Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "Sikora, R" wg kryterium: Autor

  Lista filtrów
Wyrównaj
    Wyświetlanie 1-6 z 6
    Tytuł:
    Phase Diagrams of Crystals with One-Dimensional Modulated Phases Induced by 2d Active Representations
    Autorzy:
    Sikora, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/1931812.pdf
    Data publikacji:
    1994-12
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    64.70.Rh
    Opis:
    A one-dimensional model of particles with a displacive degree of freedom for crystals possessing incommensurate phases which arise as a result of the condensation of either real two-dimensional or complex one-dimensional irreducible representations, has been proposed. For these representations all invariants of the free energy expansion can be divided to four general forms. For the active irreducible representations for which the invariants belong to the first form a complete list of invariants is derived. In this case the incommensurate modulation propagates along the symmetry axis and for such crystals a proposed one-dimensional model may be a good approach to describe the main features of the devil's staircase curve. The particles of the model interact with harmonic and anharmonic terms. The last ones may contain an additional third order term provided a soft phonon branch has a symmetry τ$\text{}^{1}$. The calculated phase diagrams show sequences of the incommensurate and commensurate one-dimensional phases. In the presence of the third order anharmonic term the incommensurate phase proves to be stable closer to the phase boundary to the normal phase.
    Źródło:
    Acta Physica Polonica A; 1994, 86, 6; 955-968
    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:
    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:
    A $\text{}^{55}$Mn NMR Study of La$\text{}_{0.33}$Nd$\text{}_{0.33}$Ca$\text{}_{0.34}$Mn O$\text{}_{3}$ with $\text{}^{16}$O and $\text{}^{18}$O
    Autorzy:
    Rybicki, D.
    Kapusta, Cz.
    Riedi, P. C.
    Oates, C. J.
    Sikora, M.
    Zając, D.
    De Teresa, J. M.
    Marquina, C.
    Ibarra, M. R.
    Powiązania:
    https://bibliotekanauki.pl/articles/2037128.pdf
    Data publikacji:
    2004
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    76.60.-k
    75.47.Gk
    Opis:
    A $\text{}^{55}$Mn NMR study of $\text{}^{16}$O and $\text{}^{18}$O containing La$\text{}_{0.33}$Nd$\text{}_{0.33}$Ca$\text{}_{0.34}$Mn O$\text{}_{3}$ is reported. The spin-echo spectra measured at 4.2 K and zero field consist of a double exchange line corresponding to the ferromagnetic metallic regions. The line intensity is more than an order of magnitude lower for the $\text{}^{18}$O compound, which indicates an order of magnitude lower content of the ferromagnetic metallic phase in this compound. The frequency dependence of the spin-spin relaxation time T$\text{}_{2}$ shows a pronounced minimum at the center of the double exchange line of both compounds due to the Suhl-Nakamura interaction, which indicates that the ferromagnetic metallic regions are at least 10~nm in size. The results are discussed in terms of the influence of oxygen isotopic substitution on phase segregation.
    Źródło:
    Acta Physica Polonica A; 2004, 105, 1-2; 183-188
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    NMR Study of (Sr,Ba,La)$\text{}_{2}$Fe$\text{}_{1+y}$Mo$\text{}_{1-y}$O$\text{}_{6}$ Double Perovskites
    Autorzy:
    Zając, D.
    Kapusta, Cz.
    Riedi, P. C.
    Sikora, M.
    Oates, C. J.
    Rybicki, D.
    De Teresa, J. M.
    Serrate, D.
    Marquina, C.
    Ibarra, M. R.
    Powiązania:
    https://bibliotekanauki.pl/articles/2041522.pdf
    Data publikacji:
    2004-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.25.+z
    76.60.-k
    78.70.Gq
    75.47.Gk
    Opis:
    The $\text{}^{95}$Mo and $\text{}^{97}$Mo NMR spin-echo study of (Sr,Ba,La)$\text{}_{2}$Fe$\text{}_{1 +y}$Mo$\text{}_{1-y}$O$\text{}_{6}$ double perovskites is reported. Powder samples of Ba$\text{}_{1.44}$Sr$\text{}_{0.36}$La$\text{}_{0.2}$FeMoO$\text{}_{6}$ and (Ba$\text{}_{0.8}$Sr$\text{}_{0.2}$)$\text{}_{2-2x}$La$\text{}_{x}$#$\text{}_{x}$ Fe$\text{}_{1+y}$Mo$\text{}_{1-y}$O$\text{}_{6}$, where# denotes vacancies, for: x=0, y=0; x=0.1, x=0.2 and x=0.3, y=0 and y=0.2 were measured at 4.2 K and no applied magnetic field. NMR signals are observed at 55-100 MHz for the main line and 30-55 MHz for low-frequency satellite. The main line and the satellite are attributed to the ideal and defect positions of Mo atoms. La and vacancy doping introduce more defects, however, increasing the Fe/Mo ratio decreases the amount of defect Mo sites. La doping causes a satellite pattern at the high frequency side of the spectrum, which is related to different numbers of the La next neighbours. The effect is attributed to an increase in the electron density and the corresponding magnetic moment at the adjacent Mo sites and reveals a local character of the electron doping.
    Źródło:
    Acta Physica Polonica A; 2004, 106, 5; 759-765
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Local Magnetic and Electronic Properties of the A$\text{}_{2}$FeM'O$\text{}_{6}$ (A = Ba, Sr, Ca, M' = Mo, Re) Double Perovskites
    Autorzy:
    Zając, D.
    Sikora, M.
    Prochazka, V.
    Borowiec, M.
    Stępień, J.
    Kapusta, Cz.
    Riedi, P. C.
    Marquina, C.
    De Teresa, J. M.
    Ibarra, M. R.
    Powiązania:
    https://bibliotekanauki.pl/articles/2047344.pdf
    Data publikacji:
    2007-06
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.30.-m
    76.60.-k
    76.60.Jx
    78.80.En
    Opis:
    The results of a combined NMR, X-ray absorption spectroscopy and X-ray magnetic cirrcular dichroism study of the AA'FeMoO$\text{}_{6}$ and AA'FeReO$\text{}_{6}$ double perovskites are presented. They revealed a dependence of electronic and magnetic properties, including a d-electron transfer between Fe and Mo sites, on the structural tolerance factor. The maximum value of the 4d Mo electron occupation and the corresponding Mo moment is obtained for the tolerance factor of unity. This corresponds to the maximum strength of the magnetic interaction and, respectively, to the Curie temperature. The dominant T$\text{}^{5}\text{}^{/}\text{}^{2}$ type temperature dependence of the Mo hyperfine field reveals the half-metallicity of the AA'FeMoO$\text{}_{6}$ compounds. Antisite defects and antiphase boundaries have been identified in NMR measurements and the strength of their magnetic coupling have been determined. A considerable orbital contribution to the Re and Fe magnetic moments were found in the NMR and X-MCD measurements on the AA'FeReO$\text{}_{6}$ compounds. Its magnitude decreases with increasing structural tolerance factor and is correlated with their magnetic anisotropy.
    Źródło:
    Acta Physica Polonica A; 2007, 111, 6; 797-820
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-6 z 6

      Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies