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Your search keyword '"Łapiński, Andrzej"' showing total 185 results
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185 results on '"Łapiński, Andrzej"'

1. Evidence of variable range hopping in the Zintl phase EuIn2P2

Author

Tolinski, Tomasz, Ain, Qurat Ul, Synoradzki, Karol, Lapinski, Andrzej, Zieba, Sylwia, Romanova, Tetiana, Singh, Karan, Pavlosiuk, Orest, Wisniewski, Piotr, and Kaczorowski, Dariusz

Subjects
Condensed Matter - Materials Science
Abstract

We report a comprehensive characterization of the magnetic, electrical transport, spectral, and thermal properties of single-crystalline Zintl-type material EuIn2P2. The compound crystallizes with a hexagonal unit cell (space group P63/mmc) and orders magnetically at TC=24K with the Eu magnetic moments aligned ferromagnetically within the ab plane but tilted alternately along the c-axis direction. The effective and saturation magnetic moments agree with the theoretical values expected for the Eu2+ ion. For a range of several tens of kelvins above 40K, the electrical transport of EuIn2P2 is dominated by short-range magnetic interactions. The temperature dependence of the electrical resistivity has been modelled in terms of variable-range hopping. Another indication of the latter scenario seems to be the observation for EuIn2P2 of a quadratic dependence of the negative magnetoresistance on the magnetic field strength and the scaled magnetization. The temperature dependence of Raman band position and FWHM, as well as phonon lifetime, confirms the presence of the distinctive regions observed in transport and magnetic studies.

Published
2024

9. The metal-insulator transition in the organic conductor $\beta^{\prime\prime}$-(BEDT-TTF)$_{2}$Hg(SCN)$_{2}$Cl

Author

Li, Weiwu, Rose, Eva, Vu, Minh, Hüber, Ralph, Łapiński, Andrzej, Świetlik, Roman, Torunova, Svetlana A., Zhilyaeva, Elena I., Lyubovskaya, Rimma N., and Dressel, Martin

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

We explore the nature of the metal-insulator transition in $\beta^{\prime\prime}$-(BEDT-TTF)$_{2}$Hg(SCN)$_{2}$Cl by x-ray, electrical transport, ESR, Raman and infrared investigations. Magnetic and vibrational spectroscopy concurrently reveal a gradual dimerization along the stacking direction $a$, setting in already at the crossover temperature of 150K from the metallic to the insulating state. A spin gap $\Delta_\sigma = 47$meV is extracted. From the activated resistivity behavior below 55K a charge gap $\Delta_\rho=60$meV is derived. At $T_{\rm CO} = 72$K the C=C vibrational modes reveal the development of a charge-ordered state with a charge disproportionation of $2\delta_{\rho}=0.34e$

Published
2017
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13. Molecular Dynamics of Steroidal Rotors Probed by Theoretical, Spectroscopic and Dielectric Methods

Author

Olszewska, Karolina, primary, Mizera, Adam, additional, Ławniczak, Paweł, additional, Kamińska, Anna, additional, Santillan, Rosa, additional, Morales‐Chamorro, Maricela, additional, Ochoa, Ma. Eugenia, additional, Farfán, Norberto, additional, Łapiński, Andrzej, additional, Górecki, Marcin, additional, Jastrzebska, Izabella, additional, and Runka, Tomasz, additional

Published
2024
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14. Effect of hydrostatic pressure on charge carriers in a conducting pyrrole-co-poly(pyrrole-3-carboxylic) copolymer.

Author

Mizera, Adam, Zięba, Sylwia, Bielejewski, Michał, Dubis, Alina T., and Łapiński, Andrzej

Abstract

The charge carriers in conducting pyrrole-co-poly(pyrrole-3-carboxylic) were examined using high-pressure Raman spectroscopy. The molecular structure of the new copolymer was investigated using high-resolution 13C ssNMR, 1H–13C 2D NMR correlation spectroscopy, and density functional theory (DFT) calculations. Bands in Raman spectra that showed the presence of polarons and bipolarons were studied. It was observed that the quantity of polarons and bipolarons correlated with the hydrostatic pressure. At a pressure of 4 GPa, an anomaly in the correlation between pressure and the position of the Raman band was identified. [ABSTRACT FROM AUTHOR]

Published
2024
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34. The metal-insulator transition in the organic conductor β"-(BEDT-TTF)2Hg(SCN)2Cl.

Author

Weiwu Li, Rose, Eva, Minh Vu Tran, Hübner, Ralph, Łapiński, Andrzej, Świetlik, Roman, Torunova, Svetlana A., Zhilyaeva, Elena I., Lyubovskaya, Rimma N., and Dressel, Martin

Subjects
METAL-insulator transitions, DISPROPORTIONATION (Chemistry), ORGANIC conductors, VIBRATIONAL spectra, DIMERIZATION
Abstract

We explore the nature of the metal-insulator transition in the two-dimensional organic compound β"-(BEDT-TTF)2Hg(SCN)2Cl by x-ray, electrical transport, ESR, Raman, and infrared investigations. Magnetic and vibrational spectroscopy concurrently reveal a gradual dimerization along the stacking direction (a-b)(a-b), setting in already at the crossover temperature of 150 K from the metallic to the insulating state. A spin gap of Δσ=47 meV is extracted. From the activated resistivity behavior below T = 55 K, a charge gap of Δρ=60 meV is derived. At TCO = 72 K, the C=C vibrational modes reveal the development of a charge-ordered state with a charge disproportionation of 2δρ=0.34e. In addition to a slight structural dimerization, charge-order causes stripes most likely perpendicular to the stacks. [ABSTRACT FROM AUTHOR]

Published
2017
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48. Vibrational and Electronic Structure, Electron-Electron and Electron-Phonon Interactions in Organic Conductors Investigated by Optical Spectroscopy

Author

Łapiński, Andrzej

Subjects
Science / Spectroscopy & Spectrum Analysis
Abstract

The physical properties of organic conductors formed by tetrathiafulvalene (TTF) derivatives have been discussed in this chapter. The results were obtained using spectroscopic methods including infrared (IR), Raman, and UV-Vis. The experimental data were supported by theoretical DFT and TD-DFT calculations. Special attention has been paid to the description of electronic and vibrational structures, electron-electron and electron-phonon interactions and determination of transport parameters.

Published
2016

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