Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 23

Number of results on page
first rewind previous Page / 2 next fast forward last

Search results

Search:
in the keywords:  77.80.-e
help Sort By:

help Limit search:
first rewind previous Page / 2 next fast forward last
1
Content available remote

Study of the Optical Activity of Ferroelectric Lead Germanate

100%
Vlokh O., Kushnir O., Shopa Y.
Acta Physica Polonica A
|
1992
|
vol. 81
|
issue 4-5
571-578
EN
A new optical method for measuring the optical activity of crystals is developed. Temperature dependence of gyration component g_{11} of ferroelectric lead germanate is measured. The obtained results confirm that lead germanate may be considered as a gyroelectric crystal.
2
Content available remote

High-Pressure Microwave Study of YBa_{2}Cu_{3}O_{7-δ}-Pb(Sc_{0.5}Ta_{0.5})O_{3} Composite

100%
Czyżak B., Stankowski J., Hilczer B., Krupski M., Morawski P., Andrzejewski B., Marfaing J., Régnier S., Caranoni C.
Acta Physica Polonica A
|
1997
|
vol. 91
|
issue 6
1103-1109
EN
The ferroelectric relaxor Pb(Sc_{0.5}Ta_{0.5})O_{3}-superconductor YBa_{2}Cu_{3}O_{7-δ} 50% in weight composite exhibits the onset critical temperature T_{c}=95 K. High pressure studies yield the factor dT_{c}/dp of 1.0 K/GPa, close to the value observed for a pure YBa_{2}Cu_{3}O_{7-δ} compound. The microwave absorption studies show the significant role of the intergrain weak links.
3
Content available remote

Behaviour of Isotropic Point in LiKSO_{4} Crystals

100%
Stadnyk V., Romanyuk M., Vachulovich V.
|
EN
The temperature-spectral dependencies of refractive indices and birefringence in wide temperature (77-1000 K) and spectral (250-850 nm) regions in LiKSO_{4} crystals were measured. The isotropic point of LiKSO_{4} crystals was investigated. It was shown that annealing and X-ray irradiation display insignificantly the isotropic point to a visible region of spectrum.
4
Content available remote

Low Field Relaxational Behavior of Taap Single Crystal (20-10^{6} Hz)

63%
Fernández del Castillo J., Iglesias T., Przesławski J., Gonzalo J.
Acta Physica Polonica A
|
1998
|
vol. 93
|
issue 3
499-503
EN
Relaxational behavior of ferroelectric telluric acid ammonium phosphate crystals were investigated in the range 20 Hz to 1 MHz by means of low field measurements of ε' and tan δ in the vicinity of ferroelectric phase transitions at a number of frequencies. Results are compared with those for triglycine selenate, a much "softer" ferroelectric material. The measuring field and frequency dependence of the effective potential barrier height for domain wall motion are compared in both crystals.
5
Content available remote

Model of Temperature Dependence of Spontaneous Polarization of Thiourea Monocrystal in Phase I

63%
Śliwa I., Wanarski W.
Acta Physica Polonica A
|
2012
|
vol. 122
|
issue 1
184-189
EN
In this paper we present a model of spontaneous polarization appearing in the crystal of thiourea in phase I, constructed on the basis of the molecular field theory, with the use of the Boltzmann statistics. The model employs the potential energy of interaction between two nonpunctual molecular electric dipoles performing reorientations within the constraints specified by the experimentally determined structural data. The temperature dependences of the spontaneous polarization for different values of the hydrostatic pressure and for different γ-ray doses were obtained. A comparison between theoretical and experimental results permitted calculation of the parameters of the theory presented.
6
Publication available in full text mode
Content available

EPR Study of Fe^{3+} Paramagnetic Centers in Doped Triglycine Sulphate Crystals

63%
Łoś S., Trybuła Z.
Acta Physica Polonica A
|
2002
|
vol. 101
|
issue 2
279-287
EN
This paper presents EPR study of Fe^{3+} in triglycine sulphate doped with Fe^{3+} crystal. Fe^{3 +} ion is in a high spin state S=5/2. EPR signal can be detected only below 200 K. At 4.2 K the EPR spectrum results from three non-equivalent sites of Fe^{3+} ions. The spin Hamiltonian: H=β BĝS+D[S^2_z-(1/3)S(S+1)]+E(S^2_x-S^2_y) has been applied to describe the spectrum. The zero field splitting parameter in this case fulfills the condition: D≫hν. An experimental spectrum reflects clearly only two resonance transitions: |±1/2ã (the lowest Kramers doublet) and |±3/2〉 (the middle Kramers doublet). The iron complexes occupy interstitial positions in the crystal with distorted octahedral or tetrahedral co-ordination.
7
Content available remote

The Model of Ferroelectricity in Thiourea

63%
Śliwa I., Wanarski W.
|
EN
In this paper we propose a mechanism of the phenomenon of ferroelectricity in the molecular crystal of thiourea (SC(NH_2)_2). The mechanism is based on the model of interaction between two molecular electric dipoles. The dipoles are not idealized to points - they have a finite length. Besides, they can reorient mutually and the reorientation is determined by the crystal structure specified by the experimental structural research. On the basis of this theory, a formula for the potential energy of interaction of a pair of two nonpunctual dipoles as a function of the angle of reorientation is derived and discussed.
8
Content available remote

Structural Transformations and Magnetic Changes in Multiferroic BiFeO₃ under External Electric Field

63%
Soloviov S., Popkov A., Kulagin N., Sukmanova K., Zvezdin A.
Acta Physica Polonica A
|
2015
|
vol. 127
|
issue 2
245-247
EN
The influence of electric field on the structure parameters and magnetic states in BiFeO₃ multiferroic is studied using the Landau theory of phase transitions taking into account experimental data and results of ab initio calculations. Main features of structure transitions near critical electric fields and a concomitant rearrangementof the magnetic structure are discussed.
9
Content available remote

Modeling and Simulation of a Photovoltaic Module in Different Operating Regimes

63%
Jadallah A., Mahmood D., Abdulqader Z.
Acta Physica Polonica A
|
2015
|
vol. 128
|
issue 2B
B-461-B-464
EN
Modern research focuses on the renewable energy sources such as solar energy. This paper presents the modeling and performance of a photovoltaic (PV) cell. A simulation code is built using MATLAB. Results show that the increase of solar radiation and of ideality factor of diode lead to an increase in the output power of PV module, while the increease of cell temperature and of the dark saturation current lead to a decrease of the power. Curves of I-V and P-V dependencies are presented for module having 50 branches connected in parallel, with each branch having 50 cells connected in series. Data for certain Iraqi governorates are taken and applied for proposed module.
10
Content available remote

Fabrication and Ferroelectric Properties of BiFeO₃/BaTiO₃ Heterostructures

51%
Aleszkiewicz M., Dybko K., Dynowska E., Dluzewski P., Przyslupski P.
Acta Physica Polonica A
|
2016
|
vol. 130
|
issue 2
511-515
EN
We report on preparation and electrical characterization of the epitaxial BaTiO₃ (BTO), BiFeO₃ (BFO) thin films and BFO/BTO bi- and multilayers, grown on (001) SrTiO₃ (STO) and (LaAlO₃)_{0.3}(Sr₂TaAlO₆)_{0.7} (LSAT) substrates. The ferroelectric properties were characterized using the electric force microscopy method to image and switch the electric domains. This fabrication process opens the routes towards wide study of magnetoelectric effect in complex oxide heterostructures.
11
Content available remote

Anharmonic Effects in the Electron Spin-Lattice Relaxation of Radiation Defects in Potassium Selenate and Rochelle Salt Single Crystals

51%
Ivanshin V., Kurkin I., Brunner W., Völkel G.
Acta Physica Polonica A
|
1992
|
vol. 81
|
issue 3
393-396
EN
An anharmonic character for the Raman processes of the electron spin-lattice relaxation of paramagnetic defect centres in γ-irradiated potassium selenate and Rochelle salt single crystals was observed at low temperatures.
12
Publication available in full text mode
Content available

EPR Study of the Phase Transition in Dimethylammonium Gallium Sulfate Hexahydrate

51%
Hrabański R., Janiec-Mateja M., Czapla Z.
Acta Physica Polonica A
|
2005
|
vol. 108
|
issue 2
283-290
EN
X-band electron paramagnetic resonance investigations of single crystals of Cr^{3+}-doped dimethylammonium gallium sulphate hexahydrate are presented from room temperature down to 110 K. The crystal undergoes a order-disorder phase transition to ferroelectric phase at 134 K and additionally a first-order transition into a low temperature non-ferroelectric phase at T_{c2}=116 K. The spin-Hamiltonian parameters were determined for paraelectric and ferroelectric phases. The spin-Hamiltonian parameters in the paraelectric phase are: g=1.982±0.002, b_2^0=(890±10)×10^{-4} cm^{-1}, b=(386±15)×10^{-4} cm^{-1}. Remarkable EPR line width changes confirm the order-disorder character of the ferroelectric phase transition. Additionally observed triplet lines demonstrate freezing-out of dimethylammonium reorientations which can be considered as a prime reason for this transition similarly as observed in dimethylammonium aluminium sulfate hexahydrate.
13
Publication available in full text mode
Content available

Non-Linear Optic Polarization in Lithium Sulphate Monohydrate Crystals

51%
Czapla Z., Dębska M., Lebedeva E., Pirozerski A.
Acta Physica Polonica A
|
2001
|
vol. 99
|
issue 5
539-543
EN
The "steady-state" non-linear optic polarization arising in lithium sulphate monohydrate crystals under the influence of the short pulse laser irradiation has been investigated in the temperature range of 95-305 K. The reversal of the sign of the components of the generalised non-linear susceptibility tensorχ has been found at about 105 K. The change of the photoresponse kinetics and a drastic temperature dependence of the componentsχ_{ijk} in the temperature range of 95-105 K, as well as the change of the spectral dependence of the photoresponse were observed.
14
Content available remote

An Influence of the Synthesis Conditions οn the PFN Ceramics Properties

51%
Bochenek D., Surowiak Z.
Acta Physica Polonica A
|
2009
|
vol. 116
|
issue 3
271-273
EN
In the work tests of the influence of the technological conditions on the basic applied properties of the Pb(Fe_{0.5}Nb_{0.5})O_3 ceramics were carried out. The Pb(Fe_{0.5}Nb_{0.5})O_3 specimens were obtained by a two-stage method of synthesizing (the niobite method), a technique of the powder mixture calcinations, changing a temperature range of the iron-niobate (FeNbO_{4}), whereas compacting was conducted by free sintering.
15
Content available remote

The Positive Temperature Coefficient of Resistivity Effect in the Pb(Fe_{1/2}Nb_{1/2})O_{3} Ceramics Admixed with Lithium

51%
Bochenek D.
Acta Physica Polonica A
|
2009
|
vol. 116
|
issue 3
268-270
EN
In the paper technological conditions were looked for to obtain the Pb(Fe_{1/2}Nb_{1/2})O_{3} (PFN) ceramics and the PFN ceramics with the lithium admixture with the highest electric conduction and conditions appropriate for the PTC-R effect formation. Measurements of dc electrical resistivity, dielectric permittivity and dielectric loss were made as functions of temperature from room temperature to 190°C, at 1 kHz. The best set of values of dielectric loss and dielectric constant, from the ferroelectricity point of view, were obtained when the precursor with orthorhombic structure was employed. By creating appropriate technological conditions in the PFN ceramics the PTC-R effect can occur above the Curie temperature. Their electric properties are determined by presence of a basic phase of the potential barrier on the grain boundaries.
16
Content available remote

Ferroelectromagnetic Smart Structures (1-x)Pb(Fe_{0.5}Nb_{0.5})O_{3}-(x)BiFeO_{3}

51%
Bochenek D., Zachariasz R., Ilczuk J., Dudek J.
Acta Physica Polonica A
|
2009
|
vol. 116
|
issue 3
274-276
EN
In this work an attempt was made to obtain three compositions of the solid solution (1-x)Pb(Fe_{0.5}Nb_{0.5})O_{3}-(x)BiFeO_{3} for x=0.8, 0.7 and 0.6. The obtained specimens were subjected to microstructure and dielectric examinations and temperature dependences of the internal friction Q^{-1}(T) and Young's modulus E(T).
17
Content available remote

Terahertz Spectroscopy of Ordered PbSc_{1/2}Nb_{1/2}O_3 Ceramics

51%
Macutkevič J., Adomavičius R., Krotkus A., Valušis G., Grigalaitis R., Banys J., Bormanis K., Sternberg A.
Acta Physica Polonica A
|
2008
|
vol. 113
|
issue 3
883-886
EN
The ordered PbSc_{1/2}Nb_{1/2}O_3 ceramics were studied by THz transmission spectroscopy in the temperature range of 80-300 K. Below ferroelectric phase transition temperature the strength of central mode gradually decreases and gives evidence for a mixed displacive and order-disorder character of the transitions. Ferroelectric phase transition is connected with an abrupt freezing and rise of polar nanoregions into ferroelectric domains.
18
Content available remote

Mobility of Ferroelectric Domains in Antimony Sulfoiodide

51%
Toroń B., Nowak M., Kępińska M., Szperlich P.
|
|
vol. 126
|
issue 5
1093-1095
EN
Different optical energy gaps in ferroelectric and paraelectric phases as well as light scattering on domain walls allow to observe ferroelectric domains in antimony sulfoiodide (SbSI) near the Curie temperature. Mobility 8.11(44)× 10^{-8} m^2/(Vs) of ferroelectric domain walls under external electric field has been determined along c-axis of SbSI single crystals using optical transmittance microscopy.
19
Publication available in full text mode
Content available

Photorefractive Wave Mixing in Periodically Poled LiNbO_3:Y:F

51%
Odoulov S., Shumelyuk A., Shinkarenko O., Barilov D., Pavljuk S., Sturman B.
Acta Physica Polonica A
|
2002
|
vol. 101
|
issue 1
159-174
EN
The review of recent experimental work on photorefractive grating recording and frequency degenerate nonlinear wave mixing in periodically poled lithium niobate is given. We report, in particular, on new results concerning photorefractive grating recording in periodically poled lithium niobate by two orthogonally polarized eigenwaves (ordinary and extraordinary), on coherent self-oscillation in semilinear cavity, on evaluation of the effective photovoltaic field in iron-doped periodically poled lithium niobate.
20
Content available remote

Ferroelectric Field Effect Transistor Based on Modulation Doped CdTe/CdMgTe Quantum Wells

51%
Kolkovsky V., Wojciechowski T., Wojtowicz T., Karczewski G.
Acta Physica Polonica A
|
2008
|
vol. 114
|
issue 5
1173-1178
EN
In this work, we observed effects of changing the electron concentration and electron mobility upon the poling of the Cd_{0.96}Zn_{0.04}Te ferroelectric gate deposited on the top of the CdTe-based modulation doped quantum well structure, which are confirmation of the existence of the electrostatic field originating from the ferroelectric material, which can be controlled by an external voltage. The analysis of the data obtained from the Hall effect measurements showed that the electron mobility and carrier concentration decreased by a factor of 2.5 and 1.5, respectively upon the negative poling of the gate with respect to the poled by the positive voltage. Moreover, the electrostatic field, depending on its directions, causes depletion of accumulation of electrons in the 2D channel, i.e., it is a source of the field effect.
first rewind previous Page / 2 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.