Single Crystals Of Nd Research Articles

Top-seeded solution growth, spectral analysis and laser properties of a novel Nd-doped Bi2Mo2.66W0.34O12 crystal

Bulk single crystals of Nd:Bi2Mo2.66W0.34O12 with dimensions up to 80 mm × 57 mm × 35 mm were grown and the laser performances were determined.

Identification of complexes of Nd(III) with dithiophosphinic acids verifying the difference in complexation between Ln(III) and An(III).

Five complex species of Nd(III) with HA have been spectroscopically and compositionally identified as NdA3, NdA3(HA), NdA3(HA)H2O, NdA3(H2O)3, and Nd(H2O)23·3A (HA, bis(2,4,4-trimethylpentyl)dithiophosphinic acid) with the help of X-ray diffraction analysis on single crystals of Nd(H2O)9·H2O·3B (HB = bis(iso-butyl)dithiophosphinic acid.

Growth of Nd:Cr:YVO4 Single Crystals by the Optical Floating Zone Technique under Different Oxygen Partial Pressures to Control the Oxidation State of Chromium

Here we address the issue of growing single crystals of Nd and Cr codoped YVO4, a promising self Q-switching laser material, in different oxygen partial pressures. Single crystals of 1.4% Cr and 0.7% Nd codoped were grown by the optical floating zone (OFZ) technique. Our findings emphasize, as the oxygen content in the growth atmosphere is increased, the absorption band corresponding to 2A1→ 2B2 transition of Cr5+, which participates in self-Q-switching, improves significantly. Similarly, a significant improvement is observed in the present case in comparison to that grown by the Czochralski method in 2% oxygen by Pan et al. [Opt. Express 2012, 20, 2178]. Crystals grown by the OFZ technique contain fewer oxygen vacancies that inhibit the tendency of Cr ions to get reduced to the undesired +3 state. Red shift in the band gap energy is observed due to the incorporation of Nd, whereas Cr does not influence the band gap energy.

Spin-wave excitations in the ferromagnetic metallic and in the charge-, orbital-, and spin-ordered states in Nd1−xSrxMnO3withx≈0.5

Inelastic neutron scattering experiments have been performed on single crystals of Nd$_{1-x}$Sr$_{x}$MnO$_{3}$ with x$\approx$0.5. Colossal magnetoresistance (CMR) in the manganites arises from the interplay between a ferromagnetic metallic and antiferromagnetic charge and orbital ordered insulating state. Therefore, it appears important to compare these phases concerning their underlying magnetic interaction parameters. Our investigations of the spin-wave disperion in the AFM ordered state of Nd$_{0.5}$Sr$_{0.5}$MnO$_{3}$ exhibits a strongly anisotropic stiffness. The sign of the anisotropy is characteristic for the site-centered model for charge and orbital ordering in half-doped manganites. Within this model, linear spin-wave theory yields a perfect description of the experimental dispersion. Furthermore, magnetic excitations in the ferromagnetic metallic state of Nd$_{1-x}$Sr$_{x}$MnO$_{3}$ with x=0.49 and x=0.50 exhibit nearly the same magnon dispersion which can be described with a Heisenberg model including nearest-neighbor interactions.

Crystal growth and optical properties of the Nd 3+ doped LuF 3 single crystals

Thirty millimeter diameter single crystal of Nd 3+ doped LuF 3 was grown using LiF as solvent. The single phase crystallization was confirmed by the powder X-ray diffraction, and high structural perfection was demonstrated by X-ray rocking curve (XRC) measurements. FWHM of XRC for 220 reflection was 32 arcsec. No remarkable absorption due to unfavorable impurities was observed from optical absorption measurements in the VUV spectral region. The crystal showed the VUV luminescence peaking around 178 nm that is consistent with the 4f 25d–4f 3 transition of Nd 3+ ion. The luminescence intensity of Nd:LuF 3 under X-ray irradiation was significantly higher than that of reported VUV scintillators such as Nd:LaF 3 or Nd:LiLuF 4.

Crystal growth and scintillation characteristics of the Nd 3+ doped LiLuF 4 single crystals

Sixty millimeter diameter single crystal of Nd 3+ doped LiLuF 4 was successfully grown by the Czochralski technique. No remarkable absorption due to unfavorable impurities was observed from optical absorption measurements in the vacuum ultra-violet spectral region. The high crystallinity and homogeneous luminescence characteristics were found from X-ray rocking curve and cathode-ray luminescence respectively. X-ray excited luminescence spectrum was measured and the significant 4f 25d–4f 3 luminescence at 182 nm was observed in the grown crystal. The pulse height spectrum was taken upon γ-ray irradiation. As a result, the grown crystals demonstrated sufficient response to the γ-ray showing the light yield of 420 ± 30 photons/MeV. The decay curve under α-ray irradiation was also investigated and described by two component decay kinetics which consists of the decay constants of 34 and 450 ns.

The Growth of Nd:YAG Single Crystals by Czochralski Method with ADC-CGS – Preliminary Work

Although Nd:YAG was invented in the 1960s in the last century, it has been and still the most commonly crystalmaterial widely used in all types of solid-state lasers systems such as frequency-doubled continuous wave,high-energy Q-switched, and so forth in applications to the medical, industrial, military and scientific research. ACrystal Growth System namely Automatic Diameter Control – Crystal Growth System (ADC-CGS) was utilizedto prepare a single crystal of Nd:YAG grown in the direction using the Czochralski. By an effectivecontrol on the growth parameter such as maintaining temperature gradient by controlling the output power andthe growth rate, an Nd:YAG single crystal with the dimensions of 75 mm in length and 30 mm in diameter wassuccessfully produced using the ADC-CGS. The color of the Nd:YAG single crystal is slightly purple whenexposed to the light. This is a unique characteristic of YAG crystal when doped with Neodymium (Nd) followedby a better fluorescence lifetime and thermal conductivity.

Doping effects on the magnetic properties of NdRhIn5 intermetallic antiferromagnet

Abstract We report temperature dependent heat capacity and magnetization measurements on single crystals of Nd 1 - x La x RhIn 5 ( x = 0.15 , 0.4 and 0.5) and NdRhIn 5 - x Sn x ( x = 0.08 , 0.12 and 0.24). NdRhIn5 is an antiferromagnetic (AFM) compound with T N ≈ 11 K which crystallizes in the same layered tetragonal structure of the CeMIn5 family ( M = Rh , Co and Ir), where different ground states can be found by tuning the interplay among different microscopic interactions such as the Kondo effect, crystal field (CEF) effects and the Ruderman–Kittel–Kasuya–Yoshida (RKKY) magnetic interaction. Here, we explore the evolution of the AFM correlations in this Nd-based (non-Kondo) compound while perturbing the RKKY exchange by using two different substitutions: (i) replacing Nd 3 + by non-magnetic La 3 + within NdIn3 atomic planes (dilution) and (ii) substituting In by Sn in the In-sites (electronic tuning). For both types of doping, our results show the suppression of the AFM state as the La- or Sn-content is increased. This doping induced suppression of the AFM order is discussed considering the effects of dilution and effects in the tetragonal CEF using a mean-field model applied to the observed data. Our results are compared to the properties of other members of the RRhIn5 family considering the role of dimensionality in the magnetic interactions.

Preparation and characterization of Nd doped gadolinium gallium garnet nanopowders and crystals

AbstractThe structural and optical features of gallium gadolinium garnet (GGG) nanopowders doped with neodymium were investigated. Nanopowders of GGG:Nd were prepared by modified sol‐gel method using acetic acid as complexing agent. This way permitted to incorporate large amounts of dopant (up to 10 %) without destroying garnet structure. Small single crystals of Nd:GGG were grown by a μ‐pulling down method and spectroscopic features of nanopowders and their single crystal counterparts were compared. It has concluded that the Nd3+ ions are located preferentially in the same type of sites in crystal lattices of GGG:Nd nanopowders and their single crystal counterparts. In addition, it follows from the perfect agreement of emission wavelengths and line width recorded for nanopowders and single crystal samples that the crystal lattice of GGG in nanopowders is not distorted. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Zur Elektronenstruktur metallorganischer Komplexe der f‐Elemente. 70, Optische und Raman‐spektroskopische Polarisationsmessungen an einem orientierten Tris(η5‐tetramethylcyclopentadienyl)neodym(III)‐(Nd(C5Me4H)3) sowie erstmalige Beobachtung “polarisierter” elektronischer Raman‐Effekte an einem orientierten metallorganischen Einkristall: Pr(C5Me4H)3

AbstractElectronic Structures of Organometallic Complexes of f Elements. 70, Optical and Raman Spectroscopical Polarization Measurements on an Oriented Tris(η5‐tetramethylcyclopentadienyl)neodymium(III) (Nd(C5Me4H)3) as well as First Observation of “Polarized” Electronic Raman Effects of an Oriented Organometallic Single Crystal: Pr(C5Me4H)3Looking for the ideal exciting line for recording the polarized vibrational Raman spectra of a small oriented single crystal of Nd(C5Me4H)3 (1), the laser lines at 785, 632.8 and 532 nm were used. Applying the laser line at 785 nm and comparing the spectra of 1 with those of La(C5Me4H)3 (2), the former are dominated by the σ and π luminescence spectra of the transition 4F3/2 → 4I9/2, which allowed to derive an improved crystal field (CF) splitting pattern of the ground manifold 4I9/2. Using the line at 632.8 nm a number of negative peaks were observed which are due to (absorbing) f‐f transitions excited by background radiation. The band positions and intensities as well as the polarizations of these signals correspond to the case of conventional σ and π absorption spectra of a big oriented single crystal. Comparing the polarized Raman spectra of 1, 2 and Pr(C5Me4H)3 (3) (using the laser line at 532 nm), it becomes evident that compound 3 exhibits additional peaks at 183 and 510 cm−1. The existence of CF levels of those energies as well as the strong frequency dependencies and the polarization properties of these bands indicate electronic Raman effects which are extremely rare in the case of organometallics.

Lmprovement of Pinning Properties on Single Crystals of Nd1+xBa2-xCu3O7+δ

To obtain useful information on how to improve the irreversibility field Hirr and critical current density Jc in RE123 systems, the critical current properties of Nd1+xBa2-xCu3O7+δ(Nd123) have been studied. Various parameters, such as partial pressure of oxygen P(O2) during the growth of single crystals, the influence of post-annealing at 900‣ and quenching under different P(O2), the oxygen annealing under high P(O2) and element-substitution into the crystals, were systematically changed. On special notice is that Hirr of the Nd123 single crystal was remarkably increased by partial substitution of Ca for the Nd-site up to 13.3 T at 77 K.

Evaluation of Jc anisotropy in Nd123 single crystals

Magneto-optical (MO) measurements were performed for the ac-plane of Nd123 single crystals to evaluate their Jc anisotropy (Jca/Jcc) as functions of temperature, carrier doping level and Nd/Ba composition. Nd123 single crystals with various Nd/Ba compositions were grown by self-flux method. The MO images taken for the ac-plane of Nd123 single crystals were transformed into the magnetic field distribution and Jc anisotropy was evaluated. Jc anisotropy was strongly influenced by carrier concentration, while it was almost unchanged by Nd/Ba composition. Jc anisotropy systematically decreased with an increase of the carrier concentration independent of the Nd/Ba composition. In addition, the notable temperature dependence was not observed in Jc anisotropy between 15 and 50 K. Absolute values of Jcc abruptly increase by approaching carrier optimally-doped state due to a decrease in the Jc anisotropy and enhancement of Jca.

Possible experimental signature of charge-orbital density waves inNd1−xCa1+xMnO4: Heat capacity and magnetization study

Single Crystals of Nd$_{1-x}$Ca$_{1+x}$MnO$_{4}$ have been prepared by the travelling floating-zone method, and possible evidence of a charge -orbital density wave in this material presented earlier [PRB68,092405 (2003)] using High Resolution Electron Microscopy [HRTEM] and Electron Diffraction [ED]. In the current note we present direct evidence of charge-orbital ordering in this material using heat capacity measurements. Our heat capacity measurements indicate a clear transition consistent with prior observation. We find two main transitions, one at temperature $T_{_H}=310-314$ K, and other at $T_{_A}=143$ K. In addition, we may also conclude that there is a strong electron-phonon coupling in this material.

Growth and fluorescence measurements of neodymium: Yttrium Aluminum Garnet, neodymium fluoride, Ti:Sapphire, ytterbium fluoride and mixture of neodymium fluoride with ytterbium fluoride thin films

The main objective of the present work was to fabricate and find evidence of fluorescence in the optical films of some well established laser materials and as well as some other new materials have also been probed. Materials such as Nd:Yttrium Aluminum Garnet (Nd:YAG), Ti:Sapphire, NdF 3 and YbF 3 were deposited on BK7 type optical glass, fused silica (Suprasil), Sapphire and YAG substrates by conventional electron beam evaporation processes. In case of Nd:YAG, the films were prepared by using pure single crystals of Nd:YAG as evaporation material. Samples with higher Nd content were also prepared in order to enhance the absorption in the film at the pump wavelength. A theoretical analysis for the lasing action in the Nd:YAG film has also been made and parameters like gain, threshold population inversion, threshold power etc. have been calculated for the realisation of laser action in thin films. In case of Ti:Sapphire, the films were prepared by an Ion Beam Sputtering process. It has been demonstrated that fluorescence can be observed in Electron-beam deposited films of Nd:YAG and NdF 3 when pumped with a diode laser at 802 nm. The maximum peak emission was observed at 1066 nm in case of Nd:YAG and 1046 nm in case of NdF 3. A Ti:Sapphire sample has also been excited using an Nd:YAG laser at 532 nm. Here a broad band fluorescence spectrum was observed. Films of YbF 3 and YbF 3 + NdF 3 (co-deposition) prepared by Electron Beam Evaporation were also studied.

Synthesis and Crystal Structure of the Neodymium Sulfate Nitrate Trihydrate Nd[SO4][NO3]×3H2O.

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Synthesis and Crystal Structure of the Neodymium Sulfate Nitrate Trihydrate Nd[SO4][NO3]·3H2O

AbstractPale violet single crystals of Nd[SO4][NO3]·3H2O emerged in a reaction of neodymium nitrate (dissolved in concentrated nitric acid) with H2S which was thereby oxidized to sulfate anions. The title compound crystallizes monoclinically in space group P21/m (a = 630.56(6), b = 692.34(6), c = 898.27(8) pm, β = 93.305(7)° with two formula units per unit cell. The Nd3+ cations are surrounded by nine oxygen atoms of three sulfate, one nitrate, and three water particles with both the [NO3]− and one [SO4]2− anion acting as bidentate chelating ligands which occupy common edges that are situated opposite to each other and form an elongated tetrahedron. The remaining three water molecules and two sulfate anions work just as terminal ligands building a corrugated five‐membered ring as waist around this bisphenoid. These polyhedra about the Nd3+ cations are connected via the sulfate tetrahedra to rods along [010] which show a sawtooth‐like shape caused by the nitrate triangles and two of the three water molecules attached to neodymium. The chains are packed according to a primitive rod packing with the [NO3]− anions of one rod pointing towards the [SO4]2− anions of the adjacent one and vice versa. They are connected to each other by hydrogen bridging bonds between the water molecules and mainly the nitrate triangles.

Imaging of spin density distribution by magnetic structure analysis in [formula omitted

Crystal- and magnetic-structure analyses for a single crystal of Nd 2 CuO 4 (NCO) have been carried out to visualize the spin density distribution on 3d-electron orbital for Cu 2 + ion. NCO is an antiferromagnet with 3 d 9 electronic configuration in Cu 2 + ion, where S = 1 / 2 spin localizes on d x 2 - y 2 orbital. Spin density distribution ρ ( r ) of Cu 2 + spin in NCO, which is directly obtained by three-dimensional Fourier synthesis of magnetic form factor f ( Q ) , quite well agree with the calculated value of ρ ( r ) for 3d-electron on d x 2 - y 2 orbital. The present results demonstrated that our method is of great use for imaging the electron orbital, and is applicable to various system where the orbital degree of freedom contributes to their physical properties.

Influence of periodic and random local crystal fields on magnetic properties of Nd xY 1−xCo 5 compounds

The magnetization processes have been studied for single crystals of Nd x Y 1− x Co 5 compounds in magnetic fields up to 360 kOe at temperatures 4.2–300 K. The experimental results have been used for determination of parameters of crystal field (CF) splitting of the energy levels of the ground J multiplet of Nd 3+ ions. A single set of CF parameters was found for all x values and all temperatures from above-mentioned range allowing satisfactory description of all experimental magnetization curves. An alternative set of parameters was obtained assuming presence, in studied compounds, of local random CFs generated by impurities (for instance, absorbed hydrogen).

Characterization of low angle grain boundaries in yttrium orthovanadate

Single crystals of Nd:YVO4 grown with the Czochralski technique frequently exhibit light scattering defects that are detrimental to their lasing and optical properties. Defects in the form of low angle grain boundaries have been characterized in what are nominally ‘single crystals’. The misorientation angles of the boundaries were determined to be typically < 1°, which corresponds to formation energies of approximately 1 Jm−2. It was found that dislocations generated during crystal growth and cooling have enough mobility in certain growth directions to form low angle grain boundaries through polygonization. Despite the relatively high energies the boundaries were stable, being immobile at annealing temperatures up to 97% of the melting point (2083 K). Suggestions are made to reduce or eliminate polygonization, including the addition of atoms with a size either much larger or smaller than Y3+.

Nd(NH2SO3)(SO4) · 1.5 H2O: a non-centrosymmetric amidosulfate-sulfate of neodymium

Abstract The thermal decomposition of Nd(NH2SO3)3 · 2 H2O in a closed tube leads to violet single crystals of Nd(NH2SO3)(SO4) · 1.5 H2O. The compound crystallizes with the space group P1 (Z = 2, a = 689.2, b = 691.4, c = 962.0 pm, α = 109.64, β = 97.00, γ = 109.62°). The triclinic unit cell can be transformed into the respective bodycentered setting I1 (Z = 2, a = 977.9, b = 795.6, c = 1113.0 pm, α = 90.69, β = 115.06, γ = 88.98°) leading to a nearly monoclinic unit cell for the compound. In the crystal structure of Nd(NH2SO3)(SO4) · 1.5 H2O two Nd3+ ions are present. Nd(1)3+ is coordinated by four NH2SO3 – and two SO4 2– ions, and one H2O molecule. Owing to the chelating attack of the sulfate groups, the CN is nine. Nd(2)3+ is surrounded by four monodentate SO4 2– and two NH2SO3 – groups. Two H2O ligands fill up the coordination sphere and lead to a CN of eight. The linkage of the polyhedra leads to a three-dimensional network.