Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 14

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Content available remote

Phase Composition of the Surface Zone of Nitrided Cast Steels and Their Mechanical Properties

100%
Brzózka K., Budzynowski T., Górka B.
Acta Physica Polonica A
|
2011
|
vol. 119
|
issue 1
28-32
EN
Conversion electron Mössbauer spectroscopy and structural X-ray diffractometry have been used to study nitrides formation in the surface layer of cast steels subjected previously to low-temperature nitriding. It has been found that creation of iron-nitrogen phases strongly depends on sample composition. Nitrides: γ'-Fe_{4}N and ε -Fe_{2-3}N arise in the course of the nitriding procedure in most investigated cast steels. Moreover, considerable changes in their microstructure and tribological properties occur. The depth profile of nitrides has been derived for selected cast steel.
2
Content available remote

Modeling of Magnetic Hyperfine Field Distribution for Spherical Nanoparticles of bcc Structure

88%
Szumiata T., Gzik-Szumiata M., Brzózka K., Gawroński M., Górka B.
Acta Physica Polonica A
|
2008
|
vol. 113
|
issue 1
537-540
EN
We propose a simple model for temperature evolution of magnetic hyperfine field distribution of spherical bcc Fe nanoparticles. We performed mean field approximation calculations of mean spin value in each spherical shell of nanoparticle. Considering magnetic hyperfine field values reported for iron thin films we predicted possible values of hyperfine fields in the internal and surface region of the particles as a function of temperature.
3
Content available remote

Phase Composition and Magnetic Properties of Nanoperm Thin Films Doped with Yttrium

88%
Brzózka K., Sovák P., Szumiata T., Górka B., Gawroński M.
Acta Physica Polonica A
|
2012
|
vol. 121
|
issue 5-6
1270-1272
EN
Thin films of Nanoperm alloys with partial substitution of iron by yttrium are the subject of investigations. The attention is fixed on the influence of yttrium substitution on structure and magnetic characteristics of the samples. The effect of film thickness is also considered. Conversion electron Mössbauer spectroscopy and magneto-optic Kerr effect were used to derive hyperfine parameters and coercive field, respectively. Coexistence of crystalline bcc-Fe phase and an amorphous one with diverse proportion was stated in most of the samples. It was found that surface and interface regions contribute to the magnetic properties of films.
4
Content available remote

Microstructural Study of Fe-Si(Ge)-Nb-Cu-B Finemet Alloys

88%
Michalik S., Bednarcik J., Brzózka K., Sovak P., Górka B.
|
|
issue 5
818-819
EN
Structural changes in Finemet based alloys invoked by germanium replacement for silicon were investigated using the X-ray diffraction, the X-ray absorption spectroscopy and the Mössbauer spectroscopy. Ge substitution preserves a nanostructural character of annealed samples at temperature 550°C; specifically the formation of a DO_3-type with about 19 at.% of (Si,Ge) was confirmed. The mean size of nanocrystals was estimated to be about 7 nm.
5
Content available remote

Mössbauer Study of Magnetic Texture of Finemet-Type Ribbons

88%
Brzózka K., Sovák P., Górka B., Szumiata T., Gawroński M.
Acta Physica Polonica A
|
2011
|
vol. 119
|
issue 1
33-36
EN
Magnetic texture of amorphous Finemet-type alloys substituted by Co, Ni, Mn, Ge and V was investigated by means of Mössbauer spectroscopy using various angular configurations. Samples in form of ribbons were manufactured by single-roller melt spinning technique. In most of investigated alloys some preference of alignment of atomic magnetic moments in-plane of sample is stated, except of some alloys substituted by germanium in which slight tendency to out-of plane spin orientation is proved.
6
Content available remote

Comparison of Magnetic and Mössbauer Results Obtained for Palaeozoic Rocks of Hornsund, Southern Spitsbergen, Arctic

88%
Szlachta K., Michalski K., Brzózka K., Górka B., Gałązka-Friedman J.
Acta Physica Polonica A
|
2008
|
vol. 114
|
issue 6
1675-1682
EN
This analysis was performed as a part of the palaeomagnetic project focused on the reconstruction of the palaeogeographic position of the Svalbard Archipelago and adjacent crustal units (European Arctic) in the Palaeozoic and Mesozoic. Three rock formations - Cambrian, Devonian and Carboniferous were sampled in the area of Hornsund, southern Spitsbergen. The main aim of the presented study is to identify ferromagnetic minerals (sensu lato) - the carriers of the natural remanent magnetisation in the investigated rocks. A wide range of magnetic methods were used: the Lowrie tests, unblocking temperatures determinations and the measurement of coercivity spectra as well as the Mössbauer studies. In Devonian and Carboniferous samples all applied methods indicate the domination of the hematite natural remanent magnetisation carrier. In Cambrian rocks magnetic measurements reveal a mixture of ferromagnetic (sensu lato) minerals with varying coercivities and unblocking temperatures. The Mössbauer data improve the identification, suggesting that in Cambrian rocks the carrier of the dominating natural remanent magnetisation component is maghemite.
7
Content available remote

Local Structure and Magnetic Characteristics of FINEMET Alloys Substituted by Vanadium

76%
Brzózka K., Szumiata T., Gawroński M., Górka B., Sovák P., Pavlík G., Kolesár V.
Acta Physica Polonica A
|
2008
|
vol. 113
|
issue 1
51-54
EN
Amorphous and nanocrystalline FINEMET-type alloys with vanadium addition up to 7 at% were investigated by the MÖssbauer spectroscopy and magnetic methods. The outcomes evidence alterations in grain structure, although the main effect is related to the changes in intergranular phase. This induces diminution of mean hyperfine field, saturation induction and Curie temperature as well as the increase in coercivity.
8
Content available remote

Structural and Magnetic Ordering in Fe-Ga Thin Films Examined by Mössbauer Spectrometry

76%
Szumiata T., Brzózka K., Gawroński M., Górka B., Javed A., Morley N., Gibbs M.
Acta Physica Polonica A
|
2011
|
vol. 119
|
issue 1
21-23
EN
The detailed analysis of atomic and magnetic structure has been performed by Mössbauer spectroscopy for polycrystalline Fe_{80}Ga_{20} films of different thickness ranging from 20 nm to 200 nm. The films were deposited on Si(100) substrate using dual sputtering and evaporation method. Obtained CEMS spectra have been fitted with several Gaussian distributions of hyperfine magnetic field. The results point to the domination of BCC disordered A2 phase and the absence of DO_{3} and L1_{2} phases in the films. Both hyperfine parameters and lattice constant reveal anomaly for 40 nm thick sample - presumably due to the change of the internal stress. Spin texture evolves from in-plane to out-of-the-plane configuration with increasing thickness.
9
Content available remote

Finemet Thin Films Substituted by Chromium - CEMS and MOKE Study

76%
Brzózka K., Szumiata T., Sovák P., Górka B., Hibner K., Balcerski J.
|
|
issue 5
794-796
EN
Conversion electron Mössbauer spectroscopy and magneto-optical Kerr effect were applied to investigate hyperfine interactions and macroscopic magnetic properties of Finemet-type thin films. Phase analysis as well as compositional evolution of hyperfine parameters and coercivity was performed in the range of chromium percentage 0 ≤ x ≤ 14. Essential differences in structure and hyperfine parameters were found for films of different chromium concentration. Coercivity shows non-monotonic dependence with minimal value at x = 5.
10
Content available remote

Stress Monitoring in Steel Elements via Detection of AC Magnetic Permeability Changes

64%
Szumiata T., Hibner K., Dziewiecki K., Mazur Z., Gockiewicz A., Gzik-Szumiata M., Górka B., Witoś M.
Acta Physica Polonica A
|
2018
|
vol. 133
|
issue 3
719-721
EN
The influence of mechanical stress on low frequency AC magnetic permeability was studied. The cold-drawn bars with C45 steel were subjected to investigation. The tensile stress (within elastic regime) was applied by means of material testing machine. Simple measuring system was assembled, which consisted of: function generator with magnetizing coil, detection coil and precise AC voltmeter. The registered changes of induced voltage were proportional to the change of magnetic permeability of the stretched rods. The obtained results were almost frequency-independent due to low frequency limit (250-500 Hz, weak eddy currents, no spin-origin energy dissipation). A significant magneto-mechanical hysteresis was observed slightly evolving from cycle to cycle with tendency of stabilization. The extension of basic Stoner-Wohlfarth model of magnetic permeability allowed to fit the data reproducing hysteretic behavior and considering the relaxation of the internal stress. The proposed, low-cost method is suitable in the industrial applications for stress control in large-sized steel elements.
11
Content available remote

Mössbauer and Magnetic Study of Fe+Vitroperm+Plastic System

64%
Brzózka K., Kollár P., Szumiata T., Sovak P., Füzer J., Fáberová M., Bureš R., Górka B., Gawroński M., Gzik-Szumiata M.
|
|
vol. 126
|
issue 1
148-149
EN
Phase composition and magnetization curves of the soft magnetic composites, fabricated by compaction of several kinds of powders mixed in various proportions, have been investigated by means of conversion electron Mössbauer spectroscopy and an alternating gradient force magnetometry. The results point to significant quantity of iron oxides - hematite and magnetite - at the surface of the samples. After the rubbing of thin surface layer, the relative content of oxides was distinctly reduced. Magnetic measurements revealed very similar characteristics of hysteresis curves for all the investigated materials.
12
Content available remote

Phase Analysis of Magnetic Inclusions in Nanomaterials Based on Multiwall Carbon Nanotubes

64%
Brzózka K., Krajewski M., Małolepszy A., Stobiński L., Szumiata T., Górka B., Gawroński M., Wasik D.
Acta Physica Polonica A
|
2017
|
vol. 131
|
issue 4
863-865
EN
Functionalized multiwall carbon nanotubes as well as nanocomposite based on that material covered by nanoparticles composed of iron oxides were the subject of investigations. In order to identify all iron-bearing phases including those reported on the base of previous X-ray diffraction measurements, the transmission Mössbauer spectroscopy was utilized. The experiments were carried out both at room temperature and also at low temperatures. It was stated that in the investigated nanotubes some impurities were present, originating from the catalyst remains, in form of Fe-C and α -Fe nanoparticles. The Mössbauer spectra collected for the nanocomposite showed a complex shape characteristic of temperature relaxations. The following subspectra related to iron-based phases were identified: sextet attributed to hematite, with hyperfine magnetic field reduced due to the temperature relaxations, sextet corresponding to iron carbide as well as two doublets linked to superparamagnetic hematite and ferrihydrites.
13
Content available remote

Magnetism and Structure Evolution in Ni-Zn Ferrites Thin Films - CEMS Study

64%
Szumiata T., Gzik-Szumiata M., Brzózka K., Górka B., Gawroński M., Javed A., Farman K., Fatima T.
Acta Physica Polonica A
|
2017
|
vol. 131
|
issue 4
836-838
EN
In this work, a ⁵⁷Fe conversion electron Mössbauer spectrometry and X-ray diffraction have been utilized in order to investigate the structural and magnetic order in 500 nm thick Ni-Zn ferrite films deposited on Si(100) substrate by laser ablation. Considering the contributions of the conversion electron Mössbauer subspectra corresponding to the tetrahedral (A) and octahedral (B) sites, the spinel inversion parameter in [Zn_{x}Fe_{1-x}]^{A}[Ni_{1-x}Fe_{1+x}]^{B}O₄ films has been estimated. The hyperfine field (B_{hf}) values in the investigated Ni-Zn ferrites thin films are about 5-8% smaller than those of bulk ferrites, which could be a sign of thermal magnetic relaxations due to the size effects. The distribution of hyperfine magnetic field directions was found to be affected by perpendicular anisotropy.
14
Content available remote

Influence of Milling and Compaction Processes οn Magnetic Properties of FeCo Powder

64%
Szumiata T., Gzik-Szumiata M., Brzózka K., Gawroński M., Górka B., Kollár P., Olekšáková D., Polański K., Szmaja W.
Acta Physica Polonica A
|
2009
|
vol. 115
|
issue 1
403-405
EN
Magnetic and structural studies were performed on Fe_{50}Co_{50} material. The samples (disk-shaped, diameter: 10 mm, thickness: 2.5 mm) were fabricated by compaction of powder under pressure of 800 MPa for 5 min at temperatures 300-600°C. The powder was obtained by milling of Fe_{50}Co_{50} alloy swarfs in high-energy planetary mill. The milling time varied from 1 h to 40 h. In the course of milling process the mean size of alloy pieces was decreasing from about 0.5 mm to 0.05 mm (scanning electron microscopy), which provided more compact structure after compression. The annealing process during compaction strongly reduces a coercive field of the samples. Parameters of conversion electron Mössbauer spectra are almost the same for all samples, which points to not significant changes of atomic and magnetic order after milling and compacting.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.