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We present a procedure to study the switching and the stability of an array of magnetic nanoparticles in the dynamical regime. The procedure leads to the criterion of multiswitching stability to be satisfied in order to have stable switching. The criterion is used to compare various magnetic-field-induced switching schemes, either present in the literature or suggested in the present work. In particular, we perform micromagnetic simulations to study the magnetization trajectories and the stability of the magnetization after switching for nanoparticles of elliptical shape. We evaluate the stability of the switching as a function of the thickness of the particles and the rise and fall times of the magnetic pulses, both at zero and room temperature. Furthermore, we investigate the role of the dipolar interaction and its influence on the various switching schemes. We find that the criterion of multiswitching stability can be satisfied at room temperature and in the presence of dipolar interactions for pulses shaped according to complementary metal oxide semiconductor specifications, for switching rates in the gigahertz regime. [ABSTRACT FROM AUTHOR]

Focused electron beam induced deposition (FEBID) is a direct-write method for the fabrication of nanostructures whose lateral resolution rivals that of advanced electron beam lithography but is in addition capable of creating complex three-dimensional nano-architectures. Over the last decade several new developments in FEBID and focused electron beam induced processing (FEBIP) have led to a growing number of scientific contributions in solid state physics and materials science based on FEBID-specific materials and particular shapes and arrangements of the employed nanostructures. In this review an attempt is made to give a broad overview of these developments and the resulting contributions in various research fields encompassing mesoscopic physics with nanostructured metals at low temperatures, direct-write of superconductors and nano-granular alloys or intermetallic compounds and their applications, the contributions of FEBID to the field of metamaterials, and the application of FEBID structures for sensing of force or strain, dielectric changes or magnetic stray fields. The very recent development of FEBID towards simulation-assisted growth of complex three-dimensional nano-architectures is also covered. In the review particular emphasis is laid on conceptual clarity in the description of the different developments, which is reflected in the mostly schematic nature of the presented figures, as well as in the recurring final sub-sections for each of the main topics discussing the respective “challenges and perspectives”. [ABSTRACT FROM AUTHOR]

Investigates the structural properties of thin epitaxial tellurium and iron (TbFe)2 and dysprosium (Dy)Fe2 films grown under various conditions, focusing on the influence of structure on their magnetic properties. Reference to the cubic Laves phase compounds of the tye RFe2.

By combining a low noise fully depleted pnCCD detector with a CsI(Tl) scintillator, an energy-dispersive area detector can be realized with a high quantum efficiency (QE) in the range from below 1 keV to above 100 keV. In direct detection mode the pnCCD exhibits a relative energy resolution of 1% at 122 keV and spatial resolution of less than 75 µm, the pixel size of the pnCCD. In the indirect detection mode, i.e. conversion of the incoming X-rays in the scintillator, the measured energy resolution was about 9–13% at 122 keV, depending on the depth of interaction in the scintillator, while the position resolution, extracted with the help of simulations, was 30 µm only. We show simulated data for incident photons of 122 keV and compare the various interaction processes and relevant physical parameters to experimental results obtained with a radioactive 57 Co source. [ABSTRACT FROM AUTHOR]

Growth and annealing behavior of epitaxial MnO films on an Au (110)–(1×2) substrate have been studied by means of Auger electron spectroscopy, low energy electron diffraction, and scanning tunneling microscopy. MnO (110) films have been successfully grown by Mn evaporation in an oxygen atmosphere at room temperature with subsequent annealing to 750K. Instead of the expected (110)-like diffraction pattern complex mosaic and facet structures are found depending on annealing conditions. The mosaics are misfit-induced and display along [001] directions a misorientation of ±1.5°. At temperatures around 850K, mosaics gradually vanish and simultaneously a saw-tooth-like film morphology develops which is formed by ribbons of narrow (100) and (010) MnO facets. At temperatures above 850K the film partially dewets from the substrate, and the film transforms to three-dimensional MnO islands that have a roof-like shape where large roof sides and small end sides are composed by {100} and by {111} facets, respectively. The experiments corroborate the theoretical predicted tendency of facet formation of MnO (110) surfaces. [ABSTRACT FROM AUTHOR]

Aminoglycosides are commonly prescribed antibiotics with deleterious side effects to the inner ear. Due to their popular application as a result of their potent antimicrobial activities, many efforts have been undertaken to prevent aminoglycoside ototoxicity. Over the years, understanding of the antimicrobial as well as ototoxic mechanisms of aminoglycosides has increased. These mechanisms are reviewed in regard to established and potential future targets of hair cell protection. [ABSTRACT FROM AUTHOR]

Abstract: The effect of the magnetostatic coupling on the magnetic vortex configuration in arrays of iron nano-cylinders is studied by means of micromagnetic simulations. Systems with neighboring cylinders with parallel or anti-parallel direction of the vortex core are considered. For cylinders with a diameter comparable to the vortex core, the stray field acts either to reduce or to enlarge the vortex core size. The polarity of the vortex core can be reversed by applying a magnetic field parallel to the axis of symmetry of the cylinder. The reversal is initiated by the nucleation of magnetic singularities (Bloch points). For systems with parallel vortex core the analysis of the reversal process shows that magnetostatically coupled cylinders have shorter reversal times. [Copyright &y& Elsevier]

Abstract: An improved analysis procedure for the extraction of intensities of diffraction spots from low-energy electron diffraction (LEED) images is described. The improvements in the removal of background intensity, in the determination of the region of interest for each spot and the tracking of the spot positions increase precision and accuracy of the resulting LEED I–V curves. Their larger dynamic range and smaller noise level at low intensities finally increase the precision in the determination of surface structures by the analysis of LEED I–V curves. [Copyright &y& Elsevier]

A challenging aspect of the usage of patterned nanostructures relates to the development of superconducting devices operating with the Abrikosov vortices in some pinning potential. To provide such a potential we have used thin epitaxial films of Nb with washboard-like nanostructures in the form of grooves or Co stripes. The nanostructures were prepared by focused ion beam milling or focused electron beam induced deposition, respectively. The results of transport measurements affirm the existence of two fluxonic effects, the guided vortex motion and the vortex ratchet effect, both invoked by the nanostructuring. In particular, the effects represent the basis for the development of advanced fluxonic devices using a directional or orientational control of the net vortex motion in Nb films nanostructured by focused particle beam techniques. [ABSTRACT FROM AUTHOR]

The magnetic states of two-dimensional cylinder arrays of iron are studied as function of thickness, diameter, and separation by means of numerical micromagnetics. The corresponding diagram of the states for cylinders with thickness and diameter in the nanoscale regime is presented. The diagram is composed of regions with a single minimum of the free energy, relevant for applications, and regions with multiple minima. The effect of the magnetostatic coupling is highlighted by comparing the state diagram for cylinders with 10 nm perimetrical separation with the one for isolated cylinders. [ABSTRACT FROM AUTHOR]

Guided vortex motion has been observed in niobium films on a faceted Al[sub 2]O[sub 3] substrate. The even and odd components of the longitudinal and transverse magnetoresistances of the samples are measured for various orientations of the transport current relative to the facetting direction. The even and odd components of the magnetoresistance are separated according to a change in the sign of the magnetic field. [ABSTRACT FROM AUTHOR]

Describes an experiment using tunnelling spectroscopy to investigate the superconducting order parameter of a uranium-based heavy-fermion superconductor, epitaxial thin films of UPd2Al3. Observation of a strong-coupling feature in the tunelling conductivity, combined with recent inelastic neutron scattering data; Suggestion of a pairing interaction mediated by spin fluctuations.

Examines the influence of lattice misfit on the growth of titanium (0001) films on magnesium oxide (MgO) (111) and aluminum oxide (0001) substrates. Use of reflection high energy electron diffraction imaging and intensity measurements; Types of island nucleations on the substrates; Dependence of surface morphology of films grown on MgO on substrate temperature during growth.

Highly ordered arrays of epitaxial iron thin film nanostructures were grown by molecular beam epitaxy techniques on m-plane sapphire α-Al2O3 (1 0 &1macr; 0) substrates. Iron was deposited by electron beam evaporation under shallow incidence onto faceted sapphire substrates held at elevated temperatures of 450°C. Scanning electron microscopy suggests the formation of morphologically and electrically isolated nanowire structures on the ridges of the facets. The topology of the structures depends strongly on the iron deposition angle. [Copyright &y& Elsevier]

A lattice of Abrikosov vortices in type II superconductors is characterized by a periodic modulation of the magnetic induction perpendicular to the applied magnetic field. For a coherent vortex motion under the action of a transport current, the magnetic induction at a given point of the sample varies in time with a washboard frequency fWB = v/d, where v is the vortex velocity and d is the distance between the vortices in the direction of motion. Here, by using a spectrum analyzer connected to a 50 nm-wide Au nanowire meander near the surface of a superconducting Nb film, we detect an ac voltage induced by coherently moving fluxons. The voltage is peaked at the washboard frequency, fWB, and its subharmonics, fTOF = fWB/5, determined by the antenna width. By sweeping the dc current value, we reveal that fWB can be tuned from 100 MHz to 1.5 GHz, thereby demonstrating that patterned normal metal/superconductor nanostructures can be used as dc-tunable generators operating in the radiofrequency range. [ABSTRACT FROM AUTHOR]

Objective Cochlear implants (CI) are standard treatment for prelingually deafened children and postlingually deafened adults. Computed tomography (CT) is the standard method for postoperative imaging of the electrode position. CT scans accurately reflect electrode depth and position, which is essential prior to use. However, routine CT examinations expose patients to radiation, which is especially problematic in children. We examined whether new CT protocols could reduce radiation doses while preserving diagnostic accuracy. Methods To investigate whether electrode position can be assessed by low-dose CT protocols, a cadaveric lamb model was used because the inner ear morphology is similar to humans. The scans were performed at various volumetric CT dose-indexes CTDIvol)/kV combinations. For each constant CTDIvol the tube voltage was varied (i.e., 80, 100, 120 and 140 kV). This procedure was repeated at different CTDIvol values (21 mGy, 11 mGy, 5.5 mGy, 2.8 mGy and 1.8 mGy). To keep the CTDIvol constant at different tube voltages, the tube current values were adjusted. Independent evaluations of the images were performed by two experienced and blinded neuroradiologists. The criteria diagnostic usefulness, image quality and artifacts (scaled 1–4) were assessed in 14 cochlear-implanted cadaveric lamb heads with variable tube voltages. Results Results showed that the standard CT dose could be substantially reduced without sacrificing diagnostic accuracy of electrode position. The assessment of the CI electrode position was feasible in almost all cases up to a CTDIvol of 2–3 mGy. The number of artifacts did not increase for images within this dose range as compared to higher dosages. The extent of the artifacts caused by the implanted metal-containing CI electrode does not depend on the radiation dose and is not perceptibly influenced by changes in the tube voltage. Summarizing the evaluation of the CI electrode position is possible even at a very low radiation dose. Conclusions CT imaging of the temporal bone for postoperative electrode position control of the CI is possible with a very low and significantly radiation dose. The tube current–time product and voltage can be reduced by 50% without increasing artifacts. Low-dose postoperative CT scans are sufficient for localizing the CI electrode. [ABSTRACT FROM AUTHOR]

Abstract: We report DC Josephson effects observed in a microbridge prepared from an individual crystalline growth domain of CeCoIn 5 thin film. Josephson effects were observed by periodic voltage modulations under external magnetic field ΔV(B) with the expected periodicity and by the temperature dependence of the Josephson critical current I c (T). The shape of ΔV(B) was found to be asymmetric, as it is expected for microbridges. The dependence I c (T) follows the Ambegaokar–Baratoff relation, which is unexpected for microbridges. Features in the dynamical resistance curves were attributed to the periodic motion of Abricosov vortices within the microbridge. [Copyright &y& Elsevier]

Abstract: We present results of a systematic growth study on the substrate temperature-driven de-wetting of CeIn3 thin films as a reference compound for the heavy-fermion superconductor CeCoIn5. This study is motivated by the last results on the improved surface morphology and in-plane orientation preference of c-axis oriented CeCoIn5 thin films. In apparently phase pure CeIn3 thin films, as far as x-ray diffraction can tell, we find evidence for minor In segregation by means of percolating resistance contributions of In in the films. We argue that further efforts into improving the films'' morphology towards optimized surfaces for the preparation of macroscopic planar tunnel junctions may be futile. As an alternative approach, we present results of electronic transport measurements on CeIn3 and CeCoIn5 microcrystals isolated from the thin films by means of focused particle beam induced processing, such as focused ion beam milling and deposition. [Copyright &y& Elsevier]

Fe-Si binary compounds have been fabricated by focused electron beam induced deposition by the alternating use of iron pentacarbonyl, Fe(CO)5, and neopentasilane, Si5H12 as precursor gases. The fabrication procedure consisted in preparing multilayer structures which were treated by low-energy electron irradiation and annealing to induce atomic species intermixing. In this way, we are able to fabricate FeSi and Fe3Si binary compounds from [Fe/Si]2 and [Fe3/Si]2 multilayers, as shown by transmission electron microscopy investigations. This fabrication procedure is useful to obtain nanostructured binary alloys from precursors which compete for adsorption sites during growth and, therefore, cannot be used simultaneously. [ABSTRACT FROM AUTHOR]

Abstract. We used imaging spectromicroscopy to characterise micro-patterned thin films of complex materials such as UPd[sub 2]Al[sub 3] and YBa[sub 2]Cu[sub 3]O[sub 7]/PrBa[sub 2]Cu[sub 3]O[sub 7]. To investigate devices built from these complex materials we applied element-sensitive photoemission electron microscopy (PEEM). Information about the chemical composition of the imaged sample can be obtained by PEEM via tuning the photon energy to X-ray absorption edges. To apply spectromicroscopy we acquired microscopic images using photon energies near and at the edges. Such images give the lateral distribution of a specific element. Microspectroscopy is performed by recording the intensity of the true secondary electrons in selected spots during a sweep of the photon energy. The main aim of our work was to observe oxygen-related defects and changes in the composition affecting the physical properties of the materials. Therefore, we applied both methods to micro-patterned devices using soft-X-ray synchrotron radiation and found that small local defects and chemical differences can be easily detected. Such defects and chemical differences are quite critical to the physical properties of the devices, since they simulate spurious effects thus influencing the reliability of the devices. [ABSTRACT FROM AUTHOR]

Extending nanostructures into the third dimension has become a major research avenue in modern magnetism, superconductivity, and spintronics, because of geometry-, curvature-, and topology-induced phenomena. Here, we introduce Co–Fe nanovolcanoes—nanodisks overlaid by nanorings—as purpose-engineered 3D architectures for nanomagnonics, fabricated by focused electron beam-induced deposition. We use both perpendicular spin-wave resonance measurements and micromagnetic simulations to demonstrate that the rings encircling the volcano craters harbor the highest-frequency eigenmodes, while the lower-frequency eigenmodes are concentrated within the volcano crater, due to the non-uniformity of the internal magnetic field. By varying the crater diameter, we demonstrate the deliberate tuning of higher-frequency eigenmodes without affecting the lowest-frequency mode. Thereby, the extension of 2D nanodisks into the third dimension allows one to engineer their lowest eigenfrequency by using 3D nanovolcanoes with 30% smaller footprints. The presented nanovolcanoes can be viewed as multi-mode microwave resonators and 3D building blocks for nanomagnonics. [ABSTRACT FROM AUTHOR]

We report an experimental study of proximity effect-induced superconductivity in crystalline Cu and Co nanowires and a nanogranular Co nanowire structure in contact with a superconducting W-based floating electrode (inducer). For electrical resistance measurements up to three pairs of Pt-based voltage leads were attached at different distances beside the inner inducer electrode, thus allowing us to probe the proximity effect over a length of 2-12 lm. Up to 30% resistance drops with respect to the normal-state value have been observed for the crystalline Co and Cu nanowires when sweeping the temperature below Tc of the inducer (5.2 K). By contrast, relative R(T) drops were found to be an order of magnitude smaller for the nanogranular Co nanowire structure. Our analysis of the resistance data shows that the superconducting proximity length in crystalline Cu and Co is about 1 μm at 2.4 K, attesting to a long-range proximity effect in the Co nanowire. Moreover, this long-range proximity effect is insusceptible to magnetic fields up to 11 T, which is indicative of spin-triplet pairing. At the same time, proximity-induced superconductivity in the nanogranular Co nanowire is strongly suppressed due to the dominating Cooper pair scattering caused by its intrinsic microstructure. [ABSTRACT FROM AUTHOR]

We have prepared the new amorphous superconductor MoxCyGazOδ with a maximum critical temperature Tc of 3.8K by the direct-write nano-patterning technique of focused (gallium) ion beam induced deposition (FIBID) using Mo(CO)6 as precursor gas. From a detailed analysis of the temperature-dependent resistivity and the upper critical field, we found clear evidence for proximity of the samples to a disorder-induced metal-insulator transition. We observed a strong dependence of Tc on the deposition parameters and identified clear correlations between Tc, the localization tendency visible in the resistance data and the sample composition. By an in-situ feedback-controlled optimization process in the FIB-induced growth, we were able to identify the beam parameters which lead to samples with the largest Tc-value and sharpest transition into the superconducting state. [ABSTRACT FROM AUTHOR]

Media with engineered magnetization are essential building blocks in magnonics, spintronics, and superconductivity. However, the established thin film and lithographic techniques insufficiently suit the realization of planar components with on-demand-tailored magnetization in the lateral dimension. Here, we demonstrate the engineering of the magnetic properties of CoFe-based nanodisks fabricated by the mask-less technique of focused electron beam-induced deposition (FEBID). The material composition in the nanodisks is tuned in situ via the e-beam waiting time in the FEBID process and their post-growth irradiation with Ga ions. The saturation magnetization Ms and exchange stiffness A of the disks are deduced from perpendicular spin-wave resonance measurements. The achieved Ms variation in the broad range from 720 emu/cm3 to 1430 emu/cm3 continuously bridges the gap between the Ms values of widely used magnonic materials such as Permalloy and CoFeB. The presented approach paves the way toward nanoscale 2D and 3D systems with controllable space-varied magnetic properties. [ABSTRACT FROM AUTHOR]

Twin structure engineering in sputtered films close to the Heusler stoichiometry Ni2MnGa (001) is used to demonstrate temperature and magnetic control of the phase transformation behavior. A custom heating apparatus integrated with a commercial microscope allows the observation of the austenite-martensite transition in epitaxially clamped films. Intermartensitic twin boundaries on cantilevers released from the epitaxial strain by focused ion beam etching are shown to move in response to an applied magnetic field with a strength of 0.6 T. We also report the observation of two coexisting twin morphologies. [ABSTRACT FROM AUTHOR]

CoSi-C binary alloys have been fabricated by focused electron beam-induced deposition by the simultaneous use of dicobaltoctacarbonyl, Co2(CO)8, and neopentasilane, Si5H12, as precursor gases. By varying the relative flux of the precursors, alloys with variable chemical composition are obtained, as shown by energy dispersive x-ray analysis. Room temperature electrical resistivity measurements strongly indicate the formation of cobalt silicide and cobalt disilicide nanoclusters embedded in a carbonaceous matrix. Temperature-dependent electrical conductivity measurements show that the transport properties are governed by electron tunneling between neighboring CoSi or CoSi2 nanoclusters. In particular, by varying the metal content of the alloy, the electrical conductivity can be finely tuned from the insulating regime into the quasi-metallic tunneling coupling regime. [ABSTRACT FROM AUTHOR]

Almost any use of a superconductor implies a non-equilibrium state. Remarkably, while a sufficiently high-power electromagnetic field of GHz frequency can stimulate superconductivity, fast motion of magnetic flux quanta (Abrikosov vortices) can trigger an instability abruptly quenching the superconducting state. Here, we show that such dynamical quenching of the vortex state in Nb thin films can be advanced or delayed by tuning the power and frequency of the microwave ac stimulus added to a dc bias current. The experimental findings are supported by time-dependent Ginzburg-Landau simulations and they can be explained, qualitatively, based on a model of "breathing mobile hot spots", implying a competition of heating and cooling of quasiparticles along the trajectories of moving fluxons whose core sizes vary in time. In addition, we demonstrate universality of the stimulation effect on the thermodynamic and transport properties of type II superconductors. Superconductivity can be quenched at large dc currents and it can be stimulated by a high-power microwave ac stimulus. Here, the authors investigate the dc- and microwave-driven quenching in a Nb superconductor in the presence of vortices and the factors contributing to the competition between the stimulation and quenching of the superconducting state. [ABSTRACT FROM AUTHOR]

We fabricated Pt-containing granular metals by focused electron beam-induced deposition from the (CH3)3CH3C5H4Pt precursor gas. The granular metals are made of platinum nanocrystallites embedded in a carbonaceous matrix. We exposed the as-grown nanocomposites to low-energy electron beam irradiation and measured the electrical conductivity as a function of irradiation dose. Postgrowth electron beam irradiation transforms the matrix microstructure and thus the strength of the tunneling coupling between Pt nanocrystallites. For as-grown samples (weak tunnel coupling regime) we find that the temperature dependence of the electrical conductivity follows the stretched exponential behavior characteristic of the correlated variable-range hopping transport regime. For briefly irradiated samples (strong tunnel coupling regime) the electrical conductivity is tuned across the metal-insulator transition. For long-time irradiated samples the electrical conductivity behaves like that of a metal. In order to further analyze changes of the microstructure as a function of the electron irradiation dose, we carried out transmission electron microscope (TEM), micro-Raman spectroscopy, and atomic force microscopy (AFM) investigations. TEM pictures reveal that crystallite size in long-time irradiated samples is larger than that in as-grown samples. Furthermore, we do not have evidence of microstructural changes in briefly irradiated samples. By means of micro-Raman spectroscopy we find that by increasing the irradiation dose the matrix changes, following a graphitization trajectory between amorphous carbon and nanocrystalline graphite. Finally, by means of AFM measurements we observe a reduction of the volume of the samples with increasing irradiation time, which we attribute to the removal of carbon molecules. [ABSTRACT FROM AUTHOR]

The properties of iron nanostructures prepared by shallow incidence molecular beam epitaxy on faceted α-Al2O3 (10&1bar;0) (m plane) are described. Depending on the angle of deposition with regard to the sapphire surface, the morphology of the structures reaches from pearl-necklet-like strung nanodrops to laced nanowires. Crystallographic measurements reveal at least four epitaxial close to (211 )-oriented twins. Magnetization measurements performed at room temperature in a vibrating sample magnetometer and magneto-optical Kerr rotation measurements reveal an easy axis of magnetization close to the facet ridges. Still, the shape of the hysteresis loops depends strongly on the morphology of the samples. The magnetization reversal process can be described by the formation of a magnetic vortex structure. [ABSTRACT FROM AUTHOR]

Highlights from the article: Anal fistula influences patients' quality of life significantly by causing pain, hygienic problems and constant perianal inflammation [[1]]. After excision of the fistula tract by the FiXcision SP ® sp device, closure of the fistula's internal opening is up to the surgeon's preference. They described a minimally invasive approach for core-out excision of the fistula tract using a rigid fistulectomy set in one patient suffering from two anal fistulas. The FiXcision SP ® sp technique is simple and safe and may also facilitate detection of secondary fistula tracts and improve fistula healing rates.

Studies preparation and transport properties of thin films on sapphire with buffer layers. Method of the study; Results and discussion; Conclusion.

The coherent nonlinear dynamics of Abrikosov vortices in asymmetric pinning nanolandscapes is studied by theoretical modeling and combined microwave and dc electrical resistance measurements. The problem is considered on the basis of a single-vortex Langevin equation within the framework of a stochastic model of anisotropic pinning. When the distance over which Abrikosov vortices are driven during one half ac cycle coincides with one or a multiple of the nanostructure period, Shapiro steps appear in the current-voltage curves (CVCs) as a general feature of systems whose evolution in time can be described in terms of a particle moving in a periodic potential under combined dc and ac stimuli. While a dc voltage appears in response to the ac drive, the addition of a dc bias allows one to diminish the rectified voltage and eventually to change its sign when the extrinsic dc bias-induced asymmetry of the pinning potential starts to dominate the intrinsic one. This rectified negative voltage in the CVCs becomes apparent as zero-bias Shapiro steps, which are theoretically predicted and experimentally observed for the first time. [ABSTRACT FROM AUTHOR]

Penetration of magnetic flux into hollow superconducting cylinders is investigated by magnetic moment measurements. The magnetization curves of a flat and a nanopatterned thin-walled superconducting Nb cylinders with a rectangular cross section are reported for the axial field geometry. In the nanopatterned sample, a row of micron-sized antidots (holes) was milled in the film along the cylinder axis. Magnetic moment jumps are observed for both samples at low temperatures for magnetic fields not only above H c 1 , but also in fields lower than H c 1 , i. e., in the vortex-free regime. The positions of the jumps are not reproducible and they change from one experiment to another, resembling vortex lattice instabilities usually observed for magnetic fields larger than H c 1 . At temperatures above 0.66 T c and 0.78 T c the magnetization curves become smooth for the patterned and the as-prepared sample, respectively. The magnetization curve of a reference flat Nb film in the parallel field geometry does not exhibit jumps in the entire range of accessible temperatures. [ABSTRACT FROM AUTHOR]

Grazing incidence and grazing emission X-ray fluorescence spectroscopy (GI/GE-XRF) are techniques that enable nondestructive, quantitative analysis of elemental depth profiles with a resolution in the nanometer regime. A laboratory setup for soft X-ray GEXRF measurements is presented. Reasonable measurement times could be achieved by combining a highly brilliant laser produced plasma (LPP) source with a scanning-free GEXRF setup, providing a large solid angle of detection. The detector, a pnCCD, was operated in a single photon counting mode in order to utilize its energy dispersive properties. GEXRF profiles of the Ni-Lα,β line of a nickel-carbon multilayer sample, which displays a lateral (bi)layer thickness gradient, were recorded at several positions. Simulations of theoretical profiles predicted a prominent intensity minimum at grazing emission angles between 5° and 12°, depending strongly on the bilayer thickness of the sample. This information was used to retrieve the bilayer thickness gradient. The results are in good agreement with values obtained by X-ray reflectometry, conventional X-ray fluorescence and transmission electron microscopy measurements and serve as proof-of-principle for the realized GEXRF setup. The presented work demonstrates the potential of nanometer resolved elemental depth profiling in the soft X-ray range with a laboratory source, opening, for example, the possibility of in-line or even in situ process control in semiconductor industry. [ABSTRACT FROM AUTHOR]

In this paper we describe a setup for x-ray scattering experiments on complex fluids using a liquid jet. The setup supports Small and Wide Angle X-ray Scattering (SAXS/WAXS) geometries. The jet is formed by a gas-dynamic virtual nozzle (GDVN) allowing for diameters ranging between 1 μm and 20 μm at a jet length of several hundred μm. To control jet properties such as jet length, diameter, or flow rate, the instrument is equipped with several diagnostic tools. Three microscopes are installed to quantify jet dimensions and stability in situ. The setup has been used at several beamlines performing both SAXS and WAXS experiments. As a typical example we show an experiment on a colloidal dispersion in a liquid jet at the X-ray Correlation Spectroscopy instrument at the Linac Coherent Light Source free-electron laser. [ABSTRACT FROM AUTHOR]

Objective This was a retrospective data analysis to evaluate the treatment response to enzyme replacement therapy (ERT) with Velaglucerase alfa using whole-body magnetic resonance imaging (MRI). Materials and methods A baseline and follow-up MRI were performed on 18 Gaucher Type 1 patients at an interval of 11.6 months. The MRI score systems determined the Bone-Marrow-Burden (BMB) score, the Düsseldorf-Gaucher score (DGS), and the Vertebra-Disc-Ratio (VDR). The Severity Score Index Type 1 (GD-DS3) was also assessed. Results The baseline MRI medians were: BMB, 7.00; DGS, 3.00; and VDR: 1.70; while, the follow-up MRI medians were: BMB, 7.00; DGS, 3.00; and VDR: 1.73. The baseline GD-DS3 median was 2.40 (BMB excl.: 0.50) and the follow-up median was 2.00 (BMB excl.: 0.50). There was weak statistical significance with the Wilcoxon signed-rank test for the DGS (p = 0.034) and GD-DS3 (p = 0.047) between both MRIs. Conclusion Velaglucerase alfa therapy is a effective long-term treatment for Gaucher Type 1 patients who are newly diagnosed or switching therapies. Measurements with whole-body MRI and an objective scoring system were reliable tools for detecting early stage bone marrow activity. Further research is needed to evaluate the "Booster-Effect" of Velaglucerase alfa therapy in Gaucher skeletal disease. [ABSTRACT FROM AUTHOR]

The half antivortex, a fundamental topological structure which determines magnetization reversal of submicron magnetic devices with domain walls, has been suggested also to play a crucial role in spin torque induced vortex core reversal in circular disks. Here, we report on magnetization reversal in circular disks with nanoholes through consecutive metastable states with half antivortices. In-plane anisotropic magnetoresistance and broadband susceptibility measurements accompanied by micromagnetic simulations reveal that cobalt (Co) disks with two and three linearly arranged nanoholes directed at 45° and 135° with respect to the external magnetic field show reproducible step-like changes in the anisotropic magnetoresistance and magnetic permeability due to transitions between different intermediate states mediated by vortices and half antivortices confined to the dot nanoholes and edges, respectively. Our findings are relevant for the development of multi-hole based spintronic and magnetic memory devices. [ABSTRACT FROM AUTHOR]

Focused electron beam induced deposition as a direct-write approach possesses great potential to meet the demands for superconducting nanostructure fabrication especially regarding its 3D patterning capabilities combined with the high resolution in the nanometer regime. So far, however, it was not possible to fabricate superconducting structures with this technique. In this work, we present a lead-based superconductor prepared by focused electron beam induced deposition by dissociation of the precursor tetraethyllead. The as-grown structures exhibit metallic behavior and a minimum resistivity in the normal state of q = 16 μΩcm at T = 9 K followed by a superconducting transition at Tc = 7.2 K. [ABSTRACT FROM AUTHOR]

For the in-situ conductance optimization of micro- and nanostructures prepared via the focused electron-beam-induced deposition technique, a direct experimental feedback control mechanism using an evolutionary genetic algorithm approach was introduced recently. The technique involves the measurement of the conductance of a deposit to which new layers are added on top of each other using a different parameter set for the deposition of each layer. A fitness value which can be deduced from the conductance measurement evaluates the negative or positive impact on conductance for every specific parameter set in order to find an optimized parameter set for the deposition of nanostructures with maximum conductance. Here, for the layer growth used in the genetic algorithm optimization experiments a theoretical model is developed which differentiates between two possible scenarios. The first scenario describes the time dependence of height and conductivity for FEBID deposition, if electron induced irradiation effects can be neglected. The second scenario includes the influence of electron irradiation effects on the height and conductivity of layered FEBID structures. The first model is used to analyze the data of the dwell-time optimization experiments for the precursor W(CO)6. For short dwell times t D < 10 μs the experimental data can be described using a growth rate model. For longer dwell times t D > 10 μs experimental values deviate from the theoretically calculated curve, which we attribute to diffusive replenishment effects not included in the rate modeling approach as well as a non-cartographic parameter search applied in the genetic algorithm optimization process. [ABSTRACT FROM AUTHOR]

We report experimental evidence of a long-range superconducting proximity effect in polycrystalline Co nanowires in contact with a superconducting W-based floating electrode (inducer). For electrical resistance measurements, voltage leads were connected to the Co nanowire on both sides of the superconducting inducer at a distance of 7.2 μm. We observed a 28% reduction of the nanowire resistance when sweeping the temperature below the inducer's transition temperature Tc = 5.2 K. Our analysis of the resistance data shows that the superconducting proximity length in polycrystalline Co is as large as 1 μm at 2.4 K, attesting to a long-range proximity effect. Moreover, this long-range proximity effect is insusceptible to magnetic fields up to 11 T, which is indicative of spin-triplet pairing. Our results provide evidence that magnetic inhomogeneity of the ferromagnet enlarges the spatial extend of the spin-triplet superconducting proximity effect. [ABSTRACT FROM AUTHOR]

Abstract: In this work we study the response of a pnCCD by means of X-ray spectroscopy in the energy range between 6keV and 20keV and by Laue diffraction techniques. The analyses include measurements of characteristic detector parameters like energy resolution, count rate capability and effects of different gain settings. The limit of a single photon counting operation in white beam X-ray diffraction experiments is discussed with regard to the occurrence of pile-up events, for which the energy information about individual photons is lost. In case of monochromatic illumination the pnCCD can be used as a fast conventional CCD with a charge handling capacity (CHC) of about 300,000 electrons per pixel. If the CHC is exceeded, any surplus charge will spill to neighboring pixels perpendicular to the transfer direction due to electrostatic repulsion. The possibilities of increasing the number of storable electrons are investigated for different voltage settings by exposing a single pixel with X-rays generated by a microfocus X-ray source. The pixel binning mode is tested as an alternative approach that enables a pnCCD operation with significantly shorter readout times. [Copyright &y& Elsevier]

The ion beam induced nanoscale synthesis of platinum nanowires using the trimethyl (methylcyclopentadienyl)platinum(IV) .MeCpPtIVMe3) precursor is investigated using helium and neon ion beams in the gas field ion microscope. The He+ beam induced deposition resembles material deposited by electron beam induced deposition with very small platinum nanocrystallites suspended in a carbonaceous matrix. The He+ deposited material composition was estimated to be 16% Pt in a matrix of amorphous carbon with a large room-temperature resistivity (∼ 3:5 × 104 -2:2 × 105 μΩ cm) and temperature-dependent transport behavior consistent with a granular material in the weak intergrain tunnel coupling regime. The Ne+ deposited material has comparable composition (17%), however a much lower room-temperature resistivity (∼600-3:0 × 103 μΩ cm) and temperature-dependent electrical behavior representative of strong intergrain coupling. The Ne+ deposited nanostructure has larger platinum nanoparticles and is rationalized via Monte Carlo ion-solid simulations which show that the neon energy density deposited during growth is much larger due to the smaller ion range and is dominated by nuclear stopping relative to helium which has a larger range and is dominated by electronic stopping. [ABSTRACT FROM AUTHOR]

A careful analysis of the magneto-transport properties of epitaxial nanostructured Nb thin films in the normal and the mixed state is performed. The nanopatterns were prepared by focused ion beam (FIB) milling. They provide a washboard-like pinning potential landscape for vortices in the mixed state and simultaneously cause a resistivity anisotropy in the normal state. Two matching magnetic fields for the vortex lattice with the underlying nanostructures have been observed. By applying these fields, the most likely pinning sites along which the flux lines move through the samples have been selected. By this, either the background isotropic pinning of the pristine film or the enhanced isotropic pinning originating from the nanoprocessing have been probed. Via an Arrhenius analysis of the resistivity data the pinning activation energies for three vortex lattice parameters have been quantified. The changes in the electrical transport and the pinning properties have been correlated with the results of the microstructural and topographical characterization of the FIB-patterned samples. Accordingly, along with the surface processing, FIB milling has been found to alter the material composition and the degree of disorder in as-grown films. The obtained results provide further insight into the pinning mechanisms at work in FIB-nanopatterned superconductors, e.g. for fluxonic applications. [ABSTRACT FROM AUTHOR]

Perlick DA, Gonzalez J, Michael L, Huth M, Culver J, Kaczynski R. Calabrese J. Miklowitz DJ. Rumination, gender, and depressive symptoms associated with caregiving strain in bipolar disorder. Objective: To evaluate the associations between indices of caregiving strain, ruminative style, depressive symptoms, and gender among family members of patients with bipolar disorder. Method: One hundred and fifty primary caregivers of patients enrolled in the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) participated in a cross-sectional study to evaluate the role of ruminative style in maintaining depressive symptoms associated with caregiving strain. Patient lifetime diagnosis and current episode status were evaluated by the Affective Disorder Evaluation and the Clinical Monitoring Form. Caregivers were evaluated within 30 days of the patient on measures of family strain, depressive symptoms, and ruminative style. Results: Men and women did not differ on depression, caregiver strain, or ruminative style scores. Scores suggest an overall mild level of depression and moderate caregiver strain for the sample. Greater caregiver strain was significantly associated ( P < 0.05) with rumination and level of depressive symptoms, controlling for patient clinical status and demographic variables. Rumination reduced the apparent association between strain and depression by nearly half. Gender was not significantly associated with depression or rumination. Conclusion: Rumination helps explain depressive symptoms experienced by both male and female caregivers of patients with bipolar disorder. Interventions for caregivers targeted at decreasing rumination should be considered. [ABSTRACT FROM AUTHOR]

High resolution x-ray absorption spectroscopy (XAS) affords new insight into the microscopic properties of perovskite transition metal oxides. Interpretation of XAS spectra in transition metal oxides requires theoretical tools capable of describing relativistic and many-body effects. In this work, full relativistic (SPR-KKR) and multiplet calculations (CTM4XAS) are carried out and compared to experimental multiedge XAS spectra of BaTiO3 single crystals. The impact of relativistic and many-body effects on the calculated density of states and x-ray absorption near edge structure spectra are individually considered. [ABSTRACT FROM AUTHOR]

A novel multilayer material system consisting of lanthanum and molybdenum nano-layers for both broadband and highly reflecting multilayer mirrors in the energy range between 80 and 130 eV is presented. The simulation and design of these multilayers were based on an improved set of optical constants, which were recorded by extreme ultraviolet (XUV)/soft-x-ray absorption measurements on freestanding lanthanum nano-films between 30 eV and 1.3 keV. Lanthanum-molybdenum (La/Mo) multilayer mirrors were produced by ion-beam sputtering and characterized through both x-ray and XUV reflectivity measurements.We demonstrate the ability to precisely simulate and realize aperiodic stacks. Their stability against ambient air conditions is demonstrated. Finally, the La/Mo mirrors were used in the generation of single attosecond pulses from high-harmonic cut-off spectra above 100 eV. Isolated 200 attosecond-long pulses were measured by XUV-pump/IR-probe streaking experiments and characterized using frequency-resolved optical gating for complete reconstruction of attosecond bursts (FROG/CRAB) analyses. [ABSTRACT FROM AUTHOR]

Introduction The airbag is an established car safety device. However, recent studies pointed out that even the airbag might cause injuries. Nevertheless, most physicians do consider a lower risk in accident victims sustaining severe injury of the chest, when a deployed frontal airbag has been reported. We set out to verify the frequency and pattern of thoracic injury in car drivers protected by a frontal airbag during traffic accidents. Methods This investigation was conducted as part of a prospective surveillance analyzing traffic accidents. Enrolled were car drivers included in a databank between January 2001 and December 2004 consecutively. The chance for sustaining chest injury with or without a frontal airbag was described using the relative risk. Results A total of 188 car drivers were included in the analysis. In 54 (28.7%) cases a deployed airbag and in 134 (71.3%) the absence of an airbag has been documented. Out of those cases 16 (29.6%) drivers with airbag and 30 (22.4%) without airbag sustained a chest injury. The mean abbreviated injury scale (AIS) of chest injuries in drivers with deployed airbag was 2.3 (1-5; SD ± 1.45; mean injury severity scale [ISS] 21.1 [SD ± 17.18]), in drivers without airbag 1.6 (1-4; SD ± 1.12; mean ISS 15.8 [SD ± 20.6]). For belted drivers with an airbag the relative risk to sustain chest injury was 1.96 compared to those without an airbag. Conclusions The airbag does not avoid chest injury definitively. Much more, it has been demonstrated that the relative risk to sustain relevant thoracic injury seems to be almost higher in restrained drivers with a frontal airbag. [ABSTRACT FROM AUTHOR]