scholarly journals Structural Properties and Water Uptake of SrTi1−xFexO3−x/2−δ

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 965 ◽  
Author(s):  
Tadeusz Miruszewski ◽  
Kacper Dzierzgowski ◽  
Piotr Winiarz ◽  
Sebastian Wachowski ◽  
Aleksandra Mielewczyk-Gryń ◽  
...  
Keyword(s):  
Great Influence ◽  
Lattice Parameter ◽  
Oxygen Nonstoichiometry ◽  
Significant Drop ◽  
Dopant Content ◽  
Proton Concentration ◽  
Fe Content ◽  
Order Of Magnitude ◽  
Proton Uptake ◽  
Structure And Microstructure

In this work, Fe-doped strontium titanate SrTi1−xFexO3−x/2−δ, for x = 0–1 (STFx), has been fabricated and studied. The structure and microstructure analysis showed that the Fe amount in SrTi1−xFexO3−x/2−δ has a great influence on the lattice parameter and microstructure, including the porosity and grain size. Oxygen nonstoichiometry studies performed by thermogravimetry at different atmospheres showed that the Fe-rich compositions (x > 0.3) exhibit higher oxygen vacancies concentration of the order of magnitude 1022–1023 cm−3. The proton uptake investigations have been done using thermogravimetry in wet conditions, and the results showed that the compositions with x < 0.5 exhibit hydrogenation redox reactions. Proton concentration at 400 °C depends on the Fe content and was estimated to be 1.0 × 10−2 mol/mol for SrTi0.9Fe0.1O2.95 and 1.8 × 10−5 mol/mol for SrTi0.5Fe0.5O2.75. Above 20 mol% of iron content, a significant drop of proton molar concentrations at 400 °C was observed. This is related to the stronger overlapping of Fe and O orbitals after reaching the percolation level of approximately 30 mol% of the iron in SrTi1−xFexO3−x/2−δ. The relation between the proton concentration and Fe dopant content has been discussed in relation to the B-site average electronegativity, oxygen nonstoichiometry, and electronic structure.

Effect of Cu-Excess on the Microstructure and Microwave Dielectric Properties of CaCu3Ti4O12 Ceramics

2015 ◽  
Vol 1087 ◽  
pp. 50-54 ◽  
Author(s):  
Mohamad Johari Abu ◽  
Julie Juliewatty Mohamed ◽  
Mohd Fadzil Ain ◽  
Zainal Arifin Ahmad
Keyword(s):  
Dielectric Constant ◽  
Microwave Dielectric Properties ◽  
Secondary Phase ◽  
Solid State Reaction Method ◽  
Lattice Parameter ◽  
Tangent Loss ◽  
Conventional Solid State Reaction ◽  
Microwave Dielectric ◽  
Order Of Magnitude ◽  
Grain Growth Behavior

CaCu(3+x)Ti4O12 (CCTO) ceramics with different Cu-excess (x = 0 – 0.6) were prepared by conventional solid-state reaction method. Characterization of the prepared ceramics with XRD and FESEM showed that lattice parameter and grain size are slightly increased, indicating Cu-excess to have the big impact on the both phase structure and microstructure. The XRD profiles indicated that the secondary phase (CuO or Cu2O) existed at edge/corner of CCTO grain, which promoted inhibited grain growth behavior. The CCTO ceramics exhibited two trends of dielectric constant related to frequency, which showed a flatter curve about ~50 in 1 – 25 GHz regions, and it’s dropped rapidly to ~35 in 25 – 50 GHz region. With Cu-excess, the dielectric constant of the ceramics was increased for an average of a quarter-order of magnitude, while the tangent loss also increased up to triple times than x = 0, for the same frequency range. Despite enormous increase of dielectric constant related to varying Cu-excess, the tangent loss also increased.

Crystallographic Texture of MgO and its Effect on the Growth of BaTiO3 Thin Films by RF Sputtering

2007 ◽  
Vol 546-549 ◽  
pp. 2175-2178
Author(s):  
Liang Qiao ◽  
Xiao Fang Bi
Keyword(s):  
Thin Films ◽  
Substrate Temperature ◽  
Crystallographic Texture ◽  
Great Influence ◽  
Rf Sputtering ◽  
Rf Magnetron Sputtering ◽  
High Substrate Temperature ◽  
Argon Pressure ◽  
Structure And Microstructure ◽  
Deposition Conditions

In this work, MgO thin films were prepared by rf magnetron sputtering technique on two different substrates of Si (100) wafers and amorphous glasses. The influence of different deposition conditions such as substrate temperature, Ar pressure, film thicknesses on the crystal structure of MgO thin films were studied. BaTiO3 ferroelectric thin films were subsequently deposited on the MgO films. The XRD results showed that the orientation of MgO films was dependent greatly on the substrate temperature. A highly (100) oriented MgO thin films were obtained at the temperature of 800°C. The crystallographic texture has been deteriorated rapidly as the argon pressure decreased to 1.0 Pa. It has been also found that the film thickness has a great influence on the film orientation. High substrate temperature, high argon pressure and a certain thickness appear to be favorable for formation of a good texture for the MgO films. The structure and microstructure of the BaTiO3 films were various both with deposition conditions and with the crystallographic texture of the MgO. A highly (001) oriented ferroelectric BTO film was obtained on the MgO films with an optimized deposition conditions.

scholarly journals The effect of the kind of Fe chelate on yielding and quality of greenhouse tomato fruits

2012 ◽  
Vol 24 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Piotr Chohura ◽  
Eugeniusz Kołota ◽  
Andrzej Komosa
Keyword(s):  
Control Treatment ◽  
Marketable Yield ◽  
Tomato Cultivar ◽  
Significant Drop ◽  
Tomato Fruits ◽  
Greenhouse Tomato ◽  
Fe Content ◽  
Growing Medium ◽  
Different Doses

Abstract A two-year-greenhouse experiment was designed to investigate the effect of four chelates, differing in percentage of Fe content and the kind of Fe bonding ligand: Fe 8 Forte (EDTA+HEEDTA), Fe 9 Premium (DTPA), Fe 13 Top (EDTA) and Librel Fe DP7 (DTPA), on the yield and fruit quality of the ‘Merkury’ F1 greenhouse tomato cultivar grown in peat substrate. Each of the tested fertilisers was applied in three different doses in order to reach the level of 50, 75 or 100 mg available Fe per 1 dm-3 of growing medium. In the control treatment the amount of this nutrient was equal to 17.9 mg dm-3. The tomato was cultivated from transplants on benches in the period from the beginning of April to the end of July. The highest marketable yield of tomato fruits was obtained from plants fertilised with Fe 9 Premium (DTPA), while the lowest was from the treatment with Fe 13 Top (EDTA) chelate. Both of these sources of iron were equally efficient for the early crop yield, which was significantly higher than that of other tested fertilisers. Irrespective of the Fe source, the most favourable dose of this nutrient for marketable and early fruit yield was 50 mg Fe dm-3. Both tested factors had little effect on fruit composition. The only exception was a significant drop of vitamin C content in the treatment supplied with Fe 9 Premium and an increment of Na in the case of Fe 13 Top use. The increase of Fe in the growing medium up to 75 and 100 mg dm-3 adversely affected the amount of P in tomato fruits.

Magnetic Studies of Ni3Al(Fe) Compounds

1984 ◽  
Vol 39 ◽  
Author(s):  
S. T. Sekula ◽  
H. R. Kerchner ◽  
J. R. Thompson ◽  
Th. Leventouri
Keyword(s):  
Curie Temperature ◽  
Magnetic Measurements ◽  
Lattice Parameter ◽  
Magnetic Studies ◽  
Fe Content ◽  
Magnetization Data ◽  
Ordered Intermetallic ◽  
Material Forming ◽  
Fcc Phase ◽  
Fe Impurities

ABSTRACTSeveral samples of the ordered intermetallic compound with the Ll2 structure and chemical composition NiO.75-xAl0.25-xFe2x (doped with 0.2 at. % B) have been studied over an Fe compositional range 0 ≤ 2x ≤ 0.20. Stoichiometric Ni3Al is known to be a strongly exchange-enhanced-material, forming a giant moment system when Fe impurities are introduced in trace amounts. For the greater Fe concentrations employed in this work, more conventional ferromagnetic systems are obtained. Well below the ferromagnetic Curie temperature Tc the samples exhibit a spontaneous moment in small magnetic fields and at higher fields the isothermal magnetization data show a clear tendency toward saturation. Magnetic investigations using vibrating-sample techniques permitted measurements over the temperature interval from 4.2 K to 800 K in fields up to 5.0 T. The Curie temperature was found to increase from ∼50 K for the Fe-free sample in the series to 410 K for the limiting concentration of 12 at. % Fe in the Ll2 structure. Samples with higher Fe content up to 20 at. % contain a second, disordered fcc phase with Tc ≃ 715 K. Peaks in the temperature dependence of the lattice parameter observed in x-ray studies yield Tc values in reasonable agreement with the magnetic measurements.

Nonstoichiometry and lattice parameter of (Mg0.22Mn0.07Fe0.71)3–δO4 ferrite

1999 ◽  
Vol 14 (10) ◽  
pp. 4070-4074 ◽  
Author(s):  
Sun-Ho Kang ◽  
Han-Ill Yoo ◽  
Hyun Min Park
Keyword(s):  
Solid State ◽  
Defect Structure ◽  
Stoichiometric Composition ◽  
Lattice Parameter ◽  
Oxygen Nonstoichiometry ◽  
Electrochemical Technique

(Mg0.22Mn0.07Fe0.71)3–δO4 ferrites with different oxygen nonstoichiometry (δ) were prepared in the range of −0.006 ≤ δ ≤ 0.0050 by a solid-state electrochemical technique, and their lattice parameter–nonstoichiometry correlation was examined. It was found that the lattice parameter decreases with increasing deviation (|δ|) from the stoichiometric composition (δ = 0). The electrochemical technique is detailed, and the correlation is discussed in light of defect structure of the ferrite.

Structure, Microsctructure and Magnetic Properties of Ternary (Fe0.6Al0.4)100-xSix Nanostructured Powders: Effect of Si Addition

2019 ◽  
Vol 58 ◽  
pp. 102-117 ◽  
Author(s):  
N. Boukherroub ◽  
M. Hemmous ◽  
A. Guittoum ◽  
D. Martínez-Blanco ◽  
N. Souami ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Volume Fraction ◽  
Lattice Parameter ◽  
Ternary Alloys ◽  
Ferromagnetic Phase ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Order Of Magnitude ◽  
Powder Particles ◽  
Si Content

Nanostructured (Fe0.6Al0.4)100-xSix powders with x= 0, 5, 10, 15 and 20 at.% were elaborated by means of mechanical alloying for a fixed milling time of 72 h. We have investigated the effect of silicon addition on the microstructure and magnetic properties of these ternary alloys. X-ray diffraction experiments reveal that these powders are single-phase disordered solid solutions with body centered cubic crystal structure. The lattice parameter diminishesalmost linearly as the Si content increases. The mean crystallite size,<D(nm)>, is around three times smaller for the samples with higher amount of Si (≈ 10 nm) compared with that of the binary alloy (27 nm). Moreover, the volume fraction of grain boundaries (fgb) seems to be higher with increasing the Si content, as well as both dislocation density (ρ) and lattice microstrain (<ε>),that follow alinear trend. The SEM images show that the Si helps in refining the shape and size of the powder particles, leading to a nearly homogeneous small particles.The addition of Si strongly affects the value of the saturation magnetization, Ms, that falls nearly an order of magnitude for the sample with 20 at.% Si, while the coercivity remains almost unchanged. The Mössbauer spectra show the presence of a sextet (ferromagnetic phase) and a singlet or a doublet (non ferromagnetic phase), except for the sample corresponding to x = 10, where only one singlet is observed in the spectrum.

Electrodeposition of NiFe Thin Films and NiFe/Cu Multilayers with a Recirculating Electrochemcial Flow Reactor

1999 ◽  
Vol 562 ◽  
Author(s):  
N. V. Myungl ◽  
K. H. Ryu ◽  
J. H. Kim ◽  
M. Schwartz ◽  
K. Nobel
Keyword(s):  
Thin Film ◽  
Corrosion Resistance ◽  
Flow Reactor ◽  
Individual Layer ◽  
Nonmagnetic Metal ◽  
Α Phase ◽  
Fe Content ◽  
Magnetic Layers ◽  
Order Of Magnitude ◽  
Bulk Alloys

ABSTRACTNano-structured Ni80Fe20NCu multilayers were electrodeposited by a newly developed electrodeposition process utilizing a recirculating electrochemical flow reactor. This process, which operates in an inert gas environment, overcomes the limitations of conventional multilayer electrodeposition methods (single and dual bath techniques) by depositing pure magnetic layers without codeposition of the nonmagnetic metal and oxidation of metal interfaces. Structure, corrosion resistance and magnetic properties of electrodeposited NiFe (0 to 100 % Fe) thin film alloys were first investigated. Three different crystal regions, α, mixed α and γ, and γ phases were observed at <50,;50, >50 % Fe in the deposit, respectively. The narrow mixed phase regions was around 50 % Fe compared to 70–80% Fe for bulk alloys. The lattice parameters of electrodeposited alloys exhibited the same trends as bulk alloys. Maximum corrosion resistance was obtained at 50% Fe content in 0.5 M NaCl similar to bulk alloys. The corrosion resistance of the α phase was an order of magnitude less than the γ phase. The magnetoresistance (MR) of electrodeposited NiFe thin film alloys was higher than bulk alloys. Based on these studies, Ni80Fe20/Cu multilayers with individual layer thicknesses ranging from 100 nm to 1.26 μm have been electrodeposited in the recirculating electrochemical flow reactor. The layer thicknesses were precisely controlled by adjusting the amount of charge passed.

Atomic Simulation of Size Effect and Surface Properties of Aluminum Nanoparticles

2013 ◽  
Vol 680 ◽  
pp. 8-14 ◽  
Author(s):  
Wei Zhu ◽  
Wu Lin Song ◽  
Jian Jun Wang
Keyword(s):  
Size Effect ◽  
Surface Properties ◽  
Metallic Nanoparticles ◽  
Lattice Parameter ◽  
Theoretical Research ◽  
Stored Energy ◽  
Atomic Simulation ◽  
Al Nanoparticles ◽  
Order Of Magnitude ◽  
Simulation Results

Here, modified analytic embedded atom method (MAEAM) has been utilized to simulate size effect and surface properties of aluminum (Al) nanoparticles. According to the simulation results, we can find that lattice parameter and excess stored energy are size dependent. The simulated excess stored energy ranges from 2.12 to 57.61 kJ/mol, which is in the same order of magnitude with experiment results; surface energy of Al nanoparticles ranges from 0.78 to 1.10 J/m2, which is not invariant but size related. Furthermore, non-uniform lattice distortion has been observed in Al nanoparticles, and mainly concentrates in the first and second shell of surface layers. Theoretical research based on our simulation results provides a novel method to predict excess stored energy of metallic nanoparticles.

Influence of Hydrogen Incorporation and Oxygen Removal on Superconducting YBa2Cu3O7-δ

1996 ◽  
Vol 453 ◽  
Author(s):  
T. Hirata
Keyword(s):  
Transition Temperature ◽  
Lattice Parameter ◽  
Oxygen Removal ◽  
Charge Carrier Concentration ◽  
Oxygen Nonstoichiometry ◽  
The Other ◽  
Superconducting Transition ◽  
Significant Suppression ◽  
Hydrogen Incorporation ◽  
Antiferromagnetic Ordering

AbstractThe influence of hydrogen incorporation and oxygen removal on superconducting YBa2Cu3O7-δ is discussed in comparison with their respective effects. Both hydrogen incorporation and oxygen removal induce the orthorhombic (O)-to-tetragonal (T) transition and antiferromagnetic ordering as well. However, there exist no consistent changes in the c-axis for the O-to-T transition and the superconducting transition temperature Tc upon hydrogen incorporation in YBa2Cu3O7-δ on the other hand, the c-axis certainly increases in the corresponding transition driven by oxygen nonstoichiometry and Tc decreases with increasing δ in YBa2Cu3O7-δ. Plots of Tc vs. the lattice parameter c reveal no significant suppression in Tc upon hydrogenation than oxygen removal. It is concluded that the Cu-O bond distances or the Cu-Cu plane spacings along the c-axis change somewhat differently in two cases; it is believed that the charge-carrier concentration is reduced less significantly upon hydrogenation than oxygen removal in YBa2Cu3O7-δ, giving rise to the aforementioned finding.

Lattice parameters determination from powder diffraction data: Results from a round robin project

1996 ◽  
Vol 11 (3) ◽  
pp. 253-258 ◽  
Author(s):  
Norberto Masciocchi ◽  
Gilberto Artioli
Keyword(s):  
Numerical Analysis ◽  
Powder Diffraction ◽  
Lattice Parameter ◽  
Unit Cell Dimension ◽  
Decimal Digit ◽  
Powder Diffraction Data ◽  
Data Set ◽  
X Ray ◽  
The Third ◽  
Order Of Magnitude

A well-crystallized sample of powdered KCl has been distributed among several laboratories in order to test the reproducibility of the lattice parameter measurement on different X-ray powder diffraction instruments. The precision of the determined unit-cell dimension is in the 10−5 Å range, while the discrepancies among the results from different laboratories using the same numerical analysis are at least one order of magnitude higher. It is shown that if different numerical analyses, including full pattern refinement, are used, values differing in the third decimal digit are obtained for the same data set.

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