Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl

Refine search results

Journals help

  1. 56 Acta Physica Polonica A

Years help

  1. 1 2015

  2. 2 2014

  3. 2 2012

  4. 1 2011

  5. 6 2010

More...
Authors help

  1. 56 Szymczak H.

  2. 22 Szymczak R.

  3. 15 Baran M.

  4. 11 Dyakonov V.

  5. 9 Nabiałek A.

More...
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 56

Number of results on page
first rewind previous Page / 3 next fast forward last

Search results

help Sort By:

help Limit search:
first rewind previous Page / 3 next fast forward last
1
Content available remote

Experimental Studies of Electronic Phase Separation in High Temperature Superconductors

100%
Szymczak H., Szymczak R.
Acta Physica Polonica A
|
1994
|
vol. 85
|
issue 1
79-88
EN
Experimental research on macroscopic phase separation in La_{2}CuO_{4+δ} superconductor and photo-doped cuprates is reviewed. It is shown that the properties of the mixed-phase state strongly depend on the shape and size of the phase domains formed during the phase separation process. The interplay of magnetic and superconducting properties in the mixed-phase state is considered in details. The mechanisms driving the phase separation in La_{2}CuO_{4} and photo-doped materials are discussed in connection with presented experimental results.
2
Content available remote

Surface Magnetostriction

100%
Szymczak H., Żuberek R.
Acta Physica Polonica A
|
1993
|
vol. 83
|
issue 5
651-659
EN
Experimental and theoretical research on magnetostriction of nanoscale magnetic multilayers is reviewed. The importance of interfaces and the occurrence of the surface magnetostriction is emphasized. It is shown that the dependence of magnetostriction on the magnetic layer thickness is due to the magnetostrictive strains localized at the interface.
3
Content available remote

Critical Current Limitations and Irradiation Effects in High-Temperature

81%
Wiśniewski A., Puźniak R., Baran M., Szymczak H.
Acta Physica Polonica A
|
1993
|
vol. 84
|
issue 1
139-164
EN
The discovery of high-temperature superconductors stimulated many groups of researchers to study properties of these materials. From the basic point of view the most important problem is to clarify the mechanism of high-temperature superconductivity. From the practical point of view the most challenging task is to find mechanisms of strong pinning of the vortices, and thereby to obtain materials with high critical current density. The aim of this paper is to discuss problems connected with critical current limitations and to present possibilities which offer irradiation effects with respect to critical current enhancement.
4
Content available remote

Spin-Wave Excitations and Fluctuations of the Exchange Interaction in Amorphous Fe_{1-x}Zr_{x} Alloys

81%
Kossacki P., Stobiecki T., Szymczak H.
Acta Physica Polonica A
|
1993
|
vol. 83
|
issue 6
785-791
EN
Detailed magnetization measurements were performed on amorphous Fe_{1-x}Zr_{x} alloys with 0.14 ≤ x ≤ 0.48 at temperatures ranging from 4.2 K to the Curie temperature in external magnetic field up to 5 T. An analysis of the experimental data reveals that' the fluctuations of the exchange integral resulting from the structural disorder give important contribution to the thermal demagnetization and high-field susceptibility of Fe-rich alloys. For Zr-rich alloys the effect of fluctuations of the exchange integral is negligible and thermal demagnetization is described in terms of spin-wave excitations. No Stoner single-particle excitations were observed for alloys with x > 0.14.
5
Publication available in full text mode
Content available

Magnon Excitations in Manganites

81%
Aleshkevych P., Baran M., Szymczak H.
Acta Physica Polonica A
|
2004
|
vol. 106
|
issue 5
593-602
EN
A review of experimental studies of magnon excitations in manganites is presented. Two kinds of techniques: the inelastic neutron scattering (in bulk materials) and the microwave resonance (in thin films) are considered. Experimental studies of spin dynamics by inelastic neutron scattering in metallic ferromagnetic manganites have shown that at low temperature for small wave vectors k → 0 the dispersion relation has a quadratic shape similar to that observed in Heisenberg ferromagnets. However, the above technique although very informative can be used only for sufficiently large samples of bulk materials. A complementary microwave resonance technique allows studying not only bulk properties, but also surface properties. There are two main theoretical approaches used to interpret the spin wave resonance spectra: the volume inhomogeneity and the surface inhomogeneity models. The last one introduced by Puszkarski has allowed for interpretation of the observed surface magnon excitations in thin films.
6
Content available remote

Anomalous Reversible Torque in Layered Superconducting Bi_{2}Sr_{2}CaCu_{2}O_{x} Single Crystal

81%
Drzazga Z., Borgieł W., Szymczak R., Szymczak H.
Acta Physica Polonica A
|
1996
|
vol. 89
|
issue 1
91-98
EN
Magnetic anisotropy of layered superconducting Bi_{2}Sr_{2}CaCu_{2}O_{x} single crystal was investigated by the torque method in the reversible regime. The torque was analyzed in the model taking into account 2D layered structure. Considered model gives the better fit to the data when the magnetic field is applied near (a, b) plane. Obtained results establish to 6×10_{3} value of the superconducting effective mass anisotropy coefficient ε.
7
Content available remote

Electronic and Magnetic Properties of Co_{3}V_{2}O_{8} Compound

81%
Jezierski A., Szymczak R., Szymczak H., Kaczkowski J.
Acta Physica Polonica A
|
2009
|
vol. 115
|
issue 1
238-240
EN
The band structures and the magnetic properties of Co_{3}V_{2}O_{8} compound have been calculated by ab initio scalar-relativistic full potential local orbital method within the local spin density approximation. The band calculations were performed for para-, ferro-, and antiferromagnetic Co_{3}V_{2}O_{8} compounds. The main contribution to the density of states at the Fermi energy comes from minority 3d states of cobalt atoms.
8
Content available remote

Magnetic Anisotropy and Magnetostriction Oscillations in Magnetic Multilayers

81%
Szymczak H., Żuberek R., Stobiecki F.
|
|
vol. 96
|
issue 3-4
495-499
EN
Interlayer pseudodipolar coupling between two ferromagnets separated by nonmagnetic spacer is analyzed. It was shown that this type of interaction should induce magnetic anisotropy and magnetostriction oscillations. It was also predicted that both magnetic anisotropy and magnetostriction decrease with an increase in the spacer thickness. This effect was observed in [permalloy/Cu]_{100} multilayers.
9
Content available remote

Raman Scattering Study of (Sr,Ca)_{10}Cu_{17}O_{29} Single Crystals

81%
Strzeszewski J., Szymczak H., Leonyuk L., Szymczak R.
Acta Physica Polonica A
|
2000
|
vol. 98
|
issue 4
429-439
EN
Polarized Raman spectra of high temperature superconducting single crystals of A_{10}Cu_{17}O_{29} (A_{10}=Ca_{4.7}Sr_{4.1}Bi_{0.3}) were studied in various scattering configurations in the range of 40-700cm^{-1}. In very distinctive spectra there were found over 20 peaks. It was observed that the flat continuum of electronic excitations in the normal state was redistributed below the critical temperature. The frequency dependent redistribution is consistent with the value of energy gap estimated using tunnelling spectroscopy techniques.
10
Content available remote

Dipolar Contributions to Magnetoelastic Energy of Crystal Grains with Interfaces

81%
Szumiata T., Żuberek R., Szymczak H., Gonzalez J.
Acta Physica Polonica A
|
2000
|
vol. 97
|
issue 3
531-534
EN
The magnetic anisotropy and magnetostriction in nanocrystalline grains in non-magnetic or magnetic matrix (nanoparticles or nanocrystalline materials) differ from their bulk properties. The interactions between atoms at the interface play the important role in these magnetic properties. In this paper the magnetic dipolar contribution to magnetostriction energy has been calculated for spherical crystal grains (of bcc and fcc symmetry) with interface layer of atoms possessing different magnetic moment. Total magnetoelastic energy of the sphere-interface system is a sum of magnetoelastic energy of the sphere, energy of the interactions between the sphere and the interface and also the energy of the interface. It was shown that magnetoelastic energy depends on the sphere size and interface thickness.
11
Content available remote

Surface Magnetostriction within Néel's Model

81%
Żuberek R., Żymierska D., Szymczak H.
Acta Physica Polonica A
|
1994
|
vol. 85
|
issue 2
439-442
EN
The aim of the present paper is to determine the surface magnetostriction in the spirit of Néel's model of the surface magnetic anisotropy. Calculations have been performed for bcc and fcc ferromagnetic crystals.
12
Publication available in full text mode
Content available

Magnetoelastic Properties of La_{0.744}Ba_{0.186}MnO_3 Single Crystals

71%
Bukhantsev Y., Mukovskii Y., Vasiliev S., Kundys B., Szymczak H.
Acta Physica Polonica A
|
2004
|
vol. 105
|
issue 1-2
155-162
EN
Magnetoelastic properties of La_{0.744}Ba_{0.186}MnO_3 single crystals have been studied. The basic magnetoelastic constants of the crystal have been estimated using the data of magnetostriction and magnetization measurements, which have been carried out in [010] and [110] crystallographic directions in a wide temperature range from 10 K to 150 K. The anomaly of the thermal expansion has been observed at about 185 K. Near this anomaly two almost degenerated phase transitions have been observed. One of these transitions may be related to the structural phase transition, while the second one to the occurrence of spontaneous strains. The magnetostriction of La_{0.744} Ba_{0.186}MnO_3 single crystal seems to arise due to the effect of applied field on the spontaneous strains.
13
Content available remote

Giant Magnetocaloric Effect in Manganites

71%
Szymczak R., Kolano R., Kolano-Burian A., Dyakonov V., Szymczak H.
|
|
issue 1
203-206
EN
In this review we briefly discuss the magnetocaloric properties of the manganites. It is evidenced that the maximum entropy change observed in manganites exceeds that of gadolinium (the prototype material for room temperature refrigerators). For the manganites characterized by second-order magnetic phase transitions the scaling hypothesis is discussed. It is shown that simple phenomenological model with only one fitting parameter, presented in this paper, satisfactorily describes experimental observations.
14
Content available remote

Effect of Neutron Irradiation on the EPR Spectra of CuGeO_{3}

71%
Mosiniewicz-Szablewska E., Gładczuk L., Dąbkowska H., Pytel B., Szymczak H.
Acta Physica Polonica A
|
2000
|
vol. 97
|
issue 5
897-900
EN
The influence of neutron irradiation on the electron paramagnetic resonance spectra of the spin-Peierls compound CuGeO_{3} was investigated in the wide temperature range 2-300 K. It was found that the irradiation induced appreciable changes in the EPR signal intensity, resonance line width and g-factor of this material. It was also shown that the irradiation leads to a decrease in the spin-Peierls transition temperature. For higher irradiation doses, an antiferromagnetically ordered phase can be observed at lower temperatures. This phase coexists with the spin-Peierls phase. The observed decrease in the spin-Peierls transition temperature after irradiation may be associated with some changes in topological and chemical short-range order or with the transmutation of the fraction of ^{63}Cu in the ^{63}Cu(n,α)^{60}Co reaction.
15
Publication available in full text mode
Content available

Orbital Correlations and Magnetic Phase Transitions in Lightly Doped La_{0.88}MnO_x and LaMn_{0.94}O_y Manganites

71%
Troyanchuk I., Khomchenko V., Tovar M., Szymczak H., Bärner K.
Acta Physica Polonica A
|
2004
|
vol. 105
|
issue 1-2
27-44
EN
The results of X-ray and neutron diffraction study as well as the elastic, magnetic, and electrotransport properties of La_{0.88}MnO_x (2.82≤ x≤2.96) and LaMn_{0.94}O_y (2.91≤ y≤3.00)$ manganites have been presented. Under oxygen doping, the transitions from antiferromagnetic to ferromagnetic or spin-glass state are observed for La-deficient and La-excessive series, respectively. These transitions have been found to correlate with the change of the type of Jahn-Teller distortions from static to dynamic ones. The dynamic orbital correlations favor a ferromagnetic state, while an A-type antiferromagnetic state is typical of the static Jahn-Teller distortions. It is argued that the canting magnetic structure in manganites is not realized. The transition to a ferromagnetic or spin-glass state occurs via the formation of inhomogeneous state with different types of orbital correlations and magnetic structure. The key role of intrinsic chemical inhomogeneity in the formation of inhomogeneous magnetic states in solid solutions of manganites is emphasized.
16
Content available remote

Magnetocaloric Effect in La_{0.8}Sr_{0.2}MnO_{3} Film

71%
Szymczak R., Dyakonov K., Radelytskyi I., Dyakonov V., Szymczak H.
Acta Physica Polonica A
|
2015
|
vol. 128
|
issue 1
56-58
EN
Thin epitaxial film of La_{0.8}Sr_{0.2}MnO_{3} has been deposited on yz-cut LiNbO_{3} by pulsed laser ablation. The film was characterized by X-ray diffraction and magnetic measurements as a single phase. The magnetic properties and the magnetocaloric effect have been measured as a function of magnetic field and temperature. A reasonably high magnetocaloric effect indicates that this film might provide an efficient material for micro magnetic refrigerators.
17
Content available remote

Magnetic Phase Transitions in Intermetallic GdNi_{5-x}Sn_{1+x} and TbNi_{5-x}Sn_{1+x} Compounds

71%
Baran M., Szymczak H., Szymczak R., Romaka L., Skolozdra R.
Acta Physica Polonica A
|
1997
|
vol. 92
|
issue 2
295-299
EN
Magnetization measurements were performed for intermetallic compounds GdNi_{5-x}Sn_{1+x} and TbNi_{5-x}Sn_{1+x} in the temperature range from 4.5 K to 280 K and in magnetic field up to 50 kOe. Complex magnetic phase diagram was revealed for both compounds. The results are discussed assuming three-sublattice magnetic structure and partial disordering of the structure.
18
Content available remote

Magnetoelastic and Optical Studies of Low Temperature Magnetic Relaxation in Rare-Earth Orthoaluminates with Ising Ions

71%
Krynetskii I., Popkov A., Borowiec M., Szymczak H., Zayarnyuk T.
Acta Physica Polonica A
|
2000
|
vol. 97
|
issue 5
889-892
EN
The new class of magnetic materials with low temperature magnetic relaxation was studied. It was evidenced that the crystal DyAlO_{3} with antiferromagnetically ordered high anisotropy rare-earth ions showed an exponential magnetic relaxation. For the first time low temperature magnetic relaxation was investigated by means of magnetostriction and rare-earth optical absorption spectra instead of standard magnetization measurements. The possible mesoscopic nature of tunneling process was suggested.
19
Publication available in full text mode
Content available

Magnetic and Transport Properties of R_3Cu_3Sb_4 Compounds (R = La, Ce, Pr, Nd, and Sm)

62%
Skolozdra R., Baran M., Horyn A., Szewczyk A., Gorelenko Y., Szymczak H., Szymczak R.
Acta Physica Polonica A
|
2002
|
vol. 102
|
issue 3
429-435
EN
Magnetic susceptibility, electrical resistivity, and thermopower of the series of the R_3Cu_3Sb_4 compounds (R=La-Sm) were measured over the temperature ranges 1.9-300 K (susceptibility and resistivity) and 80-370 K (thermopower). Below 25 K, resistivity of these compounds grows exponentially with decreasing temperature. For some compounds, R = Ce, Sm, a maximum on temperature dependence of resistivity is observed. Ce_3Cu_3Sb_4 compound undergoes a magnetic transition at 12 K.
20
Publication available in full text mode
Content available

Moderation of the Flux Jumps Dynamics by Eddy-Currents in a Disk Shape NbTi Superconductor

62%
Vasiliev S., Chabanenko V., Nabiałek A., Rusakov V., Piechota S., Szymczak H.
Acta Physica Polonica A
|
2004
|
vol. 106
|
issue 5
777-783
EN
We studied the moderation of the flux jumps dynamics in a disc shape NbTi-50% superconductor caused by eddy-currents induced in two copper cylinders attached to both surfaces of the investigated sample. We investigated experimentally the time of the flux jump duration, amount of the magnetic flux entering the sample during the jump as well as the fine structure of the jumps as a function of temperature and the external magnetic field. A simple theoretical model, which describes the magnetic field dependence of the amount of the magnetic flux entering the superconducting sample during the flux jump, was developed.
first rewind previous Page / 3 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.