共查询到20条相似文献,搜索用时 31 毫秒
1.
Ya. A. Ugai A. M. Samoilov M. K. Sharov B. L. Agapov E. A. Dolgopolova 《Inorganic Materials》2001,37(11):1106-1111
In depositing thin PbTeGa films onto Si and SiO2/Si substrates by the hot-wall method, Pb1 – x
Ga
x
melts were used as Ga vapor sources in combination with separate Pb and Te vapor sources. The vaporization of Pb1 – x
Ga
x
(0.15 x 0.95) melts was studied between 1000 and 1300 K in the reaction chamber of the deposition unit. Using electron probe x-ray microanalysis, all the deposited films were shown to contain Ga. Pb1 – x
Ga
x
melts were also used as separate Pb and Ga vapor sources. 相似文献
2.
The synthesis, structure and properties of indium-intercalated compounds of molybdenum sulphoselenide, In1/3MoSxSe2–x (0x 2) compounds were investigated. X-ray analysis shows that all these compounds possess layer-type structure with hexagonal symmetry. Studies of room-temperature magnetic susceptibility, thermoelectric power experiments and two-probe conductivity measurements in the temperature range 25–350 °C, confirmed that these are diamagnetic semiconductors with In1/3MoS2, In1/3MoS1.5Se0.5 and In1/3MoSxSe2–x (0x1.5) exhibiting n- and p-type conductivity, respectively. These results have been explained on the basis of existing band models. Thermal stability behaviour of these compounds in an air atmosphere and X-ray analysis of the oxidized product were also studied. 相似文献
3.
V. D. Volodin S. G. Dorofeev T. A. Kuznetsova V. F. Kozlovskii P. N. Tananaev O. I. Tananaeva 《Inorganic Materials》2003,39(9):931-936
Vapor growth of In-doped PbTe crystals by the sublimation–condensation and vapor–liquid–solid (VLS) processes is examined. Well-faceted Pb1 – x
In
x
Te crystals with x = 0.04–0.06 are prepared by the sublimation method. The effects of the charge composition on the facial development and growth rate in the range 0 x 0.02 are discussed. The growth process at x 0.02 is shown to follow the VLS mechanism. Bulk Pb1 – x
In
x
Te crystals with x 0.05 are grown by a vertical VLS process. The crystal composition is shown to depend significantly on the rate of ampule translation through the temperature field of the furnace and the separation between the evaporation and condensation zones. The longitudinal indium profiles in the crystals are correlated with growth kinetics. 相似文献
4.
N. Balchev K. Nenkov B. Kunev A. Souleva Ts. Tsacheva S. Hoste 《Journal of Superconductivity》2001,14(6):713-717
The effect of Sn doping in (Pb0.6Sn
y
Cu0.4 – y
)Sr2(Y1 – x
Ca
x
)Cu2O
z
with 0 y 0.3 and 0 x 0.7 was investigated. It was established that a nearly pure 1212 phase can be obtained at 0 y 0.1 and 0 x 0.3. The obtained XRD patterns as well as the results of the EDX and ICP-AES analyses showed that Sn substitution is possible in the (Pb,Cu)-1212 phase. Superconductivity was observed at 0.4 x 0.7. The onset of the diamagnetic transitions varied from 10 to 30 K. The influence of the strong Pb deficiency on the superconducting properties of the samples was discussed. 相似文献
5.
H. Hamouda M. Lassri M. Abid H. Lassri D. Saifaoui R. Krishnan 《Journal of Materials Science: Materials in Electronics》2004,15(6):395-398
The magnetization of Co(tCo)/Pt(tPt) (4 tCo10 , 7 tPt20 ) multilayers has been measured as a function of temperature. For Co/Pt multilayers with fixed cobalt layer thickness of 4 , the magnetization decreases faster with temperature as the platinum layers are made thicker. A simple theoretical model based on an anisotropic ferromagnetic system has been used to explain the temperature dependence of the magnetization and the approximate values for the in-plane exchange interaction J0 and the interlayer coupling strength J1 for various Co/Pt multilayers have been obtained. 相似文献
6.
L. A. Reznichenko L. A. Shilkina O. N. Razumovskaya S. I. Dudkina E. S. Gagarina A. V. Borodin 《Inorganic Materials》2003,39(2):139-151
Detailed data are presented on the structure and electrical properties of Na1 – x
Li
x
NbO3 (0 x 0.145), Na1 – x
K
x
NbO3 (0 x 1.0), and (Na1 – x
Pb
x
)(Nb1 – x
Ti
x
)O3 (0 x 1.0) solid solutions prepared by solid-state reactions followed by hot pressing. The sequences of phase changes and the stability ranges of the resulting phases are identified. The results are used to map out the compositional phase diagrams of the NaNbO3-based binary systems. 相似文献
7.
Bulk glasses Pb
x
Ge42 – x
Se48Te10(0 x 15) and Pb20Ge
x
Se70 – x
Te10(17 x 24) have been prepared by quenching the melt. The non-isothermal properties of these glasses have been determined using a Differential scanning calorimeter (DSC). The composition dependence of the glass transition temperature, crystallisation temperature, excess heat capacity at glass transition, glass forming tendency and activation energy of glass transition and crystallisation show anomalous features near the composition at which the p- to n-type transition occurs. These observations reflect the changes occurring in the chemical bonding and the nature of the glassy network in these glasses. The results have been interpreted in terms of existing models and the majority charge carrier reversal phenomenon occurring in these glasses. 相似文献
8.
O. O. Balyts'kyi 《Materials Science》2002,38(5):653-658
We have determined the characteristic temperature ranges of heating of In
x
Se1 – x
(0.50 x 0.52) alloys in air. We have established that the annealing of InSe powder in selenium vapors leads to the stabilization of the rhombohedral structure. 相似文献
9.
W. Wendler T. Herrmannsdörfer S. Rehmann F. Pobell 《Journal of Low Temperature Physics》1998,111(1-2):99-118
We have measured ac susceptibility, nuclear magnetic resonance, and nuclear heat capacity of two PtFe
x
samples with concentrations of magnetic impurities x = 11 ppm and 41 ppm at magnetic fields (0 ± 0.05) mTB248 mT. The susceptibility data have been measured at temperatures of 0.3 KT100 mK, no hint for nuclear magnetic ordering could be detected to a temperature of 0.3 K. The nuclear heat capacity data taken at 1.4 KT10 mK show enhanced values which scale with x at low polarization. This effect is described by a model assuming an internal magnetic field caused by the impurities. No indication for nuclear magnetic ordering could be detected to 1.4 K. The nuclear magnetic resonance experiments have been performed on these samples at 0.8 KT0.5 mK and 2.5 mTB22.8 mT as well as on three other samples with x = 5, 10, 31 ppm in a different setup at 40 KT0.5 mK and at 5.4 mTB200 mT. Spin-lattice and effective spin-spin relaxation times
1and
2
*
of 195
Pt strongly depend on x and on the external magnetic field. No temperature dependence of
1and
2
*
could be detected and the NMR data, too, give no hint for nuclear magnetic ordering to 0.8 K. 相似文献
10.
Alternating current susceptibility and direct current magnetization have been studied for polycrystalline Ca1–x
Mn
x
O. On increasing the Mn content, magnetic ordering changes from spin glass behavior for 0.25 x 0.4 to antiferromagnetic order. The paramagnetic/antiferromagnetic transition is of second order for 0.5 x 0.65 and of first order for x 0.7. For low Mn concentrations, the high-temperature alternating current susceptibility can be described by a diluted Heisenberg magnet model developed for diluted magnetic semiconductors. 相似文献
11.
Magnetization measurements have been performed on the oxygen-isotopeexchanged samples (16O and 18O) of the one-layer cuprate superconductorsLa2–x
Sr
x
CuO4 (0.06x0.20). We find that there is an oxygen-isotopeeffect on the effective supercarrier mass m**, which is huge for x=0.06,and reduced to a smaller value for x=0.15. We also find that there coexistsmall (bi)polarons and free carriers for x0.09, but only small (bi)polaronsare present for x0.09. The normal-state gap is related to the bipolaronbinding energy which is inversely proportional to x for 0.05x0.15. Theobserved isotope effects, supercarrier mass anisotropy, normal-state gap,and mid-infrared spectra for x0.09 can be quantitatively explained by the small(bi)polaron theory of superconductivity proposed by Alexandrov, Kabanov, andMott (AKM). 相似文献
12.
Nd1 – x
Ba
x
MnO3 ± (0.1 x 0.5) and R0.7Ba0.3MnO3 ± (R = La, Pr, Sm, Eu) solid solutions were prepared from nitrate mixtures by solid-state reactions in air and were characterized by x-ray diffraction and thermogravimetry. The oxygen content of the solid solutions was determined by iodometric titration. The materials were found to have a nearly perfect oxygen stoichiometry ( 0). As shown by pH measurements, the solid solutions have a high water resistance (extent of water degradation no larger than 0.1%). The dissociation of the Nd1 – x
Ba
x
MnO3 ± (0.2 x 0.4) solid solutions was studied as a function of temperature and oxygen partial pressure (–10 log(Po
2/Pa) 1.4) by a special TG technique. 相似文献
13.
The manner in which oxygen is incorporated into YBa2Cu3O
x
(YBCO) at 800°C for values ofx close to 6 is shown to be in the form of neutral oxygen interstitials, O
i
x
. The experimental data on which this conclusion is based are obtained from measurements of oxygen partial pressure,P(O2), as a function of compositionx and temperatureT (5.99x 6.35, 825T1120 K). The data are obtained by a solid-state electrochemical method. Other conclusions of this study include: (a) O
i
x
are noninteracting forx 6. (b) The stoichiometric composition of YBCO isx 6.0. (c) The reaction enthalpy of oxidation is 179 kJ/mol O2. (d) The Fermi level changes by –0.2 eV asx increases from 6.05 to 6.35. 相似文献
14.
L. V. Kokhanovskii V. V. Vashuk O. P. Ol'shevskaya O. I. Kirilenko 《Inorganic Materials》2001,37(7):730-736
The oxygen stoichiometry of SrCo1 – x
Fe
x
O3 – (0.1 x 0.9) solid solutions was determined by solid-electrolyte coulometry as a function of temperature (20–1000°C) and oxygen partial pressure (1–100 Pa). The results, together with X-ray diffraction studies between 400 and 900°C, indicated a sequence of phase transitions: perovskite brownmillerite high-temperature perovskite. The composition stability region of the parent perovskite structure was shown to be 0.2 <x 1.0. The Co-rich samples (x 0.2) consisted of perovskite and hexagonal phases. 相似文献
15.
A. Di Chiara U. Scotti di Uccio M. Senatore L. Maritato 《Journal of Low Temperature Physics》1986,62(5-6):385-396
Results concerning V3Si films produced by a simple annealed multilayer technique are reported together with X-ray diffraction patterns, Auger spectroscopy, and Rutherford backscattering analysis. Low-temperature electrical resistivity measurements are discussed. It is found that the V3Si films exhibit aT
2 dependence in the temperature rangeT
c
T23 K and aT
2.6 dependence in the rangeT
c
T40 K. The normal-state resistivity in the whole temperature range (T
c
T600 K) is analyzed in the framework of Cote-Meisel theory. Consistent values of the saturation resistivity
m
and of the Debye temperature are obtained by fitting the experimental data with the Cote-Meisel expression for (T). 相似文献
16.
Polycrystalline samples La1.85Sr0.15Cu1–xZnxO4– (0 x 0.3), La1.85Sr0.15Cu1–xNixO4– (0 x 0.3), and La1.85Sr0.15Cu1–xMgxO4– (0 x 0.3) were synthesized by the solid-state reaction method. The crystal structure and phonon vibration were investigated by means of X-ray diffraction (XRD) and infrared spectrum. Zn, Ni, and Mg doping results in the lattice parameter c decreasing and a (b) increasing. The change of the phonon modes around 504 cm–1 and 681 cm–1 can be satisfactorily interpreted in terms of the change of the crystal structure and the itinerant nature of charge carrier in CuO2 sheet. The relation between the structure and phonon vibration is discussed. 相似文献
17.
Yoshimasa A. Ono Jun'ichiro Hara Katsuhiko Nagai Kiyoshi Kawamura 《Journal of Low Temperature Physics》1977,27(3-4):513-536
The shear viscosity (T) in the Balian-Werthamer (BW) state of superfluid
3
He is calculated variationally throughout the region 0t 1(t=T/T
c) from the transport equation for Bogoliubov quasiparticles. Coherence factors are treated exactly in the calculation of the collision integral. The numerical result for
=s= s(T)/n(Tc) agree very well with experiment in the range 0.8t1.0. Analytic expressions
= 0.577 (1–1.0008t) and
=1–(23/64) [=(T)/k
B
T] are obtained in the low-temperature region and in the vicinity ofT
c, respectively. From the numerical analysis it is shown that the latter equation is valid only in the temperature range 0.9997t1.0.Supported by the Research Institute for Fundamental Physics, Kyoto University. 相似文献
18.
S. T. B. Goennenwein T. Graf T. Wassner M. S. Brandt M. Stutzmann A. Koeder S. Frank W. Schoch A. Waag 《Journal of Superconductivity》2003,16(1):75-78
We report on ferromagnetic resonance measurements of Ga1–x
Mn
x
As thin films with Mn contents 0.022 x 0.051. For x 0.036 and the external magnetic field normal to the thin film, we observe several resonances, which we identify as spin wave resonances. The non-quadratic mode spacing can be consistently explained by a linear gradient in the magnetic properties of the films. From the measurements, the exchange constant A can be deduced for different Mn contents x. 相似文献
19.
A superconductor/semimetal/superconductor (S/SM/S) Josephson junction has been developed. We have used an alloy of Pb1–x
Bi
x
(0x 0.6) as the superconductor and Bi as the semimetal. By irradiating at X-band microwave of 10 GHz, Shapiro steps were observed for various bismuth barrier thicknesses inÅ and bismuth weight ratiosx. Finally, we obtained the empirical relationship for barrier thickness, below which microwaves could be detected for various bismuth weight ratiosx at the temperature of 4.2 K. 相似文献
20.
S. B. Kiselev I. M. Abdulagatov A. H. Harvey 《International Journal of Thermophysics》1999,20(2):563-588
A parametric crossover model is adapted to represent the thermodynamic properties of pure D2O in the extended critical region. The crossover equation of state for D2O incorporates scaling laws asymptotically close to the critical point and is transformed into a regular classical expansion far from the critical point. An isomorphic generalization of the law of corresponding states is applied to the prediction of thermodynamic properties and the phase behavior of D2O + H2O mixtures over a wide region around the locus of vapor-liquid critical points. A comparison is made with experimental data for pure D2O and for the D2O + H2O mixture. The equation of state yields a good representation of thermodynamic property data in the range of temperatures 0.8T
c(x)T1.5T
c(x) and densities 0.35c(x)1.65c(x). 相似文献