共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
O. M. Fedorova A. M. Jankin L. B. Vedmid G. A. Dorogina I. A. Zvereva 《Bulletin of the Russian Academy of Sciences: Physics》2009,73(8):1159-1160
The mechanisms of formation of NdSr2− x
Ca
x
Mn2O7 (0 ≤ x ≤ 2.0) solid solution have been studied. The dependence of its volume magnetic susceptibility on the calcium concentration
is obtained. The stability of this solid solution is compared with that of similar solid solutions in lanthanum-containing
systems. 相似文献
3.
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
4.
I. O. Troyanchuk A. N. Chobot N. V. Tereshko O. S. Mantytskaya E. A. Efimova 《Physics of the Solid State》2011,53(7):1340-1347
The magnetic and magnetotransport properties of Pr0.5Sr0.5Mn1 − x
Co
x
O3 (x ≤ 0.5) solid solutions have been investigated using neutron diffraction methods. The magnetization and electrical conductivity
have been measured in magnetic fields up to 140 kOe. It has been established that, during cooling in the temperature range
from 160 to 110 K, the compounds of compositions with a cobalt content x ≤ 0.07 undergo a structural phase transition from the high-temperature ferromagnetic phase to the antiferromagnetic phase.
A further substitution of cobalt for manganese leads to a stabilization of the inhomogeneous dielectric ferromagnetic state,
whereas a state of the cluster spin-glass type has been revealed in compositions with x = 0.15 and 0.20. At x ≥ 0.25, a new magnetic phase with a Curie temperature up to 210 K is formed as a result of the magnetic interaction between
manganese and cobalt ions. A magnetic phase diagram of the system under investigation has been constructed. 相似文献
5.
6.
A. N. Georgobiani A. Kh. Matiyev C. V. Bulyarski T. A. Matiyeva 《Bulletin of the Russian Academy of Sciences: Physics》2009,73(1):129-131
The IR reflection and Raman spectra of β-Tl1 − x
Cu
x
InS2 (0 ≤ x ≤ 0.015) single crystals have been studied in the temperature range 84–300 K. It is shown that partial replacement of thallium
by copper atoms leads to a decrease in the frequencies of the corresponding oscillations in the frequency range 40–500 cm−1 and does not induce (at given concentrations) local oscillations. Analysis of the transformation of the IR reflection spectra
at T
2 ≈ 185 K revealed a ferroelectric phase transition.
Original Russian Text ? A.N. Georgobiani, A.Kh. Matiyev, C.V. Bulyarski, T.A. Matiyeva, 2009, published in Izvestiya Rossiiskoi
Akademii Nauk. Seriya Fizicheskaya, 2009, Vol. 73, No. 1, pp. 138–140. 相似文献
7.
E. S. Zhukova N. P. Aksenov B. P. Gorshunov Yu. G. Selivanov I. I. Zasavitskii D. Wu M. Dressel 《Physics of the Solid State》2011,53(4):810-814
The spectra of epitaxial Pb1 − x
Eu
x
Te (0 ≤ x ≤ 0.37) solid solution layers grown on BaF2 and Si substrates have been investigated over a wide frequency range 7–4000 cm−1 at temperatures of 5–300 K. Apart from the phonon and impurity absorption lines, the absorption in a local mode in PbEuTe
layers of substrates and buffer layers has been observed in the frequency range 110–114 cm−1. As the temperature decreases from 300 to 5 K, the transverse phonon mode softens from 33.0 to 19.5 cm−1. 相似文献
8.
采用电弧熔炼法在高纯氩气保护下合成了一系列TbGa1-xGex(0≤x≤0.4)样品. X射线粉末衍射数据表明,样品均为正交晶系的CrB型结构,空间群为Cmcm. TbGa1-xGex化合物的晶格常数随Ge含量的增加而线性减小,TbGa和TbGe赝二元系在0≤x≤0.4范围内形成固溶体. 化合物的顺磁居里温度以及有效磁矩由热磁测量结果确定. 相变温度由交流磁化率的测量获得. 随Ge含量的增加,化合物的相变温度单调下降. 变温X射线粉末衍射实验表明,x=0.2和0.3的样品在110—273K范围内无结构相变.
关键词:
TbGa-TbGe 赝二元系
CrB结构
居里温度
磁化强度 相似文献
9.
K. Bhattacharjee C. K. Ghosh M. K. Mitra G. C. Das S. Mukherjee Kalyan Kumar Chattopadhyay 《Journal of nanoparticle research》2011,13(2):739-750
Nanocrystalline Ni
x
Zn1−x
Fe2O4 (0 ≤ x ≤ 1) ferrite powders with average particle size 15–20 nm have been successfully prepared at a very low temperature (180 °C)
by a novel auto combustion process using citric acid and ethylenediamine as a coordinating agent and bridging ligand, respectively.
Phase purity of the solid solutions has been confirmed by X-ray diffraction. Morphological characterizations of the prepared
samples were performed by high resolution transmission electron and field emission scanning electron microscopy. Extensive
Fourier transformed infrared spectroscopic characterization has been carried out to identify the plausible mechanism of the
synthesis process. Composition-dependent electrical properties (resistivity and dielectric constant) of the synthesized solid
solution have been investigated. Interestingly, a non-linear variation of dielectric permittivity with respect to composition
has been observed. The room temperature electrical resistivity as well as the dielectric permittivity of Ni0.5Zn0.5Fe2O4 was found to decrease with the decrease of particle size. 相似文献
10.
Adolfo Franco Thiago Eduardo Pereira Alves Emília Celma de Oliveira Lima Eloisa da Silva Nunes Vivien Zapf 《Applied Physics A: Materials Science & Processing》2009,94(1):131-137
For the first time nanocrystalline magnetic particles of Mg
x
Fe(3−x)O4 with x ranging from 0.5 to 1.5 have been synthesized by a combustion reaction method using iron nitrate Fe(NO3)3.9H2O, magnesium nitrate Mg(NO3)2.6H2O, and urea CO(NH2)2 as fuel without intermediate decomposition and/or calcining steps. X-ray diffraction patterns of all systems showed broad
peaks consistent with cubic inverse spinel structure of MgFe2O4. The absence of extra reflections in the diffraction patterns of as-prepared materials ensures the phase purity. The mean
crystallite sizes determined from the prominent (311) peak of the diffraction using Scherrer’s equation and transmission electron
microscopy micrographs were c.a. 40 nm with spherical morphology. Fourier transform infrared spectra of the as-prepared material
showed traces of organic and metallic salt by-products; however, these could be removed by washing with deionized water. Typical
hysteresis curves were obtained for all specimens in magnetic field up to 14 T between 4 and 340 K. The saturation magnetization
was 48.3 emu/g and 31.3 emu/g, 44.8 emu/g, and 28.4 emu/g for x=1.0 and 0.8 at 4 K and 340 K, respectively. The saturation magnetization, M
s
, of nanoparticles of the MgFe2O4 specimen is about 50% higher when compared to the bulk. The enhanced magnetization measured in our nanoparticles MgFe2O4 specimens may be attributed to the uncompensated magnetic moment of iron ions between the A- and B-sites, i.e., changes in
the inversion factor. Our magnetization results of MgFe2O4 specimens are comparable to the existing data for the same compound but with different particle size and prepared by different
synthesis methods. 相似文献
11.
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
12.
A. N. Georgobiani A. Kh. Matiyev S. V. Bulyarski T. A. Matiyeva 《Bulletin of the Russian Academy of Sciences: Physics》2008,72(10):1445-1447
The refractive index dispersion in β-Tl1 − x
Cu
x
InS2 (0 ≤ x ≤ 0.015) crystals has been studied using intrinsic interference. It is shown that these crystals are characterized by anomalous-dispersion
regions at wavelengths slightly exceeding those corresponding to exciton peaks. It is established that, using intrinsic interference,
one can detect excitons in these crystals at room temperature. Modulation of interference patterns is revealed, and explanation
of this phenomenon is proposed.
Original Russian Text ? A.N. Georgobiani, A.Kh. Matiyev, S.V. Bulyarski, T.A. Matiyeva, 2008, published in Izvestiya Rossiiskoi
Akademii Nauk. Seriya Fizicheskaya, 2008, Vol. 72, No. 10, pp. 1523–1525. 相似文献
13.
Yu. N. Zakharov A. A. Pavelko A. G. Lutokhin I. N. Andryushina V. Z. Borodin L. A. Reznichenko 《Bulletin of the Russian Academy of Sciences: Physics》2009,73(8):1125-1127
The influence of thermostating at 450°C on the dielectric and pyroelectric properties of PbZr1 − x
Ti
x
O3 polarized ferroelectric specimens the range 0.02 ≤ x ≤ 0.05 has been investigated. An irreversible increase in the temperature of the ferroelectric-antiferroelectric phase transition
was observed in all specimens upon their cooling after exposure to an elevated temperature for more than 1 h. The original
position of the phase-transition point on the temperature scale was not recovered as a result of afterpoling upon cooling
through the Curie temperature. Heating of the same specimens in the bridged mode up to 650°C with subsequent abrupt immersion
in silicone oil at room temperature (hardening) is accompanied by an additional increase in the range of existence of the
antiferroelectric phase from 3 to 15°C with an increase in the x concentration. 相似文献
14.
Deepika K. S. Rathore N. S. Saxena 《Applied Physics A: Materials Science & Processing》2010,98(2):441-448
Se58Ge42−x
Pb
x
(9≤x≤20) glasses have been prepared using conventional melt quenching technique. Differential Scanning Calorimetric (DSC) measurements
show single glass transition and double crystallization, which indicate the occurrence of phase separation in the samples.
The phases present in the samples were identified using XRD. The kinetics of the glass transition has been studied in terms
of the variation of glass transition temperature with composition and heating rate. In addition to this, activation energy
of the glass transition (E
t
) has also been evaluated and its composition dependence is also investigated. The thermal stability of these glasses has
been investigated using various stability criteria: Deiztal first glass criterion, ΔT, Saad and Poulain weighted thermal stability, H′ and the S-parameter. The values of these parameters were obtained using various characteristic temperatures such as the glass transition
temperature, T
g
, the onset temperature of crystallization, T
c
, and the peak crystallization temperature, T
p
. The values of stability parameters show that the phase corresponding to second crystallization is more stable than the phase
corresponding to first one. The stability in terms of the lead (Pb) content has been determined considering the values of
stability parameters of the phase corresponding to second peak. It was found that the stability increases with the lead content. 相似文献
15.
A. A. Pavelko A. G. Lutokhin S. I. Raevskaya Yu. N. Zakharov M. A. Malitskaya I. P. Raevskii I. N. Zakharchenko E. I. Sitalo N. A. Korchagina V. G. Kuznetsov 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(8):1104-1106
(1 − x)PbFe1/2Nb1/2O3−x
PbTiO3 (PFN-xPT) ferroelectric ceramics with low dielectric loss and pronounced anomalies of dielectric and pyroelectric properties near
the ferroelectric-ferroelectric phase transition was obtained by doping with lithium. The temperature dependence of the position
of the morphotropic boundary between the rhombohedral (monoclinic) and tetragonal phases in the x-T phase diagram of the PFN-xPT system was determined for the first time. 相似文献
16.
Phase x-T diagram of actual solid solutions of the (1 ? x )PbZrO3- x PbTiO3 system (0.37 ≤ x ≤ 0.57)
L. A. Reznichenko L. A. Shilkina O. N. Razumovskaya E. A. Yaroslavtseva S. I. Dudkina O. A. Demchenko Yu. I. Yurasov A. A. Esis I. N. Andryushina 《Physics of the Solid State》2008,50(8):1527-1533
Ceramics of PbZr1 − x
Ti
x
O3 solid solutions were systematically studied in the range 0.37 ≤ x ≤0.57. The x-T phase diagram of the system is constructed in the range 25°C ≤ T ≤ 650°C. The diagram has a region of an indefinite symmetry in the vicinity of the transition to the nonpolar cubic phase.
It is established that solid solutions in this region are characterized by weak distortions and temperature-time instability
of the crystal structure. Three concentration regions are separated differing in the value of the jump in the unit cell volume
ΔV at the line of transitions from the rhombohedral (tetragonal) phase to the region of indefinite symmetry. It is revealed
that there are three temperature ranges differing in the behavior of the temperature dependence of the inverse permittivity,
which are due to the existence of two critical Curie points at the boundary separating the ferroelectric phases from the cubic
phase.
Original Russian Text ? L.A. Reznichenko, L.A. Shilkina, O.N. Razumovskaya, E.A. Yaroslavtseva, S.I. Dudkina, O.A. Demchenko,
Yu.I. Yurasov, A.A. Esis, I.N. Andryushina, 2008, published in Fizika Tverdogo Tela, 2008, Vol. 50, No. 8, pp. 1469–1475. 相似文献
17.
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
18.
S. F. Dubinin V. I. Sokolov V. D. Parkhomenko S. G. Teploukhov N. B. Gruzdev 《Physics of the Solid State》2008,50(12):2285-2288
The magnetic state and the structure of a Zn1 − x
Ni
x
Se (x = 0.0025) bulk crystal were studied at low temperatures. It is revealed that the magnetic and crystal structures below T ≅ 15 K are dependent on the cooling rate of this dilute semiconductor. For example, on fast cooling to 4.2 K, about 10% hexagonal
ferromagnetic phase is formed in the crystal. During heating, the phase disappears at T ≅ 15 K. The results obtained are discussed with allowance for the specific features of the Jahn-Teller distortions in this
compound.
Original Russian Text ? S.F. Dubinin, V.I. Sokolov, V.D. Parkhomenko, S.G. Teploukhov, N.B. Gruzdev, 2008, published in Fizika
Tverdogo Tela, 2008, Vol. 50, No. 12, pp. 2188–2191. 相似文献
19.
S. V. Grigoriev V. A. Dyadkin S. V. Maleyev D. Menzel J. Schoenes D. Lamago E. V. Moskvin H. Eckerlebe 《Physics of the Solid State》2010,52(5):907-913
Two systems of noncentrosymmetric cubic helical magnets Mn1 − y
Fe
y
Si (y = 0.06, 0.08, 0.10) and Fe1 − x
Co
x
Si (x = 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.50) have been compared. The concentration dependences of the critical temperature
and magnetic field have been obtained using small-angle polarized-neutron scattering and analyzed in the framework of the
Bak-Jensen model. It has been established that, among the two interactions that play the main role in these systems, i.e.,
the isotropic symmetric ferromagnetic exchange and the Dzyaloshinskii-Moriya isotropic antisymmetric interaction, the former
interaction determines the critical temperature in the Mn1 − y
Fe
y
Si system and the latter interaction determines this temperature in the Fe1 − x
Co
x
Si system. 相似文献
20.
In this paper, we report on the pulsed laser deposition of epitaxial (0002) oriented Zn1−x
Mg
x
O thin films onto (0001) sapphire substrate in O2 ambient at different deposition temperatures. Pulsed laser deposited Zn1−x
Mg
x
O films showed (0002) oriented hexagonal wurtzite structure up to 34% of Mg concentration. The bandgap of Zn1−x
Mg
x
O thin films is successfully tuned from 3.3 to 4.2 eV by adjusting the Mg concentration x=0.0 to x=0.34. Pulsed laser deposited Zn1−x
Mg
x
O thin films were characterized by XRD, AFM, SEM, PL and UV–VIS spectrometer. We have also studied the effect of deposition
temperature on to the structure, surface morphology and optical properties of Zn1−x
Mg
x
O thin films. 相似文献