Search results

1

Evolution of the β Phase Flux Dissolution during Quasicrystal Formation

100%

Surowiec M., Bogdanowicz W., Sozańska M.

Acta Physica Polonica A

|

2014

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vol. 126

|

issue 2

594-596

EN

This study focuses mainly on the verification of a peritectic reaction during the crystallization of quasicrystals. The β and λ phases apparently provide the necessary material for crystallization of the quasicrystalline ψ phase. We present results of an experimental visualization of the evolution of the flux dissolution process of the high temperature β phase. Solidified droplets of the β phase, formed primarily by the surface tension of the liquid within a bubble or a shrinkage, after crumbling during the flux dissolution may contribute to the quasicrystal formation process according to a peritectic reaction: β_{c} + λ + L → ψ, where β_{c} denotes the crumbled β phase immersed in the liquid.

2

Solubility Limit of Ni in Cd_{1-x}Ni_{x}Te Crystals

100%

Miotkowska S., Miotkowski I., Dynowska E.

Acta Physica Polonica A

|

1994

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vol. 86

|

issue 5

737-739

EN

The Cd_{1-x}Ni_{x}Te crystals were grown by the Bridgman method. The investigated samples were cut from five different ingots with nominal contents of nickel varied from 0.005 to 0.05. The investigations were performed using X-ray powder diffraction method and energy dispersive and wavelength dispersive electron microprobe analysis. The samples were ałso examined in a scanning electron microscope. Examinations of wavelength dispersive electron microprobe analysis show that the actual contents of nickel differ from the nominal values. The solubility limit of nickel was determined to be x = 0.005. The precipitates of NiTe were found in samples of a greater content of nickel. Their dimensions were between 5 to 90 micrometers. X-ray powder diffraction measurements did not reveal any significant change of the lattice constant of investigated crystals in comparison with pure CdTe.

3

Growth and Characterization of Vanadate Laser Crystals

100%

Yu H., Zhang H., Wang J.

Acta Physica Polonica A

|

2013

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vol. 124

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issue 2

301-304

EN

Based on the invention and widely application of the Czochralski pulling method, vanadate crystals have been grown and commercialized in recent decades. In this paper, the growth and characterization of a series of neodymium doped vanadate crystals have been reviewed, including Nd:YVO_4, Nd:GdVO_4, and Nd:LuVO_4. The excellent thermal-mechanical and laser property make them to be used in many respects.

4

Evolution of Pb_{1-x}Cd_{x}Te Solid Solution Structure at High Temperatures

100%

Minikayev R., Dynowska E., Kamińska E., Szczerbakow A., Trots D., Story T., Szuszkiewicz W.

Acta Physica Polonica A

|

2011

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vol. 119

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issue 5

699-701

EN

The recent successful growth of single, bulk Pb_{1-x}Cd_{x}Te crystals by self-selecting vapor transport method at the Institute of Physics of the Polish Academy of Sciences in Warsaw opened new opportunities to study the physical properties of this interesting material in detail. In this work we report the preliminary results of X-ray powder diffraction studies performed on a set of Pb_{1-x}Cd_{x}Te solid solutions (where x ≤ 0.056) at high temperatures (295 K ≤ T ≤ 1100 K) and analyzed with the Rietveld refinement. Our results demonstrate the necessity of some correction of the relevant phase diagram and of the solubility limit, known from the literature.

5

Growth of Oxide Laser Crystals by Czochralski Method

100%

Zharikov E., Lis D., Subbotin K., Dudnikova V., Zaitseva O.

Acta Physica Polonica A

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2013

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vol. 124

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issue 2

274-285

EN

The growth of series of actual laser crystals belonging to different structural types by the Czochralski method is presented. The primary attention is given to single crystalline compounds and their solid solutions with garnet structure (scandium-containing rare-earth garnets with general formula {LnSc}_3[ScMe]_2Me_3O_{12}, Me = Al, Ga) as well as with olivine (forsterite Mg_2SiO_4) and scheelite structure (double tungstates and molybdates with formula NaLn(TO_4)_2, where T = Mo or W). The broad bands of luminescence and absorption produced by activator ions in these laser hosts that appear either as a result of structural disorder (garnets, scheelites) or due to the doping by transition metal ions (chromium in forsterite) join together these representatives of different structural classes and determine their application in photonics. The paper considers the problems of growing of large crystals with uniform distribution of components and dopants, determination of congruently melting composition, especially in compounds with complex isomorphism. The mutual influence of components and dopants, redistribution of ions along crystallographically non-equivalent sites in the structure, alteration of valency of transition metal ions accompanied with the change of their segregation coefficients under variation of redox conditions is discussed.

6

Czochralski-Grown Silicon Crystals for Microelectronics

100%

Bukowski A.

Acta Physica Polonica A

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2013

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vol. 124

|

issue 2

235-238

EN

The Czochralski method of crystal growth is used since 1950s in scientific and industrial laboratories for growth of single crystals of large size and high quality. The article presents the general characteristics and selected improvements of the Czochralski method, and discusses its meaning and advantages in growth of silicon single crystals playing a key role in microelectronics.

7

Structural Properties of Cd_{1-x}Mg_{x}Te and Cd_{1-x-y}Mg_{x}Mn_{y}Te Crystals

100%

Miotkowska S., Dynowska E., Miotkowski I.

Acta Physica Polonica A

|

1994

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vol. 86

|

issue 4

605-611

EN

Electron probe microanalysis and X-ray diffraction studies have been performed on samples of ternary Cd_{1-x}Mg_{x}Te (0.05 ≤ x ≤ 0.09) and quaternary Cd_{1-x-y}Mg_{x}Mn_{y}Te (0.025 ≤ x ≤ 0.4; 0.025 ≤ y ≤ 0.7) alloys. The investigated samples were cut from 24 different ingots grown by Bridgman method. Microprobe examinations have revealed significant differences between actual and nominal content of Mg along the longitudinal direction for both ternary and quaternary ingots. In contrast to Mg, for most Cd_{1-x-y}Mg_{x}Mn_{y}Te samples the actual Mn content was within ±5% of nominal content. The lattice constants have been determined by X-ray powder diffraction method. Whereas Cd_{1-x-y}Mg_{x}Mn_{y}Te samples exhibit only zinc blende crystal structure for the entire region of x and y investigated, the Cd_{1-x}Mg_{x}Te alloy has two different structures depending on Mg content; a zinc blende structure below x = 0.5 and a wurtzite structure above it. In both alloys the lattice constant decreases with increasing Mg content.

8

Research and Development of ZnBO_{4} (B = W, Mo) Crystal Scintillators for Dark Matter and Double Beta Decay Searching

100%

Dubovik A., Vostretsov Y. Y., Grinyov B., Danevich F., Kraus H., Nagornaya L., Mikhailik V., Tupitsyna I.

Acta Physica Polonica A

|

2010

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vol. 117

|

issue 1

15-19

EN

Oxide crystal scintillators play a considerable role in fundamental and applied researches. However, working out of new generation of high-sensitivity equipment and new methods of research puts higher requirements. The ZnBO_{4} (B = W, Mo) crystals were grown from charge in platinum crucibles with high frequency heating, using the Czochralski method. The raw powder with optimum composition was prepared by solid phase high temperature synthesis using ZnO and BO_{3} (B = W, Mo) with 4-5N purity. Single crystals with sizes up to ∅ 50 × 100 mm were grown and scintillation elements of various sizes and shapes (cylinders, rectangular and hexahedron prisms) were produced. High spectrometric characteristics were obtained for ZnWO_{4}:R = 8-10% under excitation by ^{137}Cs (E_{γ}=662 keV), low radiation background (less than 0.2 mBq/kg) and low afterglow (0.002%, 20 ms after excitation). The obtained results demonstrate good prospects for ZnWO_{4} and ZnMoO_{4} crystal scintillators for application in low-count rate experiments, searching for double beta decay processes, interaction with dark matter particles, and also studies of rare decay processes. The material has also a good potential for application in modern tomography, scintillation bolometers and for other major researches using scintillators.

9

Homoepitaxial Growth of YBa_{2}Cu_{3}O_{7} on Single Crystal YBa_{2}Cu_{3}O_{x} Substrates

80%

Morishita T., Zama H., Shiohara Y.

Acta Physica Polonica A

|

1997

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vol. 92

|

issue 1

97-103

EN

a- and c-axis oriented YBa_{2}Cu_{3}O_{x} (YBCO) films were epitaxially grown on (100) and (001) YBCO single-crystal substrates, respectively, by metalorganic chemical vapor deposition under the same preparation conditions including substrate temperature. As a Ba precursor Ba(DPM)_{2}-2tetraen was adopted. This precursor increased a deposition rate for YBCO films to 50 nm/h at 140°C. The substrates were formed from a 14.5x14.5x13 mm YBCO single crystal grown by a modified top-seeded crystal pulling method. Only a few surface atomic layers remained damaged after polishing and cleaning, which however did not affect the epitaxy of film growth. The crystallinity of the interface between an epilayer and substrate was much improved compared to that on usual perovskite substrates.

10

Growth and Characterization of Titanium Doped Spinel Crystals

80%

Gritsyna V., Kazarinov Y., Kobyakov V., Lytvynov L.

Acta Physica Polonica A

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2018

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vol. 133

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issue 4

774-777

EN

MgAl₂O₄ (magnesium aluminates spinel, MAS) single crystals doped with titanium ions obtained by the Verneuil method were non-uniformly colored along of the growth crystallographic direction. The crystals were characterized measuring lattice parameter, optical absorption spectra and relative concentration of impurity atoms (Ti, Mn, Cr, and Fe) in different spots of grown Ti:MAS boule. There was observed the correlation of the intensity of absorption band at 800 nm to the relative concentration of iron supporting the identification of this band with charge transfer transition in complexes Ti⁴⁺+Fe²⁺ → Ti³⁺+Fe³⁺. The new resonant structure at the wavelength of 470 nm was found and tentatively identified with the Fano resonance in the complexes formed by lattice defects and impurity ions.

11

High Quality (100) and (001) Oriented Substrates Prepared from Czochralski Grown SrLaGaO_{4} and SrLaAlO_{4} Single Crystals

80%

Berkowski M., Fink-Finowicki J., Sass J., Mazur K.

Acta Physica Polonica A

|

1997

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vol. 92

|

issue 1

201-204

EN

The growth of SrLaGaO_{4} and SrLaAlO_{4} crystals on ⟨100⟩ and ⟨001⟩ oriented seeds was investigated. Various defects, which appeared in crystals grown on these two orientations, were observed in polarized light and by X-ray diffraction topography. It was found that to obtain a substrate of the best quality, the crystal should be cut along the growth directions. Therefore, crystals pulled along ⟨100⟩ direction are utilized for preparation of (001) substrates, whereas (100) substrates are better to cut from crystals grown on ⟨001⟩ seed. The quality of the prepared substrates was determined by high resolution X-ray diffraction study in terms of rocking curve and mean mosaic angle.

12

Role of Crystal-Melt Interface and Surface Tension on Czochralski Growth of Substrate Materials with K_{2}NiF_{4} Structure

80%

Berkowski M., Fink-Finowicki J., Gutowski M.

Acta Physica Polonica A

|

1997

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vol. 92

|

issue 1

197-200

EN

Crystal-melt interface was investigated during Czochralski growth of SrLaGaO_{4} and SrLaAlO_{4} crystals on ⟨001⟩ oriented seeds. Relations between the ratio of the core diameter, grown on (001) plane, and the crystal diameter, as a function of seed rotation speed were determined. It was confirmed that it is possible to control the core diameter during the crystal growth. A new module was introduced into the crystal growth controlling program. It enables to estimate the surface tension coefficient between crystal and melt at the beginning of crystallization. This value is then used to compute proper corrections for automatic weighting system.

13

SrLaGaO_{4}-SrLaAlO_{4} Solid Solutions - Substrate Materials with Tuneable Lattice Parameter for Various HTSC Compounds

80%

Berkowski M., Fink-Finowicki J., Mojaiskaia E.

Acta Physica Polonica A

|

1997

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vol. 92

|

issue 1

182-186

EN

The increase in Τ_{c} for high temperature superconductors can be realized, among others, by appropriate substrate/film combinations. SrLaGaO_{4}-SrLaΑlO_{4} solid solutions were grown by the Czochralski method. The already achieved results allow to obtain single crystals of SrLaΑl_{1-x}Ga_{x}O_{4} with lattice constant a in the range from 0.3754 to 0.3775 nm, and SrLaGa_{1-x}Αl_{x}O_{4} crystals with lattice constant a in the range from 0.3843 to 0.3826 nm. Electron-probe microanalysis along obtained single crystals was used for determination of segregation coefficient between aluminum and gallium ions.

14

Optical and Scintillation Properties of Bi_{4}(Ge_{x}S_{1-x})_{3}O_{12} Single Crystal

80%

Xiao X., Xu J., Lu B., Cai W., Zhang Y., Shen H., Yang B., Xiang W.

Acta Physica Polonica A

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2015

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vol. 127

|

issue 3

854-858

EN

The solid solution crystals, Bi_{4}(Ge_{x}Si_{1-x})_{3}O_{12} (BGSO) with x=0, 0.05, and 0.15, have been grown by the modified vertical Bridgman method. The as-grown crystals show 80% of transmittance with an absorption edge of 285 nm. The relative light yields of BGSO crystals are found to be 7.2%, 6.3%, and 4.2% of CsI(Tl) crystal for x=0, 0.05, and 0.15, respectively. The energy resolutions of these crystals are 18.9%, 21.3%, and 24.7%, respectively, with PMT for 662 keV gamma rays at room temperature when exposed to ^{137}Cs γ -ray. The scintillation performance of BGSO crystals clearly deteriorates with the increase of Ge content. However, the appropriate number of germanium ions doped to BSO crystal can improve its crystallization behavior and effectively restrain component segregation. It is expected that large size crystals of BGSO will be grown and applied to the dual readout calorimeter in the nearest future.

15

Decomposition Processes in the Anomalous Supersaturated Solid Solution of Binary and Ternary Aluminium Alloys Alloyed with~Sc and~Zr

80%

Berezina A., Monastyrska T., Molebny O., Nosenko V., Kotko A.

Acta Physica Polonica A

|

2012

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vol. 122

|

issue 3

539-543

EN

Decomposition of supersaturated solid solution of aluminium alloys alloyed with Sc and Zr have been studied in the work. The binary hypereutectic Al-Sc alloys, hyperperitectic Al-Zr alloys and ternary Al-Sc-Zr alloys were chosen. Alloys were obtained by the melt-spinning. Melts were quenched from temperatures of T = 1000C and T = 1400°C. The crystallization of anomalously supersaturated solid solution (T_{quen.} = 1400°C) or the crystallization with the formation of "fan" structure (T_{quen.} = 1000°C) are possible. The decomposition of anomalously supersaturated solid solution is continuous, with the precipitation of nanosized spherical Al_3X (X = Sc, Zr) particles. The loss of thermal stability of Al-Sc alloys is due to the loss of coherence of the strengthening Al_3Sc phase. In Al-Zr alloys the loss of strength is due to the formation of a stable tetragonal DO_{23}-ordered Al_3Zr phase. After co-alloying of Al by Sc and Zr a bimodal grained structure was observed for the hypereutectic ternary alloy (T_{quen.} = 1400°C). Nanosized grains of 50-60 nm were present on the boundaries of 1-2 μm large-sized grains. Transmission electron microscopy shows the formation of nanocomposite Al_3Zr/Al_3Sc particles. The formation of Al_3Zr shell changes the nature of the interfacial fit of the particle with the matrix and slows down the decomposition during the coalescence.

16

Impact of Different Conditions of Technological Process on Thermoelectric Properties of Fine-Grained PbTe

80%

Królicka A., Materna A., Piersa M., Mirowska A.

Acta Physica Polonica A

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2016

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vol. 130

|

issue 5

1255-1258

EN

The aim of this work was to obtain PbTe material in the desired way in order to control the combined impact of lattice disorder, nanoscale precipitates and reduced grain sizes on the thermoelectric properties of this material. To achieve this, PbTe ingot doped with Ag was obtained by the Bridgman method, followed by ball-milling, cold pressing and sintering. In order to estimate crystallites diameters grain size measurements were carried out using the optical microscopy. Studies of electrical and thermoelectric properties of fine-grained material were performed. In order to analyze the morphology and the composition scanning electron microscopy and energy-dispersive X-ray spectroscopy were performed. Energy-dispersive X-ray spectroscopy analysis also revealed presence of Ag-Te precipitates.

17

X-Ray Diffraction Investigations of NdGaO_{3} Single Crystal

80%

Mazur K., Sass J., Giersz W., Reiche P., Schell N.

Acta Physica Polonica A

|

1997

|

vol. 92

|

issue 1

226-230

EN

Neodymium gallium perovskite single crystals grown with the Czochralski method were examined with several complementary X-ray methods. By means of X-ray diffraction topography and reciprocal space diagram the structural perfection and crystal homogeneity of the studied wafers were determined. Additionally, the results of the X-ray reflectometry investigations of the surface perfection after the mechanochemical treatment are presented.

18

Precipitates in Cd_{1-x}Ni_{x}Se Crystals Grown by the Bridgman Method

80%

Kachniarz J., Dynowska E., Miotkowska S., Paszkowicz W., Miotkowski I., Ramdas A.

Acta Physica Polonica A

|

1992

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vol. 82

|

issue 5

725-728

EN

Single crystals of Cd_{1-x}Ni_{x}Se alloys (x ranging from 0 to 0.075) were investigated using electron microprobe and X-ray diffraction. The analysis shows the presence of Ni-Se precipitates. The solubility limit of Ni is estimated to be 0.008.

19

Luminescence and Excitation Spectra of U^{3+} doped RbY_{2}Cl_{7} Single Crystals

80%

Karbowiak M., Murdoch K., Drożdżyński J., Edelstein N., Hubert S.

Acta Physica Polonica A

|

1996

|

vol. 90

|

issue 2

371-376

EN

Uranium(3+) doped single crystals of RbY_{2}Cl_{7} with a uranium concentration of 0.05% and 0.2% were grown by the Bridgman-Stockbarger method using RbU_{2}Cl_{7} as the doping substance. Polished plates of ca. 5 mm in diameter were used for measurements of luminescence and excitation spectra. Since the U^{3+} ions occupy two somewhat different site symmetries, a splitting of all observed f-f bands was observed. The analysis of the spectra enabled definitively an assignment of 22 crystal field bands for both site symmetries as well as the total crystal field splitting of the ground level, equal to 473 cm^{-1} and 567 cm^{-1} for the first and second site symmetry, respectively.

20

Analysis of Emission and Vibronic Transitions in Uranium(3+) Doped Cs_{2}LiYCl_{6} Single Crystals

80%

Karbowiak M., Simoni E., Drożdżyński J., Hubert S.

Acta Physica Polonica A

|

1996

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vol. 90

|

issue 2

367-370

EN

Uranium(3+) doped single crystals of Cs_{2}LiYCl_{6} with a 0.3 and 2.0% U^{3+} concentration have been obtained by the Bridgman-Stockbarger method. Luminescence spectra of the crystals were recorded at 27 and 15 K, respectively. The emission bands observed in the visible and near infrared regions have been assigned to transitions from the ^{4}I_{11/2}, ^{4}F_{3/2}, and ^{4}G_{7/2} levels to the ^{4}I_{9/2} ground level.

Refine search results

Evolution of the β Phase Flux Dissolution during Quasicrystal Formation

Solubility Limit of Ni in Cd_{1-x}Ni_{x}Te Crystals

Growth and Characterization of Vanadate Laser Crystals

Evolution of Pb_{1-x}Cd_{x}Te Solid Solution Structure at High Temperatures

Growth of Oxide Laser Crystals by Czochralski Method

Czochralski-Grown Silicon Crystals for Microelectronics

Structural Properties of Cd_{1-x}Mg_{x}Te and Cd_{1-x-y}Mg_{x}Mn_{y}Te Crystals

Research and Development of ZnBO_{4} (B = W, Mo) Crystal Scintillators for Dark Matter and Double Beta Decay Searching

Homoepitaxial Growth of YBa_{2}Cu_{3}O_{7} on Single Crystal YBa_{2}Cu_{3}O_{x} Substrates

Growth and Characterization of Titanium Doped Spinel Crystals

High Quality (100) and (001) Oriented Substrates Prepared from Czochralski Grown SrLaGaO_{4} and SrLaAlO_{4} Single Crystals

Role of Crystal-Melt Interface and Surface Tension on Czochralski Growth of Substrate Materials with K_{2}NiF_{4} Structure

SrLaGaO_{4}-SrLaAlO_{4} Solid Solutions - Substrate Materials with Tuneable Lattice Parameter for Various HTSC Compounds

Optical and Scintillation Properties of Bi_{4}(Ge_{x}S_{1-x})_{3}O_{12} Single Crystal

Decomposition Processes in the Anomalous Supersaturated Solid Solution of Binary and Ternary Aluminium Alloys Alloyed with~Sc and~Zr

Impact of Different Conditions of Technological Process on Thermoelectric Properties of Fine-Grained PbTe

X-Ray Diffraction Investigations of NdGaO_{3} Single Crystal

Precipitates in Cd_{1-x}Ni_{x}Se Crystals Grown by the Bridgman Method

Luminescence and Excitation Spectra of U^{3+} doped RbY_{2}Cl_{7} Single Crystals

Analysis of Emission and Vibronic Transitions in Uranium(3+) Doped Cs_{2}LiYCl_{6} Single Crystals