the range of 30–80nm. Optical properties of Nd:GSAG nano-powders were characterized by using photoluminescence spectroscopy. The highest photoluminescence intensity was achieved for the powder sintered at 900°C.

Improved microwave dielectric properties of Nd(Mg0.5Sn0.5)O3 ceramics by substituting Mg2+ with Zn2+

This study elucidates the microwave dielectric properties and microstructures of Nd(Mg0.5−xZnxSn0.5)O3 ceramics for their potential applications in microwave devices. The Nd(Mg0.5−xZnxSn0.5)O3 ceramics were prepared by the conventional solid-state method with various sintering temperatures. X-ray diffraction (XRD) patterns of the Nd(Mg0.4Zn0.1Sn0.5)O3 ceramics revealed only a slight variation of phase with sintering temperatures. Additionally, a dielectric constant (εr) of 19.5, a quality factor (Q×f) of 129,200GHz, and a temperature coefficient of resonant frequency (τf) of −66ppm/°C were obtained for Nd(Mg0.4Zn0.1Sn0.5)O3 ceramics sintered at 1500°C for 4h.