scholarly journals Crystal chemistry and the role of ionic radius in rare earth tetrasilicates: Ba2RE2Si4O12F2(RE = Er3+–Lu3+) and Ba2RE2Si4O13(RE = La3+–Ho3+)

2017 ◽  
Vol 73 (5) ◽  
pp. 907-915 ◽  
Author(s):  
Kyle Fulle ◽  
Liurukara D. Sanjeewa ◽  
Colin D. McMillen ◽  
Joseph W. Kolis
Keyword(s):  
Rare Earth ◽  
Ionic Radius ◽  
Rare Earth Ions ◽  
Hydrothermal Fluids ◽  
Structural Variations ◽  
Ionic Radii ◽  
Space Group ◽  
New Compounds ◽  
Insight Into

Structural variations across a series of barium rare earth (RE) tetrasilicates are studied. Two different formulas are observed, namely those of a new cyclo-silicate fluoride, BaRE2Si4O12F2(RE = Er3+–Lu3+) and new compounds in the Ba2RE2Si4O13(RE = La3+–Ho3+) family, covering the whole range of ionic radii for the rare earth ions. The Ba2RE2Si4O13series is further subdivided into two polymorphs, also showing a dependence on rare earth ionic radius (space group P{\overline 1} for La3+–Nd3+, and space groupC2/cfor Sm3+–Ho3+). Two of the structure types identified are based on dinuclear rare earth units that differ in their crystal chemistries, particularly with respect to the role of fluorine as a structural director. The broad study of rare earth ions provides greater insight into understanding structural variations within silicate frameworks and the nature off-block incorporation in oxyanion frameworks. The single crystals are grown from high-temperature (ca953 K) hydrothermal fluids, demonstrating the versatility of the technique to access new phases containing recalcitrant rare earth oxides, enabling the study of structural trends.

scholarly journals Modelling Cationic Diffusion in Nickel-Based Honeycomb Layered Tellurates using Vashishta-Rahman Interatomic Potential and Relevant Insights

2021 ◽  
Author(s):  
Kartik Sau ◽  
Tamio Ikeshoji ◽  
Godwill Mbiti Kanyolo ◽  
Titus Masese
Keyword(s):  
Performance Enhancement ◽  
Interatomic Potential ◽  
Theoretical Studies ◽  
Layered Oxides ◽  
Ionic Radii ◽  
Diffusion Channel ◽  
Exponential Increase ◽  
Potential Parameters ◽  
Insight Into

<b>Although the fascinatingly rich crystal chemistry of honeycomb layered oxides has been accredited as the propelling force behind their remarkable electrochemistry, the atomistic mechanisms surrounding their operations remain unexplored. Thus, herein, we present an extensive molecular dynamics study performed systematically using a refined set of inter-atomic potential parameters of <i>A</i><sub>2</sub>Ni<sub>2</sub>TeO<sub>6</sub> (where <i>A</i> = Li, Na, and K). We demonstrate the effectiveness of the Vashishta-Rahman form of the interatomic potential in reproducing various structural and transport properties of this promising class of materials and predict an exponential increase in cationic diffusion with larger interlayer distances. The simulations further demonstrate the correlation between broadened inter-layer (inter-slab) distances associated with the larger ionic radii of K and Na compared to Li and the enhanced cationic conduction exhibited in K<sub>2</sub>Ni<sub>2</sub>TeO<sub>6</sub> and Na<sub>2</sub>Ni<sub>2</sub>TeO<sub>6</sub> relative to Li<sub>2</sub>Ni<sub>2</sub>TeO<sub>6</sub>. Whence, our findings connect lower potential energy barriers, favourable cationic paths and wider bottleneck size along the cationic diffusion channel within frameworks (comprised of larger mobile cations) to the improved cationic diffusion experimentally observed in honeycomb layered oxides. Furthermore, we explicitly study the role of inter-layer distance and cationic size in cationic diffusion. Our theoretical studies reveal the dominance of inter-layer distance over cationic size, a crucial insight into the further performance enhancement of honeycomb layered oxides.</b><br>

scholarly journals Modelling Cationic Diffusion in Nickel-Based Honeycomb Layered Tellurates using Vashishta-Rahman Interatomic Potential and Relevant Insights

2021 ◽  
Author(s):  
Kartik Sau ◽  
Tamio Ikeshoji ◽  
Godwill Mbiti Kanyolo ◽  
Titus Masese
Keyword(s):  
Performance Enhancement ◽  
Interatomic Potential ◽  
Layered Oxides ◽  
Ionic Radii ◽  
Diffusion Channel ◽  
Atomic Potential ◽  
Exponential Increase ◽  
Potential Parameters ◽  
Insight Into

<b>Although the fascinatingly rich crystal chemistry of honeycomb layered oxides has been accredited as the propelling force behind their remarkable electrochemistry, the atomistic mechanisms surrounding their operations remain unexplored. Thus, herein, we present an extensive molecular dynamics study performed systematically using a reliable set of inter-atomic potential parameters of </b><i>A</i><sub>2</sub><b>Ni</b><sub>2</sub><b>TeO</b><sub>6</sub><b> (where </b><i>A</i><b> = Li, Na, and K). We demonstrate the effectiveness of the Vashishta-Rahman form of the inter-atomic potential in reproducing various structural and transport properties of this promising class of materials and predict an exponential increase in cationic diffusion with larger inter-layer distances. The simulations demonstrate the correlation between broadened inter-layer (inter-slab) distances associated with the larger ionic radii of K and Na compared to Li and the enhanced cationic conduction exhibited in K</b><sub>2</sub><b>Ni</b><sub>2</sub><b>TeO</b><sub>6</sub><b> and Na</b><sub>2</sub><b>Ni</b><sub>2</sub><b>TeO</b><sub>6</sub><b> relative to Li</b><sub>2</sub><b>Ni</b><sub>2</sub><b>TeO</b><sub>6</sub><b>. Whence, our findings connect lower potential energy barriers, favourable cationic paths and wider bottleneck size along the cationic diffusion channel within frameworks (comprised of larger mobile cations) to the improved cationic diffusion experimentally observed in honeycomb layered oxides. Furthermore, we elucidate the role of inter-layer distance and cationic size in cationic diffusion. Our theoretical studies reveal the dominance of inter-layer distance over cationic size, a crucial insight into the further performance enhancement of honeycomb layered oxides.</b><br>

Room temperature p-orbital magnetism in carbon chains and the role of group IV, V, VI, and VII dopants

Nanoscale ◽  
2018 ◽  
Vol 10 (23) ◽  
pp. 11186-11195 ◽  
Author(s):  
C. H. Wong ◽  
E. A. Buntov ◽  
A. F. Zatsepin ◽  
J. Lyu ◽  
R. Lortz ◽  
...  
Keyword(s):  
Rare Earth ◽  
Transition Metals ◽  
Room Temperature ◽  
Group Iv ◽  
Rare Earth Ions ◽  
Next Generation ◽  
Spintronic Devices ◽  
Carbon Chains ◽  
Orbital Magnetism

The study of magnetism without the involvement of transition metals or rare earth ions is considered the key to the fabrication of next-generation spintronic devices.

scholarly journals The origins of binding specificity of a lanthanide ion binding peptide

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Takaaki Hatanaka ◽  
Nobuaki Kikkawa ◽  
Akimasa Matsugami ◽  
Yoichi Hosokawa ◽  
Fumiaki Hayashi ◽  
...  
Keyword(s):  
Water Molecule ◽  
Ionic Radius ◽  
Binding Specificity ◽  
Lanthanide Ions ◽  
Ion Binding ◽  
Deep Insight ◽  
Ionic Radii ◽  
Linear Peptide ◽  
High Affinity ◽  
Insight Into

Abstract Lanthanide ions (Ln3+) show similar physicochemical properties in aqueous solutions, wherein they exist as + 3 cations and exhibit ionic radii differences of less than 0.26 Å. A flexible linear peptide lanthanide binding tag (LBT), which recognizes a series of 15 Ln3+, shows an interesting characteristic in binding specificity, i.e., binding affinity biphasically changes with an increase in the atomic number, and shows a greater than 60-fold affinity difference between the highest and lowest values. Herein, by combining experimental and computational investigations, we gain deep insight into the reaction mechanism underlying the specificity of LBT3, an LBT mutant, toward Ln3+. Our results clearly show that LBT3-Ln3+ binding can be divided into three, and the large affinity difference is based on the ability of Ln3+ in a complex to be directly coordinated with a water molecule. When the LBT3 recognizes a Ln3+ with a larger ionic radius (La3+ to  Sm3+), a water molecule can interact with Ln3+ directly. This extra water molecule infiltrates the complex and induces dissociation of the Asn5 sidechain (one of the coordinates) from Ln3+, resulting in a destabilizing complex and low affinity. Conversely, with recognition of smaller Ln3+ (Sm3+ to Yb3+), the LBT3 completely surrounds the ions and constructs a stable high affinity complex. Moreover, when the LBT3 recognizes the smallest Ln3+, namely Lu3+, although it completely surrounds Lu3+, an entropically unfavorable phenomenon specifically occurs, resulting in lower affinity than that of Yb3+. Our findings will be useful for the design of molecules that enable the distinction of sub-angstrom size differences.

Crystal chemistry of hydrothermally grown ternary alkali rare earth fluorides

2015 ◽  
Vol 71 (6) ◽  
pp. 768-776 ◽  
Author(s):  
Colin D. McMillen ◽  
Sara Comer ◽  
Kyle Fulle ◽  
Liurukara D. Sanjeewa ◽  
Joseph W. Kolis
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Single Crystals ◽  
Structural Information ◽  
Structure Type ◽  
Crystal Structure Analysis ◽  
Structural Variations ◽  
Ionic Radii ◽  
Wide Range ◽  
Potential Applications

The structural variations of several alkali metal rare earth fluoride single crystals are summarized. Two different stoichiometric formulations are considered, namely those of ARE2F7 and ARE3F10 (A = K, Rb, Cs; RE = Y, La–Lu), over a wide range of ionic radii of both the alkali and rare earth (RE) ions. Previously reported and several new single-crystal structures are considered. The new single crystals are grown using hydrothermal methods and the structures are compared with literature reports of structures grown from both melts and hydrothermal fluids. The data reported here are combined with the literature data to gain a greater understanding of structural subtleties surrounding these systems. The work underscores the importance of the size of the cations to the observed structure type and also introduces synthetic technique as a contributor to the same. New insights based on single-crystal structure analysis in the work introduce a new disordered structure type in the case of ARE2F7, and examine the trends and boundaries of the ARE3F10 stoichiometry. Such fundamental structural information is useful in understanding the potential applications of these compounds as optical materials.

Improved Infrared Emissions of Er3+-Tm3+ Co-Doped Al2O3 Thin Films: The Role of Cross Relaxation Among Rare Earth Ions

2011 ◽  
Vol 11 (12) ◽  
pp. 10673-10676
Author(s):  
Bo Zhou ◽  
Zhisong Xiao ◽  
Lu Yan ◽  
Fang Zhu ◽  
Feng Zhang ◽  
...  
Keyword(s):  
Thin Films ◽  
Rare Earth ◽  
Cross Relaxation ◽  
Rare Earth Ions ◽  
Infrared Emissions ◽  
Co Doped

Role of Rare Earth Ions in Anodic Gate Dielectrics for Indium-Zinc-Oxide Thin-Film Transistors

2012 ◽  
Vol 159 (5) ◽  
pp. H502-H506 ◽  
Author(s):  
Dongxiang Luo ◽  
Linfeng Lan ◽  
Miao Xu ◽  
Hua Xu ◽  
Min Li ◽  
...  
Keyword(s):  
Thin Film ◽  
Zinc Oxide ◽  
Rare Earth ◽  
Thin Film Transistors ◽  
Gate Dielectrics ◽  
Rare Earth Ions ◽  
Oxide Thin Film ◽  
Zinc Oxide Thin Film ◽  
Indium Zinc Oxide

Role of rare earth ions in the magnetic, magnetocaloric and magnetoelectric properties of RCrO3 (R = Dy, Nd, Tb, Er) crystals

2016 ◽  
Vol 4 (47) ◽  
pp. 11198-11204 ◽  
Author(s):  
L. H. Yin ◽  
J. Yang ◽  
P. Tong ◽  
X. Luo ◽  
C. B. Park ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Ions ◽  
Magnetoelectric Effects ◽  
Magnetoelectric Properties

H-induced stair-like metamagnetic transitions, large magnetocaloric and magnetoelectric effects related to the 4f electrons of rare-earth ions were revealed in chromite crystals.

Growth of rare-earth niobate-based pyrochlores on textured Ni–W substrates with ionic radii dependency

2005 ◽  
Vol 20 (4) ◽  
pp. 904-909 ◽  
Author(s):  
M.S. Bhuiyan ◽  
M. Paranthaman ◽  
S. Sathyamurthy ◽  
A. Goyal ◽  
K. Salama
Keyword(s):  
Rare Earth ◽  
Ionic Radius ◽  
Pyrochlore Structure ◽  
Precursor Solution ◽  
Deposition Process ◽  
Coated Conductors ◽  
Buffer Layers ◽  
Ionic Radii ◽  
Solution Deposition ◽  
Force Microscopy

Epitaxial films of rare-earth (RE) niobates, RE3NbO7 with pyrochlore structures, were grown on biaxially textured nickel–3 at.% tungsten (Ni–W) substrates using a chemical solution deposition process. A precursor solution of 0.3–0.50 M concentration of total cations was spin coated on to short samples of Ni–W substrates, and the films were crystallized at 1050–1100 °C in a gas mixture of Ar–4% H2 for 15 min. Detailed studies revealed that RE-niobates with ionic radius ratio RRE/RNb (R = ionic radius) from 1.23 to 1.40 (i.e., Sm, Eu, Gd, Ho, Y, and Yb) grow epitaxially with the pyrochlore structure. X-ray studies showed that the films of pyrochlore RE niobate films were highly textured with cube-on-cube epitaxy. Scanning electron and atomic force microscopy investigations of RE3NbO7 films revealed a fairly dense and smooth microstructure without cracks and porosity. The rare-earth niobate layers may be potentially used as buffer layers for YBa2Cu3O7−δ coated conductors.

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