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1
Content available Synthesis and characterization of iron oxide magnetic nanoparticles
Surowiec Z., Budzyński M., Durak K., Czernel G.
Nukleonika
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2017
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Vol. 62, No. 2
73--77
EN
Small particles of magnetite, i.e. 7.5, 13.4 and 14.1 nm in diameter, were obtained by the method of co-precipitation. The crystal structure and size distributions were determined by means of transmission electron microscopy and X-ray diffraction. The magnetic properties of the nanoparticles were tested by Mössbauer spectroscopy within the temperature range from 3 K to room temperature (RT). The Mössbauer study of magnetic nanoparticles reveals relaxation behaviour related to the existence of the superparamagnetic phase. The blocking temperature depends on the sizes of the nanoparticles and the ammonia concentration.
2
Content available Spin reorientation process in Tm2–xHoxFe14B : analysis of conical arrangement based on Mössbauer spectra
Kurzydło P. M., Pędziwiatr A. T., Bogacz B. F., Przewoźnik J., Oleszak D.
Nukleonika
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2017
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Vol. 62, No. 2
123--127
EN
The spin reorientation process in the Tm2–xHoxFe14B series of compounds was studied using 57Fe Mössbauer spectroscopy over the temperature range 5.2–320 K with a focus on the analysis of conical spin arrangement. Each compound was studied by precise Mössbauer scanning in the vicinity of the transition and during the transition. By applying computer simulations based on the simplified Yamada-Kato model, as well as on some literature data for R2Fe14B (R = Tm, Ho) compounds, the above series was selected for studies as it contains compounds with different spin arrangements (axial, planar, conical). It was a crucial requirement for obtaining unambiguous angular dependences when applying a simultaneous fitting procedure of Mössbauer spectra. Such an extended procedure was applied which allowed the temperature dependence of the angle describing the position of the magnetization vector to be obtained. The results were compared with those from theoretical simulations. The spin arrangement diagram was constructed. A conical spin arrangement was confirmed over a wide temperature range.
3
Content available Investigation of magnetite Fe3O4 nanoparticles for magnetic hyperthermia
Surowiec Z., Miaskowski A., Budzyński M.
Nukleonika
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2017
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Vol. 62, No. 2
183--186
EN
The paper presents the investigation of magnetic nanoparticles (MNPs) dedicated to hyperthermia application. The crystal structure and size distributions have been determined by means of transmission electron microscope (TEM) and X-ray diffraction (XRD). Magnetic properties of the nanoparticles were tested by Mössbauer spectroscopy together with calorimetric experiments. The Mössbauer spectroscopic study of MNPs revealed the existence of a superparamagnetic phase. The relative contribution of the relaxing component to the total spectrum at room temperature was about 10%. The heating effect of these MNPs under alternating magnetic field was examined. The temperature increase has reached 5°C in 10 min. The preliminary temperature rise suggests that the investigated materials are applicable for hyperthermia.
4
Content available Features of the structural and magnetic properties of Pb(TixZr1–xO3)-NiFe1.98Co0.02O4 in the polarized state
Baev V., Budzyński M., Laletin V., Mitsiuk V., Poddubnaya N., Surowiec Z., Yanushkevich K.
Nukleonika
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2017
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Vol. 62, No. 2
91--94
EN
Composites with a 90%Pb(TixZr1–xO3)-10%NiFe1.98Co0.02O4 composition have been synthesized. It has been established that the polarization of samples resulting from exposure to an electric field for 1 hour of 4 kV/mm in strength at a temperature of 400 K leads to crystal structure deformation. The compression of elementary crystal cells in some areas during polarization of the sample creates conditions suitable for the enhancement of magnetic exchange interactions. It has been found that the polarization process of such compositions leads to increases in specific magnetization and magnetic susceptibility. The analysis of Mössbauer spectra has shown that the polarization of the 90%Pb(TixZr1–xO3)-10%NiFe1.98Co0.02O4 composite leads to significant changes in the effective magnetic fields of iron subspectra in various positions.
5
Content available The study of crystal and magnetic properties of MnNi0.85Fe0.15Ge
Budzyński M., Valkov V. I., Golovchan A. V., Mitsiuk V. I., Sivachenko A. P., Surowiec Z., Tkachenka T. M.
Nukleonika
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2015
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Vol. 60, No. 1
11--14
EN
Magnetic and Mössbauer measurements were performed for MnNi0.85Fe0.15Ge. The Mössbauer data indicate that Fe atoms in MnNi0.85Fe0.15Ge are randomly distributed over two types of metal sites in hexagonal structure. At 77 K, the hyperfi ne magnetic fi elds at Fe located in different crystal sites have similar values of about 12.7 and 12.3 T. The random site distribution of the iron atoms in the non-magnetic hexagonal phase at high temperatures is confi rmed by the theoretical calculations in fully relativistic Korringa−Kohn−Rostoker (KKR) method.
6
Content available Search for canted spin arrangement in Er2-xTbxFe14B with Mössbauer spectroscopy
Kurzydło P. M., Bogacz B. F., Pędziwiatr A. T., Oleszak D., Przewoźnik J.
Nukleonika
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2015
|
Vol. 60, No. 1
93--96
EN
The materials studied were polycrystalline compounds Er2-xTbxFe14B (x = 0.1, 0.2, 0.3, 0.4) which crystallize in a tetragonal lattice and display a variety of spin arrangements. The compounds have been measured with 57Fe Mössbauer spectroscopy over the temperature range 80–320 K in order to investigate the spin reorientation processes. Each compound was studied in a wide temperature range, with precise Mössbauer scanning in the vicinity of the transition. The set of spectra obtained for a given compound was analyzed using simultaneous fi tting procedure to investigate the infl uence of the transition on the shape of the spectra. The fi tting program was specifi ed to analyze the transition according to the ‘two state model’: spins fl ip abruptly from initial angle to fi nal arrangement (90° angle). Obtained results suggest that spin reorientation process cannot be described using only the mentioned above model. Additional computer simulations based on the Yamada–Kato model were conducted to determine temperature range and the type of spin alignments in the vicinity of the transition. These theoretical results supported by spectra analysis suggest the existence of intermediate (canted) spin arrangements in the studied compounds. The spin arrangement diagram was constructed.
7
Content available Magnetic and structural properties of Sc(Fe1−xSix)2 Laves phases studied by Mössbauer spectroscopy and neutron diffraction
Wiertel M., Surowiec Z., Budzyński M., Sarzyński J., Beskrovnyi A. I.
Nukleonika
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2015
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Vol. 60, No. 1
155--160
EN
The investigations of iron-containing phases existing in fly ashes were performed using transmission Mössbauer spectrometry. The examined samples of fly ashes were collected from different coal combustion systems, that is, stoker-fired boiler in municipal heating plant and pulverized coal boiler in power plant. Several phases are identifi ed in the samples: iron oxides, paramagnetic aluminosilicate glass with Fe3+ ions and Al2O4- -type spinel with Fe2+ ions. It was pointed out that proportions of contents of phases strongly depend not only on the combustion temperature but also on the way of ash collection.
8
Content available Influence of annealing temperature on structural and magnetic properties of MnFe2O4 nanoparticles
Surowiec Z., Wiertel M., Gac W., Budzyński M.
Nukleonika
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2015
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Vol. 60, No. 1
137--141
EN
Nanoparticles of manganese ferrite were obtained by the impregnation of highly ordered mesoporous MCM-41 silica support. The investigated sample contained 20% wt. Fe. The obtained nanocrystallites were strongly dispersed in silica matrix and their size was about 2 nm. The sample annealing at 500°C led to increase of particle size to about 5 nm. The Mössbauer spectroscopy investigations performed at room temperature show on occurrence of MnFe2O4 nanoparticle in superparamagnetic state for the sample annealed in all temperatures. The coexistence of superparamagnetic and ferromagnetic phase was observed at liquid nitrogen temperature. The sample annealed at 400°C and 500 °C has bigger manganese ferrite particle and better crystallized structure. One can assign them the discrete hyperfi ne magnetic field components.
9
Content available Synthesis and characterization of iron - cobalt nanoparticles embedded in mesoporous silica MCM - 41
Surowiec Z., Wiertel M., Budzyński M., Gac W.
Nukleonika
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2013
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Vol. 58, No. 1
87-92
EN
Fe1.xCox/MCM-41 nanocomposite materials were prepared by wet impregnation of the silica mesoporous support with aqueous solution of iron and cobalt salt mixtures. Samples, after calcination, were reduced at 573 K in order to obtain homogeneous distribution of (Fe-Co)3O4 oxide species over the MCM-41 support. Bimetallic systems were achieved through high temperature reduction, carried out at 1073 K. The temperature-programmed reduction studies indicated complex nature of the oxide species. The phase analysis of the obtained samples after low temperature reduction process carried out by means of X-ray diffraction method and using 57Fe Mossbauer spectroscopy revealed the presence of nanostructured magnetite- and maghemite-like phases. The samples with higher cobalt contents (x . 0.2) contained additionally bimetallic phases. The complete transformation of oxide phases to bimetallic Fe-Co systems occurred during reduction process in hydrogen at 1073 K. It was observed that high temperature processing caused partial transformation of highly dispersed iron oxide nanocrystallites into fayalite species embedded in the silica walls.
10
Content available Study of B8 - type solid solutions of Al and Si in manganese antimonide
Budzyński M., Mitsiuk V. I., Ryzhkovskii V. M., Surowiec Z., Tkachenka T. M.
Nukleonika
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2013
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Vol. 58, No. 1
149-152
EN
The Mn1.1Sb1.yAly (0 less-than or equal to y less-than or equal to 0.2) and Mn1.1Sb1-ySiy (0 less-than or equal to y less-than or equal to 0.1) solid solutions with the B8-type of crystal structure were obtained. The magnetic measurement revealed that the partial substitution of Sb atoms by Al or Si practically do not affect the specific magnetization and Curie temperatures. Mossbauer data showed the local redistribution of atoms in solid solutions by comparison with that in the parent Mn1.10Sb.
11
Content available Structural and magnetic properties of Sc(Fe1-xCux)2 compounds studied by means of Mössbauer effect and neutron diffraction
Wiertel M., Surowiec Z., Budzyński M., Sarzyński J.
Nukleonika
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2013
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Vol. 58, No. 1
173-178
EN
The subject of the investigations were quasibinary Sc(Fe1-xCux)2 Laves phases in which structural and magnetic properties depend on replacement of Fe atoms by Cu atoms. Powder X-ray diffraction and neutron diffraction measurements carried out at room temperature revealed that samples were a mixture of two phases: the quasibinary Sc(Fe1-xCux)2 compounds with cubic C15 structure and ScCu2 with tetragonal structure. 57Fe Mossbauer spectroscopy revealed that the Sc(Fe1-xCux)2 compounds are ferrimagnetic up to an actual concentration xact less than 0.30. A decreasing of mean values of hyperfine magnetic fields was observed. On the basis of analysis of the neutron diffraction spectra the mean values of Fe magnetic moments were determined, considering the component connected with the quasibinary Sc(Fe1-xCux)2 phases. These moments change from 1.45(29) �ĘB in the Sc(Fe0.92Cu0.08)2 to 1.18(32)mi B in Sc(Fe0.72Cu0.28)2 phase at 8 K. From the results of independent hyperfine magnetic field on 57Fe probes and magnetic Fe moments measurements, the hyperfine coupling constant in quasibinary ferrimagnetic Sc(Fe1.xCux)2 phases is estimated as equal to 13 T/mi B at room temperature.
12
Content available Mössbauer investigations of Mn2-xFexP0.5As0.5
Mitsiuk V. I., Tkachenka T. M., Budzyński M., Surowiec Z., Valkov V. I.
Nukleonika
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2013
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Vol. 58, No. 1
169-172
EN
Magnetic and Mossbauer measurements were performed for Mn2.xFexP0.5As0.5, 0.5 less-than or equal to x less-than or equal to 1.0. It was shown that with decreasing Fe content magnetic interaction significantly weakens. Low temperature magnetic structure could be explained as a superposition of ferromagnetic and antiferromagnetic contributions to the whole magnetic moment of the alloy.
13
Content available Hyperfine interactions in Tb0.27-xYxDy0.73Fe2 compounds at 295 K
Krawczyk A., Zwoźniak A., Guzdek P., Stoch P., Zachariasz P., Suwalski J., Pszczoła J.
Nukleonika
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2013
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Vol. 58, No. 1
133-135
EN
This paper concerns the synthesis of yttrium-dilute Tb0.27-xYxDy0.73Fe2 intermetallic series with a borderline compound Tb0.27Dy0.73Fe2 known as Terfenol-D by arc melting, XRD analysis and 57Fe Mössbauer effect studies at 295 K. XRD analysis (295 K) shows that all samples crystallize in a cubic, Fd3m, MgCu2-type structure. The lattice parameter increases along with yttrium content. Mössbauer effect spectra for the Tb0.27-xYxDy0.73Fe2 series collected at 295 K consist of two subspectra due to easy direction of magnetization <111>. Hyperfine interaction parameters: isomer shift, magnetic hyperfine field and a quadrupole splitting were obtained from the fitting procedure of the spectra.
14
Content available Hyperfine interactions in Dy(Co0.4-xNixFe0.6)2 compounds at 295 K
Zwoźniak A., Krawczyk A., Stoch P., Guzdek P., Zachariasz P., Suwalski J., Pszczoła J.
Nukleonika
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2013
|
Vol. 58, No. 1
179-181
EN
57Fe Mössbauer effect studies were performed for the cubic C15, Fd3m, MgCu2-type Dy(Co0.4-xNixFe0.6)2 intermetallics. Hyperfine interaction parameters : isomer shift, magnetic hyperfine field and quadrupole interaction parameter were obtained from the fitting procedure of the collected 57Fe Mössbauer effect spectra. As a result of Co/Ni substitution, a Slater-Pauling type curve for the average magnetic hyperfine field vs. Ni content in the Dy(Co0.4-xNixFe0.6)2 series is observed.
15
Content available Crystal electric field parameters determination for R2Fe14B compounds based on Yamada - Kato model
Bogacz B. F., Pędziwiatr A. T.
Nukleonika
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2013
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Vol. 58, No. 1
31-33
EN
Semi-empirical model developed by Yamada-Kato enables calculation of magnetic spin directions for R2Fe14B compounds, based on minimization of free energy, and - in further steps - determination of spin reorientation temperatures for transitions from basal plane to axial easy magnetization direction. In our study, this model has been successfully used to determine crystal field and exchange field parameters for Er2-xCexFe14B compounds based on spin reorientation temperatures obtained experimentally from Mössbauer measurements.
16
Content available An application of Mössbauer spectroscopy in the studies of iron - molybdenum silica mesoporous materials
Surowiec Z., Wiertel M., Marynowska A., Gac W., Zawadzki W.
Nukleonika
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2013
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Vol. 58, No. 1
137-141
EN
Iron-molybdenum silica mesoporous materials were obtained by the application of direct hydrothermal method. Four samples with different metal contents relative to silica were investigated. Incorporation of iron and molybdenum ions in the synthesis stage led to structural changes of the MCM-41 support. With an increasing metals content, cylindrical pores of silica initially transformed into bottle-ink type pores, and then into the slit-like ones. Mössbauer spectroscopy investigations indicated that Fe ions were embedded in the silica walls and then formed nanosized crystallites in the pores. Superparamagnetic phase was observed at liquid nitrogen temperature.
17
Content available remote Struktura krystaliczna oraz właściwości magnetoelektryczne roztworów stałych 0,7Bi0,95Dy0,05FeO3-0,3Pb(Fe1/2Nb1/2)O3 oraz 0,7Bi0,95Dy0,05FeO3-0,3Pb(Fe2/3W1/3)O3
Stoch P., Stoch A., Zachariasz P., Maurin J.
Materiały Ceramiczne
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2012
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T. 64, nr 4
541-548
PL
Materiały multiferroiczne stanowią tworzywa nowej generacji łączące w sobie przynajmniej dwa stany uporządkowania, np. ferroelektryczny oraz ferromagnetyczny. Ze względu na swoje właściwości fizyczne stały się w ostatnim okresie przedmiotem licznych badań, zarówno teoretycznych jak i aplikacyjnych. W pracy podjęto próbę syntezy dwóch typów multiferroicznych roztworów stałych 0,7Bi0,95Dy0,05FeO3-0,3Pb(Fe1/2Nb1/2)O3 oraz 0,7Bi0,95Dy0,05FeO3-0,3Pb(Fe2/3W1/3)O3. Na podstawie przeprowadzonych badań stwierdzono, że otrzymane materiały posiadają strukturę romboedryczną typu R3c. Stosując technikę spektroskopii mössbauerowskiej pokazano przypadkowe rozmieszczenie kationów Bi3+ oraz Pb3+ w podsieci struktury krystalicznej. Wyliczono teoretycznie oraz zaobserwowano eksperymentalnie redukcję momentu magnetycznego na atomach Fe wraz ze wzrostem zawartości Pb w drugiej strefie koordynacyjnej. Na podstawie przeprowadzonych pomiarów efektu magnetoelektrycznego stwierdzono, że roztwory stałe z Pb(Fe1/2Nb1/2)O3 cechują się prawie 4-krotnie większymi wartościami napięciowego współczynnika magnetoelektrycznego w porównaniu z roztworami zawierającymi Pb(Fe2/3W1/3)O3.
EN
Multiferroics are new materials that exhibit at least two types of ordering in one phase for example ferroelectric and ferromagnetic. In the last couple of years, multiferroics become a subject of many theoretical and practical studies because of their unusual properties. In the present work, two kinds of solid solutions 0,7Bi0,95Dy0,05FeO3-0,3Pb(Fe1/2Nb1/2)O3 and 0,7Bi0,95Dy0,05FeO3-0,3Pb(Fe2/3W1/3)O3 were synthesized. According to x-ray studies both materials crystallized in the rhombohedral R3c structure. Mossbauer spectroscopy measurements confirmed a random distribution of Bi(3+) and Pb (3+) cations at their sublattice. A gradual reduction of iron magnetic moments with increasing Pb content in the second coordination sphere was observed. Magnetoelectric voltage coefficient was also examined and the ME parameter was almost 4 times higher for solid solutions with Pb(Fe1/2Nb1/2)O3 than Pb(Fe1/2Nb1/2)O3.
18
Content available Positron annihilation study of iron oxide nanoparticles in mesoporous silica MCM-41 template
Surowiec Z., Wiertel M., Zaleski R., Budzyński M., Goworek J.
Nukleonika
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2010
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Vol. 55, No. 1
91-96
EN
The subject of investigation were the samples obtained by impregnation of MCM-41 template with an aqueous solution prepared from Fe(NO3)3ź9H2O. As a result of such a procedure, iron oxides deposits on MCM-41 were formed. The Mössbauer studies revealed an occurrence of Fe3O4 nanocrystallites in the both ferri- and superparamagnetic states. Almost 80% small particles exist in a paramagnetic state. The positron annihilation lifetime spectroscopy (PALS) spectra were measured in air or in vacuum. The long-lived ortho-positronium (o-Ps) components and their intensities are time dependent due to air molecules interaction with iron oxide nanocrystallites and silica walls surfaces. The adsorption of air on the nanocrystallites surface causes a total screening of their surface and a raise of the o-Ps lifetime values. Observed anti-quenching effect is a result of competition of two phenomena: practically switching off a pick-off mechanism related to interaction of o-Ps with magnetite nanoparticles and considerably weaker usual quenching by paramagnetic oxygen molecules.
19
Content available Hyperfine interactions in Ho(Fe1-xCox)2 compounds at 295 K
Bednarski M., Stoch P., Bodnar W., Zachariasz P., Pszczoła J., Suwalski J.
Nukleonika
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2010
|
Vol. 55, No. 3
279-284
EN
Synthesis of Ho(Fe1–xCox)2 intermetallic compounds, studies of their crystal structure and 57Fe Mössbauer effect analysis were carried out at 295 K. X-ray measurements evidence a pure cubic Fd3m, C15, MgCu2-type Laves phase. The unit cell parameter decreases non-linearly with composition parameter x. Mössbauer effect spectra for the Ho(Fe1–xCox)2 series were composed of a number of locally originated subspectra due to random Fe/Co nearest neighbourhoods. Hyperfine interaction parameters, i.e. isomer shift, the magnetic hyperfine field and a quadrupole interaction parameter were determined from the fitting procedure of the spectra, for both the individual nearest neighbourhoods, and for the sample as bulk. As a consequence of Fe/Co substitution a Slater-Pauling type curve for the average magnetic hyperfine field vs. x is observed. The correlation between the local magnetic hyperfine fields and the average magnetic hyperfine fields is related to weak and strong ferromagnetism of the transition metal sublattice.
20
Content available Hyperfine interactions in Tb0.27Dy0.73(Fe1–xCox)2 compounds at 77 K
Bodnar W., Szklarska-Łukasik M., Stoch P., Zachariasz P., Pszczoła J., Suwalski J.
Nukleonika
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2009
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Vol. 54, No. 4
227-232
EN
The synthesis of materials, crystal structure and 57Fe Mössbauer effect studies at 77 K were performed for intermetallics Tb0.27Dy0.73(Fe1–xCox)2. The starting compound Tb0.27Dy0.73Fe2 of this Fe/Co substituted series is known as Terfenol-D. XRD measurements evidence a pure cubic Laves phase C15, MgCu2-type. The determined unit cell parameter decreases across the series. Co substitution introduces a local area, in the subnanoscale, with random Fe/Co neighbourhoods of the 57Fe atoms. Mössbauer effect spectra for the Tb0.27Dy0.73(Fe1–xCox)2 series collected at 77 K consist of a number of locally originated subspectra due to random composition of Fe and Co atoms in the nearest neighbourhood. Hyperfine interaction parameters: isomer shift, magnetic hyperfine field and a quadrupole interaction parameter were obtained from the fitting procedure of the spectra, both for the local area and for the sample as bulk. As a result of Fe/Co substitution, a Slater-Pauling type curve for the average magnetic hyperfine field vs. Co content in the Tb0.27Dy0.73(Fe1–xCox)2 series is observed. It is found that the magnetic hyperfine fields corresponding to the local area sorted out against Co contribution in the Fe/Co neighbourhoods also create a dependence similar to the Slater-Pauling type curve.
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