Autor: Pikula, T. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Correlations between hyperfine magnetic field and some macroscopic magnetic quantities in mechanosynthesized CoxFeyNiz alloys
Autorzy:: Pikula, T.
Tematy:: CoFeNi alloys
hyperfine interactions
mechanical alloying
Mössbauer spectroscopy
soft magnetic materials; Pokaż więcej
Wydawca:: Instytut Chemii i Techniki Jądrowej
Powiązania:: https://bibliotekanauki.pl/articles/147844.pdf Link otwiera się w nowym oknie
Opis:: 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.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Zależność częstotliwościowa napięciowego współczynnika magnetoelektrycznego w ceramikach (BiFeO3)x-(BaTiO3)1-x
Частотна залежність магнітоелектричного коефіцієнту напруги у кераміці (BiFeO3)X-(BaTiO3)1-X
Frequency dependence of the magnetoelectric voltage coefficient in (BiFeO3)x-(BaTiO3)1-x ceramics
Autorzy:: Pikula, T.
Kowal, K.
Guzdek, P.
Tematy:: multiferroiki
efekt magnetoelektryczny (ME)
materiały magnetoelektryczne
napięciowy współczynnik magnetoelektryczny
dynamiczna metoda pomiaru
multiferroics
magnetoelectric effect (ME)
magnetoelectric materials
magnetoelectric voltage coefficient
lock-in technique
dynamic measurement of ME effect; Pokaż więcej
Wydawca:: Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Powiązania:: https://bibliotekanauki.pl/articles/407817.pdf Link otwiera się w nowym oknie
Opis:: Zależność właściwości magnetoelektrycznych od składu chemicznego w ceramikach (BiFeO3)x-(BaTiO3)1-x została w ostatnim czasie zaobserwowana i odnotowana w literaturze. Pomiary efektu magnetoelektrycznego (ME) w tych materiałach wykonywane były metodą dynamiczną. Próbki o x = 0,9, 0,8 i 0,7 umieszczano w stałym (DC) polu magnetycznym generowanym przez elektromagnes, na które nałożono zmienne (AC) pole magnetyczne o częstotliwości f = 1kHz wytwarzane przez cewki Helmholtza. W niniejszej pracy przedstawiono podstawy teoretyczne tego rodzaju pomiarów oraz wyznaczono optymalną częstotliwość pola AC, która minimalizuje procesy powodujące redukcję mierzonego sygnału napięciowego.
Залежність магнітоелектричних властивостей від хімічного складу кераміки (BiFeO3)x-(BaTiO3)1-x цей факт був досліджений нещодавно і занотований в літературі. Вимірювання магнітоелектричного ефекту (ME) в цих матеріалах були виконані за допомогою динамічною методу. Зразки o x = 0,9, 0,8 i 0,7 розміщені в магнітному полі постійного струму (DC), що генерується електромагнітом, на який накладено змінне (AC) магнітне поле з частотою f = 1 кГц, утворюване катушками Гельмгольца. В цій статті показана теоретична основа цього виду вимірювання та визначена оптимальна частота поля АС, яка мінімалізує процеси, які зменшують вимірюваний сигнал напруги.
Composition-dependent magnetoelectric properties of sintered (BiFeO3)x-(BaTiO3)1-x ceramics have been recently observed and reported in the literature. Measurements of the magnetoelectric effect (ME) for these materials have been performed by usage of the dynamic method. The samples with x = 0.9, 0.8 and 0.7 were placed in a static (DC) magnetic field created by an electromagnet on which a sinusoidal (AC) magnetic field with a frequency of 1 kHz produced by Helmholtz coils was superimposed. In this work the theory of the dynamic measurement was presented and the optimal frequency of the AC field was determined in order to minimize the processes causing undesired reduction of the measured voltage signal.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Hyperfine Interactions and Some Magnetic Properties of Nanocrystalline $Co_{40}Fe_{50}Ni_{10}$ and $Co_{50}Fe_{45}Ni_{5}$ Alloys Prepared by Mechanical Synthesis and Subsequently Heat Treated
Autorzy:: Pikula, T.
Oleszak, D.
Pękała, M.
Tematy:: 81.20.Ev
75.50.Kj
61.10.-i
76.80.+y
75.60.Ej; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1506594.pdf Link otwiera się w nowym oknie
Opis:: $Co_{40}Fe_{50}Ni_{10}$ and $Co_{50}Fe_{45}Ni_{5}$ ternary alloys were prepared by mechanical alloying method. To check the stability of their structure thermal treatment was applied subsequently. As X-ray diffraction studies proved the final products of milling were the solid solutions with bcc lattice and the average grain sizes ranged of tens of nanometers. After heating of the $Co_{50}Fe_{45}Ni_{5}$ alloy up to 993 K the mixture of two solid solutions with bcc and fcc lattices was formed. In other cases thermal treatment did not change the type of the crystalline lattice. Mössbauer spectroscopy revealed hyperfine magnetic field distributions which reflected the different possible atomic surroundings of $\text{}^{57}Fe$ isotopes. Results of the macroscopic magnetic measurements proved that both investigated alloys had relatively good soft magnetic properties.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Sacral insufficiency fracture following rectal cancer treatment – case report
Autorzy:: Pikula, A.
Pikula, T.S.
Pastuszak, M.
Tematy:: sacral fracture
rectal cancer
treatment
carcinoembryonic antigen
magnetic resonance imaging
radiotherapy; Pokaż więcej
Wydawca:: Instytut Medycyny Wsi
Powiązania:: https://bibliotekanauki.pl/articles/2098211.pdf Link otwiera się w nowym oknie
Opis:: Introduction and Objective. Locally advanced rectal cancers witha high risk of recurrence need multimodal treatment Rusing neoadiuvant preoperative chemoradiotherapy or preoperative radiotherapy. Both rectal cancer surgery and the additional chemoradiotherapy or radiotherapy may cause late sequelae. The aim of the study is to present a clinical situation in which a pelvic recurrence of rectal cancer has to be distinguished from therapy side effects. Insufficiency fracture (IF) is one of the therapy side-effects. It can cause pain and decrease mobility and it is a well-known late complication to pelvic radiotherapy, but can be misinterpreted as a local recurrence. Conclusions. It is extremely important to distinguish IF from metastases, which may require biopsies and initiation of potentially toxic treatments such as chemotherapy. MRI and CT scans are complementary modalities to make an accurate diagnosis of IF.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Structure and Hyperfine Interactions of Mechanically Activated Delafossite CuFeO₂
Autorzy:: Siedliska, K.
Pikula, T.
Oleszak, D.
Jartych, E.
Tematy:: 75.85.+t
31.30.Gs
76.80.+y; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1030821.pdf Link otwiera się w nowym oknie
Opis:: Delafossite CuFeO₂ belongs to multiferroic class of materials. In this work, copper ferrite was prepared by mechanical activation with subsequent thermal treatment. X-ray diffraction and Mössbauer spectroscopy were used as complementary methods to study the structure and hyperfine interactions of the material. As proved by X-ray diffraction, CuFeO₂ compound was obtained with relatively low amount of secondary phases like CuO and CuFe₂O₄. The Mössbauer spectroscopy revealed paramagnetic character of the compound at room temperature. The purest delafossite CuFeO₂ was obtained by mechanical activation of pre-milled precursors and sintering at 1173 K. The temperature of thermal treatment is lower by 100 K as compared to the traditional solid-state synthesis.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Local atomic configuration in mechanically synthesized Co-Fe-Ni alloys
Autorzy:: Pikula, T.
Oleszak, D.
Żurawicz, J.
Jartych, E.
Tematy:: nanocrystalline alloys
mechanical alloying
hyperfine interactions
Mössbauer spectroscopy; Pokaż więcej
Wydawca:: Instytut Chemii i Techniki Jądrowej
Powiązania:: https://bibliotekanauki.pl/articles/148207.pdf Link otwiera się w nowym oknie
Opis:: 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.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Synthesis and characterization of AgFeO2 delafossite with non-stoichiometric silver concentration
Autorzy:: Siedliska, K.
Pikula, T.
Chocyk, D.
Jartych, E.
Tematy:: delafossite
silver ferrite
co-precipitation
hyperfine interactions
Mössbauer spectroscopy; Pokaż więcej
Wydawca:: Instytut Chemii i Techniki Jądrowej
Powiązania:: https://bibliotekanauki.pl/articles/148622.pdf Link otwiera się w nowym oknie
Opis:: 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.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Effect of BaTiO3 concentration on structural and magnetic properties of mechanically activated BiFeO3-BaTiO3 system
Autorzy:: Malesa, B.
Pikula, T.
Oleszak, D.
Jartych, E.
Wydawca:: Instytut Chemii i Techniki Jądrowej
Powiązania:: https://bibliotekanauki.pl/articles/146512.pdf Link otwiera się w nowym oknie
Opis:: In this research, the mechanical activation method is proposed as an alternative process of preparation of the (BiFeO3)1–x-(BaTiO3)x solid solutions with various concentrations of barium titanate (x = 0.1÷0.9). However, mechanical milling itself does not allow obtaining the desired products and additional thermal treatment is needed to complete the solid-state reaction. In the present studies, X-ray diffraction and 57Fe Mössbauer spectroscopy were applied as complementary methods in order to study the structural and magnetic properties of materials. The investigations revealed that an increase of BaTiO3 concentration causes changes in the crystalline and hyperfine magnetic structure of the studied (BiFeO3)1–x-(BaTiO3)x system.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Structure and Mössbauer spectroscopy studies of mechanically activated (BiFeO3)1-x-(BaTiO3)x solid solutions
Autorzy:: Malesa, B.
Antolak-Dudka, A.
Oleszak, D.
Pikula, T.
Tematy:: ceramic solid solutions
hyperfine interactions
mechanical activation
Mössbauer spectroscopy; Pokaż więcej
Wydawca:: Instytut Chemii i Techniki Jądrowej
Powiązania:: https://bibliotekanauki.pl/articles/148236.pdf Link otwiera się w nowym oknie
Opis:: (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.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Structure and Mössbauer Spectroscopy Studies of Multiferroic Mechanically Activated Aurivillius Compounds
Autorzy:: Mazurek, M.
Oleszak, D.
Pikula, T.
Karolus, M.
Jartych, E.
Tematy:: 75.85.+t
81.20.-n
61.05.cp
76.80.+y; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1382196.pdf Link otwiera się w nowym oknie
Opis:: X-ray diffraction and $\text{}^{57}Fe$ Mössbauer spectroscopy were applied as complementary methods to investigate the structure and hyperfine interactions of the Aurivillius compounds prepared by mechanical activation and subsequent heat treatment. Preliminary milling of precursors enhanced the diffusion process and pure Aurivillius compounds were obtained at lower temperature as compared with conventional solid-state sintering technology (lower at least by 50 K). All the investigated Aurivillius compounds are paramagnetic materials at room temperature.
Dostawca treści:: Biblioteka Nauki

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