Search results

1

Elastic Constants of β-HgS

100%

Prieur J., Joffrin J., Szuszkiewicz W., Dynowska E., Górecka J., Witkowska B.

Acta Physica Polonica A

|

1998

|

vol. 94

|

issue 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.

2

Crystallization Process of Fe_{75}Co_5Zr_{10}B_{10} Amorphous Alloy

100%

Sun Y., Zuo B., Wang D., Meng X., Liu J., Wang L., Hua Z.

Acta Physica Polonica A

|

2013

|

vol. 124

|

issue 4

685-687

EN

Fe_{75}Co_5Zr_{10}B_{10} amorphous alloy prepared by melt-spinning was annealed at various temperatures. The thermal property and microstructures were investigated by differential thermal analysis, X-ray diffraction, and transmission electron microscopy. The crystallization process of Fe_{75}Co_5Zr_{10}B_{10} amorphous alloy is complex. The α-Fe phase precipitates from the amorphous matrix in the initial stage of crystallization. The α-Mn type (χ) phase precipitates at 570°C, but transforms to α-Fe phase and the Laves C14(λ) phase at higher temperature. In the final stage of crystallization, Fe_3Zr, Fe_2Zr, and unknown phases are observed and the λ-phase disappears. The α-Fe phase preferentially nucleates after annealing at 530C for 10 min and the χ-phase preferentially nucleates after annealing at 600C for 10 min. The nucleation barrier of χ-phase is larger than that of α-Fe phase. The local structure of χ-phase is more similar to amorphous phase.

3

Phase Field Modeling of the Zn_{1-x}Cd_xO Solid Solutions

80%

Shtepliuk I., Podolskaia N., Lashkarev G.

|

vol. 126

|

issue 5

1079-1082

EN

The analysis of spinodal decomposition in the Zn_{1-x}Cd_xO ternary alloy was carried out by means of the nonlinear Cahn-Hilliard equation. Interaction parameter as a function of composition x was provided by valence force field simulations and was used in this analysis. The morphological patterns for the ternary alloys with different Cd content (x=5, 10, 50%) were experimentally obtained using the semi-implicit Fourier-spectral method. The simulated microstructure evolution Zn_{0.95}Cd_{0.05}O demonstrates that the microstructure having a form of bicontinuous worm-like network is evolved with the progress of aging. An effect of the phase-field mobility and the gradient energy on the microstructure evolution of the Zn_{1-x}Cd_xO alloys is discussed. It was found that the higher driving force for the decomposition in the higher Cd content film results in a higher decomposition rate revealed by the simulations. The temporal evolution of the simulated Zn_{0.95}Cd_{0.05}O microstructure is in good agreement with experimental results, which have been obtained for this solid solution.

4

Orientational Ordering for System of Ellipsoidal Molecules Dispersed in Cubic Lattice

80%

Mejdani R.

Acta Physica Polonica A

|

1996

|

vol. 90

|

issue 6

1127-1141

EN

We represent here some results for a model of migrating and nonmigrating ellipsoidal molecules dispersed in a cubic lattice, describing: the orientational ordering in nematics, the possibility of a biaxial ordered liquid state, the orientational ordering in solid hydrogen (orto-H_{2} or para-D_{2}) or the orientational glassy structure (the "higher rank"glass state). Through this kind of molecular ensemble (in the case of the system of ellipsoidal and spherical molecules) it is also possible to study the orientational and positional orderings in binary mixtures and to obtain the so-called plastic state.

5

Properties of Fe Doped β-HgS under Hydrostatic Pressure

80%

Szuszkiewicz W., Skierbiszewski C., Paszkowicz W., Dybko K., Domagała J., Dynowska E., Witkowska B., Zinn P.

Acta Physica Polonica A

|

1998

|

vol. 94

|

issue 3

570-574

EN

High pressure- high temperature studies of the structural (zinc blende- cinnabar) phase transitions were performed in Hg_{1-x}Fe_{x} S mixed crystals (x<0.1) using synchrotron radiation and multianvil X-ray diffraction press. Pressure investigations of the Hall effect and conductivity of crystals containing up to a few percent of Fe were also performed at 295 K and 77 K. It was demonstrated that Fe in β-HgS creates deep, localized donor state resonant with the conduction band.

6

^{57}Fe Mössbauer Spectroscopy οf Radiation Damaged Allanites

80%

Malczewski D., Grabias A.

Acta Physica Polonica A

|

2008

|

vol. 114

|

issue 6

1683-1690

EN

Metamict minerals contain radioactive elements that degrade the crystal structure of the minerals. The degradation occurs primarily through progressive overlapping recoil nuclei collision cascades from α-decays of ^{238}U, ^{232}Th, ^{235}U and their daughter products. We report the results of ^{57}Fe Mössbauer spectroscopy, gamma-ray spectrometry and microprobe analysis of three partially metamict allanites, (Ca,Ce,REE)_2(Fe^{2+},Fe^{3+})(Al,Fe^{3+})_2O[Si_2O_7][SiO_4](OH) where REE stands for rare earth elements. The samples were collected in pegmatites from Reno, Nevada (USA), Franklin, New Jersey (USA) and Nya Bastnas Field (Sweden). The absorbed α-dose for these minerals was found to range from 5.8×10^{14} α-decay/mg for the allanite from Reno to 1.9×10^{15} α-decay/mg for the allanite from Franklin. The Mössbauer spectra show a decrease in the Fe^{2+} doublet intensity with increasing absorbed α-dose. We also observe an increase in the line widths of the Fe^{2+} and Fe^{3+} doublets with increasing absorbed α-dose.

7

Deterioration of Mechanical Properties of MBE-Grown, Metastable Semiconductor Layer with Time: the Case of Zinc Blende MnTe

80%

Adamiak S., Dynowska E., Dziedzic A., Szmuc K., Janik E., Wiater M., Wojtowicz T., Szuszkiewicz W.

|

EN

Several few μm thick (001)-oriented, metastable MnTe layers with the zinc blende structure grown onto (001)GaAs substrate by MBE during different periods for the last twenty years were investigated by the scanning electron microscopy, atomic force microscopy, X-ray diffraction, and nanoindentation methods. A partial decomposition of the oldest investigated layers was demonstrated. An important decrease of Young's modulus from about 34 GPa to about 17 GPa, resulting from a deterioration of the crystal structure of such layers, was found.

8

Stable and Metastable Phases in the Atomic Limit of the Extended Hubbard Model with Intersite Density-Density Interactions

70%

Kapcia K., Robaszkiewicz S.

Acta Physica Polonica A

|

2012

|

vol. 121

|

issue 5-6

1029-1031

EN

We have studied a simple effective model of charge ordered insulators. The tight binding Hamiltonian consists of the effective on-site interaction U and the intersite density-density interaction W_{ij} (both: nearest-neighbor and next-nearest-neighbor). In the analysis of the phase diagrams and thermodynamic properties of this model we have adopted the variational approach, which treats the on-site interaction term exactly and the intersite interactions within the mean-field approximation. Our investigations of the general case (as a function of the electron concentration n) have shown that the system exhibits various critical behaviors including among others bicritical, tricritical, critical-end, and isolated critical points. In this report we concentrate on the metastable phases and transitions between them. One finds that the first- and second order transitions between metastable phases can exist in the system. These transitions occur in the neighborhood of first as well as second order transitions between stable phases. For the case of on-site attraction the regions of metastable homogeneous phases occurrence inside the ranges of phase separated states stability have been also determined.

Refine search results

Elastic Constants of β-HgS

Crystallization Process of Fe_{75}Co_5Zr_{10}B_{10} Amorphous Alloy

Phase Field Modeling of the Zn_{1-x}Cd_xO Solid Solutions

Orientational Ordering for System of Ellipsoidal Molecules Dispersed in Cubic Lattice

Properties of Fe Doped β-HgS under Hydrostatic Pressure

^{57}Fe Mössbauer Spectroscopy οf Radiation Damaged Allanites

Deterioration of Mechanical Properties of MBE-Grown, Metastable Semiconductor Layer with Time: the Case of Zinc Blende MnTe

Stable and Metastable Phases in the Atomic Limit of the Extended Hubbard Model with Intersite Density-Density Interactions