Autor: Plesiewicz, W. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Conductivity Near the Metal-to-Insulator Transition in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Se:Sc
Autorzy:: Głód, P.
Sawicki, M.
Lenard, A.
Dietl, T.
Plesiewicz, W.
Tematy:: 71.30.+h
71.55.Jv; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1887158.pdf Link otwiera się w nowym oknie
Opis:: Earlier studies of transition metal impurities in II-VI compounds suggest that Sc acts as a resonant donor. We performed Hall effect and conductivity measurements of CdSe:Sc and Cd$\text{}_{0.95}$Mn$\text{}_{0.05}$Se:Sc. The results, particularly the critical concentration of the metal-to-insulator transition, turned out to be similar to those obtained previously for Cd$\text{}_{1-x}$Mn$\text{}_{x}$Se doped with hydrogenic-like impurities, such as In and Ga. Therefore, if the ground state of Sc impurity is indeed located above the bottom of the conduction band, our data demonstrate that the metal-to-insulator transition is primarily driven by the scattering, i.e. it corresponds to the Anderson localization.
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 2.

Tytuł:: Metal-Insulator Transition in Zinc-Doped LaSrCuO
Autorzy:: Malinowski, A.
Cieplak, M. Z.
Berkowski, M.
Plesiewicz, W.
Skośkiewicz, T.
Tematy:: 74.72.-h
71.30.+h
74.25.Fy; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2046782.pdf Link otwiera się w nowym oknie
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.
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 3.

Tytuł:: Influence of Bound Magnetic Polarons on Magnetic and Electrical Properties in Metallic n-Cd$\text{}_{0.95}$Mn$\text{}_{0.05}$Se
Autorzy:: Głód, P.
Sawicki, M.
Dietl, T.
Skośkiewicz, T.
Lenard, A.
Plesiewicz, W.
Tematy:: 71.30.+h
71.38.+i
75.20.Hr; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1931936.pdf Link otwiera się w nowym oknie
Opis:: Doping-induced contribution to the millikelvin magnetic susceptibility of Cd$\text{}_{0.95}$Mn$\text{}_{0.05}$Se:In has been found to undergo a maximum at n ≈ 2n$\text{}_{c}$, and to vanish for n ≥ 8n$\text{}_{c}$, where n$\text{}_{c}$ is the electron concentration corresponding to the metal-insulator transition. This confirms the presence, also in the metallic phase, of bound magnetic polarons. Their slow dynamics may account for hysteresis visible in our magnetoresistance data.
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 4.

Tytuł:: Magnetoresistance of Si/Nb/Si Trilayers
Autorzy:: Zaytseva, I.
Cieplak, M.
Abal'oshev, A.
Dluzewski, P.
Grabecki, G.
Plesiewicz, W.
Zhu, L.
Chien, C.
Tematy:: 74.62.-c
74.25.F-
74.25.Ha
74.62.En; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1537220.pdf Link otwiera się w nowym oknie
Opis:: We study the superconductor-insulator transition in Si/Nb/Si trilayers, in which the thickness of Si is fixed at 10 nm, and the nominal thickness of Nb changes in the range between d = 20 nm down to d = 0.3 nm. The transmission electron microscopy indicates the formation of the mixed Nb-Si layer for small d. Both the thickness-induced, and the magnetic-field induced superconductor-insulator transition is observed. The crossing point of the isotherms at the critical field $B_{c}$ decreases with decreasing d, and it is T-independent at temperatures below 300 mK. At larger fields the weak peak in magnetoresistance appears in some of the films.
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 5.

Tytuł:: Conductance Fluctuations in Microstructures of HgCdMnTe Bicrystals
Autorzy:: Grabecki, G.
Lenard, A.
Plesiewicz, W.
Jaroszyński, J.
Cieplak, Marek
Skośkiewicz, T.
Dietl, T.
Kamińska, E.
Piotrowska, A.
Bulka, B.
Tematy:: 73.40.Lq; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1890700.pdf Link otwiera się w nowym oknie
Opis:: Microscopic four-contact probes to semimagnetic HgCdMnTe grain-boundary inversion layers have been photolithographically patterned. Magnetoresistance measurements performed on these samples revealed aperiodic conductance fluctuations of the magnitude of the order of e$\text{}^{2}$/h. Quantitative analysis of both fluctuation amplitude and their mean period indicate that we have approached the mesoscopic regime in our system. This opens new possibilities in studies of spin-subsystem dynamics in semimagnetic semiconductors.
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 6.

Tytuł:: Mesoscopic Phenomena in Microstructures of IV-VI Epilayers
Autorzy:: Grabecki, G.
Dietl, T.
Plesiewicz, W.
Lenard, A.
Skośkiewicz, T.
Kamińska, E.
Piotrowska, A.
Papis, E.
Frank, N.
Bauer, G.
Tematy:: 71.55.Jv; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1877113.pdf Link otwiera się w nowym oknie
Opis:: Magnetoresistance measurements of photolithographically patterned PbSe and Pb$\text{}_{1-y}$Mn$\text{}_{x}$Se microstructures were performed. Reproducible magnetoconductance fluctuations with the amplitude increasing with decreasing temperature were observed. Unexpectedly, these fluctuations contain a component periodic in the magnetic field, and their magnitude is greater than that expected from the current theory of the universal conductance fluctuations. Possible explanations are discussed.
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 7.

Tytuł:: Second Harmonic Generation in Spin-Glass Microstructures and Fabrication of Microstructures in IV-VI Epilayers
Autorzy:: Grabecki, G.
Dietl, T.
Cieplak, Marek
Plesiewicz, W.
Lenard, A.
Skośkiewicz, T.
Kamińska, E.
Piotrowska, A.
Żarecka, R.
Springholz, G.
Bauer, G.
Tematy:: 71.55.Jv; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1929753.pdf Link otwiera się w nowym oknie
Opis:: We studied magnetoconductance of two different mesoscopic systems: microregions containing two-dimensional electron gas adjacent to a grain-boundary plane in bicrystals of Hg$\text{}_{0.79}$Cd$\text{}_{0.19}$Mn$\text{}_{0.02}$Te and photolithographically patterned microstructures of Pb$\text{}_{1-x}$Mn$\text{}_{x}$Se. In both systems universal conductance fluctuations and generation of the second-harmonic voltage were observed at T ≤ 1 K. Moreover, in the former system the second harmonic signal exhibited distinct rise when the sample was cooled below the spin-glass freezing temperature (100 mK).
Dostawca treści:: Biblioteka Nauki

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