The role of electron-stimulated desorption in focused electron beam induced deposition

• Willem F. van Dorp,
• Thomas W. Hansen,
• Jakob B. Wagner and
• Jeff T. M. De Hosson

Beilstein J. Nanotechnol. 2013, 4, 474–480, doi:10.3762/bjnano.4.56

• desorption. Keywords: desorption energy; focused electron beam induced processing; scanning transmission electron microscopy; temperature dependence; tungsten hexacarbonyl; Introduction When the electron beam in an electron microscope is focused on a sample in the presence of a precursor gas, it can be

Structural and thermoelectric properties of TMGa₃ (TM = Fe, Co) thin films

• Sebastian Schnurr,
• Ulf Wiedwald,
• Paul Ziemann,
• Valeriy Y. Verchenko and
• Andrei V. Shevelkov

Beilstein J. Nanotechnol. 2013, 4, 461–466, doi:10.3762/bjnano.4.54

• resistivity of ρ = 200 μΩ·cm for CoGa3 and an electrical resistivity of about 600 μΩ·cm with a small negative temperature dependence for FeGa3. The observed values and temperature dependencies are typical of high-resistivity metallic glasses. This is especially surprising in the case of FeGa3, which as

• crystalline bulk material exhibits a semiconducting behavior, though with a small gap of 0.3 eV. Also the thermoelectric performance complies with that of metallic glasses: Small negative Seebeck coefficients of the order of −6 μV/K at 300 K with almost linear temperature dependence in the range 10 K ≤ T

• temperature-dependence rather than the Arrhenius behavior expected for a semiconductor. Although at low temperatures this may be masked by uncontrolled doping effects. But even in such a case, the pronounced linear temperature-dependence would appear as fortuitous. On the other hand, for the family of high

Synthesis and thermoelectric properties of Re₃As_6.6In_0.4 with Ir₃Ge₇ crystal structure

• Valeriy Y. Verchenko,
• Anton S. Vasiliev,
• Alexander A. Tsirlin,
• Vladimir A. Kulbachinskii,
• Vladimir G. Kytin and
• Andrei V. Shevelkov

Beilstein J. Nanotechnol. 2013, 4, 446–452, doi:10.3762/bjnano.4.52

• , Seebeck coefficient and thermal conductivity, we calculate the temperature dependence of ZT shown in Figure 7. ZT increases with temperature, and reaches ZT = 0.0008 at room temperature, which is 30 times lower than for Re3As7−xGex [13]. Given the compositional width of the Re3As7−xInx solid solution and

Ni nanocrystals on HOPG(0001): A scanning tunnelling microscope study

• Michael Marz,
• Keisuke Sagisaka and
• Daisuke Fujita

Beilstein J. Nanotechnol. 2013, 4, 406–417, doi:10.3762/bjnano.4.48

• number of cluster and their sizes, a sample with a medium coverage deposited at high flux has been used. At medium coverage, there is a large number of clusters, but it is still possible to measure their height, width and number. Figure 5a–Figure 5c shows the temperature dependence of the cluster height

• width (b) dependence on deposition time (black circles) and flux (blue diamonds) during the evaporation process. The plots show no significant influence of the evaporation conditions on the size of the clusters. Temperature dependence of the annealing behaviour of the Ni clusters. STM topographic images

• . Temperature dependence of the annealing behaviour for (a) the height of the clusters, (b) the percentage of surface covered by the clusters, and (c) the number of clusters per area (cluster density n). The annealing process can be divided into two parts: First, for mild annealing (T ≤ 500 K) where no

Antiferromagnetic coupling of TbPc₂ molecules to ultrathin Ni and Co films

• David Klar,
• Svetlana Klyatskaya,
• Andrea Candini,
• Bernhard Krumme,
• Kurt Kummer,
• Philippe Ohresser,
• Valdis Corradini,
• Valentina de Renzi,
• Roberto Biagi,
• Loic Joly,
• Jean-Paul Kappler,
• Umberto del Pennino,
• Marco Affronte,
• Heiko Wende and
• Mario Ruben

Beilstein J. Nanotechnol. 2013, 4, 320–324, doi:10.3762/bjnano.4.36

• for a smaller antiferromagnetic coupling strength may be the higher temperature for the measurements on Co (T ≥ 10 K) than on Ni (8 K). This temperature difference may cause changes in the field dependence of the XMCD, because a significant temperature dependence of the magnetic coupling is expected

Nanoscopic surfactant behavior of the porin MspA in aqueous media

• Ayomi S. Perera,
• Hongwang Wang,
• Tej B. Shrestha,
• Deryl L. Troyer and
• Stefan H. Bossmann

Beilstein J. Nanotechnol. 2013, 4, 278–284, doi:10.3762/bjnano.4.30

• and octameric oligomers [13]. In the near future, designer proteins with tailored biophysical properties will become increasingly available [14], and therefore, the influence of temperature on their supramolecular aggregation behavior will become more significant. Recently, the temperature dependence

• temperature is completely different. ζ is slightly positive (ζ = 10 ± 14 mV) in the temperature range from 296 to 320 K. Beyond 320 K, a remarkable increase in ζ is observed. At 344 K, ζ = 100 ± 12 mV indicates an excellent stabilization of the MspA vesicles in PBS. The temperature dependence of ζ is

Revealing thermal effects in the electronic transport through irradiated atomic metal point contacts

• Bastian Kopp,
• Zhiwei Yi,
• Daniel Benner,
• Fang-Qing Xie,
• Christian Obermair,
• Thomas Schimmel,
• Johannes Boneberg,
• Paul Leiderer and
• Elke Scheer

Beilstein J. Nanotechnol. 2012, 3, 703–711, doi:10.3762/bjnano.3.80

• contact at a conductance value of a few G0, adjusted during deposition, even in the dry state. With these samples we were able to identify two sources of signals appearing upon illumination of the junction, namely thermovoltage and temperature dependence of the lead resistance. Thermovoltage As an

• effects were observed in lithographically defined junctions that were never exposed to electrolytes, Figure 8c. These control experiments demonstrate that no electrochemical process is at the origin of the observations. Temperature dependence of the lead resistance The leads towards the nanocontact, as

• increase during the illumination. Conclusion The results show that the temperature dependence of the Helmholtz double layer is the main reason for the light-induced signal of a GCQS under laser illumination. In contrast, for the electrochemically closed, but dried contacts the thermovoltage due to a two

Focused electron beam induced deposition: A perspective

• Michael Huth,
• Fabrizio Porrati,
• Christian Schwalb,
• Marcel Winhold,
• Roland Sachser,
• Maja Dukic,
• Jonathan Adams and
• Georg Fantner

Beilstein J. Nanotechnol. 2012, 3, 597–619, doi:10.3762/bjnano.3.70

• the Hall voltage are shown in Figure 10 for sample B (Figure 10a and Figure 10c) and B' (Figure 10b and Figure 10d). The as-grown sample exhibits a roughly linear temperature dependence of the conductivity down to about 12 K, which is followed by a quite sudden drop to a very small conductance level

Spontaneous dissociation of Co₂(CO)₈ and autocatalytic growth of Co on SiO₂: A combined experimental and theoretical investigation

• Kaliappan Muthukumar,
• Harald O. Jeschke,
• Roser Valentí,
• Evgeniya Begun,
• Johannes Schwenk,
• Fabrizio Porrati and
• Michael Huth

Beilstein J. Nanotechnol. 2012, 3, 546–555, doi:10.3762/bjnano.3.63

• vacuum chamber are continuously dissociated resulting in a further increase of the thickness of the Co layer. After exposure of the sample to air the layer thickness was determined by atomic force microscopy and found to be approximately 50 nm. (a) Temperature dependence of resistivity of Co deposit

Self-assembled monolayers and titanium dioxide: From surface patterning to potential applications

• Yaron Paz

Beilstein J. Nanotechnol. 2011, 2, 845–861, doi:10.3762/bjnano.2.94

• substrate effect on the onset of burning and on the temperature dependence of the process [22]. Data on contact-angle comparisons between organosilanes on silica and on titania is quite scarce. In this respect, contact-angle measurements of CVD-made tetrafunctional cyclic siloxane monolayers (1,3,5,7

Nanostructured, mesoporous Au/TiO₂ model catalysts – structure, stability and catalytic properties

• Matthias Roos,
• Dominique Böcking,
• Kwabena Offeh Gyimah,
• Gabriela Kucerova,
• Joachim Bansmann,
• Johannes Biskupek,
• Ute Kaiser,
• Nicola Hüsing and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2011, 2, 593–606, doi:10.3762/bjnano.2.63

• orders A third aspect deals with inherent reaction properties such as the apparent activation energy (temperature dependence of the reaction rate) and the reaction orders (partial pressure dependence of the reaction rate). Here it is of interest whether the model systems exhibit characteristics that are

Dense lying self-organized GaAsSb quantum dots on GaAs for efficient lasers

• Thomas H. Loeber,
• Dirk Hoffmann and
• Henning Fouckhardt

Beilstein J. Nanotechnol. 2011, 2, 333–338, doi:10.3762/bjnano.2.39

• temperature dependence. But the latter is still smaller than that of a 50 nm thin GaSb quantum well (between 100 nm thick AlAs0.084Sb0.916 barriers) with 0.35 nm/K (measured PL peak shifts from 1.533 to 1.594 µm for TPL = 20 to 200 K). These results justify the conclusion that our dots have QD character. With

Magnetic interactions between nanoparticles

• Steen Mørup,
• Mikkel Fougt Hansen and
• Cathrine Frandsen

Beilstein J. Nanotechnol. 2010, 1, 182–190, doi:10.3762/bjnano.1.22

• collective state of nanoparticles. This collective state has many similarities to spin-glasses. In samples of aggregated magnetic nanoparticles, exchange interactions are often important and this can also lead to a strong suppression of superparamagnetic relaxation. The temperature dependence of the order

• nanoparticle systems are often called super-spin glasses. Dipole interactions can have a significant influence on DC magnetization measurements. In zero field cooled (ZFC) magnetization studies one measures the temperature dependence of the magnetization in a small applied field after the sample has been

• Fe100−xCx particles (x ≈ 22) in decalin as a function of temperature. The data were obtained from AC susceptibility measurements. The open circles are data from a dilute sample, whereas the full circles are data for a concentrated sample. The temperature dependence of the relaxation time for the dilute

Ultrafine metallic Fe nanoparticles: synthesis, structure and magnetism

• Olivier Margeat,
• Marc Respaud,
• Catherine Amiens,
• Pierre Lecante and
• Bruno Chaudret

Beilstein J. Nanotechnol. 2010, 1, 108–118, doi:10.3762/bjnano.1.13

• temperature dependence is characteristic of a superparamagnetic transition. The NPs, which have relaxation times (τ) longer than the measurement time (τm), give rise to a sextet (blocked NPs). The superparamagnetic NPs with a short relaxation time (τ < τm) show paramagnetic like behaviour. In the case of

• measuring times corresponding to the Mössbauer experiment. This deviation is reduced when the temperature dependence of τ0(T) √T is taken into account [33][34][35][42]. This value is small compared to the expected, and usually measured, values, which are in the nanosecond range [43]. However, it is within

• the same range as Co NPs of similar size [44]. In a second step, we determine the temperature dependence of MS, from the static magnetization ZFC-FC curves by plotting MS(T) (mSup_Exp T)1/2 versus Tn. As shown in the inset of Figure 6, MS follows a MS(T) = MS(T = 0)[1−αTn] law, where n = 1.6 ± 0.05

Uniform excitations in magnetic nanoparticles

• Steen Mørup,
• Cathrine Frandsen and
• Mikkel Fougt Hansen

Beilstein J. Nanotechnol. 2010, 1, 48–54, doi:10.3762/bjnano.1.6

• 10.3762/bjnano.1.6 Abstract We present a short review of the magnetic excitations in nanoparticles below the superparamagnetic blocking temperature. In this temperature regime, the magnetic dynamics in nanoparticles is dominated by uniform excitations, and this leads to a linear temperature dependence of

• the magnetization and the magnetic hyperfine field, in contrast to the Bloch T3/2 law in bulk materials. The temperature dependence of the average magnetization is conveniently studied by Mössbauer spectroscopy. The energy of the uniform excitations of magnetic nanoparticles can be studied by

• schematically in Figure 1. The magnetic dynamics well below the Curie or Néel temperature in both bulk materials and nanoparticles can be described by excitation of spin waves, but the spin wave spectrum of small particles is size-dependent and this can have a substantial influence on the temperature dependence

Preparation and characterization of supported magnetic nanoparticles prepared by reverse micelles

• Ulf Wiedwald,
• Luyang Han,
• Johannes Biskupek,
• Ute Kaiser and
• Paul Ziemann

Beilstein J. Nanotechnol. 2010, 1, 24–47, doi:10.3762/bjnano.1.5