scholarly journals Single-Crystal Growth of Metallic Rare-Earth Tetraborides by the Floating-Zone Technique

Crystals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 211 ◽  
Author(s):  
Daniel Brunt ◽  
Monica Ciomaga Hatnean ◽  
Oleg A. Petrenko ◽  
Martin R. Lees ◽  
Geetha Balakrishnan
Keyword(s):  
Rare Earth ◽  
Single Crystal Growth ◽  
Rare Earth Ions ◽  
Floating Zone ◽  
X Ray Diffraction ◽  
Zone Method ◽  
X Ray ◽  
Resistivity Measurements ◽  
Field Dependent ◽  
The Rare Earth

The rare-earth tetraborides are exceptional in that the rare-earth ions are topologically equivalent to the frustrated Shastry-Sutherland lattice. In this paper, we report the growth of large single crystals of RB 4 (where R = Nd, Gd → Tm, and Y) by the floating-zone method, using a high-power xenon arc-lamp furnace. The crystal boules have been characterized and tested for their quality using X-ray diffraction techniques and temperature- and field-dependent magnetization and AC resistivity measurements.

scholarly journals Annular dynamical disorder of the rare earth ions in a La2Zr2O7 pyrochlore via single crystal synchrotron X-ray diffraction

2001 ◽  
Vol 216 (2) ◽  
Author(s):  
Y. Tabira ◽  
R. L. Withers ◽  
T. Yamada ◽  
N. Ishizawa
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Intensity Distribution ◽  
Rare Earth Ions ◽  
X Ray Diffraction ◽  
Diffuse Intensity ◽  
X Ray ◽  
Rare Earth Titanate ◽  
Dynamical Disorder ◽  
The Rare Earth

AbstractThe reciprocal lattices of a range of rare earth titanate and zirconate pyrochlores have recently been shown to exhibit an extremely characteristic diffuse intensity distribution identical in form to that characteristic of

scholarly journals High-pressure synthesis of REB5O8(OH)2 (RE = Ho, Er, Tm)

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Michael Zoller ◽  
Hubert Huppertz
Keyword(s):  
High Pressure ◽  
Rare Earth ◽  
Ir Spectroscopy ◽  
Earth Metal ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Solution ◽  
Pressure Synthesis ◽  
The Rare Earth

AbstractThe rare earth oxoborates REB5O8(OH)2 (RE = Ho, Er, Tm) were synthesized in a Walker-type multianvil apparatus at a pressure of 2.5 GPa and a temperature of 673 K. Single-crystal X-ray diffraction data provided the basis for the structure solution and refinement. The compounds crystallize in the monoclinic space group C2 (no. 5) and are composed of a layer-like structure containing dreier and sechser rings of corner sharing [BO4]5− tetrahedra. The rare earth metal cations are coordinated between two adjacent sechser rings. Further characterization was performed utilizing IR spectroscopy.

Single-crystal Data of Ternary Germanides RE2Nb3Ge4 (RE = Sc, Y, Gd–Er, Lu) and Sc2Ta3Ge4 with Ordered Sm5Ge4-type Structure

2013 ◽  
Vol 68 (5-6) ◽  
pp. 625-634 ◽  
Author(s):  
Bastian Reker ◽  
Samir F. Matar ◽  
Ute Ch. Rodewald ◽  
Rolf-Dieter Hoffmann ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Coordination Number ◽  
Electronic Structure Calculations ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Arc Melting ◽  
Structure Calculations ◽  
The Rare Earth

Small single crystals of the Sm5Ge4-type (space group Pnma) germanides RE2Nb3Ge4 (RE = Sc, Y, Gd-Er, Lu) and Sc2Ta3Ge4 were synthesized by arc-melting of the respective elements. The samples were characterized by powder and single-crystal X-ray diffraction. In all structures, except for Sc2.04Nb2.96Ge4 and Sc2.19Ta2.81Ge4, the rare earth and niobium atoms show full ordering on the three crystallographically independent samarium sites of the Sm5Ge4 type. Two sites with coordination number 6 are occupied by niobium, while the slightly larger site with coordination number 7 is filled with the rare earth element. Small homogeneity ranges with RE=Nb and RE=Ta mixing can be expected for all compounds. The ordered substitution of two rare earth sites by niobium or tantalum has drastic effects on the coordination number and chemical bonding. This was studied for the pair Y5Ge4/Y2Nb3Ge4. Electronic structure calculations show larger charge transfer from yttrium to germanium for Y5Ge4, contrary to Y2Nb3Ge4 which shows stronger covalent bonding due to the presence of Nb replacing Y at two sites

Synthesis, Morphology Control and Luminescent Properties of Rare Earth Ion-Doped CaWO4 Microstructures

2016 ◽  
Vol 16 (4) ◽  
pp. 4029-4034 ◽  
Author(s):  
Chunxia Liu ◽  
Lixia Yang ◽  
Dan Yue ◽  
Mengnan Wang ◽  
Lin Jin ◽  
...  
Keyword(s):  
Rare Earth ◽  
Uv Light ◽  
Luminescent Properties ◽  
Average Diameter ◽  
Rare Earth Ions ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
Rare Earth Ion ◽  
X Ray ◽  
Facile Hydrothermal Route

Rare earth ions (Tb3+, Eu3+) doped CaWO4 microstructures were synthesized by a facile hydrothermal route without using any templates and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectrum. The results indicate that the asprepared samples are well crystallized with scheelite structure of CaWO4, and the average diameter of the microstructures is 2∼4 μm. The morphology of CaWO4:Eu3+ microstructures can be controllably changed from microspheres to microflowers through altering the doping concentration of Eu3+ from 3% to 35%, and the microflowers are constructed by a number of CaWO4:Eu3+ nanoflakes. Under the excitation of UV light, the emission spectrum of CaWO4:Eu3+ is composed of the characteristics emission of Eu3+ 5D0-7FJ (J = 1, 2, 3, 4) transitions, and that of CaWO4:Tb3+ is composed of Tb3+ 5D4-7FJ (J = 6, 5, 4, 3) transitions. Both of the optimal doping concentrations of Tb3+ and Eu3+ in CaWO4 microstructures are about 5%.

scholarly journals Crystal Growth of Quantum Magnets in the Rare-Earth Pyrosilicate Family R2Si2O7 (R = Yb, Er) Using the Optical Floating Zone Method

Crystals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 196 ◽  
Author(s):  
Harikrishnan Nair ◽  
Tim DeLazzer ◽  
Tim Reeder ◽  
Antony Sikorski ◽  
Gavin Hester ◽  
...  
Keyword(s):  
Rare Earth ◽  
Crystal Growth ◽  
Rietveld Analysis ◽  
Honeycomb Lattice ◽  
Floating Zone ◽  
Zone Method ◽  
Floating Zone Method ◽  
Range Magnetic Order ◽  
Schottky Type ◽  
The Rare Earth

We report on the crystal growth of rare-earth pyrosilicates, R 2Si 2O 7 for R = Yb and Er using the optical floating zone method. The grown crystals comprise members from the family of pyrosilicates where the rare-earth atoms form a distorted honeycomb lattice. C-Yb 2Si 2O 7 is a quantum dimer magnet with field-induced long range magnetic order, while D-Er 2Si 2O 7 is an Ising-type antiferromagnet. Both growths resulted in multi-crystal boules, with cracks forming between the different crystal orientations. The Yb 2Si 2O 7 crystals form the C-type rare-earth pyrosilicate structure with space group C 2 / m and are colorless and transparent or milky white, whereas the Er-variant is D-type, P 2 1 / b , and has a pink hue originating from Er 3 +. The crystal structures of the grown single crystals were confirmed through a Rietveld analysis of the powder X-ray diffraction patterns from pulverized crystals. The specific heat of both C-Yb 2Si 2O 7 and D-Er 2Si 2O 7 measured down to 50 mK indicated a phase transition at T N ≈ 1.8 K for D-Er 2Si 2O 7 and a broad Schottky-type feature with a sharp anomaly at 250 mK in an applied magnetic field of 0.8T along the c-axis in the case of C-Yb 2Si 2O 7 .

Effects of Acidity on Nitrogen-Heterocyclic Compounds with Rare Earth Coordination and the Structure of Protonated Phenanthroline

2011 ◽  
Vol 233-235 ◽  
pp. 2808-2811
Author(s):  
Huan Huan Li ◽  
Hai Bin Chu ◽  
Ying Nan Chen ◽  
Xiao Tao Fu ◽  
Hui Juan Sun ◽  
...  
Keyword(s):  
Rare Earth ◽  
Heterocyclic Compounds ◽  
Crystal Structure Analysis ◽  
Rare Earth Ions ◽  
Molecular Formula ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
X Ray ◽  
Rare Earth Coordination ◽  
Single Crystal Structure Analysis

2,3-bis(2-pyridyl)-5,6-dihydropyrazine and a protonated phenanthroline (Phen) have been synthesized and the structure of protonated Phen is established by X-ray diffraction single crystal structure analysis. The coordination reactions of Phen, 2,2'- bipyridine and 2,3-bis(2-pyridyl)-5,6-dihydropyrazine with rare earth ions in low pH have been studied. The results show that 2,3-bis(2-pyridyl)-5,6-dihydropyrazine is hydrolyzed to be 2,2’-pyridil and protonated ethylenediamine. Meanwhile, Phen combines with proton, which results that nitrogen atoms can not coordinate with rare earth ions. The molecular formula of protonated Phen is C12H8N2HCl·H2O. It crystallizes in the triclinic space group P -1 (2), with a = 7.1212(14) Å, b = 7.2786(15) Å, c = 20.817(4) Å, α = 90.00º, β = 96.69(3) º, γ = 90.00 º, V = 1071.65(379) Å3, Z = 4.

scholarly journals Identification of rare-earth minerals associated to K-feldspar: Capacsaya project in Peru

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
J. Ochoa ◽  
E. Monteblanco ◽  
L. Cerpa ◽  
A. Gutarra-Espinoza ◽  
L. Avilés-Félix
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Size Range ◽  
X Ray Diffraction ◽  
High Concentration ◽  
Particle Size Range ◽  
X Ray ◽  
Rare Earth Minerals ◽  
Heavy Rare Earth Elements ◽  
The Rare Earth

AbstractA recently discovered the rare-earth-rich site in Capacsaya, located at 123 km northwest of Cusco, at the south of Peru, contains significant quantities of light and heavy rare-earth elements such as neodymium, lanthanum, cerium, europium, and yttrium. This work reports the identification of rare-earth elements and their associated minerals using scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analyses. Five (5) samples extracted from different locations at the Capacsaya site were characterized and identified K-feldspar as the mineral associated with the rare-earth elements in a representative sample with a high concentration of lanthanum and cerium. The results showed rare-earth elements contained within the mineral phase monazite, being cerium the dominant element in the phase (La, Ce, Nd)PO$$_4$$ 4 . Finally, through the electrostatic separation process we demonstrate that it was possible to achieve an efficient separation of the K-feldspar phase in the particle size range 75–150 $$\upmu$$ μ m.

The vanadate garnet Ca2NaCd2V3O12: a single-crystal X-ray diffraction study

2018 ◽  
Vol 74 (4) ◽  
pp. 460-464 ◽  
Author(s):  
Makoto Tokuda ◽  
Akira Yoshiasa ◽  
Tsutomu Mashimo ◽  
Kazuake Iishi ◽  
Akihiko Nakatsuka
Keyword(s):  
Single Crystal ◽  
Edge Length ◽  
Geometric Constraints ◽  
Structural Studies ◽  
Floating Zone ◽  
X Ray Diffraction ◽  
Zone Method ◽  
X Ray ◽  
Atomic Coordinates ◽  
Shared Edge

Single crystals of the vanadate garnet Ca2NaCd2V3O12 (dicalcium sodium dicadmium trivanadate) were synthesized using the floating-zone method and the crystal structure was investigated using single-crystal X-ray diffraction. We considered the effectiveness of substitution of the Y-site cation with reference to previous structural studies of vanadate garnets. The structures of vanadate garnets are subject to geometric constraints similar to those of silicate garnets. These constraints force the tetrahedral–dodecahedral shared edge length in vanadate garnets to become shorter than the unshared dodecahedral edge length, as in ugrandite (uvarovite, grossular and andradite) garnets. However, the vanadate garnet Ca2NaCd2V3O12 exhibits the normal structural feature, similar to pyralspite (pyrope, almandine and spessartine) garnets, namely that the dodecahedral–dodecahedral shared edge length is shorter than the unshared dodecahedral edge length. With increasing ionic radius of the Y-site cation, the atomic coordinates x, y and z of oxygen adopt values which satisfy Pauling's third rule.

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