Wyniki wyszukiwania - Biblioteka Nauki

Ten serwis zostanie wyłączony 2025-02-11.

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

5 Acta Physica Polonica A

Znaleziono wyników: 5

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Magnetic Properties of "As-Prepared" and Chemically Modified Multiwalled Carbon Nanotubes

100%

Kuryliszyn-Kudelska I. , Małolepszy A. , Mazurkiewicz M. , Stobinski L. , Dobrowolski W.

Acta Physica Polonica A

2011

tom 119

nr 5

597-599

In this work we have studied the structural and magnetic properties of "as-prepared" multiwalled carbon nanotubes, synthesized by the chemical vapor deposition method, and chemically modified multiwalled carbon nanotubes. Transmission electron microscopy was used to show multiwalled carbon nanotubes structure. The results of systematic magnetic property measurements on multiwalled carbon nanotubes are presented. The static and dynamic magnetic responses, such as the temperature dependence of the linear AC susceptibility and DC magnetization up to 9 T were studied. We have observed significant changes in magnetic AC susceptibility and magnetization for "as-prepared" and chemically modified multiwalled carbon nanotubes samples.

Synthesis by Wet Chemical Method and Characterization of Nanocrystalline ZnO Doped with Fe_2O_3

86%

Narkiewicz U. , Sibera D. , Kuryliszyn-Kudelska I. , Kilański L. , Dobrowolski W. , Romčević N.

Acta Physica Polonica A

2008

tom 113

nr 6

1695-1700

Nanocrystalline samples of ZnO doped with Fe_2O_3 were synthetized by wet chemical method. The series of ZnO nanosized samples in the wide range of Fe_2O_3 concentration (from 5 wt.% to 95 wt.%) was prepared by precipitation from nitrate solutions using ammonia. The phase composition of the samples was determined using X-ray diffraction measurements. The phases of hexagonal ZnO, and/or rhombohedric Fe_2O_3, and/or ZnFe_2O_4 were identified. The mean crystalline size of nanocrystals, determined with the use of Scherrer's formula, varied from 8 to 52 nm. The preliminary micro-Raman spectroscopy measurements were performed. The observed features are typical of Fe doped ZnO nanoparticles. The magnetic measurements revealed the presence of different types of magnetic behavior. For samples with high Fe_2O_3 contents (above 70 wt.%) the ferromagnetic ordering was observed at room temperature. For samples with lower Fe_2O_3 contents we observed the phenomenon of superparamagnetism above the blocking temperature.

Low-Frequency Raman Scattering from ZnO(Fe) Nanoparticles

72%

Kostić R. , Romčević N. , Romčević M. , Hadžić B. , Rudolf R. , Kuryliszyn-Kudelska I. , Dobrowolski W. , Narkiewicz U. , Sibera D.

Acta Physica Polonica A

2009

tom 116

nr 1

65-67

Nanocrystalline samples of ZnO(Fe) were synthesized by wet chemical method. Samples were characterized by X-ray diffraction to determine the sample composition and the mean crystalline size. Low-frequency Raman modes were measured and assigned according to confined acoustic vibrations of spherical nanoparticles. Frequencies of these vibrational modes were analyzed in elastic continuum aproximation, which considers nanoparticle as homogeneous elastic sphere.

Nanocrystalline ZnO Doped with Fe_2O_3 - Magnetic and Structural Properties

72%

Kuryliszyn-Kudelska I. , Hadžić B. , Sibera D. , Kilanski L. , Romčević N. , Romčević M. , Narkiewicz U. , Dobrowolski W.

Acta Physica Polonica A

2011

tom 119

nr 5

689-691

We have studied the magnetic properties of ZnO nanocrystals doped with Fe_2O_3 in the magnetic dopant range from 5 to 70 wt%. The nanocrystals were synthesized by wet chemical method. The detailed structural characterization was performed by means of X-ray diffraction and micro-Raman spectroscopy measurements. The results of systematic measurements of magnetic AC susceptibility as a function of temperature and frequency are presented. We observed different types of magnetic behavior. For ZnO samples doped with low content of Fe_2O_3, the results of low-field AC susceptibility are satisfactorily explained by superparamagnetic model including inter-particle interactions. With the increase of magnetic Fe_2O_3 content, the spin-glass-like behavior is observed.

Raman Scattering from ZnO(Fe) Nanoparticles

72%

Romčević N. , Kostić R. , Romčević M. , Hadžić B. , Kuryliszyn-Kudelska I. , Dobrowolski W. , Narkiewicz U. , Sibera D.

Acta Physica Polonica A

2008

tom 114

nr 5

1323-1328

Nanocrystalline samples of ZnO(Fe) were synthesized by wet chemical method. Samples were characterized by X-ray diffraction to determine composition of the samples (ZnO, Fe₂O₃, ZnFe₂O₄) and the mean crystalline size (8-52 nm). In this paper we report the experimental spectra of the Raman scattering (from 200 to 1600 cm¯¹). Main characteristics of experimental Raman spectrum in 200 to 1600 cm¯¹ spectral region are: sharp peak at 436 cm¯¹ and broad two-phonon structure at ≈ 1150 cm¯¹, typical of ZnO;broad structure below 700 cm¯¹ that has different position and shape in case of ZnFe₂O₄ or Fe₂O₃ nanoparticles.