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1
Content available Synthesis and characterization of AgFeO2 delafossite with non-stoichiometric silver concentration
Siedliska K., Pikula T., Chocyk D., Jartych E.
Nukleonika
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2017
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Vol. 62, No. 2
165--170
EN
The simple co-precipitation method was used to prepare AgxFeO2 delafossite with non-stoichiometric silver concentration in the range of x = 0.05–1. The obtained material was investigated using X-ray powder diffraction and 57Fe Mössbauer spectroscopy at room temperature. The structural and hyperfine interaction parameters were recognized in relation with decreasing silver concentration. The study revealed that the delafossite structure of AgxFeO2 was maintained up to x = 0.9; as the range of silver concentration was decreased to 0.05 ≤ x ≤ 0.8, a mixture of AgFeO2, Fe2O3 or/and FeOOH was formed.
2
Content available Crystal structure and Mössbauer effect in multiferroic 0.5BiFeO3-0.5Pb(Fe0.5Ta0.5)O3 solid solution
Stoch A., Maurin J., Stoch P., Kulawik J., Szwagierczak D.
Nukleonika
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2017
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Vol. 62, No. 2
177--181
EN
Multiferroic 0.5BiFeO3-0.5Pb(Fe0.5Ta0.5)O3 solid solution is a material that exhibits ferroelectric and antiferromagnetic orderings in ambient temperature. The solid solution was obtained as a result of a conventional reaction in a solid state. The obtained material is a dense, fine-grained sinter whose surface was observed by scanning electron microscopy (SEM) and stoichiometry was confirmed by energy dispersive X-ray spectroscopic (EDS) analysis. According to the X-ray powder diffraction (XRD) measurements, the main phase is R3c space group with admixture of Pm-3m regular phase. Small contribution of pyrochlore-like phase was also observed. Mössbauer spectroscopy suggested random distribution of Fe3+/Ta5+ cations in the B sites of ABO3 compound. Reduction of the magnetic hyperfine field with an increase in the substitution of Ta5+ in Fe3+ neighbourhood was also observed.
3
Content available Compositional dependence of hyperfine interactions and magnetoelectric coupling in (BiFeO3)x-(BaTiO3)1–x solid solutions
Kowal K., Guzdek P., Kowalczyk M., Jartych E.
Nukleonika
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2017
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Vol. 62, No. 2
117--122
EN
In this work the compositional dependence of hyperfine interactions and magnetoelectric coupling in (BiFeO3)x-(BaTiO3)1–x solid solutions where x = 0.5–0.9 fabricated from commercial BaTiO3 in terms of the solid-state sintering method at various temperatures and over different time periods is described. In general, as the content of BaTiO3 increases, a decrease in the hyperfine magnetic field (Bhf) at 57Fe nuclei was observed. However, for samples exhibiting lower homogeneity in which the ions of Bi3+ and Fe3+ are replaced by Ba2+ and Ti4+ with lower probability, higher values of Bhf are obtained. For the sample where x = 0.6 that exhibits the coexistence of rhombohedral, regular and tetragonal phases, the highest value of the αME coefficient (3.57 mV/A) was observed, which is more than three times higher when compared to the hitherto published results.
4
Content available Structure and some magnetic properties of (BiFeO3)x-(BaTiO3)1-x solid solutions prepared by solid-state sintering
Kowal K., Kowalczyk M., Czekaj D., Jartych E.
Nukleonika
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2015
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Vol. 60, No. 1
81--85
EN
This paper presents the results of the study on structure and magnetic properties of the perovskite-type (BiFeO3)x-(BaTiO3)1-x solid solutions. The samples differing in the chemical composition (x = 0.9, 0.8, and 0.7) were produced according to the conventional solid-state sintering method from the mixture of powders. Moreover, three different variants of the fabrication process differing in the temperatures and soaking time were applied. The results of X-ray diffraction (XRD), Mössbauer spectroscopy (MS), and vibrating sample magnetometry (VSM) were collected and compared for the set of the investigated materials. The structural transformation from rhombohedral to cubic symmetry was observed for the samples with x = 0.7. With increasing of BaTiO3 concentration Mössbauer spectra become broadened refl ecting various confi gurations of atoms around 57Fe probes. Moreover, gradual decreasing of the average hyperfi ne magnetic fi eld and macroscopic magnetization were observed with x decreasing.
5
Content available Structure and Mössbauer spectroscopy studies of mechanically activated (BiFeO3)1-x-(BaTiO3)x solid solutions
Malesa B., Antolak-Dudka A., Oleszak D., Pikula T.
Nukleonika
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2015
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Vol. 60, No. 1
109--114
EN
(BiFeO3)1-x-(BaTiO3)x solid solutions with x = 0.1–0.4 and 0.7 were investigated. The ceramics were prepared by mechanical activation technology and subsequent heat treatment. As was proved by X-ray diffraction, increase of BaTiO3 concentration causes a change in the crystalline structure from the rhombohedral structure characteristic of BiFeO3 to a cubic one. 57Fe Mössbauer spectroscopy allowed observation of a gradual transformation from an ordered spin structure of Fe3+ ions to the paramagnetic state with an increase of x.
6
Content available Mean hyperfine fields at 57Fe in dilute iron-based alloys studied by Mössbauer spectroscopy
Idczak R., Konieczny R., Chojcan J.
Nukleonika
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2015
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Vol. 60, No. 1
39--42
EN
The room temperature Mössbauer spectra of 57Fe were measured for numerous dilute iron-based alloys Fe1-xDx (D = Al, Co, Cr, Mn, Mo, Ni, Os, Pt, Re, Ru, Ta, Ti, V, W, Zn), annealed at 1270 K for 2 h before the measurements. The spectra were analyzed using the Hesse–Rübartsch method in order to determine the mean hyperfi ne magnetic fi eld at the 57Fe nuclei as a function of concentration x of the minority component of the alloy. As the binary alloys are one-faze solid solutions of an element D in iron, a linear relationship between and x is observed. The result supports the suggestion that Mössbauer spectroscopy is a useful tool for the study of dissolution of different elements in iron.
7
Content available Atomic short-range order in mechanically synthesized iron based Fe-Zn alloys studied by 57Fe Mössbauer spectroscopy
Konieczny R., Idczak R.
Nukleonika
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2015
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Vol. 60, No. 1
69--73
EN
Mechanical alloying method was applied to prepare nanocrystalline iron-based Fe1-xZnx solid solutions with x in the range 0.01 ≤ x ≤ 0.05. The structural properties of the materials were investigated with the Mössbauer spectroscopy by measuring the room temperature spectra of 57Fe for as-obtained and annealed samples. The spectra were analyzed in terms of parameters of their components related to unlike surroundings of the iron probes, determined by different numbers of zinc atoms existing in the neighborhood of iron atoms. The obtained results gave clear evidence that after annealing process, the distribution of impurity atoms in the fi rst coordination spheres of 57Fe nuclei is not random and it cannot be described by binomial distribution. The estimated, positive values of the short-range order parameters suggest clustering tendencies of Zn atoms in the Fe-Zn alloys with low zinc concentration. The results were compared with corresponding data derived from Calphad calculation and resulting from the cellular atomic model of alloys by Miedema.
8
Content available Oddziaływania nadsubtelne w ceramice (BiFeO3)0.9-(BaTiO3)0.1 wytworzonej przez aktywację mechaniczną
Malesa B., Mazurek M.
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska
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2014
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nr 2
16--19
PL
W pracy przedstawiono wyniki badań strukturalnych i magnetycznych dla ceramiki (BiFeO3)0.9-(BaTiO3)0.1 otrzymanej w procesie aktywacji mechanicznej. Badania struktury i oddziaływań nadsubtelnych przeprowadzono odpowiednio metodami dyfrakcji promieniowania X oraz spektroskopii efektu Mössbauera.
EN
In this work the results of structural and magnetic investigations for (BiFeO3)0.9-BaTiO3)0.1 ceramics prepared by mechanical activation are presented. The structural analysis and hyperfine interactions investigations were performed by X-ray diffraction and Mössbauer spectroscopy.
9
Content available X-ray diffraction, Mössbauer spectroscopy, and magnetoelectric effect studies of (BiFeO3)x-(BaTiO3)1-x solid solutions
Kowal K., Jartych E., Guzdek P., Stoch P., Wodecka-Duś B., Lisińska-Czekaj A., Czekaj D.
Nukleonika
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2013
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Vol. 58, No. 1
57-61
EN
In this work the hyperfine interactions in (BiFeO3)x-(BaTiO3)1-x solid solutions with relation to their structural properties have been investigated. X-ray diffraction, Mössbauer spectroscopy and magnetoelectric effect measurements have been used for studies of sintered (BiFeO3)x-(BaTiO3)1-x solid solutions with x = 0.9, 0.8 and 0.7. With increasing contents of BaTiO3, the structural transformation from rhombohedral to cubic was observed. The weakening of the hyperfine magnetic fields accompanied by this transformation. On the other hand, the increasing amount of BaTiO3 caused an increase of the magnetoelectric effect.
10
Content available Structure and hyperfine interactions of multiferroic Bim+1Ti3Fem-3O3m+3 ceramics prepared by mechanical activation
Mazurek M., Jartych E., Oleszak D.
Nukleonika
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2013
|
Vol. 58, No. 1
143-147
EN
The structure and hyperfine interactions in the Bi5Ti3FeO15, Bi6Ti3Fe2O18 and Bi7Ti3Fe3O21 multiferroic ceramics were studied using X-ray diffraction and Mössbauer spectroscopy. Samples were prepared by mechanical activation process in a high-energy ball mill from a mixture of TiO2, Fe2O3 and Bi2O3 oxides as polycrystalline precursor materials. The mechanical milling process was completed by thermal processing. A pure single-phased material was obtained in the case of Bi7Ti3Fe3O21 compound. The proposed mechanical activation technology allows to produce the Aurivillius compounds at lower temperature, by about 50 K, as compared to the solid-state sintering method.
11
Content available Structural, magnetic, and Mössbauer effect studies of bornite
Przewoźnik J., Żukrowski J., Gondek Ł., Lemański A., Kapusta C., Piestrzyński A.
Nukleonika
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2013
|
Vol. 58, No. 1
43-46
EN
The results of a combined study of bornite with Mossbauer spectroscopy, X-ray diffraction and DC magnetometry are reported. The orthorhombic crystallographic structure of the mineral is observed at 15 K and 300 K. It exhibits an increase of the orthorhombic distortion with decreasing temperature. Magnetic susceptibility shows a Curie-Weiss like behaviour between 230 K and 380 K corresponding to the effective magnetic moment of 7.2(3) mi B per formula unit. The material undergoes a transition to an antiferromagnetic-like state at 75 K. Mossbauer spectra at the paramagnetic range are doublets with a small quadrupole splitting and the isomer shift corresponding to a high spin Fe3+ state. Upon magnetic ordering, a coexistence of the paramagnetic doublet with a broadened magnetic sextet is observed indicating an inhomogeneous character of the magnetic transition. The hyperfine field of 350 kOe at 4.2 K is much lower than that observed for a high spin Fe3+ in oxides (510 kOe) which is attributed to covalence effects and a possible copper contribution to the effective magnetic moment of the compound.
12
Content available Hyperfine interactions and irreversible magnetic behavior in multiferroic Aurivillius compounds
Jartych E., Gąska K., Przewoźnik J., Kapusta C., Lisińska-Czekaj A., Czekaj D., Surowiec Z.
Nukleonika
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2013
|
Vol. 58, No. 1
47-51
EN
In this work investigations of structure and magnetic properties of conventionally sintered Bim+1Ti3Fem.3O3m+3 compounds with 4 less-than or equal to m less-than or equal to 8 were performed using X-ray diffraction, Mossbauer spectroscopy and vibrating sample magnetometry. Room-temperature Mossbauer spectra of the compounds correspond to a paramagnetic state, however, low temperature measurements (80 K) reveal the antiferromagnetic state with a residual paramagnetic phase. Temperature dependencies of magnetic susceptibility,chi sigma(T), provided magnetic ordering temperatures and revealed an irreversibility in Aurivillius compounds with m greater-than or equal to 5. In the case of Bi5Ti3FeO15 compound the chi sigma(T) dependence shows a paramagnetic behavior down to 2 K. The Bi6Ti3Fe2O18 compound reveals a magnetic ordering at 11 K. The compounds with m = 6-8 show a magnetic ordering at temperatures higher than 200 K. Highly irreversible character of their temperature dependencies of chi sigma indicates a spin-glass type disordered magnetism with frustration due to a random distribution of Fe on Ti at their sites.
13
Content available Correlations between hyperfine magnetic field and some macroscopic magnetic quantities in mechanosynthesized CoxFeyNiz alloys
Pikula T.
Nukleonika
|
2013
|
Vol. 58, No. 1
153-157
EN
In this work correlations between some macroscopic magnetic quantities and hyperfine magnetic field (HMF) were studied in the case of mechanosynthesized CoxFeyNiz alloys. The series of twelve samples was prepared by high energy ball milling. As the products of such process, disordered solid solutions with bcc or fcc crystalline lattice type were obtained. The magnetic measurements proved that in this case soft magnetic alloys with relatively high value of saturation magnetization were obtained. The semi-phenomenological relationship between the HMF value and the mean magnetic moment was also found for the studied samples. Moreover, correlations between some magnetic quantities and mean concentration of the 3d+4s electrons were investigated.
14
Content available Structural and magnetic investigations of Sc(Fe1-xNix)2 compounds by means of Mössbauer effect and neutron diffraction
Wiertel M., Surowiec Z., Sarzyński J., Budzyński M., Beskrovnyi I.
Nukleonika
|
2007
|
Vol. 52, supl. 1
71-75
EN
The structural and microscopic magnetic properties of the pseudobinary Sc(Fe1 xNix)2 system were studied by XRD and Mössbauer measurements in the range of 0.10 less-than or equal to - x less-than or equal to - 0.60. All investigated samples have the cubic C15-type structure. Both the magnetic hyperfine field on 57Fe and the Curie temperature decrease with increasing Ni content and the system becomes paramagnetic for x H 0.60 at room temperature. The form and temperature dependences of the Mössbauer spectra for 0.40 less-than or equal to - x less-than or equal to - 0.50 indicate the coexistence of paramagnetic and ferromagnetic regions in the samples and occurrence of magnetic clusters with a wide distribution of the Curie temperatures. As follows from the near to zero values of quadrupole shifts in Mössbauer spectra it results that a <100> direction is a local easy magnetization axis for x e 0.10.
15
Content available Mössbauer study of magnetite nanowire in MCM-41 type mesoporous silica templates
Surowiec Z., Goworek J., Ryczkowski J., Budzyński M., Wiertel M., Sarzyński J.
Nukleonika
|
2007
|
Vol. 52, supl. 1
33-36
EN
Arrays of Fe3O4 nanowires embedded in mesoporous ordered silica were obtained in two ways: dissolving Fe3+ ions in an aqueous medium and their adsorption on internal and external surfaces, with the use of a Fe-EDTA complex. Magnetite polycrystalline nanowires were characterized by means of X-ray diffraction and 57Fe Mössbauer spectroscopy (MS). The average length of these nanowires is about 70 nm and their diameter is about 3 nm. Mössbauer studies evidenced that the composites consist of very small Fe3O4 particles. Almost 80% of particles exist in a paramagnetic state.
16
Content available Local atomic configuration in mechanically synthesized Co-Fe-Ni alloys
Pikula T., Oleszak D., Żurawicz J., Jartych E.
Nukleonika
|
2007
|
Vol. 52, supl. 1
47-50
EN
Ternary Co-Fe-Ni alloys were prepared from the elemental powders by the mechanical alloying method. Structural properties and hyperfine interactions parameters were determined using X-ray diffraction and Mössbauer spectroscopy. X-ray diffraction proved that during milling Co-Fe-based solid solutions with b.c.c. lattice were formed in the case of Co40Fe40Ni20 and Co50Fe40Ni10 alloys, while for Co52Fe26Ni22 and Co65Fe23Ni12 compositions Co-Ni-based solid solutions with f.c.c. lattice were obtained. Mössbauer spectroscopy revealed similar values of the average hyperfine magnetic fields for all the alloys. These values corresponded to the different surroundings of 57Fe isotopes by Co, Fe and Ni atoms, depending on the chemical composition of the alloy. The possible atomic configurations around 57Fe isotopes were discussed on the basis of the local environment model under the assumption that only the first nearest neighbours contribute to the hyperfine magnetic field at 57Fe site.
17
Content available remote Evolution of hyperfine parameters in Co-doped FINEMET
Szumiata T, Brzózka K., Górka B., Gawroński M., Pavlík G., Sovák P.
Materials Science Poland
|
2006
|
Vol. 24, No. 3
599--603
EN
The influence of Co addition on microstructure and hyperfine parameters of (Fe1-xCox)73.5Cu1Nb3Si13.5B9 alloys has been studied by means of 57Fe Mössbauer spectrometry. In the amorphous ribbons fabricated by melt-spinning technique, the systematic changes of mean hyperfine field and isomer shift with cobalt content have been stated. In the annealed, nanocrystalline samples, the DO3-type structure of Fe(Co)-Si grains evolves into the bcc (Fe,Co)Si substitutional solid solution when increasing x. Simultaneously, the amorphous matrix is depleted in iron and cobalt. The observed increase of mean hyperfine field is attributed to the enrichment of nanocrystallites in magnetic elements as well as segregation of iron.
18
Content available Mössbauer effect studies of Dy(Mn0.4-xAlxFe0.6)2 intermetallics
Stoch P., Pszczoła J., Guzdek P., Jabłońska A., Suwalski J., Dąbrowski L., Pańta A.
Nukleonika
|
2004
|
Vol. 49,suppl.3
23-25
EN
Both 3d subbands in the Dy(Mn0.4Fe0.6)2 compound are filled up only partially with 3d electrons. So, it was interesting to study the consequence of Mn/Al substitution in the Dy(Mn0.4 xAlxFe0.6)2 series. The cubic, MgCu2-type, Fd3m crystal structure was observed across the series. However, for x = 0.35 and 0.40 a stoichiometric admixture of the hexagonal, MgZn2-type, P63/mmc structure was evidenced. Mössbauer effect measurements at 57Fe nuclei were performed at 77 K. The magnetic hyperfine field decreases vs. the aluminium content x. This dependence is related to the possible 3d-electron band structure.
19
Content available Mössbauer effect studies of Dy(Fe0.7-xNixCo0.3)2 intermetallics
Jabłońska A., Suwalski J., Pszczoła J., Guzdek P., Stoch P., Pańta A.
Nukleonika
|
2004
|
Vol. 49,suppl.3
85-88
EN
Abstract A consequence of the Fe/Ni substitution in the series of Dy(Fe0.7 xNixCo0.3)2 was studied in the presented paper. The synthesis and X-ray analysis (300 K) of the Dy(Fe0.7 xNixCo0.3)2 system were performed. The cubic, MgCu2-type, Fd3m crystal structure was evidenced for this solid solution. 57Fe Mössbauer effect measurements for the system were carried out at 77 K. The obtained crystallographic lattice parameters and the hyperfine interaction data are presented. The magnetic hyperfine field values form a separate branch of the Slater-Pauling curve situated above the branch corresponding to the Dy(Fe1 xCox)2 intermetallics.
20
Content available Effect of the substitution of Ti for Y on structural properties and hyperfine interactions in Y1-xTixFe2 compounds
Surowiec Z., Sarzyński J., Budzyński M., Wiertel M.
Nukleonika
|
2004
|
Vol. 49,suppl.3
17-21
EN
Abstract Room temperature 57Fe Mössbauer spectroscopy and X-ray diffraction measurements are reported for a series of Y1 xTixFe2 polycrystalline samples. Our research shows that except for x = 0 and x = 1, the samples are a mixture of two C15 and C14 pseudobinary Laves phases. Some Ti atoms occupy the crystallographic positions 8a characteristic of the Y atoms in the cubic C15 structure while the rest of them form the hexagonal C14 phase. However, the lattice constant dependencies on concentration x suggest the occurrence of Y atoms in the positions 4f characteristic of Ti atoms in the hexagonal C14 structure. The partial substitution of Ti atoms for Y atoms is responsible for the HMF changes in the cubic phase. Contrary to the situation taking place in the Zr1 xTixFe2 compounds, magnetic arrangement in the pseudobinary hexagonal phases is not observed at room temperature.
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