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  1. 45 Acta Physica Polonica A

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  1. 45 Paszkowicz W.

  2. 9 Godlewski M.

  3. 8 Domagała J.

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1
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Graphical Representation of Correlations Between Peak Positions

100%
Paszkowicz W.
Acta Physica Polonica A
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1992
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vol. 82
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issue 1
157-161
EN
The properties of linear combinations of peak positions are analysed. It is concluded that the distribution of combinations contains the information on lattice constants. These combinations are represented by sharp maxima. Examples of the distribution for a powder pattern of orthorhombic symmetry are presented.
2
Content available remote

X-Ray Study of Synthetic Alunite

52%
Paszkowicz W., Dynowska E., Świerkocki J.
Acta Physica Polonica A
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1994
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vol. 86
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issue 4
621-627
EN
Synthetic alunite was obtained by two different synthesis methods. Powder data obtained with a standard Bragg-Brentano geometry of two analyzed samples are reported for a broad angular range. The chemical analysis as well as the unit-cell dimensions indicate that the analyzed alunite is K and Al deficient and contains excess water. A need for high resolution diffraction experiments is expressed.
3
Content available remote

Old Studies with New Authors: A Discovery Ending with Retraction

52%
Paszkowicz W., Pełka J., Krupka J., Abramowicz A.
Acta Physica Polonica A
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2011
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vol. 119
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issue 6
901-903
4
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Application-of Quasi-Forbidden Reflections for Determination of Composition of Pseudobinary Semiconductors

52%
Bąk-Misiuk J., Paszkowicz W., Domagała J.
Acta Physica Polonica A
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1993
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vol. 84
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issue 4
681-684
EN
An application of X-ray quasi-forbidden reflection method of composition determination for A^{II}B^{VI} pseudobinary compounds is discussed. Three typical cases of the intensity dependence on the composition, as well as the choice of the most suitable reflection are presented.
5
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High Pressure - High Temperature Diffraction Study of MnTe Using Synchrotron Radiation

52%
Paszkowicz W., Dynowska E., Peun T.
|
EN
High pressure - high temperature experiments for MnTe of NiAs type were performed using a synchrotron radiation as X-ray source and a cubic anvil X-ray diffraction press to produce nonambient sample environment. In the investigated range of pressure (0-67.5 kbar) on uploading and with following temperature rise from 296 to 1273 K (at 67.5 kbar), the structure type of MnTe is conserved. An earlier reported nonlinear behaviour of lattice-parameter c_{0} is not found in the present study. Possible reasons of this discrepancy are discussed. The value of bulk modulus and its pressure derivative were calculated from the pressure-volume dependence by fitting the Birch-Murnaghan equation.
6
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Impact of Strain on the Superconducting Properties of Strongly Underdoped La_{2-x}Sr_xCuO_4 Thin Films

46%
Zaytseva I., Cieplak M., Paszkowicz W., Abal'oshev A., Berkowski M.
Acta Physica Polonica A
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2012
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vol. 121
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issue 4
858-865
EN
Using pulsed laser deposition we have grown films of La_{2-x}Sr_xCuO_4 with x in close vicinity of the superconductor-insulator transition, x=0.051 and x=0.048, on SrLaAlO_4 substrates, and of different thickness d (from 25 nm to 250 nm). The X-ray diffraction shows that for each d the films grow with variable degree of compressive in-plane strain, with the largest strain achieved in thinnest films. The resistivity measurements show strong enhancement of superconductivity with increasing strain, so that the onset of superconductivity at temperature as high as 27 K is observed. With increasing strain the character of resistivity changes from the insulating to metallic.
7
Publication available in full text mode
Content available

Lattice Parameters of Aluminium Nitride in the Range 10-291 K

46%
Paszkowicz W., Knapp M., Podsiadło S., Kamler G., Pełka J.
Acta Physica Polonica A
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2002
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vol. 101
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issue 5
781-785
EN
Lattice parameters for aluminium nitride were determined using X-ray powder diffraction at a synchrotron radiation source (beamline B2, Hasylab/DESY, Hamburg) in the temperature range from 10 K to 291 K. The measurements were carried out using the Debye-Scherrer geometry. The relative change of both, a and c, on rising the temperature in the studied range (10-291 K) is about 0.03%. The results are compared with earlier laboratory data and theoretical predictions.
8
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Experimental and Theoretical Study of Zircon and Scheelite Phases of DyVO_4

46%
Ermakova O., Paszkowicz W., López-Solano J., Muñoz A., Dabkowska H.
Acta Physica Polonica A
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2012
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vol. 121
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issue 4
920-927
EN
Polycrystalline zircon-type dysprosium orthovanadate, DyVO_4, prepared from a single crystal grown by slow cooling from PbO/PbF_2 flux, was studied by X-ray diffraction. Rietveld refinement provided the following unit cell size and oxygen atom coordinates: a=7.14811(4) Å; c=6.30825(4) Å, V=322.323(3) Å3, y(O^{2-})=0.4300(4); z(O^{2-})=0.2082(4) which are of a particularly high accuracy and show consistency with earlier reported values. Density functional theory calculations within the generalized gradient approximation for the exchange-correlation energy were also performed, providing values of structure parameters which differ by less than 2% from the experimental ones. The agreement between theory and experiment demonstrates the value of these calculations for understanding the structure of compounds of RVO_4 family. In addition, density functional theory calculations were performed for the scheelite-type DyVO_4; also for this polymorph the discrepancy with the only known set of lattice parameters is less than 2%. Values of oxygen atom coordinates have not been reported yet for this polymorph; here, the calculated ones are quoted.
9
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Composition Determination of Some A^{II}B^{VI} Ternary Semiconductors from Quasi-Forbidden Reflection Intensity

46%
Bąk-Misiuk J., Domagała J., Dynowska E., Miotkowska S., Paszkowicz W.
Acta Physica Polonica A
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1994
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vol. 86
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issue 4
575-578
EN
The aim of the present paper is to study the possibility of application of the X-ray quasi-forbidden reflection method to the composition determination of the sphalerite-type Cd_{1-x}M_{x}Te = Mg, Zn, Mn) single crystals. The method is based on the property of quasi-forbidden reflections that their integral intensity is very sensitive to composition and weakly sensitive to crystal lattice defects. An example of application for a Cd_{1-x}Mn_{x}Te single crystal is presented.
10
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Effect of Annealing on the Crystal Structure and Microstructure of Pr Doped ZrO_{2}-Y_{2}O_{3} Nanocrystals

46%
Werner-Malento E., Paszkowicz W., Fidelus J., Godlewski M., Yatsunenko S.
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issue 1
91-97
EN
Rare-earth doped nanocrystalline yttria-stabilized zirconia (YSZ, ZrO_{2}-Y_{2}O_{3}) is, recently, a subject of studies because of its luminescent properties. The luminescence may be strongly influenced by the crystal structure and microstructure of the material. In this work, the X-ray diffraction study for Pr doped YSZ nanocrystals is presented. The phase composition dependence on the Y_{2}O_{3} content and on heat treatment conditions is quantitatively determined using the Rietveld method and the similarities and differences between the present data for doped samples and earlier reported data for undoped material are discussed. A formation of high symmetry phases (cubic and tetragonal) is observed for high yttria content in agreement with general tendencies observed in literature for undoped samples.
11
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High-Pressure Diffraction Study of Ga_{1-x}Al_{x}As

46%
Paszkowicz W., Dynowska E., Żytkiewicz Z. R., Dobosz D., Otto J. W.
Acta Physica Polonica A
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1997
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vol. 91
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issue 5
993-996
EN
The Ga_{1-x}Al_{x}As sample of x=0.5 was prepared from a high quality single crystal grown by electroepitaxy on GaAs. The high-pressure diffraction experiments were performed using a diamond anvil cell and a germanium solid state detector. The zinc-blende phase is stable up to about 17.5 GPa on uploading. A high-pressure phase manifests itself at about 17 GPa, a complete phase change occurs at 18.7 GPa. On downloading, the zinc-blende phase reappears at about 10 GPa. The powder pattern of the high-pressure phase shows some similarities with the GaAs high pressure phases.
12
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Lattice Parameter of Polycrystalline Diamond in the Low-Temperature Range

46%
Paszkowicz W., Piszora P., Łasocha W., Margiolaki I., Brunelli M.
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issue 2
323-327
EN
The lattice parameter for polycrystalline diamond is determined as a function of temperature in the 4-300 K temperature range. In the range studied, the lattice parameter, expressed in angstrom units, of the studied sample increases according to the equation a = 3.566810(12) + 6.37(41) × 10^{-14} T^{4} (approximately, from 3.5668 to 3.5673 Å). This increase is larger than that earlier reported for pure single crystals. The observed dependence and the resulting thermal expansion coefficient are discussed on the basis of literature data reported for diamond single crystals and polycrystals.
13
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Equation of State of Zircon-Type TbVO_{4}

46%
Minikayev R., Paszkowicz W., Werner-Malento E., Lathe C., Dąbkowska H.
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issue 2
319-322
EN
High-pressure energy-dispersive X-ray diffraction study were performed on zircon-type phase of terbium orthovanadate, TbVO_{4}, in the pressure range up to 7 GPa. For analysis of the collected diffraction spectra, Le Bail refinements were performed. The values of bulk modulus and its pressure derivative (B_0 = 121 GPa, B' = 4.1) were obtained from fitting of the second-order Birch-Murnaghan equation of state. The equation of state derived for TbVO_{4}, is compared with earlier data based on the Raman spectroscopic studies and with data of several other rare-earth orthovanadates.
14
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Combined X-Ray Diffraction and Absorption Study οf Crystalline Vanadium-Doped Lithium Disilicate

46%
Paszkowicz W., Wolska A., Klepka M., abd el All S., Ezz-Eldin F.
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|
issue 2
315-318
EN
Structure of vanadium-doped lithium disilicate, Li_{2}Si_{2}O_{5} (Ccc2 space group) is studied. This crystalline phase is obtained by annealing of the doped lithium disilicate glass for 4 h at 550°C. X-ray diffraction and X-ray absorption near-edge structure analysis indicate location of vanadium atoms at Si sites. the lattice parameters are found to increase isotropically with increasing vanadium content. the valency of vanadium ions is discussed on the basis of X-ray absorption near-edge structure results.
15
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Magnetic Nature of a Ni Dopant in La_{1.85}Sr_{0.15}CuO_4: Spin-Glass Behavior

40%
Malinowski A., Bezusyy V., Minikayev R., Paszkowicz W., Dziawa P., Syryanyy Y., Sawicki M.
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|
issue 2
244-248
EN
The magnetic properties of La_{1.85}Sr_{0.15}CuO_4 doped with Ni was investigated in the field up to 5 T and in the temperature range from 2 K to 400 K using both dc and ac techniques. For Ni content larger than 0.05 the system exhibits irreversibility of low-field susceptibility χ(T) below a certain temperature depending on y and a cusp at T_{g} in χ(T) measured after zero-field cooling. The decay of remnant magnetization below T_{g} with time is described by a stretched-exponential function. In accordance with scaling theory, all the χ(T) data for y = 0.50 sample taken in the vicinity of T_{g} at different fields collapse onto two separate curves when plotted as q|t|^{-β} vs. B^2 |t|^{-β - γ}, where q is the spin-glass order parameter, t = (T - T_{g})/T_{g}, and β and γ are the critical exponents. All these features taken together reveal existence of spin-glass phase below T_{g}. Variation of T_{g} with y is linear below y = 0.25 and T_{g} extrapolates to 0 K for y → 0 what strongly suggests that spin-glass phase extends into superconducting region of the phase diagram.
16
Publication available in full text mode
Content available

Study of Si-Implanted and Thermally Annealed Layers of Silicon by Using X-ray Grazing Incidence Methods

40%
Klinger D., Lefeld-Sosnowska M., Pełka J., Paszkowicz W., Gierłowski P., Pankowski P.
Acta Physica Polonica A
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2002
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vol. 101
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issue 5
795-801
EN
This paper reports on the study of structural modifications induced by the implantation process and by the subsequent thermal annealing in near-surface layers of Si single crystals implanted with Si^{2+} ions of energy 140 keV and doses from 1×10^{15} to 1× 10^{16} ions/cm^2. The grazing incidence X-ray diffraction and X-ray reflectivity measurements were applied to determine the thickness and structural composition of the damaged layers. The fitted electron density profiles indicated an existence of an interfacial layer with density higher than the density of Si matrix or near-surface oxide layer. Formation of polycrystalline phases of silicon and silicon oxides is discussed in dependence on the conditions of annealing treatment and implantation dose.
17
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Content available

X-ray Characterization of Films Formed by Pulsed Laser Deposition on Cold Substrates from YBaCuO Targets

40%
Pełka J., Paszkowicz W., Gierłowski P., Lewandowski S., Zieliński M., Barbanera S., Knapp M.
Acta Physica Polonica A
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2002
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vol. 101
|
issue 5
787-794
EN
Grazing-incidence X-ray diffraction supplemented with atomic force microscopy and secondary ion mass spectroscopy were applied to the characterization of films deposited by laser ablation on cold substrates from YBaCuO targets and subsequently irradiated with additional laser pulses of lower energy density. Evolution of X-ray diffraction pattern was observed as a function of irradiation dose. For the as-deposited films the pattern was typical of the amorphized solids. For the films irradiated with doses higher than the threshold, the pattern was enriched with the diffraction peaks, whose general features, like peak positions, widths and relative intensities were almost independent of the dose. The size of the crystallites was deduced from the peak widths to be not smaller than 12-16 nm. Comparison of the pattern with patterns of known phases indicates that, apart of the amorphous component, a structure with an admixture of some new metastable or high temperature phase(s) is formed during the process of pulsed laser annealing. The atomic force microscopy observations revealed that the surface roughness shows a pronounced minimum at low irradiation doses. The secondary ion mass spectroscopy investigation confirms that the strongest chemical changes (increase in concentration of yttrium and copper) due to irradiation with higher doses are observed in the near-surface film material.
18
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From Cuprate to Nickelate: Evolution of the Normal State Properties with Ni from La_{1.85}Sr_{0.15}CuO_4 to La_{1.85}Sr_{0.15}NiO_4

40%
Bezusyy V., Malinowski A., Minikayev R., Paszkowicz W., Dziawa P., Gorzelniak R.
|
|
issue 2
402-405
EN
The influence of Ni doping on the normal-state pseudogap in La_{1.85}Sr_{0.15}CuO_4 is studied by dc magnetic susceptibility measurements, accompanied by X-ray powder diffraction analysis and resistivity measurements. The measurements are carried out on the polycrystalline La_{1.85}Sr_{0.15}Cu_{1-y}Ni_yO_4 samples in the whole doping range from y=0.01 up to y=1. The temperature of pseudogap opening is found to decrease above y=0.05 and to vanish when y exceeds 0.07. At small Ni content, up to y=0.07, the magnetic moment induced by Ni is constant and equal to 0.7 μ_{B} per Ni, while for larger y it increases abruptly and reaches about 1.6 μ_{B} per Ni ion for y = 0.5. The dependence of the normal-state resistivity on temperature evolves smoothly from the metallic-like for small y, to the variable range hopping, described by the Mott law with the exponent 1/4, for samples with y>0.15.
19
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Composition Dependence of Photoluminescence Spectra in Zn_{1-x}Mg_{x}Se Mixed Crystals

40%
Firszt F., Łęgowski S., Μęczyńska H., Szatkowski J., Paszkowicz W., Spolnik Z. M.
Acta Physica Polonica A
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1995
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vol. 88
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issue 4
711-714
EN
Ζn_{1-x}Mg_{x}Se mixed crystals with x ranging from 0 to 0.56 were obtained by high pressure Bridgman method. It has been found that a phase transition from sphalerite structure to wurtzite one occurs at x = 0.185 ± 0.03. The crystals exhibit blue-violet and yellow-green (depending on x) luminescence in the temperature range from 40 K to room temperature. An attempt has been also made to dope Ζn_{1-x}Μg_{x}Se crystals with Al. The incorporation of Al produces a strong green photoluminescence in the temperature range from 40 K to 300 K but almost completely quenches the near-band-edge emission.
20
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Content available

Strain Relaxation in Thin Films of La_{1.85}Sr_{0.15}CuO_4 Grown by Pulsed Laser Deposition

40%
Zaytseva I., Cieplak M., Abal'oshev A., Berkowski M., Domukhovski V., Paszkowicz W., Shalimov A.
Acta Physica Polonica A
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2007
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vol. 111
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issue 1
185-188
EN
X-ray diffraction, resistivity, and susceptibility measurements are used to examine the effects of film thickness d (from 17 to 250 nm) on the structural and superconducting properties of La_{1.85}Sr_{0.15}CuO_4 films grown by pulsed laser deposition on SrLaAlO_4 substrates. For each d the film sgrow with a variable strain, ranging from a large compressive strain in the thinnest films to a negligible or tensile strain in thick films. Our results indicate that the tensile strain is not caused by the off-stoichiometric layer at the substrate-film interface. Instead, it may be caused by the extreme oxygen deficiency in some of the films.
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