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Tytuł:
I-V Characteristics of Resistive Oxides: DC versus Pulsed Measurements
Autorzy:
Fisher, B.
Genossar, J.
Chashka, K. B.
Patlagan, L.
Reisner, G. M.
Powiązania:
https://bibliotekanauki.pl/articles/2047215.pdf
Data publikacji:
2007-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Ht
75.47.Lx
77.80.Fm
Opis:
We investigated pulsed and DC I-V characteristics of a variety of resistive oxides. Examples of pulsed, compared with DC characteristics, are shown for samples of La$\text{}_{1.2}$Sr$\text{}_{1.8}$Mn$\text{}_{2}$O$\text{}_{7}$ (a double layer manganite), Pr$\text{}_{2}\text{}_{/}\text{}_{3}$ Ca$\text{}_{1}\text{}_{/}\text{}_{3}$ MnO$\text{}_{3}$ and Bi$\text{}_{1}\text{}_{/}\text{}_{2}$ Sr$\text{}_{1}\text{}_{/}\text{}_{2}$ MnO$\text{}_{3}$ (charge-ordered manganites), Sr$\text{}_{2}$FeMoO$\text{}_{6}$, Sr$\text{}_{2}$CrWO$\text{}_{6}$ and Ba$\text{}_{2}$MnReO$\text{}_{6}$ (double perovskites). For pulsed measurements, single pulses in the ms range were applied. For short-rise-time square pulses, the Joule heating is negligible, as long as the response remains independent of time. The DC I-V characteristics were measured up to current runaway in the negative resistance regime;Δ T never exceeded a fraction of a degree. In most cases the DC characteristics mask a perfectly ohmic or moderately non-ohmic conductivity obtained by pulsed measurements. This demonstrates that the widely used DC I-V measurements in the high current regime are frequently misleading.
Źródło:
Acta Physica Polonica A; 2007, 111, 1; 57-61
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Synchrotron X-Ray Topography to the Study of Materials
Autorzy:
Tanner, B. K.
Powiązania:
https://bibliotekanauki.pl/articles/1931651.pdf
Data publikacji:
1994-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.85.+n
61.10.Lx
Opis:
In this article, we review the application of synchrotron X-ray topography to the study of the defect structure of materials. Following a discussion of source and detector requirements, in situ dynamic, stroboscopic, and ultra-high strain sensitivity experiments are discussed in the context of the new, third generation, synchrotron radiation sources. The intensity and continuous spectrum of synchrotron radiation is particularly important but further use of the time structure and polarization is timely. The future potential of the technique is discussed in the context of recent results at the European Synchrotron Radiation Facility in Grenoble.
Źródło:
Acta Physica Polonica A; 1994, 86, 4; 537-544
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sintering Behavior and Machinability in Mica Glass-Ceramic of the System $SiO_2-Al_2O_3-MgO-K_2O-B_2O_3-F$
Autorzy:
Ercenk, E.
Yilmaz, S.
Powiązania:
https://bibliotekanauki.pl/articles/1293704.pdf
Data publikacji:
2014-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.cp
68.37.Hk
81.20.Ev
81.20.Wk
81.05.Je
81.05.Mh
Opis:
Mica glass-ceramic was prepared by sintering method from in the $SiO_2-Al_2O_3-MgO-K_2O-B_2O_3-F_2$ system. The sintering behavior and machinability of a glass-ceramic composition were examined. The starting materials were mixed and milled in an alumina ball mill for 2 h. Then the powders were sieved to obtain grain sizes smaller than 75 μm. For the shaping process, disc samples were prepared by pressing at 100 MPa. The pressed discs were sintered at temperatures in the range from 900 to 1200C for 2 h in an electric furnace using a heating rate of 5°C/min. X-ray diffraction analysis, scanning electron microscopy, and machinability tests for characterization were performed on sintered samples. The results showed that all samples exhibited similar phases formation and good machinability.
Źródło:
Acta Physica Polonica A; 2014, 125, 2; 629-631
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positron Affinities and Deformation Potentials in Cubic Semiconductors
Autorzy:
Panda, B. K.
Brauer, G.
Powiązania:
https://bibliotekanauki.pl/articles/2008145.pdf
Data publikacji:
1999-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.20.Mb
73.30.+y
Opis:
Positron affinities and deformation potentials are calculated in cubic bulk semiconductors using the density functional theory with the electron and positron energies in the local density approximation and generalized gradient approximation, respectively. In order to estimate these quantities, two different forms of the electron-positron correlation potential are used. Positron affinities calculated using these two correlation potentials differ by about 0.3 eV. Our calculated affinities in 3C-SiC are in better agreement with experiments than those obtained previously by another first principles method. In the present work the positron affinity in BN is found to be quite close to the one in diamond.
Źródło:
Acta Physica Polonica A; 1999, 95, 4; 641-646
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charged Excitons in the Quantum Hall Regime
Autorzy:
Schüller, C.
Broocks, K.-B.
Schröter, P.
Heyn, C.
Heitmann, D.
Bichler, M.
Wegscheider, W.
Apalkov, V. M.
Chakraborty, T.
Powiązania:
https://bibliotekanauki.pl/articles/2038336.pdf
Data publikacji:
2004-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.-y
71.30.+h
71.35.Ji
71.70.Ej
Opis:
We review our recent optical experiments on two-dimensional electron systems at temperatures below 1 K and under high magnetic fields. The two-dimensional electron systems are realized in modulation-doped GaAs-AlGaAs single quantum wells. Via gate electrodes the carrier density of the two-dimensional electron systems can be tuned in a quite broad range between about 1×10$\text{}^{10}$ cm$\text{}^{-2}$ and 2×10$\text{}^{11}$ cm$\text{}^{-2}$. In dilute two-dimensional electron systems, at very low electron densities, we observe the formation of negatively charged excitons in photoluminescence experiments. In this contribution we report about the observation of a dark triplet exciton, which is observable at temperatures below 1 K and for electron filling factors <1/3, i.e., in the fractional quantum Hall regime only. In experiments where we have increased the density of the two-dimensional electron systems so that a uniform two-dimensional electron system starts to form, we have found a strong energy anomaly of the charged excitons in the vicinity of filling factor 1/3. This anomaly was found to exist in a very narrow parameter range of the density and temperature, only. We propose a model where we assume that localized charged excitons and a uniform Laughlin liquid coexist. The localized charged exciton in close proximity to the Laughlin liquid leads to the creation of a fractionally-charged quasihole in the liquid, which can account for the experimentally observed anomaly.
Źródło:
Acta Physica Polonica A; 2004, 106, 3; 341-353
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of van Hove Singularity on T$\text{}_{c}$ in Rb doped C$\text{}_{60}$
Autorzy:
Agrawal, B. K.
Agrawal, S.
Yadav, P. S.
Srivastava, P.
Srivastava, R.
Singh, S.
Powiązania:
https://bibliotekanauki.pl/articles/2035748.pdf
Data publikacji:
2003-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.25.Jb
74.62.Fj
74.70.Wz
Opis:
In the present study we investigate the role of van Hove singularity on the optimization of T$\text{}_{c}$ in Rb doped fullerenes C$\text{}_{60}$ Rb$\text{}_{3}$. A first principles self-consistent full potential linear muffin-tin orbital method using density functional theory in local density approximation was employed. The doped Rb atoms are of two types occupying the tetrahedral and interstitial positions in the fcc lattice. The added Rb atoms fill the t$\text{}_{1u}$ band of the undoped fullerenes C$\text{}_{60}$ up to half which makes C$\text{}_{60}$Rb$\text{}_{3}$ conducting. Saddle points leading to van Hove singularities are observed in the neighbourhood of the symmetry point L. The shifting of the van Hove singularity with the volume of the lattice is investigated. We observe a saddle point just at the Fermi level for a lattice constant of 14.435Å. The highest value of T$\text{}_{c}$ should thus be observed at the above lattice constant. This result is in excellent agreement with the observed high value of T$\text{}_{c}$ measured in C$\text{}_{60}$Rb$\text{}_{3}$ for a lattice constant of 14.435Å.
Źródło:
Acta Physica Polonica A; 2003, 103, 5; 477-482
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Compensation Models in Chlorine Doped CdTe Based on Positron Annihilation and Photoluminescence Spectroscopy
Autorzy:
Stadler, W.
Hofmann, D. M.
Meyer, B. K.
Krause-Rehberg, R.
Polity, A.
Abgarjan, Th.
Salk, M.
Benz, K. W.
Azoulay, M.
Powiązania:
https://bibliotekanauki.pl/articles/1934007.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Gs
78.70.Bj
78.55.Et
Opis:
In this investigation positron annihilation, photoluminescence and electron paramagnetic resonance techniques are employed to gain insight in the compensation of CdTe doped with the halogen Cl. We will demonstrate that the high resistivity of CdTe:Cl cannot be explained by the interaction between the shallow effective mass type donor Cl on Te site and the doping induced shallow acceptor complex, a Cd vacancy paired off with a nearest-neighbour Cl atom (A centre). From electron paramagnetic resonance investigations we conclude that the mid gap trap, often detected by electrical methods in CdTe, is not the isolated Cd vacancy.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 921-924
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Band Structure of Cubic HgS
Autorzy:
Guziewicz, E.
Kowalski, B.
Orłowski, B. A.
Dybko, K.
Witkowska, B.
Szuszkiewicz, W.
Powiązania:
https://bibliotekanauki.pl/articles/1873013.pdf
Data publikacji:
1995-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Fi
Opis:
Reflectivity spectra of Hg$\text{}_{1-x}$Fe$\text{}_{x}$S (x < 0.04) and HgSe$\text{}_{1-y}$S$\text{}_{y}$ (y < 0.5) mixed crystals were measured in the vacuum ultraviolet energy range from 4 to 12 eV. Information about the electronic band structure of cubic modification of HgS resulting from the above data is analyzed and discussed.
Źródło:
Acta Physica Polonica A; 1995, 87, 2; 395-398
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface Carburizing by Valorization of Organic Waste
Autorzy:
Boutessouna, B.
Allaoui, O.
Allaoui, L.
Powiązania:
https://bibliotekanauki.pl/articles/1031860.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.65.-b
89.60.-k
Opis:
The organic waste recycling problem remains an important economic issue for the industry, where much research is done in this area. In this study, we are interested in the enhancement of some organic waste from slaughterhouses (blood and horns) with two objectives: recycling wastes and producing cheap cement for surface carburizing. The waste is converted into coal and added to an activator to produce a solid medium, witch can be used for surface carburizing of carbon steels. Preparation of waste and physical and chemical carbonating of blood and horns resulted in production of coal, that was used as an effective carbon source for cementation treatment. Comparison of the obtained results with other works on carburizing treatment, using industrial solid mixtures, has shown that carburizing layers in both cases are very similar. Indeed, metallographic analysis, X-ray diffraction and Vickers hardness testing of obtained layers have led to results very similar to those in literature.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 1173-1175
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quasi Fermi Levels in Semiconductor Photovoltaic Heterojunction
Autorzy:
Orlowski, B.
Pieniazek, A.
Goscinski, K.
Kopalko, K.
Powiązania:
https://bibliotekanauki.pl/articles/1185195.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Lq
Opis:
The photovoltaic heterojunction elements are build of two different semiconductors of n and p type. Under cell illumination the same density of n and p carriers are created in each generation point but it leads to the remarkably higher increase of relative concentration for minority than for majority carriers. It is causing bigger energy change of the quasi Fermi level of minority than of majority carriers. The minority carriers decide of the value of generated photovoltage while the majority carriers contribution to it, in most cases can be neglected. Measured change of the generated open circuit photovoltage versus illumination light intensity allows to estimate corresponding to it increase of the minority carrier concentration. These allows as well to scan the part of the forbidden gap region by the minority carriers quasi Fermi level and in a case of impurity or defect levels located in forbidden gap it can influence on the continuous dependence of generated photovoltage versus light intensity e.g. for pinning of the Fermi level. To create efficient photovoltaic heterojunction it will need to study electronic properties of the used impurities and their proper distribution in the region of junction.
Źródło:
Acta Physica Polonica A; 2016, 129, 1a; A-100-A-102
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of Magnetic and Mössbauer Results Obtained for Palaeozoic Rocks of Hornsund, Southern Spitsbergen, Arctic
Autorzy:
Szlachta, K.
Michalski, K.
Brzózka, K.
Górka, B.
Gałązka-Friedman, J.
Powiązania:
https://bibliotekanauki.pl/articles/1811894.pdf
Data publikacji:
2008-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
91.25.F-
Opis:
This analysis was performed as a part of the palaeomagnetic project focused on the reconstruction of the palaeogeographic position of the Svalbard Archipelago and adjacent crustal units (European Arctic) in the Palaeozoic and Mesozoic. Three rock formations - Cambrian, Devonian and Carboniferous were sampled in the area of Hornsund, southern Spitsbergen. The main aim of the presented study is to identify ferromagnetic minerals (sensu lato) - the carriers of the natural remanent magnetisation in the investigated rocks. A wide range of magnetic methods were used: the Lowrie tests, unblocking temperatures determinations and the measurement of coercivity spectra as well as the Mössbauer studies. In Devonian and Carboniferous samples all applied methods indicate the domination of the hematite natural remanent magnetisation carrier. In Cambrian rocks magnetic measurements reveal a mixture of ferromagnetic (sensu lato) minerals with varying coercivities and unblocking temperatures. The Mössbauer data improve the identification, suggesting that in Cambrian rocks the carrier of the dominating natural remanent magnetisation component is maghemite.
Źródło:
Acta Physica Polonica A; 2008, 114, 6; 1675-1682
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron-Molecular Vibration Coupling in TTF-Based Donors
Autorzy:
Pokhodnia, K. I.
Powiązania:
https://bibliotekanauki.pl/articles/1933373.pdf
Data publikacji:
1995-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.70.-b
Opis:
BEDT-TTF, BMDT-TTF and BEDO-TTF are well known thio-TTF and oxo-TTF (in the former case) derivatives on the basis of which cation-radical salts with 2D type of conductivity can be produced. In this work the comparative analysis of electron-molecular vibration coupling constants (obtained by MNDO quantum-chemical method) that describe the interaction between totally symmetric A$\text{}_{g}$ modes and electron on HOMO level is performed.
Źródło:
Acta Physica Polonica A; 1995, 87, 4-5; 815-818
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Localization Effects in GaN/AlGaN Quantum Well - Photoluminescence Studies
Autorzy:
Chwalisz, B.
Wysmołek, A.
Bożek, R.
Korona, K. P.
Stępniewski, R.
Knap, W.
Pakuła, K.
Baranowski, J. M.
Grandjean, N.
Massies, J.
Prystawko, P.
Grzegory, I.
Powiązania:
https://bibliotekanauki.pl/articles/2036024.pdf
Data publikacji:
2003-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
73.20.-r
73.21.-b
74.40.+k
Opis:
Exciton localization in GaN/AlGaN quantum well structures is studied by photoluminescence. An anomalous temperature behavior of the photoluminescence from the quantum well is observed. With increasing temperature the energy position of the excitonic emission line first decreases up to 20 K, then increases, reaching a maximum around 90 K, and then decreases again in the higher temperature range. The observed behavior is discussed in terms of localization at the interface potential fluctuations. It is argued that the temperature activated migration and subsequent release of the excitons from traps that occurs between 20 K and 90 K are responsible for the observed S-like shape of the energy dependence. The obtained results allow a direct characterization of the energy fluctuations present in GaN/AlGaN quantum wells grown by different techniques.
Źródło:
Acta Physica Polonica A; 2003, 103, 6; 573-578
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reflectivity Study of HgSe$\text{}_{1-x}$Te$\text{}_{x}$ Crystals
Autorzy:
Kowalski, B. J.
Dybko, K.
Lemańska, A.
Orłowski, B. A.
Powiązania:
https://bibliotekanauki.pl/articles/1923860.pdf
Data publikacji:
1992-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Ci
Opis:
The room temperature reflectivity spectra of HgSe$\text{}_{1-x}$Te$\text{}_{x}$ (x = 0, 0.4, 0.5, 1.0) crystals were measured in the visible and ultraviolet range from 1.5 to 12 eV. The maxima characteristic of the binary HgA$\text{}^{IV}$ compounds can be revealed in the mixed crystals spectra, but their position depends on the crystal composition. There is no duplication of the spectral features in spite of the different energy position of the maxima for HgSe and HgTe. This suggests that the virtual crystal approximation could be used to describe basic optical properties of HgSe$\text{}_{1-x}$Te$\text{}_{x}$.
Źródło:
Acta Physica Polonica A; 1992, 82, 5; 845-848
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface Property of Indium Tin Oxide (ITO) After Various Methods of Cleaning
Autorzy:
Kim, K.
Ihm, K.
Kim, B.
Powiązania:
https://bibliotekanauki.pl/articles/1401317.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.-r
Opis:
We investigated the surface property change of indium tin oxide (ITO) with the various cleaning methods, using photoemission spectroscopy (PES), work function change and near-edge X-ray adsorption fine structure (NEXAFS). The detergent treatments of ITO with acetone (C₃H₆O), methanol (CH₄O), 2-propanol (C₃H₈O), and deionized (D) water yielded work function shifts as high as 0.99 eV compared to the no-treatment ITO. In contrast, work function shifts of 0.10-0.35 eV were measured after other treatments. The lowest C 1s concentration was obtained after O2 plasma treatment of ITO. There was no big change in the peak position and the shape of $In 3d^{5//2}$, and $Sn 3d^{5//2}$ after each treatment. But C 1s and O 1s spectra shows a peak shift and shape change. Presence of carbon can be minimized by NaOH treatment combined with oxygen plasma. In NEXAFS spectra of C K-edge on each sample, we found two π-binding states whose positions are 284.5 and 287.9 eV, C=C and C=O, respectively.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 1176-1179
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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