... perovskites (that are not too distorted) are included. ... Slist to 1125 compounds which are either confirmed perovskites or compounds which ...

... VANADIUM, TITANIUM COMPOUNDS, CHROMIUM COMPOUNDS, STRONTIUM COMPOUNDS, PEROVSKITES, LANTHANUM COMPOUNDS ...

... ELECTROOPTICS, TANTALUM COMPOUNDS, ELECTRICAL PROPERTIES, POTASSIUM COMPOUNDS, NIOBATES, COMPLEX COMPOUNDS ...

... Descriptors : *PEROVSKITES, *PRECIPITATES, *TITANIUM COMPOUNDS, ATTACK, UNITED KINGDOM, LAYERS, RADIOACTIVE WASTES ...

... LEAD COMPOUNDS, SILICON COMPOUNDS, TITANIUM COMPOUNDS, STRONTIUM COMPOUNDS, PEROVSKITES, NICKEL COMPOUNDS ...

... SEMICONDUCTORS, BARIUM COMPOUNDS, SOLID STATE ELECTRONICS, PHOTOELECTRONS, STRONTIUM COMPOUNDS, PEROVSKITES ...

... HAFNIUM COMPOUNDS, MICROWAVES, ZIRCONIUM, POTASSIUM COMPOUNDS, STANNATES, PEROVSKITES, FERRITES, OPERATORS ...

... ANALYSIS, FERROMAGNETIC MATERIALS, PERMANENT MAGNETS, CHEMICAL COMPOUNDS, PEROVSKITES, LANTHANUM COMPOUNDS ...

... PEROVSKITES), FLUORIDES, ANTIFERROMAGNETISM, MANGANESE COMPOUNDS, POTASSIUM COMPOUNDS, RUBIDIUM COMPOUNDS ...

... Descriptors : *PHASE TRANSFORMATIONS, *PEROVSKITES, *CALCIUM FLUORIDES, *RUBIDIUM COMPOUNDS, REPRINTS, CRYSTAL ...

... MATERIALS, ALKALINE EARTH COMPOUNDS, TUNGSTEN, SOLID STATE ELECTRONICS, PEROVSKITES, NIOBATES, CZOCHRALSKI ...

... Descriptors : *FERROELECTRIC CRYSTALS, PHASE STUDIES, TRANSITION TEMPERATURE, PEROVSKITES, HYDROGEN COMPOUNDS ...

... PROPERTIES, CRYSTALS, EVAPORATION, BARIUM TITANATES, FINE GRAINED MATERIALS, PEROVSKITES, SULFUR COMPOUNDS ...

... Descriptors : (*PEROVSKITES, *LANTHANUM COMPOUNDS), (* FERROMAGNETIC MATERIALS, SPECIFIC HEAT), (*INTEGRALS, PHYSICS ...

A two year research and development program on electrooptically active perovskite crystals was initiated. The program consists of three parts; growth improvement of potassium tantalate niobate (KTN) crystals, development of new complex perovskite compound...

... COMPOUNDS, OXIDES, IRON OXIDES, X RAY DIFFRACTION, TWINNING( CRYSTALLOGRAPHY), PEROVSKITES, CALCIUM COMPOUNDS ...

... Descriptors : *MANGANESE COMPOUNDS, *MAGNETORESISTANCE, *SULFIDES, PEROVSKITES, ANTIFERROMAGNETISM ...

... SPECTRA, QUENCHING, FLUORIDES, STOICHIOMETRY, LITHIUM COMPOUNDS, POTASSIUM COMPOUNDS, PEROVSKITES, SODIUM ...

The brownmillerite-type A 2B 2O 5 structure is considered as a parent one, giving rise to different derivatives: layered double perovskites, A-site and anion-vacancy-ordered perovskites, and the perovskite-like compounds with crystallographic shear planes. The structural relationships and synthesis pathways for ...

Insertion of a Two-Dimensional Iron-Chloride Network between Perovskite Blocks. Synthesis between the perovskite blocks of a double-layered Dion-Jacobson compound. The product, (FeCl)- LaNb2O7, contains iron coordinated by two apical oxygens from the perovskite layer and four in-plane chlorines

... PHASE STUDIES), (*FERRITES, *CRYSTAL STRUCTURE), LEAD COMPOUNDS, OXIDES, IRON OXIDES, PEROVSKITES, CRYSTAL LATTICES ...

... THERMODYNAMIC REGULARITIES IN THE STABILITY OF PEROVSKITES, PYROCHLORE-TYPE COMPOUNDS, AND FLUORITE-TYPE SOLID ...

... of the oxides and carbonates. The compounds are ordered perovskites except for Ba2InSbO6. All compounds are cubic ...

This invention relates to a class of lead-free or low lead perovskite oxide compounds useful to electromechanical actuators. It also relates to composite actuators utilizing these compounds in the form of oriented polycrystals or crystallites. The inventi...

The time-differential perturbed angular correlation (TDPAC) technique was used to measure the electric field gradient (EFG) and its temperature dependence in ferroelectric perovskite-type compounds of cadmium. The number of simple ferro and antiferroelect...

The Czochralski growth of KTN was continued in order to determine reproducibility. In addition, a new growth technique was tested. Thirteen perovskite compounds were selected from the computer output data for melt studies on the strip heater. Twelve of th...

An electrical energy storage device comprises a container, an electrolyte in the container, a metal anode, and a cathode-active material. The cathode-active material is an oxide of the general formula ABO/sub 3/ having perovskite structure, where A is selected from the group consisting of nontransition metals of Group IIa of the Periodic Table and B is a nonnoble transition ...

Topochemical Synthesis of Three-Dimensional Perovskites from Lamellar Precursors Raymond E. Schaak-dimensional perovskites. Experimental Section Synthesis. K2Eu2Ti3O10 and CsEu2Ti2NbO10 were prepared by the solid. Synthesis and Structure of Dion-Jacobson Precursors and Perovskites. AEu2Ti2NbO10 compounds of the ...

... Descriptors : *FERROELECTRIC MATERIALS, *FERROMAGNETIC MATERIALS, *PEROVSKITES, *OXIDES, BARIUM COMPOUNDS, THIN FILMS ...

... Abstract : The successful synthesis of high-Tc YBa2Cu3O7 ... COPPER COMPOUNDS, OXIDES, TITANIUM OXIDES, STRONTIUM, PEROVSKITES. ...

Polycrystalline La1-xAgxMnO3 perovskite compounds (with x=0.10-0.30) have been synthesised by both the conventional solid-state reaction and the sol-gel method. While all samples with Ag concentrations up to 0.20 consist of single-phase perovskites with rhombohedral structure, unreacted Ag was found in the samples with Ag ...

Recently, it has been found that copper-containing oxides have super-conducting transition temperatures as high as 90 K. Further, T/sub c/ values up to room temperature have been rumored. The discovery that these oxides have the perovskite and related structure has renewed interest in these structures. An examination of the structure and properties of ...

... FILMS, SYNTHESIS(CHEMISTRY), SUPERLATTICES, DIELECTRIC PROPERTIES, TITANATES, POTASSIUM COMPOUNDS, PEROVSKITES, ...

... In addition to superconducting films, non-superconducting mixed-valence manganite perovskites, which exhibit so-called colossal ...

work is most closely tied. Materials under investigation in Dr. Haile's group include proton-conducting solid acid compounds, proton-conducting perovskites, mixed oxygen- and...

The preparation of perovskite type compounds containing trivalent or quadrivalent plutonium was attempted. Crystallographic data for the compounds PuAl0/sub 3/, PuV0/sub 3/, PuCr0/sub 3/, and BaPu0/sub 3/ are reported. (auth)

From the class of oxygen perovskites type A(II) sub 2 B(III)sub(1/2)B(I)sub(1/2)M(VI)O sub 6 , some compounds with A = Ba (in some cases also A = Sr) and M = Mo, Te, W, and U are presented. The structures of these compounds are discussed, and the related ...

The efficacy of the oxidation systems: O3, UV radiation, O3/UV radiation, O3/perovskite, UV radiation/perovskite, O3/UV radiation/perovskite, H2O2/UV radiation, H2O2/UV radiation/perovskite, has been investigated by using pyruvic acid as probe compound. Under the operating conditions used, the ...

Among perovskite-type compounds exhibiting one or another of the types of dipole ordering, considerable attention is given to mixed niobates and tantalates, AB{sub 1/2}{sup 3+} Nb{sub 1/2}O{sub 3} and AB{sub 1/2}{sup 3+} Ta{sub 1/2}O{sub 3}, containing Ba{sup 2+} ions on the A site. Barium-containing perovskites with complex ...

The layered compound consists of bilayers of metallic MnO2 sheets separated by insulating material. The compound exhibits markedly anisotropic magnetoresistance at temperatures well below the three-dimensional magnetic ordering temperature Tc=90 K in addi...

More recently compounds such as BaTi03 (perovskites 1, Ni -Cr alloys of various compositions and the semiconductors 111-V compounds like GaAs, ...

The ferromagnetic compound La{sub 3{minus}3x}Ca{sub 1+3x}Mn{sub 3}O{sub 10} with a triple perovskite structure can be successfully synthesized by using a thin-film growth method. Sputtered a-axis thin films with x=0.3 have been examined with respect to their magnetotransport properties. For the triple perovskite ...

The organic-inorganic hybrid [(CH(3))(3)NCH(2)CH(2)NH(3)]SnI(4) presents a layered perovskite structure, templated by an organic dication containing both a primary and a quaternary ammonium group. Due to the high charge density and small size of the organic cation, the separation of the perovskite layers is small and short iodine-iodine contacts of 4.19 A ...

Structures and magnetic properties of double perovskite-type oxides Eu2LnTaO6 (Ln=Eu, Dy-Lu) were investigated. These compounds adopt a distorted double perovskite structure with space group P21/n. Magnetic susceptibility, specific heat, and 151Eu M�ssbauer spectrum measurements show that the Eu2+ ions at the 12-coordinate sites of ...

It was proved earlier that ferroelastic phase transition takes place in the metastable perovskite Pb(Al, Nb)/sub 0.5/O/sub 3/ at approx. 170K. The goal of this work was to study the kinetics of isothermal polymorphic perovskite-pyrochlore transition in this compound. In order to determine the ratio of the pyrochlore and ...

This book is a compendium of research on perovskite-type compounds beginning with discovery in 1945 up to and including recent developments and modern applications. It provides information on structure, x-ray diffraction, conductivity, phase transitions, oxide preparation, etc., as well as new information on high-T{sub c} superconductors.

An analysis of the effect that chemical and hydrostatic pressures have on the thermodynamic properties of perovskite-like fluorine-oxygen compounds A 2 A' MeO x F6 - x has revealed that materials under-going order-disorder transitions and having significant external-pressure compliance have the highest caloric efficiency. Some of the fluorides and ...

This paper describes how the luminescence properties of the octahedral uranate group in compounds with ordered perovskite structure are influenced by the chemical constitution of its surroundings. The quenching temperature of the emission is more strongly influenced by the neighboring cations in the (100) direction than by those in the (111) direction. ...

... Abstract : Lanthanum perovskite compounds, La(B(1/2)Ti(1/2))O3 and La(B(2/3)Nb(1/3))O3 (B=Ni, Co, Mg), are studied as candidates for perovskite ...

A laser is described that employs solid-state crystalline materials in which the active ion is not a dopant but an integral part of the compound of the crystal. A suitable kind of ordering of ions occurs in halide crystals of the perovskite type. The resulting high concentrations permissible have yielded surprisingly small lasers. Drawings of a preferred ...

We show that the symmetry of the spin zigzag chain E phase of the orthorhombic perovskite manganites and nickelates allows for the existence of a finite ferroelectric polarization. The proposed microscopic mechanism is independent of spin-orbit coupling. We predict that the polarization induced by the E-type magnetic order can potentially be enhanced by up to 2 orders of ...

Page 1. SINGLE CRYSTAL PEROVSKITES AS ELECTROOPTICALLY ACTIVE MATERIALS ... Computer Study of Complex Perovskites ...

Size-induced suppression of permittivity in perovskite thin films is a fundamental problem that has remained unresolved for decades. This size-effect issue becomes increasingly important due to the integration of perovskite nanofilms into high-? capacitors, as well as concerns that intrinsic size effects may limit their device performance. Here, we report ...

Topochemical reaction strategies offer an important low-temperature (<500 �C) approach to the conscious manipulation of various inorganic host materials, allowing access to compounds that cannot be prepared by standard high-temperature methods. As the utility of these strategies continues to expand, researchers will be able to more effectively target materials with ...

New members of Dion-Jacobson (D-J)-type layered perovskites of the general formula A'[A2B3O10] (A'=Rb, Cs; A=Sr, Ba; B=Nb, Ta) were prepared by solid-state reactions between the metal oxides, nitrates, and carbonates under specific conditions. The crystal structures were determined using powder X-ray diffraction data in combination with Rietveld analysis. The c-axis lattice ...

High pressure and high temperature experiments on CaSiO3, FeSiO3, MnSiO3 and CoSiO3 using a laser-heated diamond anvil cell combined with synchrotron X-ray diffraction were conducted to explore the perovskite structure of these compounds and the transition to the post-perovskite structure. The experimental results revealed that MnSiO3 ...

... STABILITY OF PB(ZN(1/3)NB(2/3))O(3) (PZN) AND CONSIDERATION OF STABILIZATION CONDITIONS OF PEROVSKITE TUPE COMPOUNDS. ...

Certain ceramic compounds such as rare-earth perovskites and transition-metal diborides that exhibit metallic conductivity are readily available or can be easily synthesized. Some are stable in air firing temperatures typical of hybrid-circuit processing....

The report includes summaries to date of several investigations. The first two sections summarize investigations into the preparation and characterization of perovskite oxides containing mixed transition metal ions. The third section treats continued effo...

The hydrogenation of ethylene over lanthanum transition metal perovskites was studied by characterizing the perovskites by X-ray diffraction, magnetic susceptibility measurements, and scanning electron microscopy; determining the catalytic activity by using a plug-flow microreactor; and determining the surface properties (i.e., work function) by ESCA. The ...

BS>The valence of cerium in perovskite compounds was studied, and the solid solutions, CeAlO/sub 3/--LaAlO/sub 3/ and CeAlO/sub 3/-- SmAlO/sub 3/, were synthesized. The influence of the gaseous medium and temperature on the stability of (x CeAlO/sub 3/, y LnAiO/sub 3/), where Ln is La and Sm, was analyzed. In synthetic ceralite mineral cerium ...

A process and structure involving a silicon substrate utilizes an ultra high vacuum and molecular beam epitaxy (MBE) methods to grow an epitaxial oxide film upon a surface of the substrate. As the film is grown, the lattice of the compound formed at the silicon interface becomes stabilized, and a base layer comprised of an oxide having a sodium chloride-type lattice structure ...

Since the discovery of the perovskite to post-perovskite transition in MgSiO3 in a laser-heated DAC, wide attention has been focussed on the post-perovskite phase of MgSiO3. This is because the post-perovskite phase is likely to play a key role in Earth�s lowermost mantle, and because the ...

Among hexagonal perovskites, the B-cation deficient perovskite-related compounds AnBn-1O3n present two kinds of structural types depending on the stacking sequences of their AO3 layers. All these structures derive from the perovskite, which is periodically disturbed by planar defects. The structures with ...

Recently multiferroic materials have attracted great interest. However, relatively a few pure multiferroic compounds are currently known. Here we show the exploration of design of multiferroic properties in double perovskites by combining the ferrolectrisity driven by the Bi lone pairs and selectively choosing the 3d transition metals following ...

Crystallographic study of compounds with the formula Ba/sub 3/Fe/sub 2 - x/Lu/sub x/UO/sub 9/ (0 less than or equal to x less than or equal to 1.2) shows that they are cubic ordered perovskite-type compounds with probable space group Fm3m. Lutetium is equally distributed between the site of coordination 12 (8c) and the site 4b. On the ...

New quadruple perovskite oxides Ba{sub 4}LnIr{sub 3}O{sub 12} (Ln=lanthanides) were prepared and their magnetic properties were investigated. They crystallize in the monoclinic 12L-perovskite-type structure with space group C2/m. The Ir{sub 3}O{sub 12} trimers and LnO{sub 6} octahedra are alternately linked by corner-sharing and form the ...

High-pressure high-temperature experiments of Ca2AlSiO5.5 were performed at 7.5-23 GPa and 1473-1873 K to clarify the high-pressure phase relations. Rhombohedral perovskite phase was recovered in runs at pressure higher than about 14 GPa. Samples synthesized below 14 GPa showed a powder X-ray diffraction pattern different from that of the rhombohedral ...

of the layered compounds generally in- creases when the compounds have Bi ions on the A site of the perovskite in Bi- layered compounds. Introduction of a compositional varia- tion in the Bi layers can solveEffect of excess Bi2O3 on the ferroelectric properties of SrBi2Ta2O9 ceramics Jung-Kun Lee

We have realized Perot Fabry microcavities containing a two-dimensional layered perovskite-type semiconductor: (C6H5C2H4 NH3)2PbI4 between a dielectric mirror and a metallic mirror. A strong coupling regime between the perovskite exciton and the confined photon mode has been evidenced at room temperature from angular-resolved reflectivity experiments, ...

Rubidium dicalcium triniobate(V), RbCa₂Nb₃O₁₀, has been synthesized by solid-state reaction and its crystal structure refined from X-ray powder diffraction data using Rietveld analysis. The compound is a three-layer perovskite Dion�Jacobson phase with the ...

The present invention comprises perovskite-phase thin films, of the general formula A.sub.x B.sub.y O.sub.3 on a substrate, wherein A is selected from beryllium, magnesium, calcium, strontium, and barium or a combination thereof; B is selected from niobium and tantalum or a combination thereof; and x and y are mole fractions between approximately 0.8 and 1.2. More ...

New Bi (V) containing perovskites oxides of the type, BaLaMBiO{sub 6} (M = Mg, Ca, Sr) have been synthesized under high oxygen pressure conditions using the thermal decomposition of peroxides in a tetrahedral anvil apparatus. These compounds have been characterized by X-ray powder diffraction and iodometric titration. All the BaLaMBiO{sub 6} (M + Mg, Ca, ...

Single phase orthorhombic perovskite Ho1?xLaxMnO3 (x = 0.1, 0.15) compounds are successfully synthesized by using a sol-gel method. We find that the orthorhombic perovskite structure of HoMoO3 compound can be stabilized by partial substitution of smaller Ho ion by larger La ion. The magnetic properties of ...

Single-crystal and powder samples of a new calcium iron (II) titanate, CaFeTi{sub 2}O{sub 6}, have been synthesized at 12-15 GPa and 1200-1400{degrees}C, and studied by X-ray diffraction. This compound is a variant of the perovskite structure and crystallizes in the tetragonal space group P4{sub 2}/nmc, a = 7.5157(2) {angstrom}, c = 7.5548(2) {angstrom}, ...

The magnetic and crystal structures of the LaCo{sub 0.5}Fe{sub 0.5}O{sub 3} perovskite are investigated. It is established that the unit cell of this compound at room temperature is characterized by rhombohedral distortions. As the temperature decreases, the compound undergoes a structural phase transition from the rhombohedral phase ...

Alkali-metal-halide layers were constructed within Dion-Jacobson (DJ) layered perovskites by a two-step sequential intercalation method. Reductive intercalation with an alkali metal, followed by oxidative intercalation with chlorine gas, leads to the formation of the compounds, (A(2)Cl)LaNb(2)O(7) (A = Rb, Cs). Rietveld refinement of X-ray powder ...

The mixed-valence oxynitride LaWO/sub 0.6/N/sub 2.4/ is a new example of a conductor with the perovskite structure. The time-of-flight neutron diffraction study has shown that this compound possesses a tetragonal symmetry (space group I/anti 4/). Oxygen and nitrogen atoms are disordered and the coordination octahedra around the tungsten atoms are tilted by ...

The perovskite-type layer compounds (Csub(n)Hsub(2n+1)NH sub 3 ) sub 2 MeCl sub 4 show a variety of different structural modifications. They differ from one another by the order and dynamical behaviour of the CH sub 3 -CH sub 2 -...-CH sub 2 -NH sub 3 cha...

A process is disclosed for producing powders of perovskite-type compounds which comprises mixing a metal alkoxide solution with a lead acetate solution to form a homogeneous, clear metal solution, adding an oxalic acid/n-propanol solution to this metal solution to form an easily filterable, free-flowing precursor powder and then calcining this powder. This ...

A process for producing powders of perovskite-type compounds which comprises mixing a metal alkoxide solution with a lead acetate solution to form a homogeneous, clear metal solution, adding an oxalic acid/n-propanol solution to this metal solution to form an easily filterable, free-flowing precursor powder and then calcining this powder. This process ...

We have investigated the structural and magnetic properties of antiferroelectric A2CoTeO6 perovskites with A=Cd, Ca, Sr, Pb, and Ba. All compounds are antiferromagnetic at low temperatures, with the antiferromagnetic transition temperature slightly decreasing with decreasing ionic size of the A cation. Such a decrease in antiferromagnetic interaction is ...

. Bulk synthesis methods, although the most direct path to this end, can often be complicated of substrates and electrode candidates have already begun to be addressed. Given the perovskite-related structures of these compounds, growth of c-axis films on 001 perovskite substrates i.e., SrTiO3 , LaAlO3 , Nd

Quadruple perovskites Ba{sub 4}LnRu{sub 3}O{sub 12} (Ln=La, Nd, Sm-Gd, Dy-Lu) were prepared and their magnetic properties were investigated. They adopt the 12L-perovskite-type structure consisting of Ru{sub 3}O{sub 12} trimers and LnO{sub 6} octahedra. All of these compounds show an antiferromagnetic transition at 2.5-30 K. For Ba{sub ...

complex perovskites, modified perovskites, and other structure families. New substrate ... on the complex oxide perovskites and related solid solutions. ...

Electrical conductivity measurements of Perovskite and a Perovskite-dominated assemblage synthesized

The temperature dependence of EXAFS Debye-Waller factors in SrGeO3 perovskite, which synthesize in a cubic anvil type apparatus under 9GPa and 1000K, was investigated with the cumulant expansion method. The Sr and Ge K-edge EXAFS spectra were measured in transmission mode at various temperatures from 30 to 300K. Effective pair potentials, V(u) =?u2/2, were evaluated by ...

The oxygen stoichiometry variation in the BaRE(Cu{sub 0.5}Fe{sub 0.5}){sub 2}O{sub 5+{delta}} series is established with rare earth elements having ionic radii (CN = 8) in the range of 0.977--1.160{angstrom}(Lu-La). The double-perovskite structure is stable with RE = Lu-Pr, while La prefers the simple-perovskite structure. In the ...

The structure and optical properties of a lead halide organic-inorganic perovskite compound containing an (R)-2-octylammonium cation have been investigated in order to confirm the construction of an optically active quantum well. As in the case of the general alkylammonium systems, a spin-coated film of the compounds took the form of a ...

A new perovskite-related compound, Y{sub 2}Ba{sub 3}Cu{sub 3}Co{sub 2}O{sub 12}, has been synthesized by solid state reaction. Its structure is tetragonal with a = 3.878(2) {angstrom} and c = 19.193(8) {angstrom}; XRD and HREM investigations indicate that it consists of a regular intergrowth of YBa{sub 2}(Cu, Co){sub 3}O{sub 7} and YBa(Cu, Co){sub 2}O{sub ...

The patent relates to a nuclear fuel material, comprising a conpound of Pu having the perovskite structure and having the formula MPuO/sub 3/ (M = Ha) or PuMO/sub 3/ (M = Al, V, Cr, or Mn). The compounds are prepared by heating PuO/ sub 2/ with the relevant metal oxide, carbonate, or hydroxide. (NPO)

When ABX3 compounds form the perovskite structure at atmospheric pressure (i.e.,SrTiO3, SrZrO3, CaTiO3), the other members of the (ABX3)(AX)n series (n=0, 1/3, 1/2, 1) can generally be formed also. However, if the relative size of the A cation is too larg...

The infinite layer or parent compounds ACuO(sub 2) (A: Ca-Sr-Ba) constitute the simplest copper oxygen perovskites that contain the CuO(sub 2) sheets essential for superconductivity. The stabilization of these basic ''building blocks'' as epitaxial films,...

We describe in this work the synthesis by the Pechini method of five Mo(VI)- and W(VI)-containing complex perovskites and their structural characterisation by HREM and XRD. The compounds studied, Ba(B2/3'B1/3'')O3 (B'=In and Y; B''=W and Mo) and Sr(In2/3W1/3)O3, were obtained after firing the precursor powders for 8h at 1200�C. Thermal analysis showed ...

We have synthesized and characterized new layered perovskites Ag2[A1.5M3O10] (A = Ca, M = Nb, Ta), from their lithium analogues, by soft-chemical ion exchange. These oxides show topotactic irreversible thermally induced A'-A site exchange, resulting in Ag1.1Ca0.9[Ca0.6Ag0.9M3O10], conferred from our high-temperature X-ray and ionic conductivity studies. The latter phases are ...

The real-space recursion method and unrestricted Hartree-Fock approximation have been applied to calculate the density of states of various Co perovskite, CeCoO3, SrCoO3 and Sr1?xCexCoO3. We have studied the magnetically ordered states of these Co perovskites in an enlarged double cell, and find its various magnetic structures due to the occupancy of 3d ...

The structure of La(1/3)NbO3 is that of a perovskite with La3+ cations ordered into alternate layers of perovskite A-sites. This is the description of a tetragonal structure and yet the room-temperature structure shows an orthorhombic distortion. The structure of La(2/3)TiO3 shows similar features. It has been recognized only very recently that the ...

The double perovskite Sr(Ni{sub 1/2}Mo{sub 1/2})O{sub 3} has been prepared with solid-state reaction and was characterized by x-ray diffraction technique. It has been indicated that the single phase is formed at 1300 deg. C in air. The compound undergoes a phase transition at 280 deg. C, where the structure of the ordered perovskite ...

The remarkable properties of manganese oxides AMnO3 with perovskite structure, such as the colossal magnetoresistance and the multiferroicity, arise from peculiar charge, spin and orbital orderings of the Mn eg electrons driven by cooperative Jahn-Teller distortions of the MnO6 octahedra. Mastering these orderings remains a challenge owing to local structural distortions and ...

The garnet-perovskite transition is studied in this work with magnetic disaccommodation on polycrystalline Nd doped YIG samples Y3-xNdxFe5O12 (0 < x < 2.5). A very different behaviour with the sintering atmosphere is observed. The results of magnetic disaccommodation for samples sintered in air reveal that the low temperature peak of YIG at 120 K disappear and another ...

New perovskites of the formula PbMn /SUB 2/3/ B /SUB 1/3/ O/sub 3/ where B is Mo, Te, or Re were produced at high pressures. In a certain temperature range, the Mo and Te perovskites correspond in their spontaneous polarization and antiferromagnetic states, and are ferromagnetic. The ferrimagnetic properties of the Re perovskite are ...

The layered perovskite structures of NaYTiO{sub 4} and homologous acid exchange form were investigated via powder X-ray diffraction and high resolution transmission electron microscopy. The NaYTiO{sub 4} layered structure differs from the previous investigation of Blasse et al., by the incorporation of perovskite-like 2 octahedra thick lamellae instead of ...

Transition-metal oxynitrides with perovskite-type structures are an emerging class of materials with optical, photocatalytic, dielectric and magnetoresistive properties that may be sensitive to oxide-nitride order, but the anion-ordering principles were unclear. Here we report an investigation of the representative compounds SrMO(2)N (M�=�Nb, Ta) using ...

Transition-metal oxynitrides with perovskite-type structures are an emerging class of materials with optical, photocatalytic, dielectric and magnetoresistive properties that may be sensitive to oxide�nitride order, but the anion-ordering principles were unclear. Here we report an investigation of the representative compounds SrMO2N (M�=�Nb, Ta) using ...

The structural and electronic properties of both inorganic and hybrid organic-inorganic perovskites based on tin halides are investigated from the first principles. In particular, we contrast the inorganic CsSnCl3 and CsSnI3 to their hybrid counterparts (CH3NH3)SnCl3 , (CH3NH3)SnI3 , and (NH2CH=NH2)SnI3 , which were obtained by substituting the inorganic Cs cation with the ...

The stability and electronic structure of perovskite hydrides ABH{sub 3} were investigated by means of first-principles density functional calculations. Two types of perovskite hydrides are distinguished: (1) When A and B are alkali and alkaline earth metals, the hydrides are ionic compounds with calculated band gaps of around 2 eV and ...

The highly accurate all electrons full potential linearized augmented plane wave method is used to calculate structural, electronic, and optical properties of cubic perovskites CsPbM3 (M=Cl, Br, I). The theoretically calculated lattice constants are found to be in good agreement with the experimentally measured values. It is found that all of these ...

The pressure effect on synthesis of oxides with perovskite ABO3 and perovskite-related structures has become more clear in recent years. The geometric tolerance factor t ? (A-O)/2(B-O) measures the structural stability. High-pressure synthesis enlarges the range of the t factor where the perovskite structure can be stabilized. For the ...

... Title : Thermodynamic Phenomenology for Perovskite Structure Ferroelectric Solid Solutions with Morphotropic Phase Boundaries. ...

... Accession Number : AD0253293. Title : SOME PROPERTIES OF BISMUTH PEROVSKITES. Corporate Author : MASSACHUSETTS ...

... Accession Number : AD0828049. Title : SINGLE CRYSTAL PEROVSKITES AS ELECTROOPTICALLY ACTIVE MATERIALS. ...

... Accession Number : AD0658461. Title : SINGLE CRYSTAL PEROVSKITES AS ELECTROOPTICALLY ACTIVE MATERIALS. ...

... Accession Number : AD0650411. Title : SINGLE CRYSTAL PEROVSKITES AS ELECTROOPTICALLY ACTIVE MATERIALS. ...

... Accession Number : ADD255364. Title : Kinetics of the Hydrothermal Crystallization of the Perovskite Lead Titanate. Descriptive ...

... Accession Number : AD0447460. Title : INFRARED STUDIES OF PEROVSKITE TITANATES,. Corporate Author : MASSACHUSETTS ...

A description is given of the preparation and characterization of a number of compounds of the type A/sub 2/BB/sup 1/O/sub 6/ where A = Ca, Sr, Ba; B/ sup 1/ = Re or Os; and B represents a variety of univalent, divalent, and trivalent cations. Evidence was obtained for the existence of heptavalent osmium in the compound Ba/sub 2/LiOsO/sub 6/. The ...

An oxide semiconductor Ca2NiWO6, with double-perovskite crystal structure, was synthesized by solid-state reaction method. The compound Ca2NiWO6 was characterized by X-ray diffraction, UV visible diffuse reflectance, and photoluminescence. The photocatalytic properties of the compound for water splitting were investigated under UV and ...

The structural and magnetic properties of cubic perovskites, PrCoO3 and NdCoO3, are studied using the full potential linearized augmented plane wave (FP-LAPW) method within the frame work of density functional theory (DFT). The structural parameters are also investigated by analytical techniques. The calculated structural parameters are consistent with the experimental ...

Using first-principles density functional calculations, we have computed the optical and magneto-optical properties of the Cr-based double perovskite compounds, Sr2CrB'O6 with B'=W,Re,Os. Our computed magneto-optic spectra show substantially large Kerr rotations of about -2� to -2.5� for Sr2CrWO6 and Sr2CrReO6 and a moderately large Faraday rotation of ...

A short range force constant model has been used within the normal coordinate analysis framework for the first time to investigate the lattice dynamics of Sr2B?UO6 (B?=Ni, Co) double perovskites having space group P21/n. The zone centre phonons have been calculated with ten stretching force constants and eight bending force constants in the nickel compound ...

We carried out a LDA+DMFT study of perovskite ruthenates SrRuO3 and CaRuO3, compounds which have been discussed in great detail in recent literature. Our results reproduced the observed mass enhancements and magnetic properties, and were in reasonable agreement with the measured photoemission spectra. Our calculations produced rather different coherence ...

The authors attempt to produce several new layered perovskite-like compounds of the composition Bi/sub 2/AB/sub 2/O/sub 9/ and to study their crystallographic and physicochemical properties. The authors examine the scope for producing new bismuth-containing layered perovskite-like compounds by heterovalent ...

A study of the crystallographic and magnetic structure of the double perovskite Sr{sub 2}CoMoO{sub 6} (SCMO) has been carried out on a polycrystalline sample using neutron powder diffraction (NPD) data between 10 and 700 K. An analysis of the NPD patterns at room temperature has shown that this compound crystallises in the tetragonal space group I4/m with ...

The structural and magnetic properties of the perovskite type compound LaFe{sub 0.5}Cr{sub 0.5}O{sub 3} have been studied by temperature dependent neutron powder diffraction and magnetization measurements. Rietveld refinement of the neutron diffraction data shows that the compound crystallizes in an orthorhombic ...

We have studied the Sr(2-x)La(x)Fe(1+x/2)Re(1-x/2)O(6) series in order to check how the increase in the number of Fe-O-Fe superexchange interactions affects the magnetic properties of this family of double perovskites. In these compounds the addition of La(3+) can be compensated by an increase of the Fe(3+) ratio leading to a non-electron-doped system. The ...

Cation-deficient hexagonal perovskites Ba{sub 5}Nb{sub 4}O{sub 15}, Ba{sub 6}Nb{sub 4}TiO{sub 18}, and their intergrowth compounds were prepared by solid-state reaction method. Dielectric measurements showed that the intergrowth compounds had a relatively low temperature coefficient of resonant frequency ({tau}{sub f}) compared to that ...

Polycrystalline double perovskites Sr2Fe1?x Cr x Mo1?x W x O6 with x=0, 0.05, 0.10, 0.15, 0.20, and 0.30 have been prepared by sold state reactions. A continuous decrease of the tetragonal unit cell parameters ? and c with increasing x values is observed. The highest Curie temperature T c =426 K is recorded for the x=0.10 compound. 57Fe M�ssbauer ...

Polycrystalline double perovskites Sr2Fe1?x Cr x Mo1?x W x O6 with x = 0, 0.05, 0.10, 0.15, 0.20, and 0.30 have been prepared by sold state reactions. A continuous decrease of the tetragonal unit cell parameters ? and c with increasing x values is observed. The highest Curie temperature T C = 426 K is recorded for the x = 0.10 compound. 57Fe M�ssbauer ...

Methods are given for preparing compounds of the formula MPuO/sub 3/ or PuMO/sub 3/ and of the perovskite structure. The compounds include BaPuO/sub 3/, PuAlO/sub 3/, PuVO/sub 3/, PuCrO/sub 3/, and PuMnO/sub 3/, which can be used as nuclear fuel material with the possible exception of PuMnO/sub 3/. (D.L.C.)

We synthesized a novel perovskite-type oxyfluoride, PbScO{sub 2}F, and investigated its crystal structure, thermal stability and dielectric properties. PbScO{sub 2}F has a cubic perovskite-type structure with Pb ions displaced from the ideal A-site positions along the <110> direction. By thermal gravity and differential thermal analyses, we ...

Among oxidic perovskites containing highly polarizable ions, many phases exhibit particular dielectric properties associated with dipole ordering. In the ferroelectric and antiferroelectric state, the crystal structure of such phases differs from the ideal cubic perovskite structure and has a lower symmetry. The group of nonlinear dielectric materials that ...

The specific features of diffuse X-ray scattering in BaTiO{sub 3}, KNbO{sub 3}, and PbTiP{sub 3} perovskite crystals have been investigated. The former two perovskite compounds in cubic, tetragonal, and orthorhombic phases exhibit anomalous sheets due to diffuse X-ray scattering, whereas no similar sheets are observed in the case of ...

A new series of complex perovskite-type compounds La{sub 1{minus}x}Sr{sub x}Cr{sub 1{minus}x}Ti{sub x}O{sub 3} involving substitutions at both A and B sites was prepared by the ceramic technique (final heating at 1350 C). X-ray powder diffraction and profile-refinement study of this series show it to comprise orthorhombic perovskites ...

B-site disordered RFe0.5V0.5O3 compounds, with R=La, Nd, Eu and Y, have been prepared by solid-state reaction technique and their structures and magnetic properties have been investigated through X-ray powder diffraction, time-of-flight neutron powder diffraction and magnetization measurements at temperatures ranging from 5 to 700 K. The four compounds can ...

The dependence of the strain energy of anion-cation bonds on the sum ?2 of squares of the angles of ordered rotations of octahedra around the coordinate axes of the reduced cell has been determined for ABX 3 compounds with perovskite structure in the two-particle approximation. A relation determining the change in the thermodynamic Gibbs potential with ...

A careful investigation has been carried out into the space group symmetries, structures and crystal chemistries of the 1:2 B-site ordered triple perovskites A3Co2+Nb5+2O9 (A=Ca2+, Sr2+, Ba2+) using a combination of bond valence sum calculations, powder XRD and electron diffraction. A recent investigation of these compounds by Yin et al. reported a random ...

The intensity of titanium fluorescence K spectra in BaTiO/sub 3/, CaTiO/ sub 3/, PbTiO/sub 3/, SrTiO/sub 3/, and Ti/sub ,2/O/sub 3/ was measured. (R.V.J.)

for Coatings, Guidelines for the Protection of Structural Steelwork and Bimetallic Corrosion. At present temperature superconductors (HTS) based on perovskite structured cuprate compounds is finding rapid considerably closer. Colour 2000 #12;As part of its DTI-funded work on micro-structured surfaces, NPL has

Absorption and reflectance spectra of crystalline SrT:O3, BaTiO3, and Cat:O3 in the IR spectral range were obtained on a long wavelength IR spectrometer. An analysis of the vibrational modes of compounds having the perovskite structure is given and its ap...

... Abstract : Since the discovery of unusual ferroelectric properties (ie relaxor effect) in a complex perovskite compound, Pb(Mg(1/3)Nb(2/3))O3 (PMN ...

A trifluoride series BF3(B=Ru, Co, V, Fe, Ti) is related to different perovskite-type series ABO3(A=Bi, Pb, La, Li and B=Fe, Zr-Ti, Co, Al, Nb, Ta) as being based on the same anion framework. This anion framework can be viewed as generated by linear chain...

The present study was carried out to determine the oxidation states of iron in lanthanum and holmium ferrites synthesized by a solid state method. The X-ray diffraction results, of both compounds, correspond to the perovskite structure of LaFeO3 and HoFeO3. The M�ssbauer spectroscopy applied to these phases show only the oxidation state of Fe (III).

Techniques were developed for the preparation of the perovskite-type compound Bi FeO3, both as a powder and in small (1 mm) single crystals. The structure of Bi FeO3 was then determined. It is ferroelectric and the space group to which it belongs, R3c, pe...

,000 Fe atoms [5]. The mole fraction (X) of total iron (Fe) in all Fe-bearing compounds is )( )( 2 He lithophiles, such as the lanthanides (or rare earth elements REE) are found dissolved in perovskite of Earth and Planetary Sciences Washington University St. Louis, MO 63130-4899 Phone: (314) 935-4852 FAX

(of the ionic crystal) on a fine grid in the whole cluster region. #12;5.2. Details of calculations 85 of ionic transition metal compounds with strong electron correlation effects is intensively studied of the wave functions in Valence Bond (VB) terms, such as ionic and covalent structures and charge transfer

Magnetic ground states in solids often arise as a result of a delicate balance between competing factors. One currently active area of research in magnetic materials involves compounds in which long-range magnetic ordering at low temperatures is frustrated by the geometry of the crystalline lattice, a situation known as geometrical magnetic frustration. The number of ...

of Perovskite-like Compounds, I. Rare Earth Orthoferrites and YFeO3, YCrO3, YAlO3," Acta Crystallogr., 9, 563 composite is an ideal material for high-temperature structural-ceramic applications.1 Over the years, most Engineering, Michigan Techno- logical University, Houghton, MI 49931. J. Am. Ceram. Soc., 82 [10] 2881

The discovery of a series of layer-perovskite superconducting compounds by Maeda et al. (1988) presented a challenge for present day electron diffraction techniques, due to their common occurrence as mixed phases, and the existence of complex structural m...

New intercalation compounds with Cu2+ ions in the interlayer of layered perovskite oxides, OA(1-x)Ca(2-x)La(x)Nb3O10) (OA = n-octylammonium ion, 0 < or = x < 1), have been prepared by ion-exchange reaction, and characterized by means of XRD and XAS. For the detail elucidation of the fine structure of the Cu K-edge XANES spectra, polarized XAS was ...

We present the results of an exploratory theoretical study of the structural and thermoelastic properties of layered perovskites KCa_2Nb_3O_10 and RbCa_3Nb_3O_10. The pressure and temperature dependence of the phonon spectra, elastic moduli, structural parameters and cohesive energies are obtained from a direct minimization of the Gibbs free energy of the crystal with respect ...

We have studied the effect of Cr substitution for Fe in Sr2Fe1?xCrxMoO6 (x?0.3) double perovskites. X-ray diffraction, neutron powder diffraction (NPD), magnetisation measurements as well as Mossbauer spectroscopy have been used to determine the structural and magnetic properties of these compounds. All these materials were found to crystallise with ...

Perovskite YFe0.5Cr0.5O3 exhibits magnetization reversal at low applied fields due to the competition between the single ion magnetic anisotropy and the antisymmetric Dzyaloshinsky-Moriya interaction. Below a compensation temperature (Tcomp), a tunable bipolar switching of magnetization is demonstrated by changing the magnitude of the field while keeping it in the same ...

A series of osmium double perovskite oxides, Ln2LiOsO6 (Ln=La, Pr, Nd, Sm), has been prepared as single crystals from acidic molten hydroxide. All four oxides crystallize in the monoclinic space group P21/n (Glazer tilt system #10, a?a?b+), forming a 1:1 ordered rock salt lattice of Li+ and Os5+ cations. Magnetic susceptibility measurements show that these ...

The Ln(B{sub 0.5}Mn{sub 0.5})O{sub 3} (Ln-lanthanoid; B = Ni, Co) compounds with the orthorhombic perovskite structure have been prepared by a solid state reaction. They are ferromagnets with relatively high Curie temperatures. The Curie temperature decreases with decreasing average radii of the Ln-ion. It is shown that the Ln(Co{sub 0.5}Mn{sub 0.5})O{sub ...

The crystal structure and magnetism of Ca2?xLaxFeReO6 (0?x?0.8) double perovskites have been investigated. The samples with low doping (x?0.4) are found to crystallize with the monoclinic P21/n superstructure, while those in the high doping ones (x?0.6) have orthorhombic Pbnm superstructure. With the increase of an La doping, the anti-site defects increases, giving rise to ...

In contrast with previous structural studies of ytterbium trirhodium boride, YbRh₃B, that suggest a boron deficiency, the current redetermination of the crystal structure of YbRh₃B revealed instead a rhodium deficiency with a refined composition of YbRh_2.67?(2)B. In the ABX ₃ ...

Perovskite-type compounds (ABO3) of (Ca,Sr)TiO3 doped with trivalent europium (Eu3+) were synthesized by sonochemical techniques. Powder X-ray diffraction measurement on (Ca,Sr)TiO3 were used to identify the perovskite crystal structure. The photoluminescence property in (Ca,Sr)TiO3 with europium substitution several atoms in the host ...

Two perovskite rare-earth manganites RMnO{sub 3} (R=Ho, Dy) were synthesized from the hydrothermal redox reactions of KMnO{sub 4} and MnCl{sub 2} at 250{sup o}C and characterized by means of X-ray diffraction, scanning electron microscopy and SQUID. They are orthorhombic, whereas the hexagonal phases, which were competitive strongly with the orthorhombic phases in solid-state ...

We have synthesized a Sr2CrReO6 double perovskite sample with the expected high Curie temperature ap 600 K, which shows negligible impurity phases and ap 15% Cr/Re structural antisite disorder as shown by X-ray and neutron diffraction. High-field magnetization measurements up to 47 T show that the saturation magnetization below room temperature is much higher than the one ...

The title compound has been prepared from BaO, NbO{sub 2} and Nb mixtures, at 1,200 C under an hydrostatic pressure of 12 kbar. It is cubic, a = 4.3239(4) {angstrom}, and the Rietveld analysis of the X-ray diffraction profile shows a strong deficiency in both Ba and oxygen positions. Unlike metallic BaNbO{sub 3}, this defect perovskite shows insulating ...

Magnetoresistance and magnetocaloric effect of a double perovskite oxide PrSrMnCoO6 (cubic, Fm3m) has been studied in fields up to 7 T. This compound is semiconductor-like and its electrical resistivity increases by 5 orders while going from 300 to 50 K. Giant magnetoresistance of ~40% is observed at 200 K in 7 T field. PrSrMnCoO6 orders ferromagnetically ...

The recent discovery that perovskite-type crystal structures composed of La-Cu oxides substituted with small amounts of alkaline earth cations have exceptionally high superconducting critical temperatures has stimulated much interest in these potentially important materials. The most promising material reported thus far in the literature is La/sub 2-x/Sr/sub x/CuO/sub 4/. The ...

Density functional perturbation theory, combined with quasi-harmonic approximation theory and the Debye theory, has been used to calculate the thermal conductivity of the double-perovskite perovskite slab�rocksalt layer oxide compounds L2SrAl2O7 (L = La, Nd, Sm, Eu, Gd, and Dy), a promising class of high-temperature thermal ...

The A-site-ordered perovskite YMn(3)Al(4)O(12) was prepared by high-pressure synthesis. Structural analysis with synchrotron powder X-ray diffraction data and the Mn L-edges X-ray absorption spectrum revealed that the compound has a chemical composition Y(3+)Mn(3+)(3)Al(3+)(4)O(2-)(12) with magnetic Mn(3+) at the A' site and non-magnetic Al(3+) at the B ...

... Structural distortions of cubic perovskites of the formula ABX3 , where the ... The number of anti-perovskites ABM 3 , where the positions of anion and ...

... Title : Single Crystals of Yttrium and Rare Earth Gallium Perovskites for Use as Substrates for Bubble Domain Iron Perovskites. ...

Discovery of a high-pressure post-perovskite phase transition of MgSiO3 opened a new paradigm for understanding the deepest region of the core-mantle boundary and the D�� region. The structure was found to be Cmcm space group as same structure as CaIrO3. However, we discovered a new structure for the post-perovskite phase of iron rich magnesium ...

Since the discovery of high-Tc superconductivity in LaFeAs(O,F), development of the materials having iron or nickel pnictide layers are subject of study. As presented in last APS March meeting, we have discovered iron and nickel pnictide oxide superconductors with perovskite-type oxide layers[1]. Until now, several compounds of this system have been found ...

The room temperature structures as well as the temperature-dependent conductivity and dielectric properties of the A{sub 3}CoNb{sub 2}O{sub 9} (A=Ca{sup 2+}, Sr{sup 2+} and Ba{sup 2+}) triple perovskites have been carefully investigated. A constrained modulation wave approach to Rietveld structure refinement is used to determine their room temperature crystal structures. ...

The pinning effects of two kinds of U-rich deposits in YBCO (YBa2Cu3O7??) are compared. One is a five-element compound, (U0.6Pt0.4)YBa2O6, which is a paramagnetic double perovskite which forms as profuse stable nanosize deposits, and pins very well. The other is a four-element compound, (U0.4Y0.6)BaO3, which is a ferromagnetic single ...

1 Overview of Results and their Significance Ceramic perovskite-like oxides with the general formula (A. A0. ...)(B. B0. ...)O3and titanium-based oxides are of great technological interest because of their large piezoelectric and dielectric response characteristics.[1] In doped and nanoengineered forms, titantium dioxide finds increasing application as an organic and ...

A-site-ordered perovskites LaMn(3)Cr(4)O(12) and LaMn(3)Ti(4)O(12) were synthesized under high-pressure and high-temperature conditions. The charge formula of LaMn(3)Cr(4)O(12) was found to be LaMn(3+)(3)Cr(3+)(4)O(12) with Mn(3+) at the square-coordinated A site. The valence of the A-site Mn ions in LaMn(3)Ti(4)O(12) appeared to be less than +2, and the charge combination in ...

The anode materials in the solid oxide fuel cell (SOFC) require properties such as high electric conductivity, high catalytic effect for hydrogen decomposition from hydrocarbon and good resistant to sulfur. For these purposes, anode materials based on double perovskite structure, A2BB'O6, were synthesized and studied. In this work, double perovskite ...

Strongly correlated electron systems, especially perovskite type of manganites, in which the electronic transport properties of transition metal oxides strongly interact with the magnetic properties and with the crystal lattice, are of great interest not only due to their application in technology but also to the need of fundamental research in understanding the origin of the ...

The formation of a pyrochlore structure phase is a major problem in the preparation of Pb(Zn/sub 1/3/Nb/sub 2/3/)O/sub 3/ (PZN) based ceramics since its presence is detrimental to the dielectric and piezoelectric properties. An analysis of electronegativity difference and tolerance factor of several ABO/sub 3/ type of compounds shows that BaTiO/sub 3/ is an excellent additive ...

The (La{sub 1{minus}} x Sr{sub x}){sub 3}Mn{sub 2}O{sub 7} compounds are layered materials that exhibit higher magneto-resistance than the corresponding 3D manganite perovskites. Quasi-elastic neutron scattering on a polycrystalline sample of La{sub 1.4}Sr{sub 1.6}Mn{sub 2}O{sub 7} shows that the spin fluctuation spectrum of the these layered CMR materials ...

The (La{sub 1{minus}x}Sr{sub x}){sub 2}Mn{sub 3}O{sub 7} compounds are layered materials that exhibit higher magneto-resistance than the corresponding 3D manganite perovskites. Quasi-elastic neutron scattering on a polycrystalline sample of La{sub 1.4}Sr{sub 1.6}Mn{sub 2}O{sub 7} shows that the spin fluctuation spectrum of these layered CMR materials is ...

Substitution of La(3+) by Sr(2+) in the double perovskite La(2)CoTiO(6) yields materials of the La(2-x)Sr(x)CoTiO(6) series showing a significant amount of trivalent cobalt ions when prepared at ambient atmosphere. The as-prepared compounds can be reduced in severe conditions retaining the perovskite structure while inducing the ...

The nuclear and magnetic structures of the oxygen-deficient perovskite YBaCuCoO[sub 5] have been determined by neutron powder diffraction at room temperature. The nuclear structure has the symmetry of space group P4/mmm and lattice parameters a = 3.8679(1), c = 7.5674(2) [angstrom]. Copper and cobalt atoms are completely disordered in this compound and the ...

Novel catalytic nano-sized materials based on LaCoO(x) perovskite nanoparticles incapsulated in the mesoporous matrix of zirconia were prepared, characterized by physicochemical methods and tested in complete methanol oxidation. LaCoO(x) nanoparticles were prepared inside the mesopores of ZrO(2) by decomposition of bimetallic La-Co glycine precursor complexes. The catalysts ...

This work presents an overview of a series of increasingly complex oxides synthesized from CrO 2, under high-pressure and high-temperature conditions, having Cr (4+) in octahedral coordination. Although the emphasis is on the structure and microstructure of the compounds as obtained from X-ray diffraction and transmission electron microscopy and diffraction, attention is also ...

Based on ambient ultrasonic measurements and x-ray diffraction under hydrostatic compression, the authors report here a comparative study of elasticity on oxygen-deficient perovskite, BaCe1-xYxO3-0.5x, with x=0.00 and 0.15. The results show that the presence of 2.5% oxygen vacancy has no measurable effect on the elastic bulk modulus. The shear modulus, however, decreases by ...

A new series of layered perovskite oxides, A/sup I/LaNb/sub 2/O/sub 7/ (A = Li, Na, K, Rb, Cs, NH/sub 4/) constituting n = 2 members of the family A A/sub n-1/B/sub n/O/sub 3n+1/, has been prepared. Their structure consists of double perovskite slabs interleaved by A atoms. Hydrated HLaNb/sub 2/O/sub 7/ is formed by topotactic proton exchange of the A ...