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Wyświetlanie 1-15 z 45
Tytuł:
Effect of Laser Scribing on Soft Magnetic Properties of Conventional Grain-Oriented Silicon Steel
Autorzy:
Petryshynets, I.
Puchý, V.
Kováč, F.
Šebek, M.
Powiązania:
https://bibliotekanauki.pl/articles/1032233.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.-y
79.20.Eb
68.55.jm
77.80.Dj
75.50.Vv
Opis:
The present work investigates the influence of laser scribing of grain-oriented silicon steel on the improvement of its soft magnetic properties via magnetic domains modification. The experimental material was represented by conventional Fe-3%Si grain-oriented electrical steel that was taken directly from industrial line after the final box annealing. The laser scribing treatments were applied onto the material surface in order to induce thermal stresses having crucial influence on the magnetic domains refinement. The laser scribing conditions have been optimized by introducing thermal stresses onto the experimental material surface leading to optimal refinement of final domains structures and desired magnetic softness minimization. A semiquantitative relationship has been found between the domain patterns and the used fiber laser treating method. The obtained modified domain structure led to a significant decrease in coercivity measured in DC magnetic field from 20 A/m to 12 A/m.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 777-779
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
$[FeCl_{4}]¯$ Ionic Liquid Based Ferrofluids
Autorzy:
Parnica, J.
Kesa, P.
Kovac, J.
Timko, M.
Antalik, M.
Powiązania:
https://bibliotekanauki.pl/articles/1368745.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.64.kp
75.50.Bb
47.65.Cb
75.50.Mm
Opis:
Magnetic ionic liquids derived from hydrochloride methyl ester alanine amino acids (AA) and $FeCl_{3}$ were synthesized in ethanol and their magnetic properties were investigated. Iron (III) chloride forms ionic liquid in ethanol at saturated concentrations by the transfer of Cl¯ anion from one molecule of $FeCl_{3}$ to the other molecule with the creation of tetrachloro ferrate anion $[FeCl_{4}]$¯ as well as dimer $[Fe_{2}Cl_{7}]$¯. Raman scattering indicates that after addition of hydrochloride methyl ester alanine to ethanol solutions of $FeCl_{3}$ increase the intensities of signal at the frequencies at 318 $cm^{-1}$ and 380 $cm^{-1}$ as markers for the presence of $[FeCl_{4}]$¯ and $[Fe_{2}Cl_{7}]$¯ complexes. The magnetization at room temperature showed in both samples a linear dependence on the applied magnetic field. On the other hand, in the Raman scattering experiments the magnetization is smaller for $FeCl_{3}$ sample in the presence of methyl ester alanine.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 276-277
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Clean bulk YBaCuO superconductors doped by paramagnetic ions of Sm and Yb
Autorzy:
Jirsa, M.
Volochová, D.
Kováč, J.
Diko, P.
Powiązania:
https://bibliotekanauki.pl/articles/1054700.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.25.Ha
74.25.Op
74.25.Sv
74.60.Ge
74.72.-h
Opis:
The recently developed clean cuprate technology was employed to study the effect of tiny amounts of paramagnetic Yb and Sm ions on electromagnetic properties of bulk YBaCuO. Small samples of about 1.5×1.5×0.5 mm³ were measured by vibrating sample magnetometer in the field range ±9 T and temperatures 30 K to 10 K in the non-superconducting tetragonal state and 300 K to 70 K in the orthorhombic, superconducting state. In the latter case, we observed the reversible paramagnetic moment above T_{C}, similar as in the tetragonal state. Below T_{C} an irreversible magnetic moment was observed from which critical current density, J_c, was evaluated using the extended Bean model. The effect of doping by Yb and Sm ions on J_c was studied and a correlation between J_c and the total paramagnetic moment was found. Both J_c(B) and the normalized pinning force density as a function of the reduced magnetic field were analyzed in terms of the classical model and discussed with respect to the material anisotropy, giving us at least a rough idea on the type of the effective pinning type and mechanism.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1027-1029
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Composites Consisting of High-T$\text{}_{c}$ Superconductor and Fine Magnetic Particles
Autorzy:
Timko, M.
Kopčanský, P.
Kováč, J.
Koneracká, M.
Plecháček, V.
Powiązania:
https://bibliotekanauki.pl/articles/2013009.pdf
Data publikacji:
2000-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.72.Hs
75.50.Tt
Opis:
The composite systems as a mixture of fine magnetic particles of Fe$\text{}_{3}$O$\text{}_{4}$ and superconducting powder such as Bi$\text{}_{1.8}$Pb$\text{}_{0.2}$Sr$\text{}_{2}$Ca$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{10+x}$ were prepared. The influence of internal magnetic field (generated by magnetic particles) on the superconducting properties of prepared composites were studied as a function of concentration of magnetic particles and their magnetic state. The observed data both of the shielding and the Meissner effect were compared with corresponding linear combination of pure signals of magnetite and superconductor, respectively. The large differences were observed for demagnetized samples. It means that result must be discussed in the frame of the distribution of internal magnetic field created by the magnetic particles.
Źródło:
Acta Physica Polonica A; 2000, 97, 3; 389-392
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical Properties of Magnetite Nanoparticles Covered by 11-Mercaptoundecanoic Acid
Autorzy:
Timko, M.
Kopčanský, P.
Antalik, M.
Simsikova, M.
Valusova, E.
Molcan, M.
Kováč, J.
Powiązania:
https://bibliotekanauki.pl/articles/1429127.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
47.65.Cb
85.70.-w
75.30.Cr
75.47.Lx
Opis:
We have investigated the magnetic behavior of magnetite nanoparticles covered by the 11-mercaptoundecanoic acid around magnetite core prepared by a standard co-precipitation method. The particles show superparamagnetic behavior at room temperature, with transition to a blocked state at blocking temperature 91 K estimated from zero field cooled and field cooled at 500 Oe experiment. The hysteresis loop measured at 293 K showed magnetization 32.8 emu/g at 50 kOe without any coercivity. The mean particle size (7.1 nm) was determined by fitting a magnetization curve obtained at 295 K assuming a log-normal size distribution.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1321-1323
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Charcoal Supporting Silver as a Water Disinfectant
Autorzy:
Valušová, E.
Antalík, M.
Pristaš, P.
Javorský, P.
Kováč, J.
Timko, M.
Powiązania:
https://bibliotekanauki.pl/articles/1201874.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Ni
75.60.Ej
75.47.Lx
81.05.U-
92.40.qc
Opis:
We investigated the magnetic behavior of charcoal composite with incorporated magnetite and silver ions. The magnetization curve measured at 282 K showed saturation magnetization of 8 emu/g. By benefiting from a mechanical process, the magnetic activated carbon, supporting silver ions (MCAG), acts as a magnetic filter uptaking the bacteria. This idea was confirmed by the DGGE analysis in which the bacterial DNA was detectable in the sediment after the treatment.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 226-227
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation and Complex Characterization of Magnetic Nanoparticles in Magnetic Fluid
Autorzy:
Kubovčíková, M.
Antal, I.
Kováč, J.
Závišová, V.
Koneracká, M.
Kopčanský, P.
Powiązania:
https://bibliotekanauki.pl/articles/1201928.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.75.Fk
78.67.Bf
36.40.Cg
47.65.Cb
75.50.Mm
75.30.Cr
Opis:
This paper deals with the preparation and complex characterization of magnetite nanoparticles (MNPs), stabilized with sodium oleate (SO), by the routine methods such as infrared spectroscopy (FTIR), magnetic measurements, scanning electron microscopy (SEM) and dynamic light scattering (DLS). The FTIR spectra showed that SO molecules were linked to MNPs through chemical bonding. Magnetic measurements proved that the MNPs are superparamagnetic in nature. Four different methods were used to determine the size and size distribution of the MNPs: SEM, DLS, differential centrifugal sedimentation (DCS) and magnetic measurements. SEM analysis showed a relatively narrow size distribution of roughly spherical MNPs with a mean diameter of 61 nm. DLS analysis confirmed monodispersed MNPs production with hydrodynamic diameter of 75 nm. The size distribution determined by DCS was found to be 69 nm. Finally, the calculated magnetic core diameter obtained from magnetization curve was 10 nm. The obtained results demonstrate that SO coated MNPs fulfil the requirements for a useful drug delivery system.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 268-269
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Polymer Immobilization on Magnetic Properties of Magnetosomes
Autorzy:
Timko, M.
Džarová, A.
Kovač, J.
Kopčanský, P.
Gojzewski, H.
Powiązania:
https://bibliotekanauki.pl/articles/1535115.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Cr
75.30.Gw
75.50.Mm
75.50.Tt
75.60.Ej
Opis:
The anisotropy of several PVA/magnetosomes magnetically textured films has been investigated from the point of view of magnetic properties. The thin film synthesized under the influence of a magnetic field (99 mT) shows the typical behavior of an anisotropic material. On sample textured in magnetic field the magnetisation loop measurements were performed in dependence on the direction of the external magnetic field with respect to the texture axis. The results of hysteresis measurements show that the magnetic field applied during the synthesis promotes an orientation of the chains of magnetosomes and permanently textured film is obtained after solidification. The obtained values for magnetic remanence and coercivity were dependent on the external magnetic field orientation and the alignment effect of particle moments may be clearly seen which is in agreement with the theoretical model of magnetic particle chains.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 995-997
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Birefringence Study of the Magnetic Core Structure of Ferritin
Autorzy:
Koralewski, M.
Pochylski, M.
Mitróová, Z.
Melníková, L.
Kováč, J.
Timko, M.
Kopčanský, P.
Powiązania:
https://bibliotekanauki.pl/articles/1428622.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Ls
87.15.-v
87.85.jf
Opis:
Magnetically induced optical birefringence (Δ n) was measured for magnetoferritin and horse spleen ferritin aqueous suspensions. The Δ n for magnetoferritin was described in the frame of the Langevin formalism taking into account distribution of core diameter. The established average magnetic dipole moment and core diameter is equal to about 460 $μ_{B}$ and 3 nm, respectively. It was shown that magnetic birefringence and the Cotton-Mouton constant can be powerful parameters in identification of the magnetic core structure of ferritin, especially useful in biomedicine.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1237-1239
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure and Transport Properties of La$\text{}_{0.75-x}$RE$\text{}_{x}$Ca$\text{}_{0.25}$MnO$\text{}_{3}$ (RE = Gd, Dy, Ho; 0≤ x≤0.75) Manganites
Autorzy:
Drozd, V.
Pękała, M.
Kovac, J.
Skorvanek, I.
Szymański, M.
Nedilko, S.
Powiązania:
https://bibliotekanauki.pl/articles/2041482.pdf
Data publikacji:
2004-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.47.Lx
71.38.-k
72.20.Ee
75.50.Dd
Opis:
Structure and transport properties have been studied for a series of La$\text{}_{0.75-x}$RE$\text{}_{x}$Ca$\text{}_{0.25}$MnO$\text{}_{3}$ manganites with heavy rare earth ions of Gd, Dy, Ho substituting La with x=0, 0.10, 0.25, 0.50, and 0.75. Polycrystalline samples were prepared by the carbonate precipitation route. The oxygen content was determined by the iodometric titration. The X-ray investigations carried out by the powder method show that the unit cell volume gradually decreases and orthorhombic distortion of the lattice increases with rising RE content. Below the room temperature the electrical resistivity is of the semiconducting type for all the samples studied. Electrical resistivity vs. temperature dependences were analyzed within different models: simple thermal activation, Mott's variable range hopping, adiabatic, nonadiabatic, and bipolaron. The Curie temperatures of Gd, Dy, and Ho substituted manganites determined from magnetization measurements show that at 280 K all the samples are in the paramagnetic phase. The increasing RE fraction reduces magnetization at 4 K as compared to La$\text{}_{0.75}$Ca$\text{}_{0.25}$MnO$\text{}_{3}$.
Źródło:
Acta Physica Polonica A; 2004, 106, 5; 751-758
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation and Investigations of $Ni_{0.2}Zn_{0.8}Fe_2O_4$ Ferrite Nanofiber Membranes by Needleless Electrospinning Method
Autorzy:
Streckova, M.
Mudra, E.
Sebek, M.
Sopcak, T.
Dusza, J.
Kovac, J.
Powiązania:
https://bibliotekanauki.pl/articles/1398266.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.75.Cd
75.50.Gg
81.07.-b
75.47.Lx
Opis:
The preparation of $Ni_{0.2}Zn_{0.8}Fe_2O_4$ nanofiber membranes by simple and versatile needleless electrospinning technique is presented. The single phase of spinel ferrite membrane was obtained after conventional thermal treatment of polyvinyl alcohol (PVA)/metal nitrate precursors at 800°C for 4 h in air. The formation of single-phase fibers was characterized using differential scanning calorimetry accompanied with thermogravimetric analysis. The surface morphology, microstructure and crystal structure were investigated by scanning electron microscopy, X-ray diffraction and transmission electron microscopy. The magnetic properties of the fibrous samples measured in the temperature range from 2 to 300 K verify a soft magnetic behavior, which is quite typical for ferrimagnetic spinel-type ferrites.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 729-731
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Thorium Ferricyanide
Autorzy:
Göbl, R.
Zentková, M.
Kavečanský, V.
Kováč, J.
Zentko, A.
Powiązania:
https://bibliotekanauki.pl/articles/2013694.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Cr
Opis:
The magnetic properties of Th$\text{}_{3}$[Fe(CN)$\text{}_{6}$]·10H$\text{}_{2}$O were investigated. It was shown that this compound is antiferromagnetically ordered in the low temperature region. The observed antiferromagnetic ordering is stable only in the low field.
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 835-838
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Losses Evolution of Ferritic Fe-Si Steel Subjected to Temper Rolling at Elevated Temperature
Autorzy:
Petryshynets, I.
Kováč, F.
Falat, L.
Puchý, V.
Šebek, M.
Powiązania:
https://bibliotekanauki.pl/articles/1030935.pdf
Data publikacji:
2018-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.-y
75.50.Vv
81.40.Ef
61.72.Cc
Opis:
The effects of heat transport phenomena and deformation gradient through the sheet cross-section on the microstructure, texture and magnetic properties of non-oriented Fe-Si steel were investigated. In order to achieve desired conditions for the steel microstructural and textural parameters improvement, a temper rolling process at elevated temperature was examined in combination with subsequent short term annealing, employing fast heating rate in laboratory conditions. The experimental material was represented by conventional medium silicon, vacuum degassed non-oriented steel that was taken directly from industrial line after final annealing. Performed electron back scattered diffraction measurements revealed that the experimental steel, treated by our proposed thermomechanical treatment, was characterized by coarse-grained microstructure with enhanced intensity of rotating cube texture. The magnetic losses of experimental samples were measured in ac magnetic field with 50 Hz frequency on the toroid with external and internal diameters of 25 mm and 15 mm, respectively. These measurements with magnetic field intensity of 2500 A/m showed that the application of our suggested treatment led to clear power losses reduction of the investigated material from initial 9.9 W/kg to 6.4 W/kg, i.e. by more than 35%.
Źródło:
Acta Physica Polonica A; 2018, 133, 4; 1065-1068
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Fe@Pt Nanoparticles with Core/Shell Morphology
Autorzy:
Zeleňáková, A.
Zeleňák, V.
Bednarčík, J.
Lauda, M.
Kováč, J.
Powiązania:
https://bibliotekanauki.pl/articles/1535141.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.75.Fk
75.50.Vv
75.40.Gb
Opis:
We have investigated the magnetic properties of iron nanoparticles coated by platinum shell prepared by chemical procedure. Magnetic measurements using SQUID magnetometer confirm the behaviour typical for a superparamagnetic system. From the M(H) loop at 300 K the magnetic moment of each particle $m_{P}$ ≈ $250 μ_{B}$ was calculated. The magnetic relaxation study by the in-phase χ' and out-of-phase χ" ac susceptibilities in frequency range 0.1-1000 Hz suggests the existence of two magnetic layers with different magnetic spin's dynamics and strong dipolar interactions between nanoparticles. The observed magnetic behaviour is caused by the blocking process of interacting superparamagnetic particles with magnetic iron core, diamagnetic platinum shell and spin-glass like behaviour magnetic interlayer between them.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 1002-1004
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and Characterization of Magnetoferritin
Autorzy:
Mitróová, Z.
Melníková, L.
Kováč, J.
Timko, M.
Kopčanský, P.
Powiązania:
https://bibliotekanauki.pl/articles/1429123.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Cr
75.50.Ee
75.60.Ej
75.50.Tt
Opis:
The paper presents detailed experimental study of synthesis and characterization a bioinorganic magnetic molecule - magnetoferritin. Magnetoferritin with loading of iron ions per protein molecule in the range from 300 to 3000 was prepared. Size distribution analysis (transmission electron microscopy, dynamic light scattering) shows spherical nanoparticles with particle size distribution from 2 to 12 nm, and hydrodynamic diameter from 12 to 25 nm. The thermomagnetic curves measured after cooling the sample in zero field (zero-field cooling) and under the presence of the measurement field (field cooling) show superparamagnetic behavior with the blocking temperature $T_{b}$ from 22 to 60 K and the magnetization loops measured below $T_{b}$ (at 2 K) show the hysteresis with coercive field from 20 to 30 kA/m depending on the concentration of the magnetic nanoparticles.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1318-1320
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 45

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