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1
Content available Magnetic nanowires (Fe, Fe-Co, Fe-Ni) : magnetic moment reorientation in respect of wires composition
Kalska-Szostko B., Wykowska U., Satuła D.
Nukleonika
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2015
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Vol. 60, No. 1
63--67
EN
Magnetic nanowires of Fe, Fe-Co, and Fe-Ni alloy and layered structure were prepared by electrochemical alternating current (AC) deposition method. The morphology of the nanowires in and without the matrix was studied by energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD), respectively. The wires either show strong dependence on the combination of elements deposition (alloy or layered) or chemical composition (Co or Ni). The magnetic properties of the nanostructures were determined on the basis of Mössbauer spectroscopy (MS).
2
Content available Determination of hyperfine fields and atomic ordering in NiMnFeGe exhibiting martensitic transformation
Satuła D., Szymański D., Rećko K., Olszewski W., Kalska-Szostko B.
Nukleonika
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2015
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Vol. 60, No. 1
127--131
EN
The hyperfi ne fi elds and atomic ordering in Ni1−xFexMnGe (x = 0.1, 0.2, 0.3) alloys were investigated using X-ray diffraction and Mössbauer spectroscopy at room temperature. The X-ray diffraction measurements show that the samples with x = 0.2, 0.3 crystallized in the hexagonal Ni2In-type of structure, whereas in the sample with x = 0.1, the coexistence of two phases, Ni2In- and orthorhombic TiNiSi-type of structures, were found. The Mössbauer spectra measured with x = 0.2, 0.3 show three doublets with different values of isomer shift (IS) and quadrupole splitting (QS) related to three different local surroundings of Fe atoms in the hexagonal Ni2In-type structure. It was shown that Fe atoms in the hexagonal Ni2In-type structure of as-cast Ni1−xFexMnGe alloys are preferentially located in Ni sites and small amount of Fe is located in Mn and probably in Ge sites. The spectrum for x = 0.1 shows the doublets in the central part of spectrum and a broad sextet. The doublets originate from the Fe atoms in the paramagnetic state of hexagonal Ni2In-type structure, whereas the sextet results from the Fe atoms in orthorhombic TiNiSi-type structure.
3
Content available Mössbauer investigation of some bcc, Fe - based, multicomponent alloys
Olszewski W., Szymański K., Satuła D., Oleszak D.
Nukleonika
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2013
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Vol. 58, No. 1
165-168
EN
Mössbauer measurements of a Fe-based, bcc multicomponent alloys with concentration of non-ferrous element x = (0.1, 0.3 and 0.6) were performed. The effective thickness parameters and the second order Doppler shifts were determined as a function of temperature. The results indicate an apparent decrease of the recoilless fraction with x. The observed trends are consistent with theoretical results indicating modifications of phonon density of states by bond disorder.
4
Content available Hyperfine interactions in (Cr0.9957Fe0.01)3 + xSi1 - x
Satuła D., Szymański K., Olszewski W., Kalska-Szostko B., Waliszewski J., Rećko K.
Nukleonika
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2013
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Vol. 58, No. 1
73-76
EN
X-ray diffraction measurements and Mossbauer spectroscopy with external magnetic field were carried out on (Cr0.99 57Fe0.01)3+xSi-x alloys. The Mossbauer spectra for A15 type of structure can be described by superposition of single line S(1) and two doublets D(1) and D(2). The relative ratio of the S(1) and D(2) strongly depends on x. The nearest neighbours of these components have been identified. It was shown that 57Fe atoms preferentially locate in Cr positions for x less-than or equal to 0.0, while for x greater 0.0 iron atoms are distributed both in Cr and Si positions. It was shown that, in A15 structure, one Cr atom located in the 57Fe nearest neighbours (n.n.) decreases isomer shift by (0.022 plus or minus 0.002) mm/s, while one Si in n.n. increases isomer shift by (0.09 plus or minus 0.01) mm/s. The measured Mossbauer spectra of bcc Cr-Si indicate that atoms are randomly distributed and can be well described as superposition of single lines, related to various local environments of 57Fe atoms.
5
Content available Magnetic texture determination by CEMS with polarized radiation
Olszewski K., Szymański K., Satuła D., Dobrzyński L.
Nukleonika
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2007
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Vol. 52, supl. 1
17-19
EN
CEMS measurements of a 57Fe foil were performed with unpolarized and polarized radiation. It is shown that the experimental results permit determination of important characteristics of a magnetic texture, an average square of the cosine((gamma-m)2) and an average cosine (gamma-m).
6
Content available Hyperfine fields in UFe5Sn compound
Satuła D., Szymański K., Tran V., Dobrzyński L.
Nukleonika
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2007
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Vol. 52, supl. 1
67-69
EN
Local hyperfine interactions on Fe nuclei in UFe5Sn compound were determined in Mössbauer experiment. The analysis of the Mössbauer spectra measured at room temperature reveals the presence of two doublets only. Absorption line width indicates that neither distribution of quadrupole splitting nor isomer shift exists in the alloy. The measurements at 13 K show the presence of four magnetic components. Because the magnetic dipole and electric quadrupole interactions are present, full Hamiltonian was used to determine the hyperfine interactions for each iron site. Electric field gradient determined at low temperatures agrees with quadrupole splitting observed at room temperature. Absorption areas of the components at low and at high temperatures correspond well to the occupation of
7
Content available remote Mössbauer investigations of the magnetic structure of A Fe-Mn
Szymański K., Olszewski W., Satuła D., Dobrzyński L.
Materials Science Poland
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2007
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Vol. 25, No. 2
363--369
EN
Mössbauer polarimetry was used for investigations of orientations of Fe magnetic moments in a AFe-Mn system. External magnetic field was applied to single crystal samples. Since the hyperfine field is a vector quantity, it forms a vector sum with the external magnetic field, and this quantity obviously depends on the magnetic structure of a system under study. Investigations with various orientations of external magnetic field with respect to the crystalline directions were performed. There is a clear experimental evidence that the distribution of Fe moments is present, which explains the already reported disagreement between simulated and measured results. Shapes of the spectra are best explained under the assumption of a coexistence of Q2 and Q3 structures. Influence of plastic deformation on the distribution of hyperfine fields is reported.
8
Content available remote Magnetization distribution in nanocrystalline Fe0.48Al0.52
Szymański K., Dobrzyński L., Satuła D., Voronina E., Yelsukov E.P.
Materials Science Poland
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2006
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Vol. 24, No. 3
753--759
EN
The Mössbauer polarimetry are used for investigation of orientation of the Fe magnetic moments in nanocrystalline Fe0.48Al0.52 disordered alloy prepared my mechanical grinding. Local Fe magnetic moments and their contributions to the net magnetization at the selected external fields and temperatures were estimated. It was found that the components of the Fe magnetic moments parallel to the net magnetizations reduce their values much faster with increasing number of neighbouring Al atoms than the total iron moments.
9
Content available The maximum entropy method in the analysis of the Mössbauer spectra
Dobrzyński L., Szymański K., Satuła D.
Nukleonika
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2004
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Vol. 49,suppl.3
89-93
EN
The paper shows the possibility of reconstruction of the distribution of hyperfine field parameters without prior assumptions concerning correlations between parameters. The method used is the maximum entropy method and the distributions considered concern the magnetic field and isomer shift. The results obtained are very encouraging and show the feasibility of the proposed method.
10
Content available Mössbauer studies of single crystal gamma-Mn-Fe
Szymański K., Olszewski W., Dobrzyński L., Satuła D., Jankowska-Kisielińska J.
Nukleonika
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2004
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Vol. 49,suppl.3
75-78
EN
Mössbauer measurements were performed on single crystals gamma-Mn60Fe37Cu3 in an external field of 1.3 T at room temperature. The hyperfine field distribution can be described as a vector sum of the external and internal fields. In addition, anisotropic response of magnetic moments was detected. The anisotropy, due to Fe atoms, has Fe-rich surroundings.
11
Content available Mössbauer study of the Fe1-xNix Invar alloys by monochromatic circularly polarized source
Satuła D., Szymański K., Dobrzyński L., Rećko K., Waliszewski J.
Nukleonika
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2003
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Vol. 48,suppl.1
71-74
EN
X-ray diffraction measurements and Mössbauer spectroscopy with and without external magnetic field parallel to beam direction have been performed for Fe1-xNix (x = 0.25, 0.30, 0.35) alloys. The compositions of the studied alloys were chosen in order to cover the concentration range where the fcc - bcc structural transformation appears, as well as where single phase fcc Fe-Ni alloys exhibit the Invar phenomena. Spatial distribution of the iron magnetic moments is discussed. The hyperfine magnetic field (h.m.f.) distribution is analyzed within a scope of two models discussed in the literature. In the first model it is assumed that any hyperfine magnetic filed vector have the same spatial distribution (the same values of (). In the second, the low field component of the hyperfine magnetic field is ordered antiferomagnetically (or disordered) while the high field component is aligned by an external magnetic field. In order to determine the mean values of cosine of the angle between teta-rays direction and hyperfine field vector of iron, (), a monochromatic circularly polarized Mössbauer source (MCPMS) was used. The analysis of the MCPMS results show that the shapes of the measured spectra can be explained by single values of .
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