scholarly journals X-RAY studies of ferroelectric lithium niobate crystals doped with rare earth elements

2021 ◽  
Vol 12 (2-2021) ◽  
pp. 114-119
Author(s):  
A. V. Kadetova ◽  
◽  
M. N. Palatnikov ◽  
O. V. Sidorova ◽  
D. A. Vorobyov ◽  
...  
Keyword(s):  
Rare Earth ◽  
Lithium Niobate ◽  
Rare Earth Elements ◽  
Crystal Lattice ◽  
Polar Axis ◽  
X Ray Diffraction ◽  
Defect Region ◽  
X Ray ◽  
Structural Distortions ◽  
Lithium Niobate Crystals

The lattice structural distortions of LiNbO3 crystals doped with samarium with a concentration of 1.0, 1.9, 2.5 mol. % were studied by X-ray diffraction methods. It was found that the samarium atoms and some of the niobium atoms occupied the vacant positions of lithium in the crystal lattice, and some of the niobium atoms were located in the empty octahedron. The octahedra of SmLiO6 was distorted more strongly than octahedra of NbLiO6 when niobium atoms entered the vacant positions of lithium. The smallest changes in the bond lengths in the octahedra of the main motif and in the defect region as well as along the polar axis in the lithium niobate lattice were observed in the sample with a samarium concentration of 2.5 mol. %.

scholarly journals Analysis of doping influence on structural defects in LiNbO3.

2020 ◽  
Vol 11 (3-2020) ◽  
pp. 87-92
Author(s):  
M. N. Palatnikov ◽  
◽  
A. V. Kadetova ◽  
L. A. Aleshina ◽  
O. V. Sidorova ◽  
...  
Keyword(s):  
Lithium Niobate ◽  
Structural State ◽  
Polar Axis ◽  
Structural Defects ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Lengths ◽  
Impurity Defect ◽  
Main Motive ◽  
Lithium Niobate Crystals

Changes in a structural state of homogeneous doped lithium niobate crystals with magnesium in the region of 5 mol. % were studied by X-ray diffraction methods. It was found that the changes in the structure of LiNbO3: Mg occured not only in the region of the impurity defect, but also in the region of the main motive of the structure. Bond lengths in the octahedra of the main motive and the Nb–Li distance along the polar axis of the crystal changed. The magnesium introduced into the vacant lithium octahedron distorted the shape of the octahedron more strongly than niobium.

Structure Maps and Phase Stability in AlTi3 Alloyed with Rare-Earth Elements

1988 ◽  
Vol 133 ◽  
Author(s):  
C. T. Liu ◽  
J. A. Horton ◽  
D. G. Petitifor
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Solubility Limit ◽  
Size Factor ◽  
X Ray Diffraction ◽  
Atomic Size ◽  
X Ray ◽  
Dependent Parameter ◽  
Rare Earth Additions

ABSTRACTRare-earth elements including Y, Er and Sc were added to AlTi3 for stabilizing the Ll2 ordered crystal structure, as predicted by the AB3 structure map. The crystal structure and phase composition in the AlTi3 alloys were studied by electron microprobe analysis, X-ray diffraction and TEM. The solubility limit of the rare-earth elements were determined and correlated with the atomic size factor. The results obtained so far indicate that rare-earth additions are unable to change the crystal structure of AlTi3 from DO19 to Ll2. The inability to stabilize the Ll2 structure demonstrates the need to characterize the structure map domains with a further period-dependent parameter.

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.

Plumbogummite-group minerals from Mull and Morvern

1970 ◽  
Vol 37 (292) ◽  
pp. 934-938 ◽  
Author(s):  
D. C. Bain
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Clay Minerals ◽  
Spectrochemical Analysis ◽  
X Ray Diffraction ◽  
Complex Composition ◽  
X Ray

SummarySandstones from Mull and Morvern, most of which are from the Greensand formation, have been shown by X-ray diffraction to contain minerals of the plumbogummite group in very small amounts in the < 1·4µm fraction. The minerals were concentrated by HF digestion of the clay minerals. X-ray spectrographic traces show concentrations of Sr, La, Ce, Yt, and Ba, and a semiquantitative spectrochemical analysis also shows a concentration of Ca and Pb and the presence of numerous rare-earth elements. Individual minerals, which have a complex composition and can not be assigned to any one named species, are disseminated throughout the rocks as particles with an estimated size of between 0·1 and 0·25µm.

Crystal structures of rare earth elements rich apatite analogues

1990 ◽  
Vol 191 (3-4) ◽  
Author(s):  
Nicoline Kalsbeek ◽  
Sine Larsen ◽  
Jørn G. Rønsbo
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
Hexagonal System ◽  
Space Group ◽  
X Ray ◽  
Cell Dimensions

AbstractThe crystal structures have been determined for britholite-(Ce) and lessingite-(Ce) from the type localities and a third sample (‘min X’) showing chemical similarities to both britholite-(Ce) and lessingite-(Ce). This sample is from the Ilímaussaq intrusion in Greenland. They are rare earth elements (REE) rich apatite analogues. Based on the X-ray diffraction results they were assigned to the hexagonal system with cell dimensions slightly larger than those of apatite. The three structures have been refined in the space group

scholarly journals Investigation of the Structural and Magnetic Properties of the Light Rare Earth Elements and Their Intermetallic Compounds

1988 ◽  
Vol 41 (2) ◽  
pp. 155 ◽  
Author(s):  
DC Creagh
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Intermetallic Compounds ◽  
Light Rare Earth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Radiation Sources ◽  
Structural And Magnetic Properties ◽  
Light Rare Earth Elements

The experimental requirements for the investigation of the structural and magnetic properties of the light rare earth elements and their intermetallic compounds at synchrotron radiation sources are discussed. Experimental techniques considered include X-ray topography, energy dispersive X-ray diffraction and X-ray powder diffraction.

scholarly journals Zr-Rich Eudialyte from the Lovozero Peralkaline Massif, Kola Peninsula, Russia

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 982
Author(s):  
Taras L. Panikorovskii ◽  
Julia A. Mikhailova ◽  
Yakov A. Pakhomovsky ◽  
Ayya V. Bazai ◽  
Sergey M. Aksenov ◽  
...  
Keyword(s):  
Rare Earth ◽  
Chemical Composition ◽  
Rare Earth Elements ◽  
Single Crystal ◽  
Kola Peninsula ◽  
Marginal Zone ◽  
X Ray Diffraction ◽  
Eudialyte Group ◽  
X Ray ◽  
Marginal Zones

The Lovozero peralkaline massif (Kola Peninsula, Russia) has several deposits of Zr, Nb, Ta and rare earth elements (REE) associated with eudialyte-group minerals (EGM). Eudialyte from the Alluaiv Mt. often forms zonal grains with central parts enriched in Zr (more than 3 apfu) and marginal zones enriched in REEs. The detailed study of the chemical composition (294 microprobe analyses) of EGMs from the drill cores of the Mt. Alluaiv-Mt. Kedykvyrpakhk deposits reveal more than 70% Zr-enriched samples. Single-crystal X-ray diffraction (XRD) was performed separately for the Zr-rich (4.17 Zr apfu) core and the REE-rich (0.54 REE apfu) marginal zone. It was found that extra Zr incorporates into the octahedral M1A site, where it replaces Ca, leading to the symmetry lowering from R3¯m to R32. We demonstrated that the incorporation of extra Zr into EGMs makes the calculation of the eudialyte formula on the basis of Si + Al + Zr + Ti + Hf + Nb + Ta + W = 29 apfu inappropriate.

Effect of Rare Earth Doping on Electrochemical Properties of Fe2O3 Nanoparticle for Supercapacitor

2018 ◽  
Vol 281 ◽  
pp. 743-747
Author(s):  
Wei Kang Yan ◽  
Jian Qiang Bi ◽  
Wei Li Wang
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Constant Current ◽  
Rare Earth Doping ◽  
X Ray Diffraction ◽  
Super Capacitor ◽  
X Ray ◽  
Constant Current Charge ◽  
Discharge Method ◽  
Structure And Microstructure

Fe2O3 nanoparticle was prepared by a hydrothermal method, and the influence of rare earth elements (Y3+, Nd3+ and La3+) on the electrochemical performance was studied. The crystal structure and microstructure of the synthesized lithium zinc ferrite were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM). The results show that the powder is well crystallized and the particles are mostly irregular.The electrochemical property was characterized via cyclic voltammetry (CV) and constant current charge-discharge method. The capacitance of the Fe2O3 nanoparticle is 258.3 F/g, 342.7 F/g after doping Y3+ ,337.1 F/g after doping Nd3+and 331.2 F/g after doping La3 +. The results show that the rare earth elements (Y3+, Nd3+ and La3+) after the specific capacitance has increased, more suitable for super capacitor materials.

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