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1
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Mössbauer Spectrometry in FeMoCuB-Type Nanocrystalline Alloys

100%
Miglierini M.
Acta Physica Polonica A
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2008
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vol. 113
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issue 1
47-50
EN
The applicability of the Mössbauer spectrometry to the study of Fe_{91-x}Mo_8Cu_1B_x (x = 12, 15, 17) nanocrystalline alloys prepared by controlled annealing of ribbon-shaped amorphous precursors is demonstrated. Differences between both surfaces of the ribbons are pointed out to be due to preparation conditions. Conclusions from the Mössbauer spectrometry are supported by diffraction of synchrotron radiation, X-ray diffraction, and atomic field microscopy investigations.
2
Content available remote

Impact of Ion-Irradiation upon Microstructure and Magnetic Properties of NANOPERM-Type Fe₈₁Mo₈Cu₁B₁₀ Metallic Glass

64%
Hasiak M., Miglierini M.
Acta Physica Polonica A
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2018
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vol. 133
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issue 3
680-683
EN
Microstructure and soft magnetic properties of the Fe₈₁Mo₈Cu₁B₁₀ amorphous alloy in the as-quenched state and after irradiation with N⁺ ions are investigated. CEMS spectra show that the irradiated surface at the air side of the ribbons was significantly affected. On the other hand, no noticeable changes were observed at the opposite wheel side. More deep subsurface regions are also not altered as evidenced by CXMS spectra. Thermomagnetic measurements have shown presence of two magnetically different phases with well distinguished Curie points. They can be ascribed to the amorphous matrix and crystalline phases. The latter were quenched-in during the production process and/or induced by ion bombardment. Curie temperatures of the amorphous matrixes were calculated using the Heisenberg model. For the as-quenched and irradiated ribbons they are of 223 K and 228 K, respectively. The behaviour of coercivity versus temperature was also analysed.
3
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Magnetic Features at the Surfaces of Nanocrystalline Ribbons

64%
Miglierini M., Šafářová K.
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issue 5
840-842
EN
Magnetic behaviour of Nanoperm Fe_{90}Zr_7B_3 nanocrystalline alloy is studied by surface sensitive techniques comprising atomic force microscopy and magnetic force microscopy. Correlation of structural arrangement and magnetic order including the orientation of net magnetization is obtained by the help of the Mössbauer spectrometry. As-quenched amorphous alloys show no magnetic features. After annealing, maze magnetic domains have developed. Their shape is governed by surface crystallization. Position of net magnetization out of the ribbon plane by about 26° was determined by the Mössbauer spectrometry.
4
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Magnetic Properties of Ion Irradiated Fe₇₅Mo₈Cu₁B₁₆ Metallic Glass

64%
Hasiak M., Miglierini M.
Acta Physica Polonica A
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2017
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vol. 131
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issue 4
768-770
EN
Microstructure and thermomagnetic properties of ion-bombarded amorphous Fe₇₅Mo₈Cu₁B₁₆ alloy are investigated. The Mössbauer spectroscopy shows that surface regions at the air side of the ribbons irradiated with 2×10¹⁶ ions/cm² were significantly affected by 130 keV N⁺ ions. On the other hand, the opposite (wheel) side that was not exposed to ion irradiation is practically intact. The analysis of temperature dependences of magnetization shows the Curie points of 313 K and 316 K for as-quenched and irradiated samples, respectively. The maximum of magnetic entropy change calculated for the irradiated alloy in a magnetic field of 1.0 T occurs at 312.5 K and equals to 0.77 J kg¯¹ K¯¹ while that of the as-quenched sample is 0.74 J kg¯¹ K¯¹.
5
Content available remote

Magnetic Behaviour of Ferritin Nanoparticles

64%
Miglierini M., Lancok A.
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issue 5
944-945
EN
Characterization of magnetic behaviour of ferritin nanoparticles of biological origin is presented. Two types of samples prepared from human and horse spleen tissues were investigated by ^{57}Fe Mössbauer spectrometry. At room temperature, ferritin nanoparticles exhibit superparamagnetic behaviour due to their small dimensions. First occurrence of magnetic interactions was noticed below 60 K. Blocking temperature of human and horse ferritin nanoparticles was determined to be of 16 K and 32 K, respectively.
6
Content available remote

Mössbauer and MFM Investigations of Surface Magnetism in NANOPERM Nanocrystalline Alloys

64%
Miglierini M., Pavúk M.
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vol. 126
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issue 1
124-125
EN
Structurally different surface regions are identified at both sides of the ribbon-shaped ^{57}Fe_{90}Zr_{7}B_{3} NANOPERM alloy. Though paramagnetic in the as-quenched state, the air side shows significant contribution of crystalline bcc-Fe that decreases towards the interior of the ribbon. After annealing at 480 °C, magnetic dipole interactions develop that are associated with enhanced number of ferromagnetic nanograins. Significant increase in the number of nanograins was revealed at the wheel side, while the one at the air side is almost saturated. The observed maze-type magnetic domains exhibit well developed structure with equally wide strips.
7
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Transformation of Hyperfine Interactions in Co-Substituted Nanoperm-Type Alloys during Annealing

64%
Hatala T., Miglierini M.
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issue 5
764-765
EN
Structure and magnetic order of rapidly quenched (Fe_{1-x}Co_{x})_{79}Mo_8Cu_1B_{12} alloys is investigated by ^{57}Fe Mössbauer spectrometry in transmission geometry and by conversion electron Mössbauer spectrometry. The effect of heat treatment upon hyperfine interactions was studied as a function of Co contents (x = 0, 0.5). Magnetic dipole interactions developed in both alloys when sufficient number of ferromagnetic nanograins is created after heat treatment. The kinetics of crystallization was derived from in situ diffraction of synchrotron radiation. The progress of crystallization is different at both sides of the ribbon-shaped samples.
8
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Thermomagnetic Properties and First-Order Reversal Curve Analysis of Annealed Fe-Co-Si-B-Mo-P Alloy

64%
Hasiak M., Miglierini M.
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EN
The paper presents thermomagnetic features and characterization of magnetic interactions in the Fe₅₁Co₁₂Si₁₆B₈Mo₅P₈ metallic glass after annealing at 798 K for 1 h. The first-order reversal curve analysis was used to investigate hysteresis curves which provide a more precise estimation of the strength of interactions. The presence of magnetically distinct regions was revealed.
9
Content available remote

Investigations and Applications of Nanoperm-Type Soft Magnetic Materials

52%
Hasiak M., Łukiewski M., Miglierini M., Kaleta J.
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issue 5
829-831
EN
The microstructure and magnetic properties of Fe_{82}Zr_4Nb_3B_{10}Cu_1, Fe_{80}Zr_4Mn_3B_{12}Cu_1 and Fe_{80}Zr_4Ti_3Cu_1B_{12} alloys were investigated. Using RALE software the basic parameters of transformers made from nanocrystalline alloys with about 25% and 50% of crystalline phase were calculated. The transformer made from Fe_{80}Zr_4Ti_3Cu_1B_{12} alloys after annealing at 773 K for 1-shows the lowest core losses and highest efficiency.
10
Content available remote

Magnetocaloric Properties of Fe₇₅Mo₈Cu₁B₁₆ and Fe₈₁Mo₈Cu₁B₁₀ Metallic Glasses

52%
Hasiak M., Miglierini M., Kaleta J., Bujdoš M.
Acta Physica Polonica A
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2015
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vol. 127
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issue 2
608-610
EN
Microstructure and thermomagnetic properties for the Fe₇₅Mo₈Cu₁B₁₆ and Fe₈₁Mo₈Cu₁B₁₀ metallic glasses in the as-quenched state and after heat treatment at 643 K and 723 K are studied. The inverse change of the Curie point was observed for Fe₇₅Mo₈Cu₁B₁₆ metallic glass after annealing below the onset of crystallization. It is attributed to structural relaxation of the amorphous phase. The maximum of magnetic entropy change calculated for magnetic field of 1.0 T occurs for the Fe₇₅Mo₈Cu₁B₁₆ alloy annealed at 643 K at temperature close to the Curie point and equals 0.74 J kg¯¹ K¯¹.
11
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Depth-Selective Study of Surface Crystallization in NANOPERM-Type Alloys

52%
Miglierini M., Hatala T., Bujdoš M.
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vol. 126
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issue 1
56-57
EN
Evolution of structure and magnetic order is studied in the ^{57}Fe_{81}Mo_{8}Cu_{1}B_{10} alloy by conversion electron and conversion X-ray ^{57}Fe Mössbauer spectrometry. Surface features exhibit differences at both sides of ribbon-shaped samples with respect to the screening depth. In the as-quenched state, traces of magnetite (in addition to bcc-Fe) are revealed only at the wheel side of the ribbon to the depth of about 200 nm. It is present also after annealing up to 510 °C, then it disappears. In deeper regions (down to 1 μm), magnetite is less abundant. At the air side, only bcc-Fe is detected, though the progress of crystallization is more pronounced here than at the wheel side. Vibration properties of the bulk of amorphous and nanocrystalline samples are obtained from experiments of nuclear inelastic scattering of synchrotron radiation using partial densities of phonon states.
12
Content available remote

New Findings in Mössbauer Studies of Amorphous FeMoCuB NANOPERM-Type Alloy

52%
Jirásková Y., Maryško M., Miglierini M.
Acta Physica Polonica A
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2008
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vol. 113
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issue 1
151-154
EN
The effect of heat treatments at 603 K (a relaxation of an amorphous structure) and at 723 K (an onset of a bulk nanocrystallization) of a rapidly quenched Fe_{76}Mo_{8}Cu_{1}B_{15} alloy is studied. The differences in sample processing are reflected in magnetization direction as seen by room- and low-temperature Mössbauer spectroscopy.
13
Content available remote

Magnetic Hyperfine Fields of Nanoperm Alloys

52%
Miglierini M., Kohout J., Lančok A., Šafářová K.
Acta Physica Polonica A
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2012
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vol. 121
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issue 5-6
1263-1265
EN
Magnetic hyperfine fields of Fe_{90}Zr_7B_3 Nanoperm nanocrystalline alloy are characterized by ^{57}Fe Mössbauer spectrometry and ^{57}Fe NMR as well as by magnetic force microscopy. ^{57}Fe NMR enables to distinguish a broad signal of iron atoms located in a residual amorphous matrix from a narrow one which belongs to Fe in nanograins. The former coincides with the distribution of hyperfine fields obtained from ^{57}Fe Mössbauer spectroscopy. In addition, it is possible to make a distinction between NMR signals of the Fe nanograins located in magnetic domains from that of the nanograins positioned in domain walls. This is confirmed by magnetic force microscopy where appearance of maze-domains is observed.
14
Content available remote

Mössbauer and SQUID Characterization of Iron in Human Tissue: Case of Globus Pallidus

52%
Miglierini M., Boča R., Kopáni M., Lančok A.
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vol. 126
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issue 1
240-241
EN
Lyophilized samples of human brain tissue from the region of Globus Pallidus were investigated in powder form by ^{57}Fe Mössbauer spectroscopy and SQUID magnetometry. The obtained hyperfine parameters including isomer shift and quadrupole splitting exhibit a ferritin-like behaviour with high-spin Fe(III) sites. Three types of features were derived from temperature development of magnetic susceptibility: dominating diamagnetism, dominating paramagnetism, and intermediate states. The magnetic characteristics of the samples do not correlate with age of the donors.
15
Content available remote

Mössbauer Spectrometry Study of Biological Tissues

52%
Bonková I., Miglierini M., Bujdoš M., Kopáni M.
Acta Physica Polonica A
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2017
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vol. 131
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issue 4
1081-1083
EN
Magnetic microstructure of iron contained in selected biological tissues is characterized and mutually compared. We have studied three types of biological samples prepared from human brain, human and horse spleen. Original samples were lyophilized (dried in a vacuum) thus providing powder forms. As a principal method of study, ⁵⁷Fe Mössbauer spectrometry in transmission mode was used. The Mössbauer spectrometry experiments were performed at room ( ≈300 K) and at liquid helium (4.2 K) temperature. At room temperature Mössbauer spectra show doublet-like features. Such behaviour indicates possible presence of nanoparticles with fluctuating magnetic moments that acquire arbitrary positions. On the other hand, low temperature Mössbauer spectrometry measurements demonstrate significant contribution of sextets that confirmed occurrence of blocked magnetic moments of iron-containing particles. Different relative contributions of magnetic components in the low temperature spectra for the three inspected biological tissues suggest differences in the blocking temperatures of the magnetic nanoparticles present in them.
16
Content available remote

Identification of Magnetic Phases in LC200N Steel by Backscattering Mössbauer Spectrometry

52%
Pašteka L., Miglierini M., Bujdoš M.
Acta Physica Polonica A
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2017
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vol. 131
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issue 4
1078-1080
EN
In this paper we identified iron phases in three different samples of highly corrosion-resistant steel LC200N using the Mössbauer spectrometry which is particularly suited method for this purpose. Special emphasis is put upon magnetically active crystalline phases. The samples had different thermal history: (1) hardened, (2) hardened with consequent rapid quenching in liquid nitrogen, (3) non-hardened and prepared in a disc form with two sides ("as cut" and polished). Both ferritic magnetic phases and non-magnetic austenite phase were found in these samples. Relative content ratios between these phases were determined for each type of the samples and their respective sides. Higher amount of magnetic phases was found in non-hardened sample and on polished sides of all samples in general. The elemental characterization was accomplished by neutron activation analysis.
17
Content available remote

Influence of Cobalt Substitution on Hyperfine Interactions in (Fe_{1-x}Co_x)_{76}Mo_8Cu_1B_{15} Alloys

45%
Kaňčuch T., Miglierini M., Lancok A., Švec P., Illeková E.
Acta Physica Polonica A
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2008
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vol. 113
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issue 1
63-66
EN
The effect of cobalt substitution on structure, magnetic behaviour, magnetic arrangement, and hyperfine interactions in (Fe_{1-x}Co_x)_{76}Mo_8Cu_1B_{15} (x = 0, 0.1, 0.2, 0.25, 0.5) is studied by the Mössbauer spectrometry for both as-quenched and annealed alloys. Partial substitution of Fe by Co resulted in an enhancement of the average value of hyperfine magnetic field distributions as a function of x probably due to higher magnetic moment of Co. After annealing, a two-phase nanocrystalline structure composed of amorphous matrix and bcc-FeCo nanocrystallites was observed. Mössbauer spectra were fitted with up to four six-line patterns of narrow lines assigned to different number of Co nearest neighbours inside a bcc-FeCo lattice.
18
Content available remote

Low Field Magnetic Properties of FeCo-Based Alloys

45%
Hasiak M., Miglierini M., Łukiewska A., Kaleta J., Zbroszczyk J.
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vol. 126
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issue 1
118-119
EN
Low field magnetic properties of amorphous (Fe_{x}Co_{1})_{76}Mo_{8}Cu_{1}B_{15} alloys (x=3, 6 and 9) were characterized by magnetic after-effect and initial magnetic susceptibility. Activation energies and pre-exponential factors of the Arrhenius law that were derived from the disaccommodation curves are of about 1.188 eV and 10^{-15} s, respectively. Local magnetic arrangement was investigated by ^{57}Fe Mössbauer spectrometry. The average hyperfine magnetic field decreases with increasing Fe/Co ratio due to smaller relative contribution of cobalt. The overall magnetic parameters of the alloy prove its good soft magnetic properties with an application potential.
19
Content available remote

Thickness Dependence of Mössbauer Parameters for Fe₇₈Si₉B₁₃ Metallic Glass Ribbons

45%
Amini N., Miglierini M., Hasiak M., Dekan J., Habibi S.
Acta Physica Polonica A
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2017
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vol. 131
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issue 4
666-668
EN
Changes in magnetic microstructure of Fe₇₈Si₉B₁₃ ribbons were investigated by the Mössbauer spectrometry as a function of their thickness. The latter decreases inversely with the quenching wheel velocity. Amorphicity of the samples was checked by X-ray diffraction and the Mössbauer spectrometry. Average values of hyperfine magnetic fields do not appreciably differ with the production velocity. On the other hand, notable deviations are observed in the position of a net magnetic moment. After annealing with moderate temperature, the magnetic anisotropy improves as indicated by an increase of the average value of hyperfine magnetic field. However, magnetic moments turn out of the ribbon plane and this process continues towards higher production velocity, i.e., smaller thickness of the ribbons. No appreciable deviations in the investigated Mössbauer parameters were revealed after annealing during different time intervals.
20
Content available remote

Effects of Heavy-Ions on Soft-Magnetic Metallic Glasses Studied by Diffraction of Synchrotron Radiation

45%
Michalik S., Pavlovic M., Gamcova J., Sovak P., Miglierini M.
Acta Physica Polonica A
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2017
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vol. 131
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issue 4
657-659
EN
In this work, influence of ²³⁸U swift (5.9 MeV/u) heavy ions on the as-prepared Fe-Cu-Nb-Si-B metallic glass was investigated by in situ temperature X-ray diffraction of synchrotron radiation. It was observed that ion irradiation strongly affected the temperature evolution of the parameters of the first diffuse peak. It is hypothesized that ion irradiation induced structural rearrangement that increased the degree of disorder of the amorphous structure. During heat treatment, structural relaxation and annealing out of this ion-induced degradation took place. Consequently, the original structure was recovered as demonstrated by the behaviour of the first diffuse peak broadening and devitrification process.
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