Kamil Wardal - Academia.edu (original) (raw)

Papers by Kamil Wardal

Research paper thumbnail of Magnetic studies of 0.7(Fe2O3)/0.3(ZnO) nanocomposites in nanopowder form and dispersed in polymer matrix

Materials Science-Poland, 2016

Research paper thumbnail of Magnetic properties of ZnFe2O4 nanoparticles

Central European Journal of Physics, 2012

Fine particles of ZnFe 2 O 4 were synthesized by a wet chemical method in the (80 wt. % Fe 2 O 3 ... more Fine particles of ZnFe 2 O 4 were synthesized by a wet chemical method in the (80 wt. % Fe 2 O 3 + 20 wt. % ZnO) system. The morphological and structural properties of the mixed system were investigated by scanning electron microscopy, X-ray diffraction, inductively coupled plasma atomic emission, and X-ray photoelectron spectroscopy. The major phase was determined to be the ZnFe 2 O 4 spinel with particle size of 11 nm. The magnetic properties of the material were investigated by ferromagnetic resonance (FMR) in the temperature range from liquid helium to room temperature. A very intense, asymmetric FMR signal from ZnFe 2 O 4 nanoparticles was recorded, which has been analyzed in terms of two Callen-lineshape lines. Temperature dependence of the FMR parameters was obtained from fitting the experimental lines with two component lines. Analysis of the FMR spectra in terms of two separate components indicates the presence of strongly anisotropic magnetic interactions. 75.75.+a, 76.50.+g

Research paper thumbnail of Magnetic study of 0.20(Fe2O3)/0.80(ZnO) nanocomposite

Journal of Magnetism and Magnetic Materials, 2014

Research paper thumbnail of Magnetic resonance study of carbon encapsulated Ni nanoparticles

Central European Journal of Chemistry, 2012

Magnetic properties of nanosize ZnO powders doped with MnO magnetic dopand have been studied. Sam... more Magnetic properties of nanosize ZnO powders doped with MnO magnetic dopand have been studied. Sample designated as 0.10MnO/0.90ZnO was characterized by XRD that revealed the presence of ZnO and ZnMnO 3 phases. An average size of magnetic ZnMnO 3 nanocrystallites was 9 nm. Magnetic resonance study has been carried out in the 4-290 K temperature range. The spectrum at each temperature was analyzed in terms of three components. The temperature dependences of resonance field, linewidth and integrated intensity of these components have been determined. Magnetic centers responsible for producing the observed spectra have been proposed.

Research paper thumbnail of FMR and Magnetization Study of ZnFe<sub>2</sub>O<sub>4</sub> Nanoparticles in 0.40Fe<sub>2</sub>O<sub>3</sub>/0.60ZnO Nanocomposite

IEEE Transactions on Magnetics, 2014

Zinc oxide (ZnO) nanocrystals containing Fe 2 O 3 have been synthesized by the calcination method... more Zinc oxide (ZnO) nanocrystals containing Fe 2 O 3 have been synthesized by the calcination method. Ferromagnetic resonance (FMR) and dc magnetization measurements of 0.40(Fe 2 O 3 )/0.60(ZnO) nanocomposite have been carried out in the 4-300 K range to study the magnetic properties of agglomerated magnetic zinc ferrite ZnFe 2 O 4 (ZFO) nanoparticles with an average crystallite size of 12 nm. Temperature dependence of the resonance field, linewidth, and the integrated intensity calculated from FMR spectra have been determined to obtain the value of the uniaxial anisotropy field and to establish the ranges of different relaxation types. Magnetization measurements in ZFC and FC modes as well as the study of hysteresis loops allowed calculating different magnetic characteristics-blocking/freezing temperature, magnetic moment, anisotropy constant, and anisotropy field. The observed magnetic properties of 0.40(Fe 2 O 3 )/0.60(ZnO) nanocomposite were explained based on the core-shell model of ZFO nanoparticles. From comparison of FMR and dc magnetization measurements, the temperature ranges of magnetic phases existing in ZFO nanoparticles in 0.40Fe 2 O 3 /0.60ZnO nanocomposite are proposed.

Research paper thumbnail of FMR study of 0.30(Fe 2 O 3 )/0.70(ZnO) nanocomposite

The European Physical Journal Applied Physics, 2013

ZnO nanocrystals doped with Fe2O3 have been synthesized by the calcination method. Ferromagnetic ... more ZnO nanocrystals doped with Fe2O3 have been synthesized by the calcination method. Ferromagnetic resonance (FMR) study of 0.3(Fe2O3)/0.7(ZnO) nanocomposite has been carried out in the 4-300 K range. The presence of magnetic zinc ferrite ZnFe2O4 nanoparticles with an average crystallite size of 11 nm was identified by XRD. Temperature dependence of the resonance field, linewidth and the integrate intensity calculated from FMR spectra has been determined. Existence of two temperature regimes: high (above 50 K) and low (below 50 K) has been established, further divided into two temperature ranges. The results of FMR study of agglomerated ZnFe 2O4 nanoparticles indicate an important role of magnetic interactions, both inter-particle (exchange and dipolar) and intra-particle connected with the core-shell magnetic structure.

Research paper thumbnail of Magnetic studies of 0.7(Fe2O3)/0.3(ZnO) nanocomposites in nanopowder form and dispersed in polymer matrix

Materials Science-Poland, 2016

Research paper thumbnail of Magnetic properties of ZnFe2O4 nanoparticles

Central European Journal of Physics, 2012

Fine particles of ZnFe 2 O 4 were synthesized by a wet chemical method in the (80 wt. % Fe 2 O 3 ... more Fine particles of ZnFe 2 O 4 were synthesized by a wet chemical method in the (80 wt. % Fe 2 O 3 + 20 wt. % ZnO) system. The morphological and structural properties of the mixed system were investigated by scanning electron microscopy, X-ray diffraction, inductively coupled plasma atomic emission, and X-ray photoelectron spectroscopy. The major phase was determined to be the ZnFe 2 O 4 spinel with particle size of 11 nm. The magnetic properties of the material were investigated by ferromagnetic resonance (FMR) in the temperature range from liquid helium to room temperature. A very intense, asymmetric FMR signal from ZnFe 2 O 4 nanoparticles was recorded, which has been analyzed in terms of two Callen-lineshape lines. Temperature dependence of the FMR parameters was obtained from fitting the experimental lines with two component lines. Analysis of the FMR spectra in terms of two separate components indicates the presence of strongly anisotropic magnetic interactions. 75.75.+a, 76.50.+g

Research paper thumbnail of Magnetic study of 0.20(Fe2O3)/0.80(ZnO) nanocomposite

Journal of Magnetism and Magnetic Materials, 2014

Research paper thumbnail of Magnetic resonance study of carbon encapsulated Ni nanoparticles

Central European Journal of Chemistry, 2012

Magnetic properties of nanosize ZnO powders doped with MnO magnetic dopand have been studied. Sam... more Magnetic properties of nanosize ZnO powders doped with MnO magnetic dopand have been studied. Sample designated as 0.10MnO/0.90ZnO was characterized by XRD that revealed the presence of ZnO and ZnMnO 3 phases. An average size of magnetic ZnMnO 3 nanocrystallites was 9 nm. Magnetic resonance study has been carried out in the 4-290 K temperature range. The spectrum at each temperature was analyzed in terms of three components. The temperature dependences of resonance field, linewidth and integrated intensity of these components have been determined. Magnetic centers responsible for producing the observed spectra have been proposed.

Research paper thumbnail of FMR and Magnetization Study of ZnFe<sub>2</sub>O<sub>4</sub> Nanoparticles in 0.40Fe<sub>2</sub>O<sub>3</sub>/0.60ZnO Nanocomposite

IEEE Transactions on Magnetics, 2014

Zinc oxide (ZnO) nanocrystals containing Fe 2 O 3 have been synthesized by the calcination method... more Zinc oxide (ZnO) nanocrystals containing Fe 2 O 3 have been synthesized by the calcination method. Ferromagnetic resonance (FMR) and dc magnetization measurements of 0.40(Fe 2 O 3 )/0.60(ZnO) nanocomposite have been carried out in the 4-300 K range to study the magnetic properties of agglomerated magnetic zinc ferrite ZnFe 2 O 4 (ZFO) nanoparticles with an average crystallite size of 12 nm. Temperature dependence of the resonance field, linewidth, and the integrated intensity calculated from FMR spectra have been determined to obtain the value of the uniaxial anisotropy field and to establish the ranges of different relaxation types. Magnetization measurements in ZFC and FC modes as well as the study of hysteresis loops allowed calculating different magnetic characteristics-blocking/freezing temperature, magnetic moment, anisotropy constant, and anisotropy field. The observed magnetic properties of 0.40(Fe 2 O 3 )/0.60(ZnO) nanocomposite were explained based on the core-shell model of ZFO nanoparticles. From comparison of FMR and dc magnetization measurements, the temperature ranges of magnetic phases existing in ZFO nanoparticles in 0.40Fe 2 O 3 /0.60ZnO nanocomposite are proposed.

Research paper thumbnail of FMR study of 0.30(Fe 2 O 3 )/0.70(ZnO) nanocomposite

The European Physical Journal Applied Physics, 2013

ZnO nanocrystals doped with Fe2O3 have been synthesized by the calcination method. Ferromagnetic ... more ZnO nanocrystals doped with Fe2O3 have been synthesized by the calcination method. Ferromagnetic resonance (FMR) study of 0.3(Fe2O3)/0.7(ZnO) nanocomposite has been carried out in the 4-300 K range. The presence of magnetic zinc ferrite ZnFe2O4 nanoparticles with an average crystallite size of 11 nm was identified by XRD. Temperature dependence of the resonance field, linewidth and the integrate intensity calculated from FMR spectra has been determined. Existence of two temperature regimes: high (above 50 K) and low (below 50 K) has been established, further divided into two temperature ranges. The results of FMR study of agglomerated ZnFe 2O4 nanoparticles indicate an important role of magnetic interactions, both inter-particle (exchange and dipolar) and intra-particle connected with the core-shell magnetic structure.