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Wyszukujesz frazę "CuO" wg kryterium: Wszystkie pola


Tytuł:
Hopping Conduction Mechanism in Amorphous CuO-Bi$\text{}_{2}$O$\text{}_{3}$ Pellets
Autorzy:
Motke, S. G.
Burghate, D. K.
Gawande, W. J.
Pakade, S. V.
Yawale, S. P.
Powiązania:
https://bibliotekanauki.pl/articles/1931822.pdf
Data publikacji:
1994-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Ng
72.90.+y
Opis:
The transport properties of CuO-Bi$\text{}_{2}$O$\text{}_{3}$ pellets (pressed at room temperature 303 K) like dc electrical conductivity etc. are measured. The activation energy, dielectric constant etc. are reported. The hopping conduction is examined. Non-adiabatic hopping conduction is observed. The plot of -log σ versus 1/T is found to be linear. Activation energy of pellets containing CuO (80, 70, 60 mol%) shows electronic conduction while the pellet containing CuO (50 mol%) shows ionic conduction. The effect of content of CuO (mol%) and frequency on dielectric constant is also studied. The variation of dielectric constant with CuO (mol%) shows zigzag nature and may be due to the relaxation effects.
Źródło:
Acta Physica Polonica A; 1994, 86, 6; 969-978
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some Electronic Properties of Sr$\text{}_{1-x}$A$\text{}_{x}$CuO$\text{}_{2+δ}$ where A=La, K, and Ca
Autorzy:
Onyszkiewicz, I.
Czarnecki, P.
Poltoracky, Yu. B.
Zimpel, M.
Powiązania:
https://bibliotekanauki.pl/articles/1929860.pdf
Data publikacji:
1994-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.30.+h
72.15.-v
76.30.Fc
Opis:
The electronic properties of Sr$\text{}_{1-x}$A$\text{}_{x}$CuO$\text{}_{2+δ}$ (A = La, K, Ca) were examined. The crystal structure of the synthesized compounds was identified as orthorhombic with some admixture of tetragonal phase. For Sr$\text{}_{1-x}$La$\text{}_{x}$CuO$\text{}_{2+δ}$ the insulator-metal like transition was observed with increasing La content. The d$\text{}_{x²-y²}$ ground state of Cu ions was deduced from electron spin resonance measurements. The electronic state of Cu ions and their surrounding local symmetry was also found to be La and oxygen content dependent.
Źródło:
Acta Physica Polonica A; 1994, 85, 2; 303-306
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Epitaxially Induced Defects in Sr- and O-doped La$\text{}_{2}$CuO$\text{}_{4}$ Thin Films Grown by MBE: Implications for Transport Properties
Autorzy:
Locquet, J.-P
Williams, E. J.
Powiązania:
https://bibliotekanauki.pl/articles/1964235.pdf
Data publikacji:
1997-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Nn
74.62.Fj
81.15.Hi
74.72.Dn
Opis:
In this paper, the critical role played by various types of defects and strain relaxation mechanisms in high-T$\text{}_{c}$ thin films is highlighted and illustrated with examples. The defects are essential for providing adequate diffusion channels for oxygen ingress during the cooling step in c-axis thin films. The operation of strain relaxation mechanisms necessitated by the lattice mismatch between film and substrate can impose a compressive or tensile biaxial pressure, which either increases or reduces the critical temperature.
Źródło:
Acta Physica Polonica A; 1997, 92, 1; 69-84
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Susceptibility of Sr$\text{}_{2}$CuO$\text{}_{3}$ and SrCu$\text{}_{2}$O$\text{}_{3}$
Autorzy:
Johnston, D. C.
Powiązania:
https://bibliotekanauki.pl/articles/1953177.pdf
Data publikacji:
1997-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.72.Jt
74.25.Ha
75.40.Cx
Opis:
The observed magnetic susceptibility χ$\text{}^{obs}$(T) data of Ami et al. for the linear-chain cuprate Sr$\text{}_{2}$CuO$\text{}_{3}$ are re-analyzed in terms of recent theory of Eggert et al. for the spin susceptibility χ(T) of the spin S=1/2 linear-chain Heisenberg antiferromagnet, which yielded the Cu-Cu exchange constant J/k$\text{}_{B}$=2150 K. Values for J', the exchange constant in the rungs, and J, that in the legs, were estimated for the S=1/2 two-leg ladder compound SrCu$\text{}_{2}$O$\text{}_{3}$, using the χ(T) data of Azuma et al. The analyses suggest that J'/J ≈ 0.5, contrary to the expectation that J'/J ≈ 1, and that J/k$\text{}_{B}$ is very large ( ≈ 2000 K), similar to that in Sr$\text{}_{2}$CuO$\text{}_{3}$.
Źródło:
Acta Physica Polonica A; 1997, 91, 1; 181-189
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mixed Valence Quasiparticles in CuO$\text{}_{2}$ Planes
Autorzy:
Bała, J.
Oleś, A. M.
Powiązania:
https://bibliotekanauki.pl/articles/1955491.pdf
Data publikacji:
1997-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.25.Jb
75.30.Ds
75.10.Lp
Opis:
The motion of a single hole doped to a CuO$\text{}_{2}$ plane of a high temperature superconductor is described by a spin-fermion model which treats explicitly the hybridization with the upper Hubbard band. One finds that sectors of Zhang-Rice bound states coexist with reasonably damped oxygen and copper-like quasiparticles, with a considerable transfer of the spectral weight to the upper Hubbard band. The oxygen states have small dispersions and can be identified in the angle-resolved photoemission experiments for Bi$\text{}_{2}$Sr$\text{}_{2}$CaCu$\text{}_{2}$O$\text{}_{8}$.
Źródło:
Acta Physica Polonica A; 1997, 91, 2; 333-336
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
STM/AFM Images and Tunneling Spectra of Nd$\text{}_{2-x}$Ce$\text{}_{x}$CuO$\text{}_{4-y}$ Single Crystals
Autorzy:
Susła, B.
Sadowski, W.
Klimczuk, T.
Czajka, R.
Powiązania:
https://bibliotekanauki.pl/articles/1964375.pdf
Data publikacji:
1997-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.16.Ch
74.72.Jt
68.35.Bs
Opis:
The results of the scanning tunneling microscopy and spectroscopy as well as atomic force microscopy measurements on the Nd$\text{}_{2-x}$Ce$\text{}_{x}$CuO$\text{}_{4-y}$ single crystals in ambient conditions are reported. Using the scanning tunneling microscopy we were able to modify the Nd$\text{}_{2-x}$Ce$\text{}_{x}$CuO$\text{}_{4-y}$ ab-plane in air under the conditions of sample bias voltage V$\text{}_{t}$=500 mV and set current I$\text{}_{s}$=0.3 nA. It is possible to prepare atomically flat and clean surfaces as well as to create new structures in a nanometer scale in these electron-doped materials. The similar processes were not observed during atomic force microscopy imaging.
Źródło:
Acta Physica Polonica A; 1997, 92, 1; 209-214
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Spin-Ladders (A$\text{}_{2}$Cu$\text{}_{2}$O$\text{}_{3}$)$\text{}_{m}$ (CuO$\text{}_{2}$)$\text{}_{n}$
Autorzy:
Baran, M.
Szymczak, H.
Szymczak, R.
Dyeyev, S.
Leonyuk, L.
Babonas, G.-J.
Powiązania:
https://bibliotekanauki.pl/articles/2013220.pdf
Data publikacji:
2000-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.40.Cx
75.30.Gw
75.45.+j
75.90.+w
Opis:
Magnetization M(T) and M(H) data of single crystals of the S=1/2 quasi-one-dimensional system (A$\text{}_{2}$Cu$\text{}_{2}$O$\text{}_{3}$)$\text{}_{m}$(CuO$\text{}_{2}$)$\text{}_{n}$ with various A-site constituents are compared. The studied orthorhombic, incommensurate crystals are characterized by m/n=5/7,7/10, and 9/13. The role of rare-earth ions located in A-sites is discussed.
Źródło:
Acta Physica Polonica A; 2000, 97, 3; 571-574
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
XPS Study of "infinite Chain" Ca$\text{}_{2}$CuO$\text{}_{3}$ and Ca$\text{}_{0.5}$Sr$\text{}_{0.5}$CuO$\text{}_{2}$ Compounds
Autorzy:
Jacyna-Onyszkiewicz, I.
Poltoracky, Yu. B.
Powiązania:
https://bibliotekanauki.pl/articles/2013234.pdf
Data publikacji:
2000-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.-i
74.72.-h
74.72.Jt
Opis:
Al K$\text{}_{α}$ excited photoelectron spectra (X-ray photoelectron spectroscopy) of the O 1s, Cu 2p, Ca 2p, Sr 3d core levels were measured for "infinite chain" Ca$\text{}_{2}$CuO$\text{}_{3}$ and Ca$\text{}_{0.5}$Sr$\text{}_{0.5}$CuO$\text{}_{2}$ compounds. The analysis indicates that for Ca$\text{}_{2}$CuO$\text{}_{3}$ the surface electronic structure is strongly influenced by a humid atmosphere. The surface layer is formed predominantly by copper hydroxide. The minor features of Cu 2p and O 1s are characteristic of the bulk bonding states. The valences of the Cu, Ca, and Sr atoms are close to 2+. The core electron binding energies (≈ 934 eV peak) are due to the 2p$\text{}_{3}\text{}_{/}\text{}_{2}$ 3d$\text{}^{10}$L$\text{}^{1}$ configuration of Cu(II) ions in the square planar coordination for both samples.
Źródło:
Acta Physica Polonica A; 2000, 97, 3; 603-606
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical Properties of (M$\text{}_{2}$Cu$\text{}_{2}$O$\text{}_{3}$)$\text{}_{m}$(CuO$\text{}_{2}$)$\text{}_{n}$ (M = Ca, Sr, Bi) Single Crystals with Bi-2212 Phase on their Surface
Autorzy:
Babonas, G.-J.
Leonyuk, L.
Maltsev, V.
Szymczak, R.
Reza, A.
Baran, M.
Dapkus, L.
Powiązania:
https://bibliotekanauki.pl/articles/2028903.pdf
Data publikacji:
2001-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.-w
74.72.Jt
74.76.Bz
Opis:
The structural, optical, and magnetic properties are studied in the (M$\text{}_{2}$Cu$\text{}_{2}$O$\text{}_{3}$)$\text{}_{m}$(CuO$\text{}_{2}$)$\text{}_{n}$-type single crystals with the surface on which the Bi-2212-type phase was indicated. The physical properties of such samples were interpreted to some extent by the contributions of two phases. When the secondary phases on the surface of the samples were removed by mechanical polishing or etching by Ar$\text{}^{+}$-ion plasma, the physical properties were typical of the (M$\text{}_{2}$Cu$\text{}_{2}$O$\text{}_{3}$)$\text{}_{m}$(CuO$\text{}_{2}$)$\text{}_{n}$-type crystals. The optical method was shown to be effective for indication of secondary Bi-rich phases on the surface of (M$\text{}_{2}$Cu$\text{}_{2}$O$\text{}_{3}$)$\text{}_{m}$(CuO$\text{}_{2}$)$\text{}_{n}$ samples.
Źródło:
Acta Physica Polonica A; 2001, 100, 4; 553-563
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Copper Deficiency - a Crystallochemical Nature of Ce-Doped Gd$\text{}_{2}$CuO$\text{}_{4}$ Phase. Part II
Autorzy:
Horyń, R.
Bukowska, E.
Sikora, A.
Wołcyrz, M.
Powiązania:
https://bibliotekanauki.pl/articles/2041471.pdf
Data publikacji:
2004-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.75.+g
81.40.Rs
75.50.-y
72.20.My
Opis:
Two samples of nominal composition Gd$\text{}_{1.80}$Ce$\text{}_{0.15}$CuO$\text{}_{4.0}$ and Gd$\text{}_{1.85}$Ce$\text{}_{0.15}$CuO$\text{}_{4.075}$ were subjected for a long-term treatment in air at 1100°C, comprised with a precise control of their weights vs. time of the treatment applied. The gravimetric analysis and the iodometric titration, both showed a deficiency on Cu-site, steadily increasing vs. time with a slight tendency to a saturation. The X-ray analysis of the resulting products showed that even after 272 h of sintering, the samples remained single phase of the "214" structure type. Refinement of their crystal structures as well as density measurements, both allowed confirming Cu deficient structure constitution of these samples. Results of dc-magnetization measurements, performed prior to reduction of the sample's overall oxygen content, did not show any sign of superconductivity down to 4.2 K. These preliminary results indicate that copper deficiency, developing during synthesis, may occur to be a decisive factor for the reported lack of superconductivity in Ce-doped Gd$\text{}_{2}$CuO$\text{}_{4}$ phase. Oxygen content reduction and further tests on the samples obtained are in progress.
Źródło:
Acta Physica Polonica A; 2004, 106, 5; 733-738
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Relations in Gd$\text{}_{2}$O$\text{}_{3}$-CeO$\text{}_{2}$-CuO System at 980°C. Part I
Autorzy:
Horyń, R.
Sikora, A.
Bukowska, E.
Powiązania:
https://bibliotekanauki.pl/articles/2041467.pdf
Data publikacji:
2004-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.75.+g
81.40.Rs
75.50.-y
72.20.My
Opis:
Phase equilibria in Gd$\text{}_{2}$O$\text{}_{3}$-CeO$\text{}_{2}$-CuO system were studied based on samples obtained from appropriate mixtures of the starting components, prepared by a conventional solid state reaction in air. The phase relations prevalent in this system have been deduced based on X-ray diffraction of well-equilibrated samples. An isothermal cross-section diagram through the system at 980°C is presented and chemical constitution of the Ce-doped Gd$\text{}_{2}$CuO$\text{}_{4}$ phase is proposed.
Źródło:
Acta Physica Polonica A; 2004, 106, 5; 727-731
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Negative Magnetoresistance in the Variable-Range-Hopping Transport of Strongly Underdoped La$\text{}_{2-x}$Sr$\text{}_{x}$CuO$\text{}_{4}$
Autorzy:
Malinowski, A.
Cieplak, M. Z.
Berkowski, M.
Guha, S.
Powiązania:
https://bibliotekanauki.pl/articles/2046779.pdf
Data publikacji:
2006-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.72.-h
74.25.Fy
73.43.Qt
Opis:
The in-plane transport of strongly underdoped La$\text{}_{2-x}$Sr$\text{}_{x}$CuO$\text{}_{4}$ films was examined in the magnetic fields up to 14 T and in temperatures down to 1.6 K. While at high temperatures the samples display metallic-like resistivity, the low-T transport is governed by variable-range-hopping mechanism. Careful analysis shows that the temperature dependence of pre-exponential factor in Mott's variable-range-hopping law may not be neglected and that the density of states at the Fermi level can be effectively expressed as g(E-E$\text{}_{F}$)=N$\text{}_{0}$ (E-E$\text{}_{F}$)$\text{}^{p}$, with a small exponent p of the order of 0.1. In the magnetic field parallel to CuO$\text{}_{2}$ planes one of the variable-range-hopping parameter,ρ$\text{}_{0}$, increases by about 20-25%, while the other one, T$\text{}_{0}$, decreases by about 10-15%, resulting in the decrease in total resistivity. This effect may be related to the decrease of the tunneling barrier between different antiferromagnetic clusters in the presence of magnetic field.
Źródło:
Acta Physica Polonica A; 2006, 109, 4-5; 611-615
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anharmonicity and Weak Mode Assignment in La$\text{}_{2-x}$Sr$\text{}_{x}$CuO$\text{}_{4}$, with Oxygen Isotopic Substitution
Autorzy:
Siranidi, E.
Lampakis, D.
Palles, D.
Liarokapis, E.
Conder, K.
Powiązania:
https://bibliotekanauki.pl/articles/2047249.pdf
Data publikacji:
2007-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.30.-j
31.30.Gs
74.25.Kc
74.72.Dn
Opis:
The oxygen isotope effect on the first- and second-order Raman active modes of high-quality La$\text{}_{2-x}$Sr$\text{}_{x}$Cu$\text{}^{16,18}$O$\text{}_{4}$ (80% substitution $\text{}^{16}$O by $\text{}^{18}$O) polycrystalline compounds with x=0.00, 0.015 was investigated at low temperatures. In the second-order Raman scattering several weak and strong peaks were observed and assigned to oxygen atom vibrations. With the isotopic substitution the apex oxygen mode follows quite well the mass harmonic law at all temperatures studied, while the soft mode is anharmonic in the temperature range of 77-180 K and for higher temperatures its anharmonicity is strongly increased. The temperature dependence of the energy of the soft mode for x=0.0 shows also a modification at≈180 K and an abnormal behaviour at≈280 K, which may be related with the transition to the antiferromagnetic phase.
Źródło:
Acta Physica Polonica A; 2007, 111, 1; 173-177
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EPR Study of Water Induced Decomposition of the SrCuO$\text{}_{2}$ and Sr$\text{}_{2}$CuO$\text{}_{3}$ Ceramics Surface. The Role of Carbon Dioxide
Autorzy:
Augustyniak-Jabłokow, M. A.
Yablokov, Yu. V.
Jacyna-Onyszkiewicz, I.
Ivanova, T. A.
Shustov, V. A.
Powiązania:
https://bibliotekanauki.pl/articles/2047737.pdf
Data publikacji:
2007-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Ee
76.30.Fc
81.05.Je
Opis:
Processes of SrCuO$\text{}_{2}$ and Sr$\text{}_{2}$CuO$\text{}_{3}$ ceramics decomposition induced by contact with water and carbon dioxide were studied by EPR. The dominant signals in the spectra were found to originate from Sr$\text{}_{2}$Cu(OH)$\text{}_{6}$ (for Sr$\text{}_{2}$CuO$\text{}_{3}$) and SrCu(OH)$\text{}_{4}$·H$\text{}_{2}$O (for SrCuO$\text{}_{2}$) compounds. The thermally induced conversion of SrCu(OH)$\text{}_{4}$·H$\text{}_{2}$O into Sr$\text{}_{2}$Cu(OH)$\text{}_{6}$ was analysed, and its product CuO was found to exist in the nanocrystalline form. The presence of CO$\text{}_{2}$, reacting with Sr(OH)$\text{}_{2}$, was shown to modify the decomposition process leading to the appearance of SrCu(OH)$\text{}_{4}$·H$\text{}_{2}$O, some hydroxycarbonates and Cu(OH)$\text{}_{2}$ on the surface of ceramics studied. At temperatures higher than 300ºC CuO reacts back with Sr(OH)$\text{}_{2}$. For the samples being in contact with atmospheric moisture this compound, deposited on a surface of SrCuO$\text{}_{2}$, decomposes to Sr$\text{}_{2}$Cu(OH)$\text{}_{6}$. The presence of the antiferromagnetic compounds Cu(OH)$\text{}_{2}$, CuO, and Cu$\text{}_{2}$[(OH)$\text{}_{2}$CO$\text{}_{3}$] in the samples can influence the results of magnetic measurements of the studied ceramics.
Źródło:
Acta Physica Polonica A; 2007, 112, 3; 525-536
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strain Relaxation in Thin Films of La$\text{}_{1.85}$Sr$\text{}_{0.15}$CuO$\text{}_{4}$ Grown by Pulsed Laser Deposition
Autorzy:
Zaytseva, I.
Cieplak, M. Z.
Abal'oshev, A.
Berkowski, M.
Domukhovski, V.
Paszkowicz, W.
Shalimov, A.
Powiązania:
https://bibliotekanauki.pl/articles/2047252.pdf
Data publikacji:
2007-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.55.-a
74.62.-c
74.72.Dn
74.78.Bz
74.25.Fy
Opis:
X-ray diffraction, resistivity, and susceptibility measurements are used to examine the effects of film thickness d (from 17 to 250 nm) on the structural and superconducting properties of La$\text{}_{1.85}$Sr$\text{}_{0.15}$CuO$\text{}_{4}$ films grown by pulsed laser deposition on SrLaAlO$\text{}_{4}$ substrates. For each d the film sgrow with a variable strain, ranging from a large compressive strain in the thinnest films to a negligible or tensile strain in thick films. Our results indicate that the tensile strain is not caused by the off-stoichiometric layer at the substrate-film interface. Instead, it may be caused by the extreme oxygen deficiency in some of the films.
Źródło:
Acta Physica Polonica A; 2007, 111, 1; 185-188
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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