Instytut Podstawowych Problemów Techniki
Polskiej Akademii Nauk


M. Sawicki

Ostatnie publikacje
1.  Demchenko I.N., Melikhov Y., Walczak M.S., Ratajczak R., Sobczak K., Barcz A., Minikaev R., Dynowska E., Domagała J.Z., Chernyshova M., Syryanyy Y., Gavrilov N.V., Sawicki M., Effect of rapid thermal annealing on damage of silicon matrix implanted by low-energy rhenium ions, JOURNAL OF ALLOYS AND COMPOUNDS, ISSN: 0925-8388, DOI: 10.1016/j.jallcom.2020.156433, Vol.846, pp.156433-1-10, 2020

The structural, electronic, and magnetic properties of low-energy rhenium implanted c-Si are examined for the first time. The damage created by rhenium ions and the following partial reconstruction of the silicon host matrix after rapid thermal annealing (RTA) are investigated as a function of the fluence. Rutherford backscattering spectrometry (RBS) results reveal that the implanted ions are located in the near-surface region with the distribution maximum at about 23 nm below the surface. The analysis of rhenium-depth distribution using the McChasy code shows that the implanted Re-ions are located in the interstitial lattice positions. The RTA leads to a partial recovery of the silicon crystal structure. According to the RBS results, the formed inclusions are not coherent with the silicon host matrix causing an increase of the lattice distortion. Analysis of channeled RBS/c spectra carried out by the McChasy code revealed different levels of bent channels in damaged regions suggesting bimodal distribution of inclusions in the silicon. Studies of high-resolution X-ray photoelectron spectroscopy (XPS) conducted after the RTA showed the shift of Re 4f7/2 binding energy (BE) by +0.68 and + 0.85 eV with respect to metallic rhenium for the samples with lower/higher fluencies, respectively. Complex XPS, density functional theory (DFT) simulations, and transmission electron microscopy (TEM) data analysis allowed us to conclude that the near-surface layer of the sample (~10 nm) consists of nanoinclusions with cubic and/or hexagonal ReSi. In the middle area of the samples, much larger nanoinclusions (>10/20 nm for higher/lower fluencies, respectively) containing pure metallic rhenium inside are formed. The RTA increases the magnetic moment of the sample with the lower dose nearly 20-fold, whereas in the sample with the higher dose a 3-fold increment is observed only. The magnetic response of the examined systems after the RTA indicates a presence of magnetic interactions between the nanoinclusions resulting in the system exhibiting super-spin glass or super-ferromagnetism.

Słowa kluczowe:
rhenium-implanted silicon, RBS, XPS, RTA, TEM, DFT

Afiliacje autorów:
Demchenko I.N. - Institute of Physics, Polish Academy of Sciences (PL)
Melikhov Y. - IPPT PAN
Walczak M.S. - University of Manchester (GB)
Ratajczak R. - National Centre for Nuclear Research (PL)
Sobczak K. - inna afiliacja
Barcz A. - Institute of Physics, Polish Academy of Sciences (PL)
Minikaev R. - inna afiliacja
Dynowska E. - inna afiliacja
Domagała J.Z. - Institute of Physics, Polish Academy of Sciences (PL)
Chernyshova M. - Institute of Plasma Physics and Laser Microfusion (PL)
Syryanyy Y. - Institute of Physics, Polish Academy of Sciences (PL)
Gavrilov N.V. - inna afiliacja
Sawicki M. - inna afiliacja
2.  Baranowska-Korczyc A., Reszka A., Sobczak K., Sikora B., Dziawa P., Aleszkiewicz M., Kłopotowski Ł., Paszkowicz W., Dłużewski P., Kowalski B.J., Kowalewski T.A., Sawicki M., Elbaum D., Fronc K., Magnetic Fe doped ZnO nanofibers obtained by electrospinning, JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY, ISSN: 0928-0707, DOI: 10.1007/s10971-011-2650-1, Vol.61, No.3, pp.494-500, 2012

Comprehensive studies of drug transport in nanofibres based mats have been performed to predict drug release kinetics. The paper presents our approach to analyze the impact of fibers arrangement, one of the parameters varied in our parallel experimental studies. Drug encapsulation in submicron fibers and subsequent controlled release of drugs is a tedious task due to the large number of process and material parameters involved. In the numerical study we constructed a 3D finite element geometry representing nanofibrous cubic element. COMSOL Multiphysics has been used to assess the impact of the various purposed arrangements of fibers within the mat. Drug release from nanofibers was modeled by adsorption -desorption and diffusion equation, where drug diffusion coefficient in the fluid between the fibers was altered depending on porosity of the material. Our study shows that for the same material porosity drug release from the matrix of regularly oriented fibers is slower than from randomly oriented, isotropic nanofibrous material. Also by decreasing distance between the fibers drug transport rate is reduced.

Słowa kluczowe:
Electrospinning, ZnO nanofibers, ZnFeO, Room temperature ferromagnetism, Magnetic oxides

Afiliacje autorów:
Baranowska-Korczyc A. - inna afiliacja
Reszka A. - inna afiliacja
Sobczak K. - inna afiliacja
Sikora B. - inna afiliacja
Dziawa P. - inna afiliacja
Aleszkiewicz M. - inna afiliacja
Kłopotowski Ł. - inna afiliacja
Paszkowicz W. - inna afiliacja
Dłużewski P. - inna afiliacja
Kowalski B.J. - inna afiliacja
Kowalewski T.A. - IPPT PAN
Sawicki M. - inna afiliacja
Elbaum D. - inna afiliacja
Fronc K. - inna afiliacja

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