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1

Microhardness and the Young Modulus of Thin, MBE-Grown, (Sn,Mn)Te Layers Containing up to 8% of Mn

100%

Adamiak S., Zięba M., Minikayev R., Reszka A., Taliashvili B., Szuszkiewicz W.

Acta Physica Polonica A

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2017

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vol. 132

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issue 2

347-350

EN

The thin layers of (Sn,Mn)Te solid solution were grown by molecular beam epitaxy onto (111)-oriented BaF₂ substrates and characterized by scanning electron microscopy, atomic force microscopy, energy dispersive X-ray spectrometry, and X-ray diffraction methods. The epitaxial character of the growth was confirmed. All the layers exhibited a regular (fcc) structure of the rock-salt type and were (111)-oriented, their thickness was close to about 1 μm. The layers contained up to 8% of Mn. The microhardness and the Young modulus values were determined by the nanoindentation measurements. The Berkovich type of the intender was applied, the maximum applied load was equal to 1 mN. The results of measurements demonstrated a lack of the composition dependence of the Young modulus value. A slight increase of the microhardness value with an increasing Mn content in the (Sn,Mn)Te solid solution was observed.

2

Fano Resonance of Eu^{2+} and Eu^{3+} in (Eu,Gd)Te MBE Layers

84%

Orlowski B., Kowalski B., Dziawa P., Pietrzyk M., Mickievicius S., Osinniy V., Taliashvili B., Kowalik I., Story T., Johnson R.

Acta Physica Polonica A

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2005

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vol. 108

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issue 5

803-807

EN

Resonant photoemission spectroscopy, with application of synchrotron radiation, was used to study the valence band electronic structure of clean surface of (EuGd)Te layers. Fano-type resonant photoemission spectra corresponding to the Eu 4d-4f transition were measured to determine the contribution of 4f electrons of Eu^{2+} and Eu^{3+} ions to the valence band. The resonant and antiresonant photon energies of Eu^{2+} ions were found as equal to 141 V and 132 eV, respectively and for Eu^{3+} ions were found as equal to 146 eV and 132 eV, respectively. Contribution of Eu^{2+}4f electrons was found at the valence band edge while for Eu^{3+} it was located in the region between 3.5 eV and 8.5 eV below the valence band edge.

3

Fano Resonance Investigation of PbTe Layers Containing Eu and Gd Ions

84%

Orlowski B., Osinniy V., Dziawa P., Pietrzyk M., Kowalski B., Taliashvili B., Story T., Johnson R.

Acta Physica Polonica A

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2008

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vol. 114

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issue 2

351-356

EN

The Fano resonance photoemission studies of Gd/(Pb, Gd)Te layers using synchrotron radiation were carried out and the electronic structure parameters like binding energies of Gd^{3+} 4f and 5p shells, resonance and antiresonance energies for Gd^{3+} were determined. The presence of Eu^{3+} ions was observed in the (Pb, Eu)Te and (Eu, Gd)Te layers grown by MBE technique. The comparison of data for (Pb, Gd)Te compound with corresponding data for (Eu, Gd)Te and (Pb, Eu)Te layers indicates that we are not able to distinct the Eu^{3+}4f and Gd^{3+}4f electrons contribution to the valence band photoemission spectra because of small content od Gd and similar binding energy values. The key parameters allowing to prove exactly the presence of either Eu^{3+} or Gd^{3+} are the resonance and antiresonance energies which are significantly different for these ions and equal to 143 eV/137 eV and 150 eV/142 eV, respectively.

4

Ferromagnetic Transition in Ge_{1-x}Mn_{x}Te Layers

68%

Knoff W., Domukhovski V., Dybko K., Dziawa P., Jakieła R., Łusakowska E., Reszka A., Świątek K., Taliashvili B., Story T., Szałowski K., Balcerzak T.

Acta Physica Polonica A

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2009

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vol. 116

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issue 5

904-906

EN

Ferromagnetic transition temperature in thin layers of diluted magnetic (semimagnetic) semiconductor Ge_{1-x}Mn_{x}Te was studied experimentally by SQUID magnetometry method and analyzed theoretically for a model Ising-type diluted magnetic system with Ruderman-Kittel-Kasuya-Yosida indirect exchange interaction. The key features of the experimentally observed dependence of the Curie temperature on Mn content (x ≤ 0.12) and conducting hole concentration p = (1-10) × 10^{21} cm^{-3} were reproduced theoretically for realistic valence band and crystal lattice parameters of p-Ge_{1-x}Mn_{x}Te taking into account short carrier mean free path encountered in this material and Ruderman-Kittel-Kasuya-Yosida mechanism with both delta-like and diffused character of spatial dependence of the exchange coupling between magnetic ions and free carriers.

5

Epitaxial Growth and Optical Properties of PbTe/CdTe Semiconductor Heterostructures

68%

Szot M., Kowalczyk L., Smajek E., Domukhovski V., Domagała J., Łusakowska E., Taliashvili B., Dziawa P., Knoff W., Wiater M., Wojtowicz T., Story T.

Acta Physica Polonica A

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2008

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vol. 114

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issue 5

1391-1396

EN

Growth optimization, optical and structural properties of PbTe/CdTe multilayers grown by molecular beam epitaxy on GaAs (001) as well as on BaF_2 (111) substrates is reported. An intense photoluminescence in the mid-infrared region is observed from PbTe quantum wells excited with 1.17 eV pulsed YAG:Nd laser. The energy of the emission peak shows blue shift with decreasing PbTe well width and has a positive temperature coefficient. The influence of thermal annealing on photoluminescence spectra of PbTe/CdTe multilayers grown on BaF_2 substrate is discussed.

6

Magnetic Properties of Epitaxial (Ge,Mn)Te Thin Films with Varying Crystal Stoichiometry

68%

Knoff W., Domukhovski V., Dybko K., Dziawa P., Górska M., Jakieła R., Łusakowska E., Taliashvili B., Story T., Reszka A., Anderson J., Rotundu C.

Acta Physica Polonica A

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2008

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vol. 114

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issue 5

1159-1165

EN

Magnetization of 1 μm thick ferromagnetic IV-VI (Ge, Mn)Te semiconductor layers with 10 at.% of Mn was studied by SQUID magnetometry method up to the magnetic fields of 70 kOe. The layers were grown on BaF₂ (111) substrates by molecular beam epitaxy with varying Te molecular flux, which permitted the control of layer stoichiometry and conducting hole concentration. X-ray diffraction and in situ electron diffraction characterization of layer growth and crystal structure revealed two-dimensional mode of growth and monocrystalline rhombohedral crystal structure of (Ge, Mn)Te layers. Controlling the layer stoichiometry influences the temperature dependence of magnetization with the ferromagnetic Curie temperature varying in Ge_{0.9}Mn_{0.1}Te layers from T_c=30 K (low Te flux) to T_c=42 K (high Te flux).

7

(Eu,Gd)Te - MBE Growth and Characterization

68%

Dziawa P., Taliashvili B., Domuchowski W., Łusakowska E., Arciszewska M., Demchenko I., Dobrowolski W., Dybko K., Fedorych O., Nadolny A., Osinniy V., Petrouchyk A., Story T.

Acta Physica Polonica A

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2004

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vol. 106

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issue 2

215-221

EN

Monocrystalline thin layers of (Eu,Gd)Te, n-type ferromagnetic semiconductor, were grown by molecular beam epitaxy technique on BaF_2 (111) substrates. Reflection high-energy electron diffraction, X-ray diffraction, and atomic force microscopy characterization proved epitaxial mode of growth and high crystal quality of the layers. Magnetic susceptibility and magnetic resonance measurements showed that in (Eu,Gd)Te layers ferromagnetic transition takes place at about 13 K. Electrical characterization carried out by the Hall effect and resistivity measurements revealed very high electron concentration of 10^{20}~cm^{-3} and sharp maximum of resistivity at transition temperature.

8

Magnetic and Structural Studies of GeMnSnTe Epitaxial Layers

68%

Grochot A., Knoff W., Taliashvili B., Wołkanowicz W., Minikayev R., Pieniążek A., Łusakowska E., Sawicki M., Jantsch W., Story T., Przybylińska H.

Acta Physica Polonica A

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2017

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vol. 132

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issue 2

340-342

EN

MBE grown Ge_{1-x-y}Mn_xSn_yTe layers with Mn content ranging from 10 to 30% and Sn content ranging from 2 to 5% have been characterized with X-ray diffraction, energy-dispersive X-Ray spectroscopy, atomic force microscopy, SQUID magnetometry, and ferromagnetic resonance. All layers (except the one with the highest Mn and Sn content) were found to be single phase rhombohedral, with the distortion axis perpendicular to the layer surface, and ferromagnetic. Ferromagnetic resonance studies have shown that co-doping with a few percent of tin makes the lattice more rigid and changes considerably the magnetocrystalline anisotropy, from purely uniaxial in GeMnTe to distorted cubic in Ge_{1-x-y}Mn_xSn_yTe at the same Mn content.

Refine search results

Microhardness and the Young Modulus of Thin, MBE-Grown, (Sn,Mn)Te Layers Containing up to 8% of Mn

Fano Resonance of Eu^{2+} and Eu^{3+} in (Eu,Gd)Te MBE Layers

Fano Resonance Investigation of PbTe Layers Containing Eu and Gd Ions

Ferromagnetic Transition in Ge_{1-x}Mn_{x}Te Layers

Epitaxial Growth and Optical Properties of PbTe/CdTe Semiconductor Heterostructures

Magnetic Properties of Epitaxial (Ge,Mn)Te Thin Films with Varying Crystal Stoichiometry

(Eu,Gd)Te - MBE Growth and Characterization

Magnetic and Structural Studies of GeMnSnTe Epitaxial Layers