Results found: 3

Number of results on page

Search results

Sort By:

Limit search:

Effects of Photoluminescence Polarization in Semiconductor Quantum Well Subjected to In-Plane Magnetic Field

100%

Semenov Y., Ryabchenko S.

Acta Physica Polonica A

2004

vol. 105

issue 6

537-545

Strong optical polarization anisotropy observed previously in the exciton photoluminescence from [100]-oriented quantum wells subjected to the in-plane magnetic field is described within microscopic approach. Developed theory involves two sources of optical polarization anisotropy. The first of them is due to correlation between ψ-functions phases of electron and heavy hole which arise owing to electron Zeeman spin splitting and joint manifestation of low-symmetrical and Zeeman interactions of heavy holes in an in-plane magnetic field. Other optical polarization anisotropy source stems from the admixture of light-holes states to heavy-holes ones by low-symmetry interactions. The heavy hole splitting caused by these interactions separately and the effects of their interference are analyzed. The domination of C_{2v} low-symmetry interaction connected with quantum wells interfaces and/or in-plane deformations takes place in relatively low magnetic field. The directions of this perturbation determine main directions of the π-periodical optical polarization anisotropy. The cubic anisotropy of valence band can add the π/2-periodical contribution to the optical polarization anisotropy. In the case of quantum wells with semimagnetic barriers the Zeeman term contribution can reach value, which dominates the C_{2v} ones, and crossover to polarization connected with magnetic field direction may be observed in low temperature.

Diluted Magnetic Semiconductor Investigations in Ukraine. Nature of Some Additional Lines in QW Optical Spectra

61%

Ryabchenko S., Abramishvili V., Komarov A., Semenov Y., Kyrychenko F., Dubowski J.

Acta Physica Polonica A

1998

vol. 94

issue 2

165-176

The general review of the history and present-day situation of diluted magnetic semiconductor investigation in Ukraine is given by S. Ryabchenko. Some noteworthy results of diluted magnetic semiconductor investigation obtained in Ukraine are pointed out. The main features of the present day situation are mentioned also. As an example of last diluted magnetic semiconductor investigations, the new result obtained by Abramishvili, Komarov, Ryabchenko, Semenov, Kyrychenko and Dubowski for Cd_{1-x}Mn_{x}Te/CdTe/Cd_{1-x}Mn_{x}Te quantum well structures grown by laser ablation method are presented. A weak additional line was observed in the reflectivity spectra of a 27 Å wide quantum well with x= 0.11 in the barrier. Such additional line has not been observed in spectra of similar molecular beam epitaxy grown structures. Based on the theoretical computations of the energies and the relation of intensities of the main and additional lines we conclude that this line might be associated with hh2 → e1 transitions, which ceases to be forbidden in the presence of technologically caused asymmetry of quantum well potential profile.

Manganite Nanoparticles as Promising Heat Mediators for Magnetic Hyperthermia: Comparison of Different Chemical Substitutions

52%

Tovstolytkin A., Shlapa Y., Solopan S., Bodnaruk A., Kulyk M., Kalita V., Zamorskyi V., Ryabchenko S., Belous A.

Acta Physica Polonica A

2018

vol. 133

issue 4

1017-1020

Magnetostatic properties and AC magnetic heating characteristics of (La,Sr)MnO₃ nanoparticles with substitutions in manganese and lanthanum sublattices have been studied. The nanoparticles with average sizes in the range 25-38 nm were synthesized via sol-gel method. Fe substitution for Mn, as well as Sm substitution for La have been used in the experiment. It is shown that the increase in substitution level (for both Fe and Sm substitutions) results in lowering the Curie temperature T_{C} and weakening heating efficiency under the action of AC magnetic field. The results demonstrate that the action of AC field causes effective heating of nanoparticles at temperatures lower than T_{C}, while heating efficiency becomes strongly reduced at higher temperatures. It is proved experimentally that the substitutions in Mn sublattice result in more rapid changes of magnetic properties, as compared to the substitutions in La one. Thus, complex substitutions based on suitable combinations of substituting elements may serve as an efficient tool to "softly" tune the maximal temperature achieved during the AC magnetic field induced heating of nanoparticles, which is important for application of these materials as heat mediators for self-controlled magnetic nanohyperthermia.

Refine search results

3 Acta Physica Polonica A

1 2018

1 2004

1 1998

3 Ryabchenko S.

2 Semenov Y.

1 Abramishvili V.

1 Belous A.

1 Bodnaruk A.

1 Dubowski J.

1 Kalita V.

1 Komarov A.

1 Kulyk M.

1 Kyrychenko F.

1 Shlapa Y.

1 Solopan S.

1 Tovstolytkin A.

1 Zamorskyi V.

Search results

Effects of Photoluminescence Polarization in Semiconductor Quantum Well Subjected to In-Plane Magnetic Field

Diluted Magnetic Semiconductor Investigations in Ukraine. Nature of Some Additional Lines in QW Optical Spectra

Manganite Nanoparticles as Promising Heat Mediators for Magnetic Hyperthermia: Comparison of Different Chemical Substitutions