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1
Content available remote Transport and Magnetic Properties of PbTe:Cr and PbSnTe:Cr
100%
Story T. , Grodzicka E. , Witkowska B. , Górecka J. , Dobrowolski W.
Acta Physica Polonica A
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1992
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tom 82
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nr 5
879-881
EN
We present the results of the experimental studies of the low temperature transport and magnetic properties of PbTe, Pb_{1-x}Sn_{x}Te (x ≤ 0.3) and SnTe crystals doped with 0.5 at.% of chromium. Cr was found to be a resonant donor in PbTe and PbSnTe. Magnetic susceptibility measurements revealed that PbTe:Cr and Pb_{1-x}Sn_{x}Te:Cr (x ≤ 0.2) are Curie paramagnets whereas SnTe:Cr exhibits van Vleck paramagnetism.
2
Content available remote X-Ray and Electron-Optical Characterization of ZnTe/CdTe and ZnTe/GaAs Epitaxial Layers Obtained by the MBE Method
100%
Auleytner J. , Dziuba Z. , Górecka J. , Pełka J. , Regiński K.
Acta Physica Polonica A
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1994
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tom 86
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nr 4
567-574
EN
X-ray diffraction topography (Bragg diffraction) and X-ray rocking curve measurements were used to study the perfection and structural properties of ZnTe epitaxial layers on the CdTe and GaAs substrates. ZnTe epitaxial layers on CdTe were grown by MBE method by using a machine made in the Institute of Physics of the Polish Academy of Sciences. The ZnTe layers on GaAs were produced on the other, factory-made MBE system. The comparison between the X-ray topographical images of the substrate and epitaxial layer shows that imperfections on the substrate surface cause imperfections in the epitaxial layer. The results of double-crystal diffractometry measurements show that the perfection of the layer on the GaAs substrate is higher than that on the CdTe. The presence of microtwining in the ZnTe layer on the CdTe substrate was confirmed by RHEED measurements. The X-ray standing wave fluorescent spectra were also measured for the samples.
3
Content available remote Study of Si(111) Implanted with As Ions by X-Ray Diffraction and Grazing Incidence Methods
100%
Pełka J. B. , Górecka J. , Auleytner J. , Domagała J. , Bąk-Misiuk J.
Acta Physica Polonica A
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1997
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tom 91
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nr 5
905-910
EN
The Si(111) wafer cut from a bulk single crystal obtained by the Czochralski method was implanted with 5×10^{16} I cm^{-2} of As ions of energy 80 keV. The dose applied was chosen above the amorphization limit of the silicon substrate. Two samples, implanted and a reference, were studied by grazing incidence X-ray reflectometry and X-ray diffraction methods using a high resolution Philips MRD system equipped with a Cu source and a channel-cut monochromator. The obtained spectra were compared with distributions of ion range and defect production calculated with TRIM program [1], as well as with theoretical models of reflectivity [2, 3]. The results of grazing incidence X-ray reflectometry reflectivity of the implanted sample show well-pronounced oscillations, which can be associated with a layer about 50 nm thick, approximately comparable to the thickness of the defected layer estimated from the TRIM method. Theoretical calculations of reflectivity clearly indicate an occurrence of a Si layer of electron density lower about 10-15% comparing to the unimplanted Si sample. This can be due to the vacancy production during ion implantation. A comparison of the spectra with a density distribution profile concluded from the TRIM calculations shows large discrepancies. The results indicate the applicability of grazing incidence X-ray reflectometry method in a study of amorphization processes in implanted layers.
4
Content available remote Elastic Constants of β-HgS
86%
Prieur J. , Joffrin J. , Szuszkiewicz W. , Dynowska E. , Górecka J. , Witkowska B.
Acta Physica Polonica A
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1998
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tom 94
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nr 3
487-491
EN
The elastic constants of single crystals of β-HgS highly doped with iron were directly determined at room temperature from the measurements of ultrasonic wave velocities by the pulse-echo technique. The values of c_{11}=6.750, c_{12}=5.186, and c_{44}=2.42 (given at 10^{10} N m^{-2} units) were obtained and compared with the experimental data taken for other mercury chalcogenides. The elastic characteristics of this group of materials is quite similar to those of Cd and Zn chalcogenides.
5
Content available remote Fe 3d Contribution to Hg_{1-x}Fe_{x}Se Valence Band by Means of Angle-Resolved Photoemission
86%
Orłowski B. , Bonnet J. , Hricovini C. , Pinchaux R. , Górecka J. , Kowalski B. , Mycielski A.
Acta Physica Polonica A
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1991
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tom 80
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nr 3
389-392
EN
The Angle-Resolved Photoemission Electron Spectroscopy (AR PES) was applied to investigate the electronic structure of HgSe and Hg_{1-x}Fe_{x}Se crystals for (110) surface. The measured set of Angle-Resolved Energy Distribution Curves (AR EDCs) permits to determine some of the elements of the electronic band structure E(k) (energy-momentum dependence for ҐKX and ҐX directions in the Brillouin zone) for measured crystals. The Fe 3d contribution gives the states lying over the edge of the valence band of HgSe crystal (0.25 eV), and into the valence band.
6
Content available remote Lattice Dynamics of Cubic Mercury Sulphide
86%
Szuszkiewicz W. , Dybko K. , Dynowska E. , Górecka J. , Witkowska B. , Hennion B.
Acta Physica Polonica A
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1996
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tom 90
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nr 5
947-950
EN
The acoustic phonon dispersion of mercury sulphide of zinc-blende structure (β-HgS) was studied by inelastic neutron scattering. The measurements were carried out at 19 K and 295 K on HgS crystals doped with Fe. A slight decrease in phonon frequencies with increasing temperature was found, the temperature dependence being the strongest for LA phonons with [ξ,ξ,0] propagation. From acoustic phonon dispersion the values of selected elastic constants were determined for β-HgS.
7
Content available remote Selected Properties of Lattice Dynamics of HgSe and β-HgS
72%
Szuszkiewicz W. , Dybko K. , Dynowska E. , Górecka J. , Witkowska B. , Hennion B. , Jouanne M. , Julien C.
Acta Physica Polonica A
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1997
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tom 92
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nr 5
1029-1032
EN
Optical phonon dispersion for β-HgS was measured by the neutron scattering for the first time. The results confirmed theoretically predicted anomalous behavior of phonon modes in this material, resulting probably from high ionicity of mercury sulphide and large difference of Hg and S atomic mass. Influence of the isotopic effects on the TO-phonon mode for HgSe and HgS is analyzed. The possible observation of such effects in IR reflectivity spectra taken for HgSe at low temperature is discussed.
8
Content available remote X-Ray Characterization of GaAs:Zn Gas-transport Grown Whiskers Using Conventional and Synchrotron Sources
72%
Paszkowicz W. , Górecka J. , Domagała J. , Dmitruk N. , Varshava S. S. , Härtwig J. , Ohler M. , Pietraszko A.
Acta Physica Polonica A
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1997
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tom 91
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nr 5
997-1002
EN
GaAs:Zn whiskers grown by the gas-transport method are characterized by diffraction methods using white and monochromatic radiation. The methods applied include the white-beam topography at ESRF synchrotron source and Laue patterns, 4-circle Bond diffractometry and high-resolution diffractometry at conventional X-ray sources. The results obtained concern the growth morphology and defect structure. It is found that GaAs:Zn whiskers grown by the described method have the form of long needles and blades of the morphologies represented by growth direction and largest lateral face ⟨112⟩{111} and ⟨111⟩{112}, respectively, with a single exception of a blade of uncommon morphology ⟨111⟩{110}.
9
Content available remote Electron Microscopy and X-ray Structural Investigations of Incommensurate Spin-Ladder Sr_{4.1}Ca_{4.7}Bi_{0.3}Cu_{17}O_{29} Single Crystals
72%
Dłużewski P. , Pietraszko A. , Kozłowski M. , Szczepańska A. , Górecka J. , Baran M. , Leonyuk L. , Babonas G.-J. , Lebedev O. , Szymczak R.
Acta Physica Polonica A
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2000
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tom 98
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nr 6
729-737
EN
Transmission electron microscopy and X-ray diffraction proved chain ladder incommensurate single crystal structure of investigated samples. The incommensurate ratio was determined from the X-ray and electron diffraction being equal to 0.704. Diffuse scattering intensities localised on the planes perpendicular to the c*-axis and passing through the spots originating from the periodicity of chain sublattice were detected. High-angle grain boundary or twinning formed by rotation of 33.3° around [100] direction was observed. High-resolution electron microscopy images revealed the stacking faults in ac planes.
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