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1.
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
2.
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
3.
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
4.
R. S. Iskhakov E. A. Denisova S. V. Komogortsev L. A. Chekanova Yu. E. Kalinin A. V. Sitnikov 《Physics of the Solid State》2010,52(11):2263-2266
This paper reports on the results of the investigation of the relation between the magnetic microstructure and ferromagnetic
resonance (FMR) in ferromagnetic metal-insulator composites by using granular alloys (Co41Fe39B20)
x
(SiO2)1 − x
and Co
x
(SiO2)1 − x
as an example. A comparative analysis of the properties of FMR spectra and parameters of random magnetic anisotropy leads
to correlations between these quantities. It has been found that the main mechanism that determines the FMR line width in
the films under investigation is the exchange narrowing mechanism. 相似文献
5.
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
6.
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
7.
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
8.
Jie Song Bing-Lin Hong Jun Zheng Pei Lin Ming-Sen Zheng Qi-Hui Wu Quan-Feng Dong Shi-Gang Sun 《Applied Physics A: Materials Science & Processing》2010,98(2):455-460
Ti-substituted LiMn2O4 (LiMn2−x
Ti
x
O4, x=0, 0.15, 0.30, 0.45, 0.60, and 0.75) has been synthesized using solid-state reactions. Their crystal and electronic structures
were investigated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and ultraviolet photoelectron spectroscopy
(UPS). XRD data suggested that the lattice parameters of LiMn2−x
Ti
x
O4 increase due to the replacement of Mn by Ti ions. XPS results indicated that the substituted Ti ions were in +4 oxidation
state; consequently, the normal oxidation state of Mn ions has been detected by measuring the binding energy splitting of
Mn 3s states, which decreases with the content of substituted Ti. The valence band spectra suggested that the intensity of
e
g
level of Mn 3d orbitals increased due to the increase of the Mn3+/Mn4+ ratio. 相似文献
9.
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
10.
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
11.
12.
V. S. Zakhvalinski? R. Laiho T. S. Orlova A. V. Khokhulin 《Physics of the Solid State》2008,50(1):63-70
The temperature dependences of the magnetic susceptibility χ(T) and the electrical resistivity ρ(T) of ceramic samples of La1 − x
Ca
x
MnO3 with x = 0.67 (LCMO) and La1 − x
Ca
x
Mn1 − y
Fe
y
O3 with x = 0.67 and y = 0.05 (LCMFO) are investigated in magnetic fields B = 50–105 G and the temperature range T = 4.2–400 K. Both samples undergo a transition from the paramagnetic state to a state with charge (orbital) ordering (CO)
at temperatures T
CO ≈ 272 K for LCMO and T
CO ≈ 222 K for LCMFO. The behavior of the paramagnetic phase in the temperature range 320–400 K for LCMO and 260–400 K for LCMFO
is described by the Curie-Weiss law with effective Bohr magneton numbers p
eff = 4.83 μB (LCMO) and 4.77 μB (LCMFO), respectively. The disagreement between the observed positive Weiss temperatures (θ ≈ 175 K (LCMO) and θ ≈ 134 K
(LCMFO)) and negative Weiss temperatures required for the antiferromagnetic ground state can be explained by the phase separation
and transition to the charge-ordered state. The magnetic irreversibility for T < T
CO is accounted for by the existence of a mixture of the ferromagnetic and antiferromagnetic phases, as well as the cluster
glass phase. At low temperatures, doping with iron enhances the frustration of the system, which manifests itself in a more
regular behavior of the decay rate of the remanent magnetization with time. The temperature dependence of the electrical resistivity
in the range of the charge-ordered phase conforms to the variable-range hopping model. The behavior of the electrical resistivity
is governed by the complex structure of the density of localized states near the Fermi level, which includes a soft Coulomb
gap Δ = 0.464 eV for LCMO and 0.446 eV for LCMFO. It is established that the ratio between the localization radii of charge
carriers a for LCMFO and a
und for LCMO is a/a
und = 0.88.
Original Russian Text ? V.S. Zakhvalinskiĭ, R. Laiho, T.S. Orlova, A.V. Khokhulin, 2008, published in Fizika Tverdogo Tela,
2008, Vol. 50, No. 1, pp. 61–68. 相似文献
13.
14.
N. V. Kazak N. B. Ivanova V. V. Rudenko A. D. Vasil’ev D. A. Velikanov S. G. Ovchinnikov 《Physics of the Solid State》2009,51(5):966-969
Ludwigite single crystals of compositions Co3O2BO3 and Co3 − x
Fe
x
O2BO3 (x ≈ 0.14) have been synthesized. The crystal structure is investigated at room temperature, and the magnetization is studied
in the temperature range T = 4.2–100 K in magnetic fields of up to 600 Oe. The orthorhombic symmetry is revealed, and the unit cell parameters are determined.
A number of features are established for the temperature dependence of the magnetization. In unsubstituted Co3O2BO3, two magnetic transitions are found at T
C1 = 43 K and T
C2 = 15 K. At temperatures below 40 K, spin-glass state is revealed. Substitution of iron ions for cobalt ions leads to a noticeable
shift in the magnetic transitions toward the high-temperature range: T
C1 = 83 K and T
C2 = 74 K. A ferromagnetic ordering of the P type is found in the Co3 − x
Fe
x
O2BO3 (x ≈ 0.14) compound.
Original Russian Text ? N.V. Kazak, N.B. Ivanova, V.V. Rudenko, A.D. Vasil’ev, D.A. Velikanov, S.G. Ovchinnikov, 2009, published
in Fizika Tverdogo Tela, 2009, Vol. 51, No. 5, pp. 916–919. 相似文献
15.
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
16.
A. A. Mukhin V. Yu. Ivanov A. M. Kuz’menko A. S. Prokhorov A. A. Pronin S. N. Barilo G. L. Bychkov S. V. Shiryaev 《JETP Letters》2010,91(3):147-154
The effect of the substitution of Co2+, Mn2+, and Zn2+ ions for Ni2+ ions on the magnetic, dielectric, and ferroelectric properties of vanadate single crystals (Ni1 − x
T
x
)3V2O8 has been analyzed. It has been found that the low-level (x ≤ 0.1) substitution of both magnetic and nonmagnetic ions stabilizes the ferroelectric state with a cycloidal magnetic structure.
The existence region of this state is expanded to low temperatures down to 3 K for Zn2+ and below 1.8 K for Co2+ and Mn2+ owing to the suppression of a low-temperature weak ferromagnetic phase. At the same time, the ferroelectric phase disappears
completely at large concentrations of Co and Mn. The effect of magnetic fields on the magnetic and ferroelectric states has
been analyzed. It has been shown that the magnetic field along the c axis suppresses the ferroelectric state, whereas the magnetization along the antiferromagnetism axis (a axis) induces the reentrant phase transition from a paraelectric weak ferromagnetic structure to a ferroelectric structure.
The corresponding H-T phase diagrams have been drawn. 相似文献
17.
S. A. Vyzulin A. V. Gorobinskii Yu. E. Kalinin E. V. Lebedeva A. V. Sitnikov N. E. Syr’ev I. T. Trofimenko I. G. Shipkova 《Moscow University Physics Bulletin》2009,64(2):136-140
The combined method of static and dynamic magnetic measurements is used to study nano-dimensional multilayer amorphous CoFeZr/α -Si films. It is established that at the thickness of magnetic layers x = 5–12 nm their magnetization does not differ from that of the bulk material. It is shown that as x is lowered to 2–3 nm, the magnetization of magnetic layers decreases, which may be due to the formation of mixed layers containing nonmagnetic silicides. At a thickness of nonmagnetic interlayers of less than 1 nm the features characteristic of a weak antiferromagnetic interaction of neighboring layers are observed. 相似文献
18.
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
19.
The electrical conductivity, magnetization, and magnetoresistance of manganites La1 − x
Ag
x
MnO3 have been investigated in the temperature range 78–300 K. The samples have been synthesized by the sol-gel method. At room
temperature, the magnetic field of 0.6 T has no effect on the electrical conductivity. As the temperature decreases, an abrupt
jump is observed in the magnetization curve due to the semiconductor-metal phase transition. This transition hardly affects
the temperature dependence of the resistance. 相似文献
20.
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