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1

Temperature Dependence of the EPR Spectra of the Nanocrystalline TiN and TiC Dispersed in a Carbon Matrix

100%

Guskos N., Bodziony T., Biedunkiewicz A., Aidinis K.

Acta Physica Polonica A

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2005

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vol. 108

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issue 2

311-316

EN

Two powder samples: nanocrystalline titanium carbide (TiC) and titanium nitride (TiN) dispersed in a carbon matrix were synthesized by a nonhydrolytic sol-gel process. Both samples were characterized by the X-ray diffraction and transmission electron microscopy. The transmission electron microscopy examination of the TiC and TiN nanoparticles showed that their average crystalline size was about 20 nm. The temperature dependence of the EPR spectra for both samples was measured in 10 K to 200 K temperature range. A similar very narrow (about 0.2 mT) EPR line centered at g≈2 (at room temperature) was recorded in both samples. The EPR line observed in both samples is arising from electron conductivity centers dispersed in the carbon matrix and it was fitted by Dysonian line shape. The temperature dependence of the EPR spectrum showed different behavior of these two samples. It is suggested that in the sample TiC/C multiwall carbon nanotubes are formed while in the sample TiN/C the graphite structure dominates.

2

Magnetic Study of Nanocrystalline TiB₂, TiC, B₄C Powders Doped to AISI 316L Austenitic Steel

88%

Bodziony T., Kaczmarek S., Biedunkiewicz A., Leniec G., Figiel P.

Acta Physica Polonica A

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2017

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vol. 132

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issue 1

62-68

EN

The investigations into ferromagnetic resonance and magnetic susceptibility of nanocrystalline TiB₂, TiC, and B₄C powders (Ti-B-C system) doped to AISI 316L austenitic steel with different amounts (3 vol.%, 5 vol.% and 7 vol.%) have been carried out. The ferromagnetic resonance spectra were recorded in the temperature range from helium up to room temperature. The three tested composite samples contain a number of magnetic phases in different proportions. They reveal a structure originating from several different complex magnetic centers. The composites revealed such magnetic phenomena as paramagnetism, (anti)ferromagnetism, and superparamagnetism. Magnetic susceptibility investigations supported the ferromagnetic resonance studies and their analysis. Magnetic properties of the TiB₂, TiC, B₄C powders doped to AISI steel may play important role in further possible applications of these composite systems.

3

Low Concentration Effect of Fe_3O_4 and Fe_3C Magnetic Nanoparticles in Non-Magnetic Matrix on the FMR Spectra

76%

Bodziony T., Guskos N., Roslaniec Z., Narkiewicz U., Kwiatkowska M., Maryniak M.

Acta Physica Polonica A

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2005

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vol. 108

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issue 2

297-302

EN

PTMO-block-PET polymer filled with a low concentration (0.1 wt.%) of binary magnetic system: magnetite (Fe_3O_4) and iron carbide (Fe_3C) with carbon (C) was prepared. Characterization of the sample was done by using X-ray diffraction and scanning electron microscopy methods. Temperature dependence of the FMR spectra was carried out in the 10-300 K temperature range. The extraordinary temperature dependence behaviour of FMR spectra was recorded. The FMR spectra were fitted by two Lorentzian lines originating from magnetite and iron carbide. The anomalous behaviour of FMR spectra below 100 K could be explained by the skin effect or by the freezing of the matrix benzene rings at about 115 K. The temperature dependence of the g parameter below 75.5 K (opposite shift of the resonance field to usually observed) was interpreted as a result of strong antiferromagnetic interaction of some portion of agglomerates.

4

Magnetic Resonance and Dielectric Studies of a Nonlinear La_3Ga_{5.5}Ta_{0.5}O_{14} Single Crystal Doped with Erbium

64%

Bodziony T., Typek J., Orlowski M., Majszczyk J., Wabia M., Berkowski M., Ryba-Romanowski W., Guskos N., Likodimos V., Anagnostakis E.

Acta Physica Polonica A

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2003

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vol. 103

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issue 2-3

315-322

EN

Single crystal of erbium doped La_3Ga_{5.5}Ta_{0.5}O_{14} grown by the Czochralski method have been investigated by electron paramagnetic resonance and dielectric spectroscopy methods. Dielectric permittivity ε measurements performed in 90-440 K temperature range have shown negligible dispersion for 1 kHz - 1 MHz frequencies and a Curie-Weiss type behaviour with C=47700 K andθ=-340 K. Electron paramagnetic resonance studies have revealed the presence of two different paramagnetic, monoclinic centres. The calculated g factor values are: g_1=1.449, g_2=11. 534, g_3=4.24 for the main M_1 centre and g_1=1.98, g_2=4.169, g_3=4.25 for the weaker M_2 centre. The temperature dependence of EPR line intensity for centre M_1 and M_2 is quite different - while lines attributed to M_1 could only be observed at low temperatures, below 20 K, lines of M_2 centre persisted up to 200 K. The M_1 centre is connected with Er^{3+} ion entering substitutionally into La^{3+} site, while M_2 is probably connected with 3d ions at the same site, unintentionally introduced into the material as an admixture.

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4 Acta Physica Polonica A

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1 Berkowski M.

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1 Leniec G.

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1 Roslaniec Z.

1 Ryba-Romanowski W.

1 Typek J.

1 Wabia M.

Temperature Dependence of the EPR Spectra of the Nanocrystalline TiN and TiC Dispersed in a Carbon Matrix

Magnetic Study of Nanocrystalline TiB₂, TiC, B₄C Powders Doped to AISI 316L Austenitic Steel

Low Concentration Effect of Fe_3O_4 and Fe_3C Magnetic Nanoparticles in Non-Magnetic Matrix on the FMR Spectra

Magnetic Resonance and Dielectric Studies of a Nonlinear La_3Ga_{5.5}Ta_{0.5}O_{14} Single Crystal Doped with Erbium