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Preservation of soft parts (collagen fibres, blood vessels and cells) in extinct vertebrates is rare and usually limited to fossilized bone and cartilage. Well-preserved coarse collagenous fibre bundles embedded in a mineralized matrix of tendons, as well as numerous hollow, tubular structures consistent morphologically with fibril bundles, blood vessels and associated cells, were identified in ossified tendons of Late Cretaceous ornithischians from North America and Central East Asia. Detailed, high-accuracy imaging, along with spectroscopic characterization of those fibrous structures and comparison with ossified tendons of modern-day turkeys, support the proposition that physiologically driven tendon ossification is common for avians and non-avian dinosaurs. The examined soft parts were preserved through the pathway of iron-induced crosslinking and alumino-silification, documenting a variety of pathways for the preservation of soft parts, depending on the burial environment. For the first time, the structure of dinosaur fossilized tendons is analysed in detail, revealing shared histogenetic principles with modern birds and the nature of preservation.

The high temperature decomposition of basalt from Lower Silesia (Poland) was followed by Mössbauer spectroscopy investigation. The Fe content of the sample was ~9.0 at.%. The X-ray diffraction analysis shows that augite (37%) and olivine (12%) are major Fe-bearing mineral components. The sample also contains significant amount of anorthite (22%) and nepheline (17%). The sample was heated at various temperatures between 200°C and 1100°C for three hours. Up to a temperature of 500°C changes in contribution of Fe-bearing minerals are insignificant. Heating in the temperature range from 500°C to 1100°C leads to a systematic increase in contribution of iron oxides at the cost of contribution of silicate minerals, like augite and olivine. Mössbauer spectrum obtained after heating at 1100°C showed hematite as the main iron oxide phase. The ratio of Fe3+/Fetot in the non-heated sample was equal to 0.51 and after heating at 1100°C this ratio amounted to 0.89.

The first example of intrachannel photo-ATRP utilizing AAO templates of different nanostructure interfaces.

This work highlights the development of a robust and universal route towards gaining control over macromolecule molecular weight, molecular weight distribution and, more importantly, morphology through the implementation of photoiniferter-mediated RAFT (photo-RAFT) carried out using mesoporous materials varying in the composition, pore arrangement, and pore diameters (metal–organic framework SBA-15 powder d = 5–15 nm, silica SiO2 templates d = 4 nm, alumina oxide AAO templates d = 10 nm). In fact, the application of these matrices that can act as nanoreactors for in situ UV-irradiated photo-RAFT of both commercial methyl methacrylate (more-activated monomer) and the synthesized N-vinyl-1,2,4-triazolium-based ionic liquid (less-activated monomer) is a key aspect of our approach. The collected data allowed us to probe the influence of the structural features of nanoreactors (i.e., transparency, porosity, roughness, and acidity) as well as confinement-related effects connected to variation in free volume and surface interactions on the polymerization path and properties of the produced ionic and non-ionic polymers. It was found that the application of all tested nanoreactors ensures greater control over photo-RAFT than analogous batch systems (macroscale photo-RAFT). However, running the reaction in mesoporous AAO templates offered by far the best control over the course of photo-RAFT of both the less-activated monomer (LAM) and the more-activated monomer (MAM) irrespective of the type of selected RAFT agent (switchable) (carbamodithioate vs. trithiocarbonate), their properties and, more importantly, the yield of the recovered polymers.

Herein we show that the nanostructured interface obtained via modulation of the pore size has a strong impact on the segmental and chain dynamics of two poly(propylene glycol) (PPG) derivatives with various molecular weights (Mn = 4000 g/mol and Mn = 2000 g/mol). In fact, a significant acceleration of the dynamics was observed for PPG infiltrated into ordinary alumina templates (Dp = 36 nm), while bulklike behavior was found for samples incorporated into membranes of modulated diameter (19 nm < Dp < 28 nm). We demostrated that the modulation-induced roughness reduces surface interactions of polymer chains near the interface with respect to the ones adsorbed to the ordinary nanochannels. Interestingly, this effect is noted despite the enhanced wettability of PPG in the latter system. Consequently, as a result of weaker H-bonding surface interactions, the conformation of segments seems to locally mimic the bulk arrangement, leading to bulklike dynamics, highlighting the crucial impact of the interface on the overall behavior of confined materials.

Investigated the structural, electronic, and magnetic properties of copper pyrophosphate dihydrate (CuPPD) by the first-principle calculations based on the density functional theory (DFT). Simulations were performed with the generalized gradient approximation (GGA) of the exchange-correlation functional (Exc) supplemented by an on-site Coulomb self-interaction (U–Hubbard term). It was confirmed that the GGA method did not provide a satisfactory result in predicting the electronic energy band gap width (Eg) of the CuPPD crystals. Simultaneously, we measured the Eg of CuPPD nanocrystal placed inside mesoporous silica using the ultraviolet–visible spectroscopy (UV–VIS) technique. The proposed Hubbard correction for Cu-3d and O-2p states at U = 4.64 eV reproduces the experimental value of Eg = 2.34 eV. The electronic properties presented in this study and the results of UV–VIS investigations likely identify the semiconductor character of CuPPD crystal, which raises the prospect of using it as a component determining functional properties of nanomaterials, including quantum dots.

The water-soluble glycofullerenes GF1 and GF2 were synthesized using two-step modified Bingel-Hirsch methodology. Interestingly, we identified buckyballs as a novel class of non-receptor Src kinases inhibitors. The evaluated compounds were found to inhibit Fyn A and BTK proteins with IC50 values in the low micromolar range, with the most active compound at 39 µM. Moreover, we have demonstrated that formation of protein corona on the surface of [60]fullerene derivatives is changing the landscape of their activity, tuning the selectivity of obtained carbon nanomaterials towards Fyn A and BTK kinases. The performed molecular biology studies revealed no cytotoxicity and no influence of engineered carbon nanomaterials on the cell cycle of PANC-1 and AsPC-1 cancer cell lines. Incubation with the tested compounds resulted in the cellular redox imbalance triggering the repair systems and influenced the changing of protein levels.

The impact of europium doping on the electronic and structural properties of the topological insulator Bi2Te3 is studied in this paper. The crystallographic structure studied by electron diffraction and transmission microscopy confirms that grown by Molecular Beam Epitaxy (MBE) system film with the Eu content of about 3% has a trigonal structure with relatively large monocrystalline grains. The X-ray photoemission spectroscopy indicates that europium in Bi2Te3 matrix remains divalent and substitutes bismuth in a Bi2Te3 matrix. An exceptional ratio of the photoemission 4d multiplet components in Eu doped film was observed. However, some spatial inhomogeneity at the nanometer scale is revealed. Firstly, local conductivity measurements indicate that the surface conductivity is inhomogeneous and is correlated with a topographic image revealing possible coexistence of conducting surface states with insulating regions. Secondly, Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) depth-profiling also shows partial chemical segregation. Such in-depth inhomogeneity has an impact on the lattice dynamics (phonon lifetime) evaluated by femtosecond spectroscopy. This unprecedented set of experimental investigations provides important insights for optimizing the process of growth of high-quality Eu-doped thin films of a Bi2Te3 topological insulator. Understanding such complex behaviors at the nanoscale level is a necessary step before considering topological insulator thin films as a component of innovative devices.

A multifunctional composite structure consisting of resorbable tricalcium phosphate with non-resorbable hydroxyapatite and NiTi shape memory alloy (SMA) has been manufactured to develop a biocompatible system for long-term implant applications. The hybrid system has been vacuum sintered to consolidate and form chemical binding between phosphate biomaterials and NiTi SMA. In this context, the impact of sintering on biomaterial’s features in relation to initial material has been analyzed using a combination of structural and surface sensitive approaches. Moreover, a partial decomposition of the NiTi parent phase to the equilibrium Ti2Ni with cubic structure, and non-equilibrium Ti3Ni4 with hexagonal structure has been detected. Moreover, a sintering has provided a reconstruction of the orthophosphate surface through the disintegration of calcium phosphate material and increase of hydroxyapatite with smaller particles in volume. The biomaterial surface has become more enriched in calcium in relation to the initial composition, with a simultaneous decline of the roughness parameters due to the gradual consolidation of orthophosphates. Finally, surface modification accompanied with heat treatment has led to an increase of surface Young’s modulus as an effect of partial recrystallization of calcium phosphates.

The introduction of transition metal oxides for building nanodevices in information technology promises to overcome the scaling limits of conventional semiconductors and to reduce global power consumption significantly. However, oxide surfaces can exhibit heterogeneity on the nanoscale e.g. due to relaxation, rumpling, reconstruction, or chemical variations which demands for direct characterization of electronic transport phenomena down to the atomic level. Here we demonstrate that conductivity mapping is possible with true atomic resolution using the tip of a local conductivity atomic force microscope (LC-AFM) as the mobile nanoelectrode. The application to the prototypical transition metal oxide TiO_{2} self-doped by oxygen vacancies reveals the existence of highly confined current paths in the first stage of thermal reduction. Assisted by density functional theory (DFT) we propose that the presence of oxygen vacancies in the surface layer of such materials can introduce short range disturbances of the electronic structure with confinement of metallic states on the sub-nanometre scale. After prolonged reduction, the surfaces undergo reconstruction and the conductivity changes from spot-like to homogeneous as a result of surface transformation. The periodic arrangement of the reconstruction is clearly reflected in the conductivity maps as concluded from the simultaneous friction force and LC-AFM measurements. The second prototype metal oxide SrTiO_{3} also reveals a comparable transformation in surface conductivity from spot-like to homogeneous upon reduction showing the relevance of nanoscale inhomogeneities for the electronic transport properties and the utility of a high-resolution LC-AFM as a convenient tool to detect them.

Magnetic properties of the Ce2Rh3Ge compound are studied by combined investigations involving magnetization and susceptibility measurements, electron microscopy with energy dispersive analysis, X-ray photoelectron spectroscopy (XPS) as well as band structure calculations. Our calculations well agree with the experimental XPS data and predict non-magnetic ground state for the Ce2Rh3Ge. We attribute the previously reported weak magnetic ordering in the Ce2Rh3Ge to the presence of the magnetic impurity phase composed mainly from the Ce5RhGe2. The amount of the impurity phase determined from structural investigations explains quantitatively magnetic properties published in previous reports. The magnetic ground state of Ce5RhGe2 phase was determined from the DFT based calculations.

The microstructure and magnetic properties of bulk crystalline and ball – milled binary HoCo3 intermetallic compounds were studied. The presence of PuNi3 type of crystal phase was confirmed in all investigated specimens. The emergence of a partly amorphous phase was demonstrated at the end of grinding process. The influence of the applied high energy ball – milling parameters on the microstructure was investigated. The influence of the increased milling time on the final size of particles and crystallites was characterized by a variety of complementary measurement methods. The fabrication of nanoflakes and agglomerates for long pulverization times was demonstrated. Furthermore, the non-linear dependence of the saturation magnetization, coercivity and remanence driven by high energy ball – milling was evidenced. The enhancement of the coercivity for a low milling time was shown. A quantitative analysis of the XPS spectra over ion etching indicates the formation of Co oxides on the nanoflakes surface.

The morphology and magnetic properties of bulk crystalline and ball – milled Ho(Ni0.8Co0.2)3 intermetallic compounds were studied. The influence of the duration of the high energy ball - milling (HEBM) for the final size of particles and crystallites was confirmed by a variety of complementary measurement methods. The crystallization of all studied specimens in the PuNi3 type of crystal structure was confirmed. The presence of an amorphous phase was evidenced at the final stage of pulverization. The influence of different grinding times is reflected in the variation of morphology and magnetism of as-milled powders. An emergence of nanoflakes having nanoflower-like morphology was found at the end of HEBM process. Furthermore, a slight variation of magnetic parameter was observed. Potential coating of the nanoflakes by Ni/Co oxides was demonstrated by XPS investigations.

Mixed matrix membranes (MMM) containing 13X zeolite particles were prepared to study the impact of hydrophilic inorganic component on membrane gas and water vapor transport properties. Rubbery ethylene-vinyl acetate copolymer (EVA), hydrogenated nitrile rubber (HNBR), and glassy polysulfone (PSF) varying in permeability were selected as membrane matrices. The incorporation of 13X decreased gas permeability of all MMMs and had only a marginal effect on ideal selectivity (e.g. 20 wt% loading reduced N2 permeability by 21%, 19%, and 4% for PSF, EVA, and HNBR, respectively). The observed trend was in agreement with the diminished free volume size obtained from the positron annihilation lifetime spectroscopy (PALS) measurements suggesting pore blockage. In contrary, water vapor permeability through all MMMs was significantly enhanced by zeolite filling (e.g. 30 wt% loading increased H2O permeability by 153%, 34%, and 22% for PSF, EVA, and HNBR, respectively). This was explained as due to the increased water solubility documented by the sorption results, that compensates for the effect of the reduced water diffusivity in MMMs. The variations in MMMs permeabilities were also found to depend on zeolite particle size and its porosity. Two opposite effects were noticed of increased water vapor permeability and decreased gas permeability for MMMs filled with smaller but more porous particles. The water permeation through PSF based membranes may cause debonding at the particle/matrix interface and deterioration of the MMMs properties as indicated by their enhanced gas permeability and reduced selectivity.

Steel production involves processes and alloys based on iron. Metallurgy is one of the most energy-intensive branches of industry and it also generates a lot of damage. The aim of the research was to recognize magnetic properties, mineral composition, and phase content of dusts from a de-dusting station, steel mill, sinter strand and filter press located in a steel metallurgical foundry in Upper Silesia, the most urbanized, industrialized and also the most polluted region of Poland. The following methods were applied: X-ray fluorescence, X-ray diffraction and the Mössbauer spectroscopy measurements.

The effect of Fe doping on SrTiO3 single crystals was investigated in terms of crystal and electronic structure over a wide temperature range in both oxidizing and reducing conditions. The electrical properties were thoroughly studied with a special focus on the resistive switching phenomenon. Contrary to the undoped SrTiO3 crystals, where isolated filaments are responsible for resistive switching, the iron-doped crystals showed stripe-like conducting regions at the nanoscale. The results showed a non-uniform Fe distribution of as-received crystals and the formation of new phases in the surface layer of reduced/oxidized samples. The oxidation procedure led to a separation of Ti(Fe) and Sr, while the reduction resulted in the tendency of Fe to agglomerate and migrate away from the surface as seen from the time of flight mass spectroscopy measurements. Moreover, a clear presence of Fe-rich nano-filament in the reduced sample was found.

In this work gas transport and structural investigations of heterogeneous membranes composed of polysulfone and copper terephthalate (CuTPA) particles are reported. Three types of CuTPA, varying in surface area, pore volume and pore size distribution, as it was shown by nitrogen physisorption, were investigated as membrane fillers. Structural characterization of pure CuTPA and composite membranes was carried out by positron annihilation lifetime spectroscopy, calorimetry, derivatography, electron microscopy, X-ray diffraction and density measurements. CuTPA possessing high porosity was found to increase permeability of heterogeneous membranes to N2, O2, He, CO2. In contrast, permeability decrease was observed for two other types of CuTPA with lower porosity. Additionally, membranes containing highly porous CuTPA were annealed at two different temperatures and it was found that higher temperature results in higher both membrane permeability and selectivity. For example, CO2 permeability for membrane annealed at 150 °C was 1.65-times higher than that for pure PSF, whereas membrane annealed at 200 °C was 3.3-times more permeable. This significant change in membrane permeability was ascribed to residual solvent removal from CuTPA pores.

The morphology and magnetic properties of the Ho(Ni0.8Co0.2)­3 crystalline and ball – milled intermetallic compounds are presented. The polycrystalline bulk compound crystallizes in the rhombohedral PuNi3 - type of crystal structure and indicates ferrimagnetic arrangement with the Curie temperature of TC = 48 ± 1 K, the helimagnetic temperature Th = 26 ± 2 K with the total saturation magnetic moment of 7.78 µB/f.u. at 2 K. The use of the HEBM method leads to the formation of nanoflakes with typical thickness of less than 100 nm. The extended milling leads to the reduction in particles/crystallites size and in the emergence of the relatively small coercivity (HC).

The SBA-15 silica thin films containing copper ions anchored inside channels via propyl phosphonate groups are investigated. Such materials were prepared in the form of thin films, with hexagonally arranged pores, laying rectilinear to the substrate surface. However, in the case of our thin films, their free standing form allowed for additional research possibilities, that are not obtainable for typical thin films on a substrate. The structural properties of the samples were investigated by X-ray reflectometry, atomic force microscopy (AFM) and transmission electron microscopy (TEM). The molecular structure was examined by Raman spectroscopy supported by numerical simulations. Magnetic measurements (SQUID magnetometry and EPR spectroscopy) showed weak antiferromagnetic interactions between active units inside silica channels. Consequently, the pores arrangement was determined and the process of copper ions anchoring by propyl phosphonate groups was verified in unambiguous way. Moreover, the type of interactions between magnetic atoms was determined.

The morphology and magnetic properties of bulk and ball – milled Ho(Fe0.5Co0.5)3 intermetallic compounds were studied. The influence of the high energy ball – milling (HEBM) duration for the final size of particles and crystallites was confirmed by a variety of complementary measurement methods. The presence of the main PuNi3 type of crystal phase was confirmed for crystalline and as – milled samples. The emergence of a partly amorphous phase was confirmed at the end of pulverization (t = 80 h). The synthesis of nanostructured flakes with a thickness of less than 100 nm after applying HEBM for various time periods was confirmed. Additionally, the formation of agglomerates for the prolonged pulverization was evidenced. The non – linear variation of magnetic parameters across milling was observed. Furthermore, a slight exchange bias and deformation of hysteresis loops for as – milled powders was noticed. A quantitative analysis of XPS spectra at the end of grinding process indicates the probable coating of flakes by Fe/Co oxides the amount of which varies over ion etching.

The morphology and magnetic properties of bulk and ball – milled Ho(Ni 0.5 Co 0.5 ) 3 intermetallic compounds were studied. The presence of PuNi 3 type of crystal phase was confirmed in crystalline as well as powdered samples. The emergence of a partly amorphous phase was confirmed at the end of pulverization. The applying of the high energy ball - milling (HEBM) method for various grinding time is reflected in the fabrication of nanostructured flakes with a thickness of less than 100 nm. The formation of agglomerates for the prolonged pulverization was demonstrated. The influence of the increased milling time for the final size of particles and crystallites was confirmed by a variety of complementary measurement methods. Furthermore, the enhanced coercivity ( H C ), non-linear dependence of remanence ( M R ) and emergence of M R / M S ratio higher than 0.5 driven by HEBM was evidenced. A quantitative analysis of XPS spectra indicates the formation of Ni/Co oxides on the nanoflakes surface, which was subsequently reduced over ion etching.

Understanding the properties of thin films remains an unresolved issue even after decades of scientific research. In this article, we investigate the role of surface roughness, one of the various factors that affect the dynamics of polymer films. The tested sample is poly-(4-chlorostyrene) coated onto silicon substrates treated with plasma for different amounts of time. By using dielectric spectroscopy, we provide experimental evidence that as substrate roughness increases (i) the segmental mobility slows down, and (ii) the distribution of the α-relaxation time becomes narrower. Ultimately, the confinement effect vanishes, and the polymer film recovers its bulk-like behavior for sufficiently rough surfaces. Further studies that employ AFM, ellipsometry, and contact angle measurements allowed us to conclude that the deviation in segmental dynamics as a function of surface roughness is due to the changes in interfacial energy that affects the number of chains irreversibly absorbed to the substrate which in turn improve packing density near the substrate. Therefore, the surface roughness is an inevitable factor to consider when designing numerous devices which rely on supported polymer films.

Conductive atomic force microscopy has become a valuable tool for investigation of electronic transport properties with utmost lateral resolution. In this chapter, we prevent an overview about C-AFM applications to high-k semiconductors, which are key materials for future energy-efficient information technology.

The present work addresses the atomic structure and electronic properties of a recently discovered mineral qatranaite (CaZn2(OH)6·2H2O). The present study was performed theoretically by means of density functional theory- (DFT-) based calculations within the frame of local density approximation (LDA) and general gradient approximation (GGA). To determine the energy band gap width, we carried out the ultraviolet-visible spectroscopy (UV-Vis) measurements. The structure relaxation performed with use of LDA and GGA provides results matching the experimentally determined crystal parameters. Interestingly, in contrast to existing interpretation of experimental data, our DFT calculations revealed energy gap of direct characteristics. Accordingly, our UV-Vis experiments yield the band gap width of 3.9 eV.

International audience; The comprehensive study of the Ni0.5Zn0.5Fe2O4 ferrite nanopowder crystallized in the inverse spinel structure and synthesized by co-precipitation method is presented. The distribution of Fe3+ cations among tetrahedral and octahedral sites was confirmed. The microstructural investigations revealed the presence of ultrafine grained structure with an average crystallites size in the range of 14 ÷ 20 nm. Raman and Fourier-Transform Infrared (FTIR) spectroscopy studies confirmed typical spinel structure with tetrahedrally and octahedrally iron occupancy as well as indicate co-associated iron-oxide phases considered as factors responsible for the structural disorder. The magnetic properties revealed the superparamagnetic behavior at the room temperature with estimated critical size of single domain particles about 63 nm. The analysis of saturation magnetization pointed to the spin canting phenomenon in the surface layer. The valuation of exchange coupling parameters based on the mean field theory calculation strengthened the conclusion about opposite magnetization arrangement between tetrahedral and octahedral magnetic sublattices.

The morphology and magnetic properties of the crystalline and ball-milled Ho(Ni0.5Fe0.5)3 intermetallic compounds are studied. The presence of PuNi3 type of crystal structure was confirmed in crystalline as well as powdered samples. The emergence of a partly amorphous phase was confirmed at the end of the pulverization process. The use of the ball-milling method for various grinding time is reflected in the fabrication of nanostructured flakes, with a thickness of less than 100 nm. Prolonged milling favors an assemblage of as-prepared nanopowder. The increase of pulverization time leads to the reduction in crystallites sizes confirmed by a variety of complementary measurement methods. Moreover, the increase in comminution duration results in the enhancement of the coercivity (HC), non-linear dependence of remanence (Mr) and emergence of Mr./MS ratio to values higher than 0.5. A quantitative analysis of XPS spectra shows an increase of Fe concentration versus sputtering which is in coincidence with magnetic measurements.

This paper focuses on X-ray diffraction, X-ray photoelectron and UV–vis spectroscopy of two different (green, orange) rondorfite samples. The differences in the sample color originate from various O/Cl ratios. The orange color was found to be related either to the isomorphic substitution of Fe 3+ /Al 3+ for Mg 2+ , the presence of atypical [MgO 4 ] tetrahedrons in crystal structure or electronegativity of the sample. The tetrahedron is known to be very prone to accumulation of impurities and substitute atoms. Moreover, the XPS data showed tetrahedrally coordinated Mg 2+ and isomorphic substitution of Al 3+ /Fe 3+ for Mg 2+ , which influences local disordering and the point defects density and distribution. Non-equilibrium chlorine positions inside the crystal cages as well as Ca-Cl bonds have also been found. The XPS measurements as a function of temperature indicate occurrence of a structural transformation at about 770 K which is accompanied by a rotation of silicate tetrahedra within magnesiosilicate pentamer and luminescence disappearance.

The morphology and magnetic properties of the HoNi{sub 3} crystalline and ball-milled intermetallic compounds are presented. The polycrystalline HoNi{sub 3} bulk compound crystallizes in the rhombohedral PuNi{sub 3} — type of crystal structure and indicates ferrimagnetic arrangement with the Curie temperature of T{sub C} = 57 ± 2 K, the helimagnetic temperature T{sub h} = 23 ± 2 K with the total saturation magnetic moment of 6.84 μ{sub B}/f.u. at 2 K. The use of the ball-milling method leads to the formation of HoNi{sub 3} nanoflakes with typical thickness of less than 100 nm prone to agglomeration upon milling. The increase of grinding duration leads to the reduction in crystallite size, which was confirmed by various complementary microscopical and diffraction studies. Moreover, the increase in milling duration results in the emergence of the relatively small coercivity (H{sub C}), remanence (M{sub r}) and a variation of the saturation magnetization (M{sub S}). - Graphical abstract: Display Omitted - Highlights: • The ball-milling method exhibits significant potential for producing RT{sub 3} nanopowders. • The AFM method was used for the first time in analysis of R–T nanoflakes morphology. • HoNi{sub 3} compound forms polycrystalline and textured nanoflakes evolving upon milling. • The decreasemore » in crystallite size via grinding is confirmed by XRD, TEM and AFM. • The magnetic parameters were sensitive to the extension of pulverization b.« less

The relation between surface morphology and local conductance was studied for single crystalline thin films of Bi2Te3 grown on mica. Atomic force microscopy and electron diffraction revealed the hexagonal order of the surface with quintuple layer steps and spiral islands. Furthermore, the experiments using contact mode AFM with conducting tip performed at room temperature revealed the high conductance of the surface, which was locally reduced due to changes in the local electronic structure at the defects (e.g. edges of the terraces). Contact current-voltage characteristics tested over the surface showed a linear behavior in every point, with the resistance significantly lower than the resistance of reference metallic samples (gold, platinum). We show that local conductivity AFM is a good technique to exploit the peculiar surface properties of topological insulators.

At present, we are witnessing a renewed interest in the properties of densified glasses prepared by isobaric cooling of a liquid at elevated pressure. As high-pressure densification emerges as a promising approach in the development of glasses with customized features, understanding and controlling their unique properties represent a contemporary scientific and technological goal. The results presented herein indicate that the applied high-pressure preparation route leads to a glassy state with higher density (∼1%) and a reduced free volume of about 7%. We show that these subtle structural changes remarkably influence the dielectric response and spectral features of β-relaxation in etoricoxib glass. Our study, combining dynamical and structural techniques, reveal that β-relaxation in etoricoxib is extremely sensitive to the variations in molecular packing and can be used to probe the changes in glass density. Such connection is technologically relevant and may advance further progress in the field.

The article is about a novel material for application in optoelectronic devices: mesoporous silica in the form of thin films with vertically aligned channels containing anchored propyl-copper-phosphonate functional groups. We described a synthesis route and carried out characterization of the structure to obtain its nonlinear optical (NLO) properties (second and third order harmonic generation). A quasi phase transition was found in the material resulting from modification of the functional group content. We also demonstrated that it is possible to modify NLO susceptibilities by tuning the distance between active polar units.

The paper reports a new route for the fabrication and determination of physicochemical properties and biological activity, of metallic silica-based nanostructure (Ag/SiO2, Cu/SiO2). A research studies shows mono-dispersed nanoparticles in silica matrix with an average size of 12 nm for silver, as well as 12 nm and 4 nm, respectively for copper in hydrophobic and hydrophilic silica composites. The chemical analysis highlights metallic silver and copper ions heterogeneously distributed in the composite as well as metallic oxides such as Ag2O, Cu2O and CuO in hydrophobic system, and CuO in hydrophilic one. Structural research evidences the presence of amorphous, stoichiometric and non-stoichiometric crystalline phase of silica. Biological studies reveal potentially inhibition of growth gram-positive and gram-negative bacteria as well as microscopic fungi. The size of metal nanoparticles and level of silica hydrophobicity show the highest inhibition bacterial growth for hydrophilic system with embedding inside them, 4 nm in size copper nanoparticles. Finally, cytotoxic interaction against human cells with respect to silver and copper silica-based nanocomposites was not found.

The study of microstructure and magnetic properties of bulk and ball–milled HoFe 3 intermetallic compounds was presented. The influence of the high energy ball-milling (HEBM) parameters i.e. applied milling time on the final size of particles/crystallites was confirmed by a variety of complementary measurement methods. The presence of the main 1:3 type of crystal phase (PuNi 3 ) was evidenced for bulk crystalline and powders specimens. The emergence of a partly amorphous phase was confirmed at the end of HEBM process ( t = 80 h). The formation of nanoflakes with their thickness dependent on various milling time periods was revealed by various techniques. An emergence of agglomerates was observed for the extended pulverization duration. The non–linear variation of magnetic parameters was evidenced across milling. Furthermore, a slight exchange bias phenomenon was noticed for as–milled powders. In the comparison between 54 Fe Mossbauer spectra for the bulk compound and selected as-milled powders an emergence of a paramagnetic component was revealed. A quantitative analysis of XPS spectra at the end of grinding process indicates the probable coating of flakes by Fe oxides.

Currently, a great effort is put on the understanding of the effect of the nanometrical constraint on the dynamics of the soft materials. Recent studies by Alexandris et al. [Macromolecules, 2016, 49, 7400–7414] and some of us [J. Phys. Chem. C, 2019, 123, 5549–5556] revealed that the enhancement of the molecular mobility and depression in the glass transition of various low and high molecular weight glass formers infiltrated into Anodic Aluminum Oxide (AAO) templates strongly correlates with the strength of the interfacial interactions between the materials and the porous medium. However, in those investigations, one very important and fundamental aspect related to the variation in the wettability, the surface tension as well as the interfacial energy due to surface curvature has been completely overlooked. Herein, we have performed systematic and unique Atomic Force Microscopy (AFM) measurements on the model glass-forming liquid, glycerol (GLY), incorporated into porous AAO membranes of varying pore diameter. It was found that with increasing degree of confinement, the adhesion force between GLY and AFM tip decreases significantly. It seems that as indicated by the Tolman relation, the interfacial tension of the confined GLY drops leading to a better wetting of polyalcohol within the smallest pores. Interestingly, for this particular system (confined within templates of d = 10 nm), a complementary Differential Scanning Calorimetry (DSC) investigations revealed the presence of the two glass transition temperatures upon heating runs. This indicated that the enhancement of the interactions between alumina and alcohol leads to the formation of the interfacial layer that vitrifies at higher temperature (Tg,interfacial) than the bulk material. Interestingly, the observed double Tgs appeared only on heating. Moreover, different thermal protocols revealed the variation of the heat capacity jump corresponding to the glass transition temperature of the interfacial layer upon the annealing experiments, indicating the ongoing desorption process. In addition, it was also found that the structural dynamics of GLY incorporated within d = 10 nm starts to deviate below Tg,interfacial from the behavior of the non-confined sample. Reported data are the first experimental evidence on the correlation between variation of the surface interactions with the substrate's curvature and enhancement of the dynamics of the confined liquids. Thus, a better understanding of the dynamics of confined soft matter, especially the relation between the finite size and surface interactions can be gained.

The uniform thin films with variable thicknesses (d = 49, 120, 220 nm) of active pharmaceutical ingredient (API) glibenclamide (GCM) was spin-coated and investigated using broadband dielectric, grazing incident FTIR spectroscopies, atomic force microscopy, and ellipsometry. Data analysis revealed that nanoconfined systems consist of a mixture of amide and imidic acid forms of this pharmaceutical, wherein the ratios of both tautomeric forms in the thin films were different with respect to the molten supercooled bulk system. Moreover, changes in the populations of glibenclamide tautomers, i.e. higher amide to imides ratio in the spatially restricted API with respect to the bulk sample, had a strong impact on the character of the proton transfer reaction. In this context, the kinetic curves constructed on the base of infrared data for the bulk system follow the sigmoidal shape, characteristic for the autocatalytic reaction, while results obtained for the confined samples provide exponential character and indicate first-order transformation. This allows hypothesizing that the autocatalytic nature of the tautomerism in the bulk sample is most likely related to the formation of the amide tautomers which further catalyze the progress of imide-amide transformation. Our results are the first studies showing that the change in the thickness of the film may affect the properties and isomerization kinetics in a pharmaceutical systems. Finally, our data open a new perspective for developing new drug delivery systems.

Synchrotron radiation was used to measure X-ray absorption and resonant photoemission of epitaxial Mn doped SrTiO3 film. The spectra together with the modeling revealed that Mn valence state depends on the ions localization in the film and on the annealing temperature. The XAS spectra can be fitted by the composition of Mn3+ and Mn2+. Surface region was richer in trivalent Mn, while deeper layers and the film annealed in UHV at 630 °C exhibited mostly divalent Mn ions. Partial density of Mn 3d electronic states derived from the resonant photoemission showed a significant contribution to the in-gap states.

One of the most important challenges of modern science and technology is the quest for novel and tuneable materials, the properties of which can be widely controlled by chemical modifications or external stimuli. Simultaneously, an interest in the development of magnetic thin films also gains significant attention. In the current paper we bring together both these challenges and present a study of a new type of low-dimensional nickel hexacyanoferrate/chromate system. Thin films were obtained by the "layer by layer" deposition technique, where the ratio of Fe/Cr was controlled by the dipping sequence. The scope of this work is a comprehensive analysis of structural, spectroscopic and magnetic properties of the compound and the investigation of the evolution of material properties induced by the change of the chemical composition.

Atomic Force Microscopy (AFM) measurements have been performed for Fe-doped SrTiO3 thin films with an Fe concentration of 1 and 2 at%. Thin films with a thickness of 15–50 nm were grown by pulsed laser deposition on single crystalline SrTi0.99Nb0.01O3 substrates. Low-energy electron diffraction examination showed that the films are single crystalline. The regions treated with the AFM tip (applied dc voltage up to 6 V) showed inhomogeneity of the electrical conductivity. Resistive switching was studied by the use of local conductive atomic force microscopy and was present in all samples. Fe doping was found to influence the character of switching.

Iron plays a very important role in the living systems. It is an integral part of many proteins, enzymes and minerals that work with other substances to create hemoglobin. During pregnancy and after birth, a woman’s requirement for iron increases. This requirement increases significantly during pregnancy as maternal blood volume increases and a baby’s blood system is developing. Absorption of iron from food requires recognition of the chemical form of iron by gut receptors. Both shape and charge are important in the recognition process. To be absorbed, dietary iron must be in its ferrous form, which is soluble, unless the Fe 3+ ion is chelated [1]. Therefore, the knowledge of the iron valence state in medicaments is very important because it may be related to the eect and toxicity of such pharmaceutical product. Many medicaments used in daily life have a reduced therapeutic eect because of their poor physico-chemical characteristics. Poor solubility, especially of the drugs used in the long-term treatment, can lead to increased number of side eects or does not give any expected ef

We studied the formation of alloys and compounds of the Eu-Fe binary system, in the form of thin films, prepared using molecular beam epitaxy. Diffraction and photoelectron spectroscopy investigations revealed mixing of the elements during the annealing at relatively low temperature. Magnetic studies showed ferromagnetic behavior up to 400 K, and strong thermomagnetic effects and exchange bias indicating the presence of an antiferromagnetic phase and superparamagnetic particles. X-ray photoemission microscopy with dichroic contrast confirmed this hypothesis, showing two types of Eu-Fe alloys with various stoichiometries and showing ferromagnetically ordered particles of 100–500 nm in size. Ferromagnetic particles contain divalent Eu atoms, whereas the antiferromagnetic alloy is probably composed of the trivalent Eu atoms detected in the photoelectron spectra.

In this work, the results of the electrocoloration of strontium titanate single crystals with different iron concentrations are presented. The samples of SrTiO3(100) doped with 0.06 at. % and 0.13 at. % of iron were electroreduced at low pressure (10−8 mbar) and elevated temperature (250 °C) using a DC voltage of 200 V. This led to the migration of oxygen vacancies and subsequent electrocoloration of the samples, which was confirmed by optical analysis and electrical measurements. Evolution of the color front was compared with finite element calculations of electric potential indicating good agreement. Both macroscopic and nanoscopic measurements showed insulator-metal transition at several hundreds of seconds (0.06%Fe) and resistive switching behavior. We found that the resistive switching is clearly modified by the oxygen partial pressure of the ambient atmosphere. Moreover, after electroreduction, in the region between the electrodes, stripes can be found following simple crystallographic directions connected with the extended defects and easy diffusion paths also observed in the single crystals of undoped strontium titanate. Furthermore, migration of negatively charged oxygen ions towards the anode led to the formation of oxygen bubbles trapped between the surface of the crystal and the electrode. Using atomic force microscopy, we were able to measure the geometry of a bubble and calculate the oxygen pressure necessary for the formation of such bubbles and the total amount of oxygen ions trapped within.