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Wyszukujesz frazę "metal-insulator" wg kryterium: Wszystkie pola


Tytuł:
Correlation-Driven Metal-Insulator Transitions
Autorzy:
Honig, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/2011236.pdf
Data publikacji:
2000-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.30.+h
71.45.Gm
Opis:
The effect of correlation-driven electronic transitions are described for the V$\text{}_{2}$O$\text{}_{3}$, NiS$\text{}_{2-x}$Se$\text{}_{x}$, and Fe$\text{}_{3}$O$\text{}_{4}$ systems. The various tranformations can all be rationalized in terms of elementary concepts pertaining to the Mott-Hubbard intraatomic electronic interactions or in terms of an order-disorder formalism involving Coulomb interactions among electrons on adjacent sites. Attention is directed to some outstanding issues that require further resolution.
Źródło:
Acta Physica Polonica A; 2000, 97, 1; 141-156
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metal-Insulator Transition in Doped Semiconductors
Autorzy:
Jaroszyński, J.
Powiązania:
https://bibliotekanauki.pl/articles/1888088.pdf
Data publikacji:
1991-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.30.+h
Opis:
A survey is given of different kinds of metal-insulator transitions (MIT) in doped semiconductors. The role of electron-electron Coulomb interactions and of disorder is discussed vis-a-vis millikelvin experimental results for semimagnetic semiconductors (SMSC) in the vicinity of MIT. Critical behavior of conductivity tensor components and dielectric susceptibility at the magnetic field-induced MIT in p-type Hg$\text{}_{1-x}$Mn$\text{}_{x}$Te is compatible with the model in which the MIT is a result of quantum localization driven by disorder-modified electron-electron interactions. At the same time the critical behavior of the Hall coefficient suggests that, in addition to electrons forming the Fermi liquid (FL) and undergoing localization at the MIT, there is certain a concentration of local electron moments, even on the metallic side of the MIT. The formation of these moments can presumably be described in terms of a disordered Hubbard-Mott model.
Źródło:
Acta Physica Polonica A; 1991, 80, 2; 255-265
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metal-Insulator Transition in Zinc-Doped LaSrCuO
Autorzy:
Malinowski, A.
Cieplak, M. Z.
Berkowski, M.
Plesiewicz, W.
Skośkiewicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/2046782.pdf
Data publikacji:
2006-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.72.-h
71.30.+h
74.25.Fy
Opis:
The magnetotransport in the vicinity of the metal-insulator transition in La$\text{}_{1.85}$Sr$\text{}_{0.15}$Cu$\text{}_{x}$Zn$\text{}_{1-x}$O$\text{}_{4}$ is studied in the mK temperature range. Both longitudinal and transverse magnetoresistance are negative indicating the importance of spin effects. The magnitude of transverse magnetoresistance is larger than the magnitude of longitudinal magnetoresistance, indicating the absence of positive orbital magnetoresistance, in sharp contrast to strongly underdoped La$\text{}_{2-x}$Sr$\text{}_{x}$CuO$\text{}_{4}$. Both transverse and longitudinal magnetoresistance are proportional to the relative change of zero-field conductivity. This suggests that low-temperature localization of carriers may originate in the spin-disorder scattering on the spin droplets around Zn-impurities.
Źródło:
Acta Physica Polonica A; 2006, 109, 4-5; 617-621
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Critical Exponents for Metal-Insulator Transition in Two-Dimensional Systems
Autorzy:
Wojtkiewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/1808033.pdf
Data publikacji:
2009-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.30.+h
71.10.Fd
02.40.Xx
Opis:
Three years ago, a new universality class, associated with the metal-insulator transition in quasi-two-dimensional compounds, was discovered. Imada has given explanation of the observed critical behaviour. Considerations in this work are based on the assumption that the one-particle dispersion is quartic one instead of the standard quadratic behaviour. In this paper, it is shown that other possible natural non-standard dispersions lead to other possible critical behaviour and critical exponents.
Źródło:
Acta Physica Polonica A; 2009, 115, 5; 931-934
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ferromagnetism and Metal-Insulator Transitions in Correlated Electron Systems with Alloy Disorder
Autorzy:
Byczuk, K.
Yu, U.
Hofstetter, W.
Vollhardt, D.
Powiązania:
https://bibliotekanauki.pl/articles/1810278.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.23.-k
75.20.Hr
75.30.Mb
Opis:
Alloy disorder can affect ferromagnetism and metal-insulator transitions of correlated lattice fermion systems in subtle and often unexpected ways. Solving the Hubbard model and the periodic Anderson model within dynamical mean-field theory we show that alloy disorder can increase the Curie temperature of a non-disordered system, and also yields novel Mott or Kondo insulators at fractional electronic densities.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 7-12
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Diagram of Metal-Insulator Transition in System with Anderson-Hubbard Centers
Autorzy:
Skorenkyy, Yu.
Didukh, L.
Kramar, O.
Dovhopyaty, Yu.
Powiązania:
https://bibliotekanauki.pl/articles/1418528.pdf
Data publikacji:
2012-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Lp
71.30.+h
Opis:
The model of a strongly correlated system in which periodically spaced Anderson-Hubbard centers are introduced into narrow-band metal is considered. Besides the interactions between localized magnetic moments and strong on-site Coulomb interaction, the model takes into account the hybridization of localized and band states. To study the effect of the lattice deformation on the electrical properties of the system, the phonon term and elastic energy have been taken into account. Green functions for band and localized electrons have been found. On this base, the energy spectrum has been investigated as a function of model parameters, temperature and external pressure. The criterion of the metal-insulator transition for an integer value of electron concentration has been derived and the phase diagram of the metal-insulator transition has been built.
Źródło:
Acta Physica Polonica A; 2012, 122, 3; 532-534
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reentrant Metal-Insulator Transition in $Ca_{1-x}Eu_{x}B_{6}$
Autorzy:
Glushkov, V.
Anisimov, M.
Baybakov, R.
Demishev, S.
Filippov, V.
Flachbart, K.
Kuznetsov, A.
Shitsevalova, N.
Sluchanko, N.
Powiązania:
https://bibliotekanauki.pl/articles/1369362.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.30.+h
72.15.Gd
75.47.Gk
Opis:
Resistivity, Hall and Seebeck effects have been studied on single crystals of $Ca_{1-x}Eu_{x}B_{6}$ (0 ≤ x ≤ 1) at temperatures 2-300 K and in magnetic fields up to 8 T. An insulating ground state is found to be limited by narrow range of Eu doping 0.6 ≤ x ≤ 0.8. This region is characterized by an enhanced colossal magnetoresistance (CMR), which reaches values of ρ(0)/ρ(7T) > $10^{6}$ for x = 0.63 at T < 10 K. Decreasing of Eu content in $Ca_{1-x}Eu_{x}B_{6}$ below x* ≈ 0.6 restores the metallic ground state with moderate resistivity (ρ ~ 1 ÷ 5 mΩ·cm) and CMR amplitude (ρ(0)/ρ(7T) < 7). The second metal-insulator transition (MIT) in $Ca_{1-x}Eu_{x}B_{6}$ is observed beyond the whole conductivity region found earlier in the narrow range of Eu doping (0.7 ≤ x ≤ 0.8). The correlation between the enhanced CMR amplitude, the onset of positive diffusive thermopower and the elevation of anomalous Hall effect, determined for Eu content 0.6 ≤ x ≤ 0.85, favors the idea that a smooth change of band structure is the main factor governing the reentrant MIT in $Ca_{1-x}Eu_{x}B_{6}$.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 294-295
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum Model for Metal-Insulator Transition in Amorphous Gd_{x}Si_{1-x}
Autorzy:
Paja, A.
Ornat, M.
Powiązania:
https://bibliotekanauki.pl/articles/1399304.pdf
Data publikacji:
2013-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.15.Cz
72.15.Lh
72.15.Rn
Opis:
The model for experimentally observed metal-insulator transition induced by magnetic field in amorphous $Gd_{x}Si_{1 - x}$ is presented. The method of calculation is based on the previously created model for amorphous alloys now developed to include magnetic field effects. The model is based on the quantum "2 $k_{F}$" scattering model theory where the pseudopotentials are replaced by the scattering matrix operators and the Fermi energy is properly determined by the accurate values of the phase shifts. The results agree very well with experimental data.
Źródło:
Acta Physica Polonica A; 2013, 124, 4; 717-719
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Matrix onto Oxidation of Metallic Nanoparticles in Metal-Insulator Nanocomposite Films
Autorzy:
Fedotova, J.
Powiązania:
https://bibliotekanauki.pl/articles/1381794.pdf
Data publikacji:
2014-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Gk
73.40.Rw
73.63.Bd
62.23.Pq
68.37.Lp
68.37.Og
Opis:
Paper reports the results of X-ray diffraction, X-ray absorption spectroscopy and the Mössbauer spectroscopy of metal-insulator films sintered in Ar+O atmosphere evidencing the difference in oxidation of FeCoZr nanoparticles embedded into $Al_2O_3$ and $Pb(ZrTi)O_3$ matrixes. It is proved that $Al_2O_3$ matrix with high resistance to oxidation favors the formation of nanoparticles with "metal core-oxide shell" structure, while fully oxidized nanoparticles are observed inside $Pb(ZrTi)O_3$ matrix.
Źródło:
Acta Physica Polonica A; 2014, 125, 6; 1418-1420
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tailored Magnetic and Electric States in 3d-Metal-Insulator Films: Characterization and Applications
Autorzy:
Fedotova, J.
Powiązania:
https://bibliotekanauki.pl/articles/1197852.pdf
Data publikacji:
2014-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Gk
73.40.Rw
73.63.Bd
62.23.Pq
68.37.Lp
68.37.Og
Opis:
Progress in designing of new low-cost magnetoelectronic planar devices requires new artificial films combining tuneable magnetic and electric properties. In this context, metal-insulator films are prospective for synthesis of materials with tailored physical properties that could be controlled with films composition and synthesis regimes. Present overview covers the summary of recent experimental results on complimentary and systematic study of macroscopic and local magnetic properties of films using vibrating sample magnetometer and Mössbauer spectroscopy with respect to phase composition and structural analysis at nanoscale by X-ray absorption spectroscopy in the extended X-ray absorption fine structure range, transmission electron microscopy and high-resolution transmission electron microscopy. Specific relationship between films structure and resulting magnetic properties (SP relaxation, core-shell exchange interaction, perpendicular magnetic anisotropy) is considered. Effects of magnetic and electric percolation in films are discussed in correlation with synthesis regimes (atmosphere of deposition, temperature of the substrate) and films composition. Physical mechanisms and models describing magnetic and electric properties of composite films are analyzed. Finally, technological approaches are proposed for tuning films properties towards their desired combination with respect to application in designing of sensors and planar (non-coil) inductive elements.
Źródło:
Acta Physica Polonica A; 2014, 125, 4; 944-952
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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