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1.
Microporous (TiO2)
x
–(SiO2)100 − x
(0 < x < 40) xerogels have been produced by sol–gel methods either by partial pre-hydrolysis or reflux of tetraethoxysilane and
titanium isopropoxide. These have been characterised by 29Si nuclear magnetic resonance, X-ray diffraction, EXAFS at the Ti–K edge, X-ray photoelectron spectroscopy, temperature-programmed
reduction, FT infrared, N2 adsorption at 78 K (BET), transmission electron microscopy and dynamic light scattering (DLS). These were dip coated onto
fused silica and characterised by atomic force microscopy and UV–visible absorption. Their photoactivity in removal of alkylphenol
ethoxylate TX100 from water was less than for less porous titania. The advantages of including thermally removable PEG or
PPG templates in terms of increasing surface, meso-porosity and photon absorbance at visible wavelengths to give nanoengineered
photocatalytic films are described. 相似文献
2.
é. P. Domashevskaya S. A. Storozhilov S. Yu. Turishchev V. M. Kashkarov V. A. Terekhov O. V. Stogne Yu. E. Kalinin A. V. Sitnikov S. L. Molodtsov 《Physics of the Solid State》2008,50(1):139-145
The electronic structure and phase composition of (Co41Fe39B20)
x
(SiO2)1 − x
nanocomposites are studied by x-ray absorption near-edge spectroscopy, which is extremely sensitive to the chemical environment
of elements in multicomponent compounds. An analysis of the recorded Fe L
2, 3, Co L
2, 3, B K, Si L
2, 3, and O K absorption spectra demonstrates interatomic interactions between the elements of the metallic and dielectric components of
the nanocomposites. As a result of these interatomic interactions, a complex multiphase system, whose electronic structure
should determine the transport and magnetic properties of the nanocomposites, forms. In particular, the transformation of
the fine structure of the iron L
2, 3 spectra reflects a change in the ratio of divalent to trivalent iron in its oxides and/or silicates. CoO and complex boron
oxides are found to exist in the nanocomposites. The electrical conductivity of a FeO · F2O3 · CoO grain embedded in the silicate-oxide medium of the nanocomposites is controlled by electron exchange between Co2+, Fe2+, and Fe3+ ions. The dielectric component consists of a mixture of silicon oxide and the silicates/borosilicates of transition metals.
Original Russian Text ? é.P. Domashevskaya, S.A. Storozhilov, S.Yu. Turishchev, V.M. Kashkarov, V.A. Terekhov, O.V. Stogneĭ,
Yu.E. Kalinin, A.V. Sitnikov, S.L. Molodtsov, 2008, published in Fizika Tverdogo Tela, 2008, Vol. 50, No. 1, pp. 135–141. 相似文献
3.
S. F. Dubinin V. I. Sokolov V. I. Maksimov V. D. Parkhomenko N. N. Kolesnikov A. V. Korolev 《Physics of the Solid State》2010,52(5):1107-1110
Neutron diffraction and magnetic measurements have been used to study the effect of doping with Mn3+ ions on the fine crystal structure of the Ga2Se3 monoclinic compound. It has been established that the structural state of the crystals is changed even at a relatively low
doping level (x = 0.04). Arguments in favor of the fact that local Jahn-Teller distortions are responsible for the formation of the fine
structure and magnetism in compounds of this class are presented. 相似文献
4.
5.
Ihor Studenyak Yuriy Neimet Csaba Cserháti Sándor K?kényesi Edvardas Kazakevi?ius Tomas ?alkus Algimantas Ke?ionis Antanas Orliukas 《Central European Journal of Physics》2012,10(1):206-209
Structural studies of (Ag3AsS3)
x
(As2S3)1−x
chalcogenide superionic glasses in the compositional range x = 0.3–0.9 were performed by scanning electron microscopy. Temperature and compositional dependences of transmission coefficient,
electrical conductivity, and activation energy were investigated 相似文献
6.
A. V. Ivanov Yu. E. Kalinin V. N. Nechaev A. V. Sitnikov 《Physics of the Solid State》2009,51(12):2474-2479
The concentration dependences of the electrical resistivity and complex permeability of [“(Co45Fe45Zr10)
x
(Al2O3)100 − x
”/“α-Si: H”]
n
multilayer structures and (Co45Fe45Zr10)
x
(Al2O3)100 − x
composites have been studied. It has been established that introduction of a semiconductor interlayer into the (Co45Fe45Zr10)
x
(Al2O3)100 − x
composites substantially decreases the electrical resistivity of [“(Co45Fe45Zr10)
x
(Al2O3)100 − x
”/“α-Si: H”]
n
multilayer structures. The concentration dependences of the real and imaginary parts of the complex permeability of the [“(Co45Fe45Zr10)
x
(Al2O3)100 − x
”/“α-Si: H”]
n
nanomultilayer structures substantially differ from those of the (Co45Fe45Zr10)
x
(Al2O3)100 − x
composites. The real part of the complex permeability of the [“(Co45Fe45Zr10)
x
(Al2O3)100 − x
”/“α-Si: H”]
n
nanomultilayer structures follows the curve with a minimum near the percolation threshold of the composite, and the imaginary
part smoothly decreases as the ferromagnetic phase concentration increases. The results obtained are explained by the increase
in the bifurcation temperature due to the conduction electrons of the semiconductor interlayer, which favor magnetic ordering
of ferromagnetic grains. 相似文献
7.
A. K. Zvezdin A. M. Kadomtseva Yu. F. Popov G. P. Vorob’ev A. P. Pyatakov V. Yu. Ivanov A. M. Kuz’menko A. A. Mukhin L. N. Bezmaternykh I. A. Gudim 《Journal of Experimental and Theoretical Physics》2009,109(1):68-73
Magnetic and magnetoelectric properties of ferroborate single crystals with complex composition (Tb1 − x
Er
x
Fe3(BO3)4, x = 0, 0.75) and with competing exchange Tb-Fe and Er-Fe interactions are investigated. Jumps in electric polarization, magnetostriction,
and magnetization are observed as a result of spin-flop transitions, as well as a considerable decrease in the critical field
upon an increase in the Er concentration, in a field H
c
parallel to the c axis. The observed behavior of phase-transition fields is analyzed and explained using a simple model taking into account
anisotropy in g factors and exchange splitting of funda-mental doublets of the easy-axis Tb3+ ion and easy-plane Er3+ ion. It is established that magnetoelectric and magnetostriction anomalies under spin-flop transitions are mainly controlled
by the Tb subsystem. The Tb subsystem makes a nonmonotonic contribution ΔP
a
(H
a
, T) to polarization along the a axis: the value of ΔP
a
reverses its sign and increases with temperature due to the contribution from the excited states of the Tb3+ ion.
Original Russian Text ? A.K. Zvezdin, A.M. Kadomtseva, Yu.F. Popov, G.P. Vorob’ev, A.P. Pyatakov, V.Yu. Ivanov, A.M. Kuz’menko,
A.A. Mukhin, L.N. Bezmaternykh, I.A. Gudim, 2009, published in Zhurnal éksperimental’noĭ i Teoreticheskoĭ Fiziki, 2009, Vol.
136, No. 1, pp. 80–86. 相似文献
8.
A. V. Savinkov A. V. Dooglav H. Alloul P. Mendels J. Bobroff G. Collin N. Blanchard 《JETP Letters》2010,91(2):83-90
Incidence of doped holes in the CuO2 plane on the AF state was studied by Cu(1) nuclear quadrupole resonance (NQR) in slightly doped YBa2(Cu1 − z
Li
z
)3O6 + x
compounds. Inhomogeneous distribution of doped holes in the plane was detected in the low temperature measurements of transverse
(1/T
2) and longitudinal (1/T
1) relaxation rates. We establish that at lower T the holes motion slows down and we estimate that the holes localize finally in restricted regions (∼3 lattice constants)
in the Coulomb potential of the Li+ ions. Also we compared the hole behavior in slightly doped YBa2(Cu1 − z
Li
z
)3O6 + x
samples with that in slightly doped Y1 − y
Ca
y
Ba2Cu3O6. A stronger trapping potential of the in-plane Li+ impurities was concluded as compared to slightly doped Y1 − y
Ca
y
Ba2Cu3O6 compound with out-of-plane Ca2+ impurities. 相似文献
9.
P. A. Popov P. P. Fedorov V. M. Reiterov E. A. Garibin A. A. Demidenko I. A. Mironov V. V. Osiko 《Doklady Physics》2012,57(3):97-99
The thermal conductivity of single crystals of Ca1 − x
Er
x
F2 + x
(x = 0.01, 0.05, 0.07, and 0.10) and Ca1 − x
Tm
x
F2 + x
(x = 0.02, 0.04, and 0.06) solid solutions is studied in the temperature ranges 50–300 and 298–673 K. With increasing content
of rare-earth elements, the behavior of thermal conductivity in these solid solutions changes from the characteristic of defect
single crystals to glasslike. The concentration dependences of thermal conductivity for the two systems differ insignificantly. 相似文献
10.
Xue-Fei Li Ying-Ying Fu Xiao-Jie Liu Ai-Dong Li Hui Li Di Wu 《Applied Physics A: Materials Science & Processing》2011,105(3):763-767
(TiO2)
x
(Al2O3)1−x
(x=0.7,0.8,0.9) gate dielectrics were deposited on Ge by atomic layer deposition using trimethylaluminium and Ti isopropoxide.
The interfacial properties and band alignment were investigated by means of transmission electron microscopy (TEM) and X-ray
photoemission spectroscopy. High-resolution TEM results show that the (TiO2)0.8(Al2O3)0.2 film annealed at 500°C is amorphous with sharp interface between (TiO2)0.8(Al2O3)0.2 and Ge. The conduction-band offsets are enhanced from 1.04 to 1.40 eV with increasing Al content. Capacitance equivalent
thickness of 15.8 ? for (TiO2)0.9(Al2O3)0.1 gate dielectrics is achieved with a gate leakage current of 2.70×10−5 A/cm2 at V
g=+1 V. 相似文献
11.
Investigations of magnetic susceptibility (χ) of (3HgS)1–x
(Al2S3)
x
(x = 0.5) crystals doped with manganese investigated by the Faraday method in the range of Т = 77–300 K and Н = 0.25–4 kOe demonstrate that peculiar magnetic properties can be due to the presence of clusters of the Mn–S–Mn–S type in
these crystals. Based on the investigation of kinetic coefficients of the crystals performed for Т = 77–300 K and Н = 0.5–5 kOe, it is established that the crystals demonstrate conductivity of the n-type, and their electric conduction only
very slightly depends on the temperature and shows a maximum, the Hall coefficient is independent of the temperature, while
the temperature dependences of mobility exhibit a maximum. Using the concentration dependence of the effective electron mass
at the Fermi level, the width of the forbidden band, the matrix element of interatomic interaction, and the effective mass
on the conduction-band bottom are obtained. Based on investigations by optical methods, the presence of direct optical interband
transitions in the crystals is established and the value of the optical forbidden band (at Т = 300 K) is determined. 相似文献
12.
Lead-free (Bi0.98−x
La0.02Na1−x
)0.5Ba
x
TiO3 ceramics have been prepared by an ordinary sintering technique and their structure, ferroelectric and piezoelectric properties
have been studied. The results of X-ray diffraction show that La2+ and Ba2+ diffuse into the Bi0.5Na0.5TiO3 lattices to form a new solid solution with a pure perovskite structure, and a morphotropic phase boundary (MPB) exists at
0.04<x<0.10. Compared with pure Bi0.5Na0.5TiO3 ceramics, the (Bi0.98−x
La0.02Na1−x
)0.5Ba
x
TiO3 ceramics possess much smaller coercive field E
c and larger remanent polarization P
r. Because of the low E
c (3.38 kV/mm), large P
r (46.2 μC/cm2) and the formation of the MPB of rhombohedral and tetragonal phases, the piezoelectric properties of the ceramics are significantly
enhanced at x=0.06: d
33=181 pC/N and k
p=36.3%. The depolarization temperature T
d reaches a minimum value near the MPB. The ceramics exhibit relaxor characteristic, which is probably a result from the cation
disordering in the 12-fold coordination sites. The temperature dependences of the ferroelectric and dielectric properties
suggest that the ceramics may contain both polar and non-polar regions at the temperatures above T
d. 相似文献
13.
M. S. Lebedev 《Optics and Spectroscopy》2009,107(5):776-779
Capabilities of the method of laser null ellipsometry for the study of optical parameters of thin films of multicomponent
alloys are demonstrated. Films of alloys (HfO2)
x
(Al2O3)1 − x
on single-crystal silicon are obtained by the chemical vapor deposition with the use of the following volatile compounds:
hafnium dipivaloylmethanate (IV) and aluminum acetylacetonate (III). The selection of initial sets for their optical parameters
is justified. The selected model is shown to correspond to experimental data. In films deposited from the mixture of precursors,
the refractive index increases from a substrate to a film surface. Due to the separation of sources, films described by a
single-layer model were deposited. This fact is indicative of the homogeneous distribution of components over the film thickness. 相似文献
14.
S. A. Vyzulin A. V. Gorobinskii Yu. E. Kalinin E. V. Lebedeva A. V. Sitnikov N. E. Syr’ev I. T. Trofimenko Yu. I. Chekrygina I. G. Shipkova 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(10):1380-1382
Comparative investigations of static magnetic properties, magnetoresistance, and ferromagnetic resonance data of multilayer
nanostructures consisting of CoFeZr-Al2O3 composite magnetic layers and amorphous silicon semiconductor spacers were performed in a layer thickness range below 5 nm.
The influence of layer dimension parameters and chemical peculiarities of silicon on the inner structure and type of magnetic
interactions in nanostructures with 35 and 46 at % magnetic phase composite layers is discussed. 相似文献
15.
M. D. Durruthy-Rodríguez J. Costa-Marrero M. Hernández-Garcia F. Calderón-Pi?ar Célia Malfatti J. M. Yá?ez-Limón 《Applied Physics A: Materials Science & Processing》2011,103(2):467-476
In this work, visible photoluminescence was observed at room temperature in a sintered Pb(Zr1-xTix)1-y NbyO3\mathrm{Pb}(\mathrm{Zr}_{1-x}\mathrm{Ti}_{x})_{1-y} \mathrm{Nb}_{y}\mathrm{O}_{3} perovskite-type structure system, doped with Nb using the next excitation bands 325, 373 and 457 nm. The intensity and energy
of such emissions have been studied by changing the Nb concentration (0<y<0.01) and the Ti content (x), with x=0.20,0.40,0.53,0.60 and 0.80, on both sides of the morphotropic phase boundary (MPB) zone. The principal bands become visible
at energies of 1.73, 2.56 and 3.35 eV. The results reveal the role of the Nb5+ ion substitutions by Zr4+ or Ti4+ ions and the symmetry presented in the rhombohedral or tetragonal side of the MPB. Raman spectra which are similar for compositions:
20/80, 40/60 and 53/47 (tetragonal phases) show nine bands, centered around 137, 194, 269, 331, 434, 550, 612, 712 and 750
cm−1. The spectra for samples 60/40 and 80/20, rhombohedral phase, show significant differences, only six bands appear, centered
around 124, 209, 234, 330, 549 and 682 cm−1. In addition, optical absorption spectroscopy, structural and micro-structural measurements were carried out by using Uv-vis
spectroscopy, X-ray diffraction and scanning electron microscopy techniques, respectively. The experimental results of band
gap energy, e.g., in our samples are in accordance with the findings by J. Baedi et al. in the calculations of band structure,
energy gap and density of states for different phases of Pb(Zr1−x
Ti
x
)O3 using density functional theory (DFT). 相似文献
16.
A. A. Demidov I. A. Gudim E. V. Eremin 《Journal of Experimental and Theoretical Physics》2012,114(2):259-272
The magnetic properties of ferroborate single crystals with substituted compositions Nd1 − x
Dy
x
Fe3(BO3)4 (x = 0.15, 0.25) with competing exchange Nd-Fe and Dy-Fe interactions are investigated. For each composition, we observed a
spontaneous spin-reorientation transition from the easy-axis to the easy-plane state and step anomalies on the magnetization
curves for the spin-flop transition induced by a magnetic field B | c. The measured parameters and effects are interpreted using a unified theoretical approach based on the molecular field approximation
and on calculations performed in the crystal-field model for the rare-earth ion. The experimental temperature dependences
of the initial magnetic susceptibility from T = 2 K to T = 300 K, anomalies on the magnetization curves for B | c in fields up to 1.8 T, and their evolution with temperature, as well as temperature and field dependences of magnetization
in fields up to 9 T are described. In the interpretation of experimental data, the crystal-field parameters in trigonal symmetry
for the rare-earth subsystem are determined, as well as the parameters of Nd-Fe and Dy-Fe exchange interactions. 相似文献
17.
M. G. Kim A. Kreyssig Y. B. Lee R. J. McQueeney B. N. Harmon A. I. Goldman 《The European physical journal. Special topics》2012,208(1):157-164
We present an X-ray resonant magnetic scattering study at the Fe-K absorption edge of the BaFe2As2 compound. The energy spectrum of the resonant scattering, together with our calculation using the full-potential linear-augmented
plane wave method with a local density functional suggests that the observed resonant scattering arises from electric dipole
(E1) transitions. We discuss the role of Fe K-edge X-ray resonant magnetic scattering in understanding the relationship between the structure and the antiferromagnetic
transition in the doped Ba(Fe1−x
Co
x
)2As2 superconductors. 相似文献
18.
I. V. Bodnar 《Journal of Applied Spectroscopy》2010,77(5):654-657
Single crystals of In2Se3 and CuIn5Se8 compounds and (In2Se3)1–x·(CuIn5Se8)x solid solutions have been grown from the melt using the Bridgman method and their composition and structure determined. It
is shown that the crystals have n-type conductivity. Their transmission spectra were studied in the self-absorption edge region
at 80 and 295 K. Based on the spectral measurements, the band gap width (Eg) was determined and the band gap concentration dependences were plotted. It is found that Eg varies with the x composition nonlinearly. Using the dielectric model of Van Vechten–Bergstresser and the Hill–Richardson
pseudo potential model, Eg(x) was calculated theoretically. 相似文献
19.
I. I. Polovinko S. V. Rykhlyuk V. B. Koman I. D. Karbovnyk 《Journal of Applied Spectroscopy》2009,76(1):116-120
We propose a new method for obtaining K2Co
x
Ni1–x
(SO4)2⋅6H2O (x = 0, 0.4, 0.8, 1) crystals, involving the use of the chlorides (CoCl2⋅6H2O and NiCl2⋅6H2O) in an aqueous solution instead of the widely used sulfates. We have studied the transmission spectra of the grown single
crystals in the range λ = 200–900 nm and the IR reflectance spectra in the 2.5–20 μm region. We have observed a change in
the position and intensity of the absorption bands as a function of the composition of the crystals. Based on the Tanabe–Sugano
diagrams, we determined the crystal field splitting (Dq) and its dependence on the nickel concentration.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 1, pp. 126–130, January–February, 2009. 相似文献
20.
M. V. Gorev I. N. Flerov Ph. Sciau S. Guillemet-Fritsch 《Physics of the Solid State》2009,51(4):790-796
Deformation and the thermal expansion coefficient of ceramic samples of (Ba1 − x
La
x
)Ti1 − x/4O3 solid solutions (x = 0, 0.026, 0.036, 0.054) were studied in the temperature range 120–700 K. Based on an analysis of the data obtained, the
temperature-composition phase diagram is refined, and the temperature dependence of the polarization is calculated. The results
are discussed in combination with the dielectric measurement data.
Original Russian Text ? M.V. Gorev, I.N. Flerov, Ph. Sciau, S. Guillemet-Fritsch, 2009, published in Fizika Tverdogo Tela,
2009, Vol. 51, No. 4, pp. 746–752. 相似文献