pl_goraZ.png
Zdj2.png
AKTUALNOŚCI / NEWS

2013

| Administrator
M. Bazarnik, J. Brede, R. Decker, R. Wiesedanger"Tailoring Molecular Self-Assembly of Magnetic Phthalocyanine Molecules on Fe- and Co-Intercalated Graphene"ACS Nan...

2014

| Administrator
R. Decker, M. Bazarnik, N. Atodiresei, V. Caciuc, S. Blügel, R. Wiesendanger"Local tunnel magnetoresistance of an iron intercalated graphene-based heterostructure...

2015

| Administrator
A. Racis, L. Jurczyszyn, M. Bazarnik, W. Koczorowski, A. Wykrota, R. Czajka, M.W. Radny"Self-organisation of inorganic elements on Si(001) mediated by pre-adsorbed...
TERMINARZ
listopad 2017
P W Ś C Pt S N
week 44 1 2 3 4 5
week 45 6 7 8 9 10 11 12
week 46 13 14 15 16 17 18 19
week 47 20 21 22 23 24 25 26
week 48 27 28 29 30
imageimageimageimageimageimageimageimageimageimageimageimageimageimage

2014

  1. R. Decker, M. Bazarnik, N. Atodiresei, V. Caciuc, S. Blügel, R. Wiesendanger
    "Local tunnel magnetoresistance of an iron intercalated graphene-based heterostructure"
    Journal of Physics Condensed Matter, 26 (2014) 394004

    Abstract

     The lateral variation of the tunnel magnetoresistance (TMR) of a graphene-based vertical heterostructure is studied by spin-polarized scanning tunneling microscopy (SP–STM) using an Fe-coated probe tip. The well-defined heterostructure is obtained by the intercalation of a magnetic Fe monolayer at the graphene/Ir(111) interface. Its structure is characterized by a moiré pattern with a high corrugation. In contrast to the Fe/Ir(111) surface, graphene/Fe/Ir(111) exhibits ferromagnetic order with an out-of-plane easy magnetization axis. At the nanometer scale, our experiments reveal that the moiré pattern induces a lateral variation of the TMR, which reaches 80%. The measured TMR at valleys of the moiré pattern is higher than at hills. We interpret this modulation in terms of a different hybridization between graphene and Fe at valleys and hills due to a different graphene–Fe distance at these sites, which leads to a different transmission of spin-polarized states.
  2. J. Brede, N. Atodiresei, V. Caciuc, M. Bazarnik, A. Al-Zubi, S. Blügel, R. Wiesendanger
    "Long-range magnetic coupling between nanoscale organic–metal hybrids mediated by a nanoskyrmion lattice"
    Nature Nanotechnology, 9 (2014) 1018-1023

    Abstract

    The design of nanoscale organic–metal hybrids with tunable magnetic properties as well as the realization of controlled magnetic coupling between them open gateways for novel molecular spintronic devices. Progress in this direction requires a combination of a clever choice of organic and thin-film materials, advanced magnetic characterization techniques with a spatial resolution down to the atomic length scale, and a thorough understanding of magnetic properties based on firstprinciples calculations. Here, we make use of carbon-based systems of various nanoscale size, such as single coronene molecules and islands of graphene, deposited on a skyrmion lattice of a single atomic layer of iron on an iridium substrate, in order to tune the magnetic characteristics (for example, magnetic moments, magnetic anisotropies and coercive field strengths) of the organic–metal hybrids. Moreover, we demonstrate long-range magnetic coupling between individual organic–metal hybrids via the chiral magnetic skyrmion lattice, thereby offering viable routes towards spin information transmission between magnetically stable states in nanoscale dimensions.
  3. T. Grzela, W. Koczorowski, G. Capellini, R. Czajka, M. W. Radny, N. Curson, S. R. Schofield, M. A. Schubert, T. Schroeder
    "Interface and nanostructure evolution of cobalt germanides on Ge(001)"
    Journal of Applied Physics, 115 (2014) 074307

    Abstract

    Cobalt germanide (CoxGey) is a candidate system for low resistance contact modules in future Ge devices in Si-based micro and nanoelectronics. In this paper, we present a detailed structural, morphological, and compositional study on CoxGey formation on Ge(001) at room temperature metal deposition and subsequent annealing. Scanning tunneling microscopy and low energy electron diffraction clearly demonstrate that room temperature deposition of approximately four monolayers of Co on Ge(001) results in the Volmer Weber growth mode, while subsequent thermal annealing leads to the formation of a Co-germanide continuous wetting layer which evolves gradually towards the growth of elongated CoxGey nanostructures. Two types of CoxGey nanostructures, namely, flattop- and ridge-type, were observed and a systematic study on their evolution as a function of temperature is presented. Additional transmission electron microscopy and x-ray photoemission spectroscopy measurements allowed us to monitor the reaction between Co and Ge in the formation process of the CoxGey continuous wetting layer as well as the CoxGey nanostructures.
  4. A. Wykrota,  W. Koczorowski,  R.Czajka
    "Functionalization of Si (100) surface with benzonitrile molecules in an ultra-high-vacuum molecular evaporator"
    Materials Science in Semiconductor Processing, 17 (2014) 168-172

    Abstract

     We investigated benzonitrile adsorption on Si(1 0 0) deposited in a home-made molecular source using scanning tunneling microscopy (STM). A high-purity molecular source was constructed for evaporation of organic molecules in the liquid phase. The molecular flux and deposition rate are stable over time and yield good control of the coverage level to less than one monolayer. The method described for creation of a molecular beam can be extended to various molecules in the liquid phase under ambient conditions and substrates. To confirm the reliability of our results, we used benzonitrile molecules on Si(1 0 0) as a substrate that is highly demanding in terms of the vacuum quality (residual gases and impurities) and level. The results were compared with previously obtained results using STM and theoretical methods. This simple molecular source yields enhanced measurement possibilities for different experimental systems without the need for significant investment or system modifications. A simple model is presented to predict the expected coverage and to evaluate device parameters appropriate for the evaporated material.
  5. M. Sadej, E. Andrzejewska, B. Kurc, H. Gojzewski, T. Jesionowski
    "Surface-Dependent Effect of Functional Silica Fillers on Photocuring Kinetics of Hydrogel Materials"
    Journal of Polymer Science, Part A: Polymer Chemistry, 52 (2014) 3472-3487

    Abstract

     Two types of silica: precipitated (P, prepared in non-polar media, a new type, submicrometer sized) and fumed (F, nanosized), both unmodified and surface modified are investigated as functional fillers for potential applications in nanocomposites with poly(2-hydroxyethyl methacrylate) matrix. Special attention is paid to the kinetics of composite formation in an in situ photopolymerization process. Silica-containing formulations polymerize faster; this effect is much stronger for silica P having much larger particle size than silica F. Surface treatment leads to further acceleration of the polymerization in case of silica P but to retardation in case of silica F; the effect of modification of the filler surface on properties of composites is different for each of the silicas. The obtained results are discussed in terms of effects of curvature of silica particles, surface properties, solvation cell, interphase region, viscosity changes, and morphology of the resulting composites.
  6. P. Ziobrowski, E. Andrzejewska, M. Szybowicz, A. Nowicka, M. Sadej-Bajerlein, H. Gojzewski, M. Drozdowski
    "Particle Clustering in Photocurable Nanocomposites: Dependence of Curing Kinetics and Viscoelastic Properties"
    Journal of Applied Polymer Science, 131 (2014) 39895

    Abstract

     The aim of this article is to investigate the effect of nanoparticle clustering on the mobility of nanoparticles in nanocomposites, using spectroscopic methods (Brillouin and Raman). Special attention is paid to the effect of particle clustering on photocuring kinetics. The model system was poly(2-hydroxyethyl acrylate) filled with fumed nanosilica in concentration range encompassing the percolation threshold. Results obtained from Brillouin spectroscopy show substantial changes in the sound velocity and the attenuation coefficient with increasing filler content. The damping of acoustic waves reaches the maximum at the percolation threshold (~15 wt %), which is related to changes in the mechanism of acoustic wave propagation. The formation of the cocontinuous silica phase strongly affects the curing kinetics of the monomer/silica system: the polymerization rate is the highest at a silica content corresponding to the percolation threshold. These results correlate well with the results of AFM surface roughness analysis.
  7. M. Molčan, A. Hashim, J. Kováč, M. Rajňák, P. Kopčanský, M. Makowski, H. Gojzewski, M. Molokáč, L. Hvizdák, M. Timko
    "Characterization of Magnetosomes After Exposure to the Effect of the Sonication and Ultracentrifugation"
    Acta Physica Polonica A, 126 (2014) 198-199

    Abstract

     Magnetosomes are intracellular organelles of widespread aquatic microorganisms called Magnetotactic bacteria. At present they are under investigation especially in biomedical applications. This ability depends on the presence of intracellular magnetosomes which are composed of two parts: first, nanometer-sized magnetite (Fe3O4) or greigite (Fe3S4) crystals (magnetosome crystal), depending on the bacterial species; and second, the bilayer membrane surrounding the crystal (magnetosome membrane). The magnetosomes were prepared by biomineralization process of magnetotactic bacteria Magnetospirillum Magnetotacticum sp. AMB-1. The isolated magnetosome chains (sample M) were centrifugated at speed of 100000 rpm for 4 hours (sample UM) and sonicated at power of 120 W for 3 hours (sample SM), respectively. The prepared suspensions were investigated with respect to morphological, structural and magnetic properties. The results from scanning electron microscopy showed that isolated chains of magnetosomes were partially broken to smaller ones after ultracentrifugation. On the other hand the application of the sonication process caused the formation of individual magnetosomes (unordered in chain). These results were confirmed by coercivity and magnetization saturation measurements.
  8. M. Kazmierczak, K. Pogorzelec-Glaser, A. Hilczer, S. Jurga, Ł. Majchrzycki, M. Nowicki, R. Czajka, F. Matelski, R. Pankiewicz, B. Leska, L. Kepinski, B. Andrzejewski
    "Morphology and magnetic properties of Fe3O4-alginic acid nanocomposites"
    Materials and Technology, 48 (2014) 59-62

    Abstract

     Morphology, structure and magnetic properties of nanocomposites of magnetite (Fe3O4) nanoparticles and alginic acid (AA) are studied. Magnetite Fe3O4 nanoparticles and the nanoparticles capped with alginic acid exhibit very distinct properties. The chemical bonding between alginic acid and surface of magnetite nanoparticles results in recovery of surface magnetization. On the other hand, it also leads to enhanced surface spin disorder and unconventional behavior of magnetization observed in Fe3O4-AA nanocomposites at low temperatures.
  9. R. Ranecki, M. Kamiński, M. Szybowicz, A. Dychalska, M. Błaszczyk, T. Luciński, B. Susła
    "Magnetic properties of multilayers [NI-FE/AU/CO/AU]6."
    8th International Conference - Electromagnetic Devices and Processes in Environment Protection, (2014)

    Abstract

    We present the possibility to study magnetic properties of thin magnetic films using Raman spectrometer. The method is based on the observation of standing spin waves. Experimental data are presented for Si(111)[NiFe(2nm)/ Au(2nm)/Co(0,8nm)/Au(2nm)]6 multilayers which exhibit perpendicular anisotropy of cobalt film and giant magnetoresistance.
  10. H. Maciejewski, J. Karasiewicz, M. Dutkiewicz, M. Nowicki, Ł. Majchrzycki
    "Effect of the type of fluorofunctional organosilicon compounds and the method of their application onto the surface on its hydrophobic properties"
    RSC Advances, 4 (2014) 52668

    Abstract

     Fluorofunctional silanes, polysiloxanes and silsesquioxanes were used for the modification of glass surfaces and their influence on hydrophobic properties were determined. To increase hydrophobicity of the surface, the modification was performed in two stages: (i) by a pretreatment using a silica sol (a rise in the surface roughness), and (ii) modification with the above silicon compounds. The hydrophobicity was determined by measuring the contact angle by drop profile tensiometry. The fluorocarbofunctional organosilicon derivatives examined were found to be good precursors for the synthesis of highly hydrophobic materials and coatings. In some cases the contact angles measured after surface modification exceeded 150o, i.e. they fell in the range characteristic of superhydrophobic surfaces.
  11. A. A. Poźniak, K. W. Wojciechowski
    "Poisson’s ratio of rectangular anti-chiral structures with size dispersion of circular nodes"
    Physica Status Solidi (b), 251 (2014) 367-374

    Abstract

     Using Finite Element computer simulations, Poisson’s ratio (PR) is determined for anti-chiral structures built on rectangular lattices with disorder introduced by stochastic distributions of circular node sizes. The investigated models are parameterized by the lattice anisotropy, the rib thickness, and the radii distribution of circular nodes. Three approaches are developed. The first approach, exact in the limit of infinitely large system and infinitely dense mesh, uses only planar elements (CPS3). Two other approaches are approximate and exploit one-dimensional elements utilizing the Timoshenko beam theory. It is shown that in the case of sufficiently large anisotropy of the studied structures PR can be highly negative, reaching any negative value, including those lower than −1. Thin ribs and thin-walled circular nodes favor low values of PR. In the case of thick ribs and thick-walled circular nodes PR is higher. In both cases the dispersion of the values of circular nodes radii has a minor effect on the lowest values of PR. A comparison of the results obtained with three different approaches shows that the Timoshenko beam based approximations are valid only in the thin rib limit. The difference between them grows with increasing thickness.
  12. E. Frydrych-Tomczak, B. Uszczyńska, T. Ratajczak, W. T. Markiewicz, M. Figlerowicz, M. Nowicki, H. Maciejewski, M. K. Chmielewski
    "Application of epoxy functional silanes in the preparation of DNA microarrays"
    Journal of Biotechnology, Computational Biology and Bionanotechnology, 95 (2014) 5-16

    Abstract

     Nucleic acid microarrays have recently become one of the basic techniques in the study of gene expression. Owing to progress in the field of miniaturization, thousands of oligonucleotides differing in terms of their sequences can be systematically placed on a small area of a solid support (usually glass). These probes are capable of simultaneously interacting with a large number of longer nucleic acids from particular genes. Nucleic acid microarray construction technology consists, primarily, of the appropriate functionalization of a glass surface with the use of organofunctional silanes. Oligonucleotides known as probes are attached to a functionalized surface using, for instance, the lithography technique and, after being linked to the surface, they are subjected to hybridization with complementary and labelled fragments of nucleic acids known as samples of unknown sequences. In this paper, we present a method for constructing DNA microarrays that is based on the use of microscopic slides modified with epoxy functional group-containing silanes. This study was aimed at optimizing the production of DNA microarrays. The study tested the usefulness of four different epoxy functional silanes with one or three alkoxy groups. In addition, slides were silanized with the use of alkylsilane. The glass slides were characterized using a goniometer and an atomic force microscope (AFM). The synthesized amino linker-containing oligonucleotide probes were printed onto the glass slides in order to check the effectiveness of their attachment to the solid surface.
  13. M. Molcan, A. Hashim, J. Kovac, H. Gojzewski, A. Skumiel, F. Royer, D. Jamon, P. Kopcansky, M. Timko
    "Magnetosomes - bacterial magnetic nanoparticles"
    Communications, 16 (2014) 26

    Abstract

     The magnetic properties, magneto-optical effects and hyperthermia effect were studied in solution of magnetosomes extracted from cultivated bacteria Magnetospirillum sp. AMB-1. The properties of magnetosomes were changed using different conditions during synthesis and by modification of particles after synthesis by using sonication and ultracentrifugation methods. It was shown that adding a higher amount of Wolfe’s vitamin solution (WVS) or ferric quinate (FQ) cause increase of the mean diameter from 47 nm (normal condition) up to 52 nm and 58 nm respectively. Hyperthermic measurements were performed for three types of magnetosome samples: (I) M - not influenced by separation method (long - chains magnetosomes), (II) UM - after centrifugation procedure, and (III) SM - after centrifugation procedure including sonication. The Specific Absorption Rate (SAR) decreased depending on chains shortening and decrease in hysteresis too. The SAR values were 1083, 934 or 463 W/g for the sample M, UM and SM, respectively.
  14. Ł. MajchrzyckiM. NowickiR. Czajka, K. Lota
    "Method of carbon-based electrode analysis by conductive-atomic force microscopy"
    Micro & Nano Letters, 9 (2014) 69-72

    Abstract

    A novel method of the characterisation of composite materials for electrochemical capacitor electrodes by conductive-atomic force microscopy is reported. The method allowed the analysis of the structure and the distribution of the non-conductive or less conductive additives dispersed in the carbon conductive matrix, which affect the surface conductivity of the electrodes. The composites of activated carbon with nickel (II) oxide, as well as activated carbon or carbon nanotubes with three different conducting polymers – polyaniline, poly(3,4-ethylenedioxythiophene) and polypyrrole – were prepared and tested and analysed by the reported method.