scholarly journals Structure and magnetism of the A site scandium perovskite (Sc 0.94 Mn 0.06 )Mn 0.65 Ni 0.35 O 3 synthesized at high pressure

2014 ◽  
Vol 372 (2013) ◽  
pp. 20130012 ◽  
Author(s):  
Chris I. Thomas ◽  
Matthew R. Suchomel ◽  
Giap V. Duong ◽  
Andrew M. Fogg ◽  
John B. Claridge ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Ambient Pressure ◽  
Oxidation States ◽  
Formula Unit ◽  
Triclinic Structure ◽  
Bond Valence Sum ◽  
A Site

Scandium perovskite (Sc 0.94 Mn 0.06 )Mn 0.65 Ni 0.35 O 3 , synthesized at high pressure and high temperature, has a triclinic structure (space group ) at room temperature and ambient pressure with a √2 a p ×√2 a p ×2 a p structure with α ≈90 ° , β ≈89 ° , γ ≈90 ° . Magnetic measurements show that the material displays Curie–Weiss behaviour above 50 K with C =2.11 emu K mol −1 ( μ eff =4.11 μ B per formula unit) and θ =−95.27 K. Bond valence sum analysis of the crystal structure shows that manganese is present in three different oxidation states (+2, +3, +4), with the +2 oxidation state on the A site resulting in a highly tilted perovskite structure (average tilt 21.2 ° compared with 15.7 ° calculated for LaCaMnNbO 6 ), giving the formula .

scholarly journals Synthesis, Structure and Properties of the (Bi0.5Sr0.5)(Co0.5Ru0.5)O3 Perovskite

2008 ◽  
Vol 63 (6) ◽  
pp. 641-646 ◽  
Author(s):  
Luis Ortega-San-Martin ◽  
Jennifer A. Rodgers ◽  
J. Paul Attfield
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperatures ◽  
High Spin ◽  
Room Temperature ◽  
Formula Unit ◽  
Variable Range Hopping ◽  
Structure And Properties ◽  
Spin Ordering ◽  
Antiferromagnetic Spin

The new perovskite (Bi0.5Sr0.5)(Co0.5Ru0.5)O3 has been prepared under high pressure (10 GPa) and temperature (900 °C). The room-temperature crystal structure is described by the space group Pnma (a = 5.5702(3), b = 7.8793(5) and c = 5.5599(4) Å ) with no observed order between Bi and Sr or between Co and Ru cations. This material shows antiferromagnetic spin ordering or freezing below 50 K and a paramagnetic moment of 4.07 μB per formula unit at high temperatures, consistent with the presence of high-spin Co2+ or Co3+ ions. (Bi0.5Sr0.5)(Co0.5Ru0.5)O3 is a variable range hopping semiconductor between 40 and 300 K with a small negative magnetoresistance.

Multiferroic Bi2NiMnO6 with a Double-Perovskite Structure: High-Pressure Synthesized Bulk and Epitaxially Grown Thin Films

2007 ◽  
Vol 1034 ◽  
Author(s):  
Yuichi Shimakawa
Keyword(s):  
Thin Film ◽  
Crystal Structure ◽  
High Pressure ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Double Perovskite ◽  
Laser Deposition ◽  
Deposition Method ◽  
Pressure Condition ◽  
A Site

AbstractA new multiferroic compound Bi2NiMnO6 was synthesized in both bulk and thin-film forms. Bulk samples were prepared under a high pressure condition at 6 GPa, and thin-film samples were epitaxially grown on single-crystal SrTiO3 substrates by a pulsed-laser deposition method. The crystal structure of the material is a double perovskite, in which Ni2+ and Mn4+ ions are ordered in a rock-salt configuration. Bi3+ ions at the A-site cause a noncentrosymmetric (C2) structural distortion which allows a spontaneous ferroelectric polarization at room temperature. Ni2+–O–Mn4+ magnetic paths lead to ferromagnetism through the superexchange interaction according to the Kanamori-Goodenough rule. A coupling between the ferromagnetic and ferroelectric interactions appears to exist, but it is quite small.

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

scholarly journals Crystal structure of a new lithium iron vanadate

2014 ◽  
Vol 70 (a1) ◽  
pp. C1101-C1101
Author(s):  
Laurent Castro ◽  
Nicolas Penin ◽  
Dany Carlier ◽  
Alain Wattiaux ◽  
Stanislav Pechev ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Charge Compensation ◽  
Li Ion Batteries ◽  
New Materials ◽  
Single Crystal Diffraction ◽  
Structural Relationships ◽  
Network Flexibility ◽  
Li Ion

Iron vanadates and phosphates have been widely explored [1-2] as possible electrode material for Li-ion batteries. In the goal of finding new materials, our approach was to consider existing materials and to investigate the flexibility of their network for possible substitutions. Among the different materials containing iron and vanadium, Cu3Fe4(XO4)6 (X = P, V) are isostructural to Fe7(PO4)6. Lafontaine et al. [3] discussed the structural relationships between β-Cu3Fe4(VO4)6 and several other vanadates, phosphates and molybdates of general formula AxBy(VO4)6. The interesting network flexibility was then demonstrated with the existence of four different crystallographic sites, which can be partially occupied depending on the x+y value : x+y = 7 for β-Cu3Fe4(VO4)6) and x+y = 8 for NaCuFe2(VO4)3. The LixFey(VO4)6 phase was then prepared considering the substitution of Li+ and Fe3+ for Cu2+ ions in β-Cu3Fe4(VO4)6 and the existence of an extra site to accommodate the charge compensation (7 ≤ x+y ≤ 8). As expected, a new lithium iron vanadate, isotructural to mineral Howardevansite was then obtained. Single crystal diffraction data were collected at room temperature on Enraf-Nonius CAD-4 diffractometer. Structure was refined with JANA-2006 program package. Mössbauer and magnetic measurements were also used to check the oxidation state of iron ions, to support the obtained crystal structure and to consider any possible structural/magnetic transitions. All the results will be presented and discussed in this presentation.

High-Pressure Synthesis and Crystal Structure of the New Orthorhombic Polymorph β-HgB4O7

2005 ◽  
Vol 60 (8) ◽  
pp. 815-820 ◽  
Author(s):  
Holger Emme ◽  
Matthias Weil ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Ambient Pressure ◽  
Normal Pressure ◽  
High Pressure Phase ◽  
Synthesis And Crystal Structure ◽  
Space Group ◽  
High Pressure Synthesis ◽  
Pressure Synthesis ◽  
Pressure Phase

The new orthorhombic polymorph β-HgB4O7 has been synthesized under high-pressure and hightemperature conditions in a Walker-type multianvil apparatus at 7.5 GPa and 600 °C. β-HgB4O7 is isotypic to the known ambient pressure phases MB4O7 (M = Sr, Pb, Eu) and the high-pressure phase β-CaB4O7 crystallizing with two formula units in the space group Pmn21 with lattice parameters a = 1065.6(2), b = 438.10(9), and c = 418.72(8) pm. The relation of the crystal structure of the high-pressure phase β-HgB4O7 to the normal pressure phase α-HgB4O7 as well as the relation to the isotypic phases MB4O7 (M = Sr, Pb, Eu) and β-CaB4O7 are discussed.

scholarly journals High-Pressure Structural Behavior and Equation of State of Kagome Staircase Compound, Ni3V2O8

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 910
Author(s):  
Daniel Diaz-Anichtchenko ◽  
Robin Turnbull ◽  
Enrico Bandiello ◽  
Simone Anzellini ◽  
Daniel Errandonea
Keyword(s):  
High Pressure ◽  
Equation Of State ◽  
Density Functional ◽  
Room Temperature ◽  
Ambient Pressure ◽  
Density Functional Theory Calculations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
A Chain

We report on high-pressure synchrotron X-ray diffraction measurements on Ni3V2O8 at room-temperature up to 23 GPa. According to this study, the ambient-pressure orthorhombic structure remains stable up to the highest pressure reached in the experiments. We have also obtained the pressure dependence of the unit-cell parameters, which reveals an anisotropic compression behavior. In addition, a room-temperature pressure–volume third-order Birch–Murnaghan equation of state has been obtained with parameters: V0 = 555.7(2) Å3, K0 = 139(3) GPa, and K0′ = 4.4(3). According to this result, Ni3V2O8 is the least compressible kagome-type vanadate. The changes of the crystal structure under compression have been related to the presence of a chain of edge-sharing NiO6 octahedral units forming kagome staircases interconnected by VO4 rigid tetrahedral units. The reported results are discussed in comparison with high-pressure X-ray diffraction results from isostructural Zn3V2O8 and density-functional theory calculations on several isostructural vanadates.

scholarly journals Ion-Exchange Reaction Of A-Site In A2Ta2O6 Pyrochlore Crystal Structure

2015 ◽  
Vol 60 (2) ◽  
pp. 941-944 ◽  
Author(s):  
M. Matsunami ◽  
T. Hashizume ◽  
A. Saiki
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Ion Exchange ◽  
Room Temperature ◽  
Electrode Materials ◽  
Pyrochlore Structure ◽  
Rechargeable Battery ◽  
Ion Exchange Reaction ◽  
Li Ion ◽  
A Site

Abstract Na+ or K+ ion rechargeable battery is started to garner attention recently in Place of Li+ ion cell. It is important that A+ site ion can move in and out the positive-electrode materials. When K2Ta2O6 powder had a pyrochlore structure was only dipped into NaOH aqueous solution at room temperature, Na2Ta2O6 was obtained. K2Ta2O6 was fabricated from a tantalum sheet by a hydrothermal synthesize with KOH aqueous solution. When Na2Ta2O6 was dipped into KOH aqueous solution, K2Ta2O6 was obtained again. If KTaO3 had a perovskite structure was dipped, Ion-exchange was not observed by XRD. Because a lattice constant of pyrochlore structure of K-Ta-O system is bigger than perovskite, K+ or Na+ ion could shinny through and exchange between Ta5+ and O2− ion site in a pyrochlore structure. K+ or Na+ ion exchange of A2Ta2O6 pyrochlore had reversibility. Therefore, A2Ta2O6 had a pyrochlore structure can be expected such as Na+ ion rechargeable battery element.

scholarly journals The low-temperature triclinic crystal structure of silver 3-sulfobenzoic acid

2020 ◽  
Vol 76 (8) ◽  
pp. 1275-1278
Author(s):  
Reuben T. Bettinger ◽  
Philip J. Squattrito ◽  
Darpandeep Aulakh
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Low Temperature ◽  
Room Temperature ◽  
Monoclinic Structure ◽  
Structure Space ◽  
Reversible Phase Transition ◽  
Triclinic Structure ◽  
Reversible Phase ◽  
Acidic Hydrogen

Poly[(μ4-3-carboxybenzenesulfonato)silver(I)], Ag(O3SC6H4CO2H) or [Ag(C7H5O5S)] n , has been found to undergo a reversible phase transition from monoclinic to triclinic between 160 and 150 K. The low-temperature triclinic structure (space group P\overline{1}) has been determined at 100 K. In contrast to the reported room temperature monoclinic structure, in which the nearly equivalent carboxylate C—O distances indicate that the acidic hydrogen is randomly distributed between the O atoms, at 100 K the C—O (protonated) and C=O (unprotonated) bonds are clearly resolved, resulting in the reduction in symmetry from C2/c to P\overline{1}.

scholarly journals ζ-Glycine: insight into the mechanism of a polymorphic phase transition

IUCrJ ◽  
2017 ◽  
Vol 4 (5) ◽  
pp. 569-574 ◽  
Author(s):  
Craig L. Bull ◽  
Giles Flowitt-Hill ◽  
Stefano de Gironcoli ◽  
Emine Küçükbenli ◽  
Simon Parsons ◽  
...  
Keyword(s):  
High Pressure ◽  
Structure Prediction ◽  
Room Temperature ◽  
Ambient Pressure ◽  
Crystal Structure Prediction ◽  
Polymorphic Phase Transition ◽  
Neutron Powder Diffraction Data ◽  
Five Phases ◽  
Pressure Phase ◽  
Insight Into

Glycine is the simplest and most polymorphic amino acid, with five phases having been structurally characterized at atmospheric or high pressure. A sixth form, the elusive ζ phase, was discovered over a decade ago as a short-lived intermediate which formed as the high-pressure ∊ phase transformed to the γ form on decompression. However, its structure has remained unsolved. We now report the structure of the ζ phase, which was trapped at 100 K enabling neutron powder diffraction data to be obtained. The structure was solved using the results of a crystal structure prediction procedure based on fullyab initioenergy calculations combined with a genetic algorithm for searching phase space. We show that the fate of ζ-glycine depends on its thermal history: although at room temperature it transforms back to the γ phase, warming the sample from 100 K to room temperature yielded β-glycine, the least stable of the known ambient-pressure polymorphs.

Sign in / Sign up

Export Citation Format

Share Document