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1.
Electron-doped metallic states of Ca1−x
Y
x
VO3 and Ca1−x
Y
x
TiO3 change into non-metallic states around x∼0.4 and 0.6, respectively. The residual resistivity in the metallic states increases with increasing effective magnetic moment
or coefficient of T
2 term of resistivity. The effective moment reaches ∼ 0.5 μB/molecule in Ca1−x
Y
x
VO3 and also in Ca1−x
Y
x
TiO3 near the metal-nonmetal phase boundary. In these metallic states. ∼ 10% of 3d atoms seem to have large localized magnetic moments. In electron-doped metallic sample of Ca1−x
Y
x
VO3, the temperature dependence of resistance shows no resistance-minimum. However, weak negative magneto-resistance is observed
for the sample with x=0.2 up to 50 Tesla at 4.2 K. 相似文献
2.
A. A. Samokhvalov T. I. Arbuzova N. A. Viglin S. V. Naumov I. B. Smolyak A. V. Korolev N. I. Lobachevskaya 《Physics of the Solid State》2000,42(4):719-721
The problem of localized superconductivity has motivated the preparation of Mg1−x
CuxO solid solutions with NaCl structure and 0.01≤x≤0.20, as well as a study of the magnetization and magnetic susceptibility χ in the 2–400 K temperature range and in magnetic fields of up to 5 T. The temperature dependence of χ is described for all
compositions by the Curie-Weiss law, χ = C/(T − θ), where the constant C is close to the value calculated for each composition for μeff = 1.7–1.9μB, and θ is close to zero. For T < 30 K, χ(T) deviates for all compositions toward lower χ, which can be attributed to magnetic ordering of exchange-coupled clusters
in the solid solution. At T∼320–330 K, an anomaly of a diamagnetic type, i.e., a decrease of χ by 6–30% of its paramagnetic value, has been observed
for all compositions against the background of the generally paramagnetic χ(T). A discussion is presented of alternative reasons for this anomaly and of its possible connection with localized superconductivity.
__________
Translated from Fizika Tverdogo Tela, Vol. 42, No. 4, 2000, pp. 701–703.
Original Russian Text Copyright ? 2000 by Samokhvalov, Arbuzova, Viglin, Naumov, Smolyak, Korolev, Lobachevskaya. 相似文献
3.
A ππ, ˉKK, and ρρ(ωω) fully coupled channel model is used to predict the lowest isospin S, P, D, F-wave phase shifts and inelasticities
for elastic ππ scattering from threshold to 2.0 GeV. As input the S-matrix is required to exhibit poles corresponding to the
meson resonance table of the Particle Data Group. As expected, the ππ inelasticity is very strongly related to the opening
of the ˉK channel near 1 GeV, and the opening of ρρ(4π) and ωω(6π) channels in the 1.5 GeV region. The predictions of this model are
compared to the various elastic ππ→ππ amplitudes, that were obtained from analyses of π− p →π−π+n data. The role of the various resonances, in particular the glueball candidate f
0(1500) and the f
J(1710) is investigated.
Received: 19 November 1997 相似文献
4.
The transport properties of the semimetallic quasi-one-dimensional S=1/2 antiferromagnet Yb4As3 have been studied by performing low-temperature (T≥0.02 K) and high magneticfield (B≤60 T) measurements of the electrical resistivity ρ(T, B). For T ≿ 2 K a ‘heavy-fermion’-like behavior Δρ(T)=AT
2 with huge and nearly field-independent coefficient A ≈ 3 μΩ cm/K2 is observed, whereas at lower temperatures ρ(T) deviates from this behavior and slightly increases to the lowest T. In B>0 and T ≾ 6 K the resistivity shows an anomalous magnetic-history dependence together with an unusual relaxation behavior. In the
isothermal resistivity Shubnikov-de Haas (SdH) oscillations, arising from a low-density system of mobile As-4p holes, with a frequency of 25 T have been recorded. From the T- and B-dependence of the SdH oscillations an effective carrier mass of (0.275±0.005)m
0 and a charge-carrier mean-free path of 215 ? are determined. Furthermore, in B≥15 T, the system is near the quantum limit and spin-splitting effects are observed. 相似文献
5.
R. N. Kyutt 《Physics of the Solid State》1997,39(7):1052-1056
Double-and triple-crystal diffractometry have been used to study structural perfection of a ∼1 μm-thick Ga1−x
InxSb1−y
Asy epitaxial film (x=0.9, y=0.8) on GaSb. It is shown that scattering from samples of this system can be divided into coherent and diffuse. The arrangement
of reciprocal-lattice points of the film and substrate in the two-dimensional intensity distribution for asymmetrical reflections
argues for the absence of elastic-strain relaxation. No dislocation networks are formed, and the diffuse scattering is produced
by Coulomb-type defects. Localization of diffuse scattering in reciprocal space suggests that these defects reside in the
epitaxial film. The diffuse-scattering distribution in asymmetrical reflections is shown to be anomalous; namely, it extends
in a direction parallel to the surface and is split into two maxima. Schemes have been proposed and realized for measuring
integral distributions of diffracted intensity along the surface and perpendicular to it, and their potential for studying
diffuse scattering from defects is explored.
Fiz. Tverd. Tela (St. Petersburg) 39, 1188–1193 (July 1997) 相似文献
6.
A. A. Samokhvalov T. I. Arbuzova N. A. Viglin V. V. Osipov N. I. Solin S. V. Naumov V. G. Bamburov N. I. Lobachevskaya O. G. Reznitskikh 《Physics of the Solid State》1999,41(2):262-264
Mg1−x
CuxO solid solutions having an NaCl structure with 0⩽x⩽0.20 are synthesized and Cu-Mg1−x
CuxO structures are prepared for superconductivity studies. The magnetic susceptibility χ, electron paramagnetic resonance (EPR), and electrical conductivity of the solid solutions are studied at temperatures of
5–550 K. It is shown that χ
−1(T) obeys the Curie-Weiss law with a paramagnetic Curie temperature Θ close to zero and an effective magnetic moment μ
eff=1.9 μ
B, close to the 1.73 μ
B of a Cu2+ ion with spin S=1/2. The width ΔH of the EPR line depends weakly on temperature and increases as x is raised. The volume narrowing of the EPR linewidth ΔH is used to estimate the exchange interaction parameter, 3×10−4 eV. The g-factor is close to 2 and is temperature independent. The electrical conductivity of Mg1−x
CuxO at T=300 K is ≈10−11–10−12 Ω−1 cm−1 for x=0 and increases to 10−5–10−6 Ω−1 cm−1 for x=0.15–0.20. The conductivity is p-type. Magnetic shielding is observed in Cu-Mg1−x
CuxO structures with x=0.15 and 0.20. The possible connection of this phenomenon with interference superconductivity in the contact layer of the
structure is discussed.
Fiz. Tverd. Tela (St. Petersburg) 41, 293–296 (February 1999) 相似文献
7.
Mail Tagiyev Farkhad Samedov Sohrap Samedov 《International Journal of Infrared and Millimeter Waves》1997,18(9):1813-1820
Thin films of Bi85Sb15 solid solution wich can be used in thermoelectric devices for cooling and stabilizing the temperature of Gann and Impatt
diodes have been obtained by extrusion method. They have surface roughness in the range 10–80μm, dielectric lossestan δ ∼ 10−3 at 10 GHz, thermal conductivityβ ∼ 4x102
W / (M · K).
Anisotropy of electroconductivityσ, thermoelectric powerα and Hall coefficientsR
H of lead doped extruded Bi85Sb15 samples has been investigated in the temperature range between 77 K and 300 K and in the presence of magnetic fieldH up to ∼ 74×104 A/m. It is shown that the value and sign of the anisotropy coefficient essentially depend on heat treatment and impurity
concentration. Experimental results are explained taking into account a crystal structure of Bi85Sb15, formation of texture and generation of deformation defects. 相似文献
8.
V. V. Naumov O. A. Grebenshchikov V. B. Zalesskii 《Journal of Applied Spectroscopy》2006,73(5):753-759
We describe a method for automated measurement of the integrated sensitivity of solar cells (SCs) and multielement photoconverters
(MPCs) using an experimental apparatus including a Pentium III personal computer (PC), an HP-34401A digital multimeter (DM),
a stabilized radiation source (SRS), a controllable focusing system, an X-Y positioning device based on CD-RW optical disk
storage devices.
The method provides high accuracy in measuring the size of photosensitive areas of the solar cells and multielement photoconverters
and inhomogeneities in their active regions, which makes it possible to correct the production process in the development
stage and during fabrication of test prototypes for the solar cells and multielement photoconverters.
The radiation power from the stabilized radiation source was ≤1 W; the ranges of the scanning steps along the X, Y coordinates
were 10–100 μm, the range of the transverse cross sectional diameters of the focused radiation beam was 10–100 μm, the measurable
photocurrents were 10−9 A to 2 A; scanning rate along the X, Y coordinates, ≤100 mm/sec; relative mean-square error (RMSE) for measurement of the
integrated sensitivity of the solar cells, 0.2 ≤ γS
int
≤ 0.9% in the ranges of measurable photocurrents 1 mA ≤ Iph ≤ 750 mA and areas 0.1 ≤ A ≤ 25 cm2 for number of measurements equal to ≤ 2· 105; instability of the radiation power (luminosity) ≤ 0.08% for 1 h or ≤ 0.4% for 8 h continuous operation; stabilized power
range for the stabilized radiation source, 10−2–102 W. The software was written in Delphi 7.0.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 5, pp. 670–675, September–October, 2006. 相似文献
9.
G. A. Sukach P. F. Oleksenko A. B. Bogoslovskaya Yu. Yu. Bilinets V. N. Kabatsii 《Technical Physics》1997,42(9):1044-1047
A study is made of the excess-energy relaxation processes and the mechanisms responsible for overheating of the active zone
of infrared emitters made from nonisoperiodic structures with stressed InGaAs layers and from nearly isoperiodic InAsSbP structures
and emitting in the wavelength range λ=2.5–5.0 μm are investigated. The relationship between the overheat ΔT of the active zone of the structure and Auger processes is established for In1−x
GaxAs infrared emitters. It is shown that the efficiency of Auger recombination decreases as x increases in the interval 0–0.09, promoting a sharp reduction in ΔT. At x>0.09 the efficiency of CHHS Auger processes decreases exponentially, but an increase in the density of dislocations due to
the appreciable value (∼6.9%) of the lattice mismatch parameter causes ΔT to increase, but slowly.
Zh. Tekh. Fiz. 67, 68–71 (September 1997)
Deceased. 相似文献
10.
V. V. Ovchinnikov N. V. Gushchina F. F. Makhin’ko L. S. Chemerinskaya A. R. Shkol’nikov S. M. Mozharovskii A. V. Filippov L. I. Kaigorodova 《Russian Physics Journal》2007,50(2):177-186
Using electron microscopy it was found that irradiation of clad cold-worked specimens made of commercial aluminium-lithium
alloy 1441 by the Ar
+ ions of energy 40 keV at low doses of irradiation (1015 cm−2, irradiation time 1 s, T < 70 °C) and ion-current density of about 100 μA/cm2 results in the transformation of the cellular structure formed in the alloy under deformation. As the dose of irradiation
is increased up to 1016 cm−2, a transition from a cellular to a subgrain structure close to a polygonal one is observed. The efficiency of the process
is increased with ion-current density. Furthermore, under ion irradiation at increased ion-current densities, the β′(Al
3
Zr) and Al
8
Fe
2
Si particles present in the deformed alloy dissolve, and disperse particles of a new Al
2
LiMg phase of platelet shape are formed. The changes in the dislocation structure and phase composition in alloy 1441 are observed
several seconds after irradiation not only in the surface layer adjacent to the ion incorporation band but also through the
thickness of the specimen tens of thousands times greater than ion projective ranges.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 73–81, February, 2007. 相似文献
11.
A. V. Voitsekhovskii A. G. Korotaev A. P. Kokhanenko D. V. Grigor’ev V. S. Varavin S. A. Dvoretskii Yu. G. Sidorov N. N. Mikhailov N. Kh. Talipov 《Russian Physics Journal》2006,49(9):929-933
The dynamics of accumulation of electrically active radiation defects under ion doping of epitaxial Cd
x
Hg
1−x
Te films is studied for various distributions of film composition in the implantation region. The epitaxial films were irradiated
by boron ions at room temperature in the continuous regime, with the dose ranging within 1011−3·1015 cm−2, energy — 20–150 keV, and ion current density — j = 0.001–0.2 μA·cm−2. It is found that the natural logarithm of the introduction rate of electrically active radiation defects linearly depends
on the epitaxial-film composition in the range of mean projected path of implanted ions. An analysis of the experimental data
shows that the dynamics of accumulation of electrically active radiation defects is determined by the epitaxial-film composition
in the implantation region.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 25–28, September, 2006. 相似文献
12.
E.G. Drukarev M.G. Ryskin V.A. Sadovnikova 《The European Physical Journal A - Hadrons and Nuclei》1999,4(2):171-186
We calculate the contribution of pions to the $\bar qq$-expectation value κ(ρ) =<M|ˉq
q|M> in symmetric nuclear matter. We employ exact pion propagator renormalized by nucleon-hole and isobar-hole excitations. Conventional
straightforward calculation leads to the “pion condensation” at unrealistically small values of densities, causing even earlier
restoration of chiral symmetry. This requires a self-consistent approach, consisting in using the models, which include direct
dependence of in-medium mass values on κ(ρ), e.g. the Nambu–Jona-Lasinio–model. We show, that in the self-consistent approach
the ρ-dependence of the condensate is described by a smooth curve. The “pion condensate” point is removed to much higher values
of density. The chiral restoration does not take place at least while ρ < 2.8ρ0 with ρ0 being the saturation value. Validity of our approach is limited by possible accumulation of heavier baryons (delta isobars)
in the ground state of nuclear matter. For the value of effective nucleon mass at the saturation density we found m
*(ρ0) = 0.6m, consistent with nowadays results of other authors.
Received: 8 October 1998 相似文献
13.
E. M. Drobyshevski 《Physics of Atomic Nuclei》2000,63(6):1037-1041
A possibility is considered of detecting Planckian particles carrying an electric charge Z≈10 and supposedly forming the dark matter of the Galactic disk, whence they are captured by combined action of the Sun and
the Earth into strongly elongated Earth-crossing orbits. The flux of such dark electric matter objects, daemons, at the Earth’s
orbit may reach f
⊕≈3×10−7cm−2s−1 at a velocity about 52 km/s. Negatively charged daemons are capable of catalyzing the fusion of light (Z
n<10) nuclei. The rate of capture (and fusion) of nuclei should be particularly high in a metallic phase. A detection system
is described that consists of beryllium plates 45 mm thick and 1200 cm2 in area coated with a ZnS(Ag) scintillator. It is assumed that the products of the fusion reaction 29Be → 18O that are ejected in amounts of up to about 104 from the points of daemon entrance and exit would give rise to scintillations with a delay of about 1μs. An exposure of the
system for 300 h revealed no event. The reason for the negative result can be (1) too optimistic an estimate of the flux (the
inclusion of some factors could lower it by 1.5–3 orders of magnitude) and (2) the poisoning of the catalyst by capture of
nuclei with Z
n≥10. The time required for the recovery of the daemon catalytic properties is estimated from the analysis of the energy release
in the Sun at no less than 3×10−7 s. The analysis of the total available data suggests that the daemon flux at the Earth is about 3×10−8 cm−2 s−1. The experiments will be continued.
From Yadernaya Fizika, Vol. 63, No. 6, 2000, pp. 1112–1117.
Original English Text Copyright ? 2000 by Drobyshevski.
This article was submitted by the author in English. 相似文献
14.
The formation of induced 5d magnetic moment on Ir in Fe100−x
Ir
x
(x=3, 10 and 17) and Co100−x
Ir
x
(x=5, 17, 25 and 32) alloys has been investigated by X-ray magnetic circular dichroism (XMCD) at Ir L2,3 absorption edges. Sum rule analysis of the XMCD data show that the orbital moment of Ir is in the range of −0.071(2)μB to
−0.030(1)μB in Fe-Ir alloys and −0.067(2)μB to 0.024(1)μB in Co-Ir alloys. We find that the total moment of Ir in Fe-Ir alloys
is approximately 1/5 of the total 3d moment on Fe at all the three compositions. In contrast, the total moment on Ir in Co-Ir alloys varies between 1/6 to 1/16
of the 3d moment on cobalt. The observed trends of Ir moments and the role of interatomic exchange interactions in 5d moment formation are discussed. 相似文献
15.
It is shown that the list of unusual mesons that are planned to be studied in photoproduction reactions can be supplemented
with I
G (J
PC)=2+ (2++) exotic states X
±(1600), which are natural to seek as manifestations of the ρ±ρ0 decay channels in the reactions γN → ρ±ρ0
N and γN → ρ±ρ0Δ. A classification of the ρ±ρ0 states according to their quantum numbers is presented. A model for the spin structure of the amplitudes for the reactions
γp → f
2(1270)p, γp → a
2
0
(1320)p, and γN → X
±(N, Δ) is proposed, and estimates are obtained for the corresponding cross sections. At E
γ≈6 GeV, it is found that σ(γP → f
2(1270)p)≈0.12 μb, σ(γp → a
2
0
(1320)p)≈0.25 μb, σ(γN → X
±
N → ρ±ρ0
N) ≈ 0.018 μb, and σ(γp → X
−Δ++ → ρ−ρ0Δ++≈0.031 μb. The problem of isolating signals from X
± states against the natural background that is associated with other channels of π±π0π+π− production is discussed. It is deduced that searches for exotic states X
±(2+ (2++)) in experiments at JLAB will be quite efficient—for example, the yield of about 2.8×106 events per month is expected to correspond to the estimated cross sections for the reactions γN → X
±
N → ρ±ρ0
N.
__________
Translated from Yadernaya Fizika, Vol. 63, No. 10, 2000, pp. 1904–1912.
Original Russian Text Copyright ? 2000 by Achasov, Shestakov. 相似文献
16.
I. M. Batyaev 《Journal of Applied Spectroscopy》1997,64(5):620-632
An attempt was made to describe and show the possibilities of new inorganic neodynium- and uranium-activated laser liquids:
SO2-GaCl3-NdCl4; SO2Cl2-GaCl3-NdCl3-UO2Cl2; POCl2-MCln-NdCl3-UO2Cl2 for development and synthesis of direct nuclear reaction-excited lasers. Luminescence data presented in the work were used
to calculate the luminescence parameters of the laser liquids such as oscillator strengths f, probability of spontaneous radiation
A, intermultiplet luminescence branching coefficient β, cross-section for induced radiation σ, luminescence decay time τ,
quantum yield η, and others. It is shown that the oscillator strengths of the normal absorption bands of Na3+, which play the main part in the pumping processes, exceed the oscillator strengths of Na3+ for aqueous and many other nonaqueous systems. In the luminescence excitation spectra of the Na3+ ion, bands are isolated in the range 400–1000 nm atλ
rec
=1.06 μm. With excitation, luminescence occurs through the4F3/2→4I9/2,11/2.13/2 channels. Luminescence spectral data are related to the lasing parameters. The threshold lasing energy is∼18 J/cm3. For a resonator with mirros h1=100% and h2=20, 40, 56, and 80%, the lasing energy is∼20–120 MJ/cm3 in the pumping energy range 18–180 J/cm3. The differential efficiency is ∼0.2% The substantial angular radiation divergence (θ∼4·10−2 rad) and strong thermostatic distortions that occur in the active element (dn/dT≈−1.9·10−4K−1) are a disadvantage of laser liquids. It is shown that operation of neodymium- and uranium-activated inorganic liquid lasers
is stable under the present conditions.
A. I. Gertsen Russian State Pedagogical University, Moika Embankment, 48, St. Petersburg, 191186, Russia. Translated from
Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 5, pp. 607–619, September–October, 1997. 相似文献
17.
I. P. Studenyak M. Kran’chets L. M. Suslikov D. Sh. Kovach 《Optics and Spectroscopy》2003,95(3):427-430
The piezobirefringence of uniaxial γ1-(GaxIn1−x
)2Se3 crystals (x=0.3, 0.4) was investigated in the spectral range 0.6–1.1 μm at temperatures from 77 to 295 K. It is shown that uniaxial compression
leads to a linear decrease in the birefringence, whereas a decrease in temperature reduces the effect of piezobirefringence.
The baric changes in the birefringence are attributed to the baric changes in the contribution of the edge transitions to
the total birefringence.
__________
Translated from Optika i Spektroskopiya, Vol. 95, No. 3, 2003, pp. 458–461.
Original Russian Text Copyright ? 2003 by Studenyak, Kran’chets, Suslikov, Kovach. 相似文献
18.
M.H. Thoma S. Leupold U. Mosel 《The European Physical Journal A - Hadrons and Nuclei》2000,7(2):219-223
Assuming that ρ-mesons exist in a quark-gluon plasma at temperatures close to the QCD phase transition, we calculate the
dilepton production rate from q-ˉq annihilation via a ρ-meson state using Vector Meson Dominance. The result is compared to the rates from direct q-ˉq annihilation and from π+-π− annihilation. Furthermore we discuss the suppression of low mass dileptons if the quarks assume an effective mass in the
quark-gluon plasma.
Received: 8 September 1999 / Revised version: 22 October 1999 相似文献
19.
A. M. Tkachuk I. K. Razumova A. A. Mirzaeva A. V. Malyshev V. P. Gapontsev 《Optics and Spectroscopy》2002,92(1):67-82
Formation of the inverse population of working levels of 3-μm laser transition in LiY1−x
ErxF4 (x=0.003–1) crystals under CW InGaAs laser-diode pumping (0.967–0.982 μm) was investigated. Dependences of population of the
4
I
11/2 and 4
I
13/2 levels on the dopant concentration and pump power were studied theoretically and experimentally. Relative changes in populations
of the studied levels were experimentally monitored by measuring the steady-state spectra of IR crystal luminescence in the
wavelength range corresponding to 4
I
11/2→4
I
13/2 (2.7–2.8 μm), 4
I
11/2→4
I
15/2 (0.96–1.04 μm), and 4
I
13/2→4
I
15/2 (1.45–1.65 μm) transitions. Theoretical and experimental estimates of the rates of intracenter and intercenter relaxation
processes (migration, self-quenching, and up-conversion) with allowance for statistics of coupling of impurity centers in
the system were used to determine the energy-transfer mechanisms, elucidate the predominant mechanisms, and obtain microparameters
and concentration dependences of the energy-transfer rates and nonlinear coupling. Dependences of the steady-state population
of the levels of laser transition 4
I
11/2→4
I
13/2 on the dopant concentration and pumping power density were calculated within the context of rate balance equations for the
scheme with the five lowest excited states of erbium. Good agreement between theory and experiment was obtained.
__________
Translated from Optika i Spektroskopiya, Vol. 92, No. 1, 2002, pp. 73–88.
Original Russian Text Copyright ? 2002 by Tkachuk, Razumova, Mirzaeva, Malyshev, Gapontsev. 相似文献
20.
The B-site substituted perovskite solid solution systems Li3xLa0.67−xREyTi1−2yPyO3 (RE=Sc, Y, Nd, Sm, Eu, Yb) have been investigated. Perovskite solid solutions formed in the range of x=0.10, y<0.10 for RE=Sc3+, Y3+, Yb3+, x=0.10, y≤0.05 for RE=Nd3+, Sm3+, Eu3+. Li0.3La0.57Nd0.05Ti0.9P0.05O3 has the highest bulk conductivity of 4.31×10−4 S·cm−1 and the highest total conductivity of 2.52×10−4 S·cm−1 at room temperature in all prepared compositions. The compositions have low activation energies of about 24–30 kJ/mol in
the temperature ranges of 298–523 K. SEM studies showed that the sample made by solid-state reaction has a sphere-like morphology
and a rough particle with particle size of about 50 μm. The research results also indicated that the reaction temperature
decreases and the electrochemical stabilities of the titanate-based perovskite-type solid solutions are improved by using
RE3+ and P5+ replaced Ti4+ on B-site in the Li3xLa0.67−xTiO3 parent. 相似文献