Nanobioarchitectures based on chlorophyll photopigment, artificial lipid bilayers and carbon nanotubes

• Marcela Elisabeta Barbinta-Patrascu,
• Stefan Marian Iordache,
• Ana Maria Iordache,
• Nicoleta Badea and
• Camelia Ungureanu

Beilstein J. Nanotechnol. 2014, 5, 2316–2325, doi:10.3762/bjnano.5.240

• 0.3 nm/s scan rate. Fluorescence analysis The fluorescence emission spectra of Chla in liposomes and hybrid structures were collected on a Perkin-Elmer, LS55 fluorescence spectrometer. The samples were excited with 430 nm excitation light. Fluorescence anisotropy measurements were carried out on the

• emission window, respectively. The anisotropy was calculated as the mean value of seven independent measurements, at a specified temperature, using the equation: where I represents the relative fluorescence intensity, the subscripts v and h represent the vertical and horizontal orientation of the

• obtained by excitation at λ = 430 nm and the emission fluorescence maximum of Chla incorporated in biomimetic membranes and in biohybrids was at 680 nm. The fluorescence anisotropy of biohybrids is greater than that of liposomes (Figure 4), thus Chla sensed a more rigid environment. This makes Chla

Influence of the supramolecular architecture on the magnetic properties of a Dy^III single-molecule magnet: an ab initio investigation

• Julie Jung,
• Olivier Cador,
• Kevin Bernot,
• Fabrice Pointillart,
• Javier Luzon and
• Boris Le Guennic

Beilstein J. Nanotechnol. 2014, 5, 2267–2274, doi:10.3762/bjnano.5.236

• hydrogen bonds play an important role in the modulation of the electrostatic environment around the DyIII center that governs the nature of its magnetic ground-state and the orientation of its anisotropy axes. We thus show here that SMM properties that rely on supramolecular organization may not be

• moment of the molecule and its magnetic anisotropy [1]. Most of SMMs have been characterized as bulk crystalline material in which intermolecular magnetic interactions are expected to be negligible when compared to the intramolecular ones. The magnetic properties of a compound have then a molecular

• extensively characterize the magnetic anisotropy of the molecules [9][10][35][36][37][38] and its evolution with ligand modifications [39][40][41]. These studies have been performed mainly on lanthanide-based SMMs as these ions are expected to be extremely sensitive to modifications of the surrounding [42][43

Optical properties and electrical transport of thin films of terbium(III) bis(phthalocyanine) on cobalt

• Peter Robaschik,
• Pablo F. Siles,
• Daniel Bülz,
• Peter Richter,
• Manuel Monecke,
• Michael Fronk,
• Svetlana Klyatskaya,
• Daniel Grimm,
• Oliver G. Schmidt,
• Mario Ruben,
• Dietrich R. T. Zahn and
• Georgeta Salvan

Beilstein J. Nanotechnol. 2014, 5, 2070–2078, doi:10.3762/bjnano.5.215

• 58 nm TbPc2 film on Co. TbPc2 films exhibit a uniaxial anisotropy of the dielectric function similar to many planar phthalocyanines, for example, CuPc [13] or H2Pc [14]. Consequently, the dielectric function parallel (in-plane) and perpendicular (out-of-plane) to the sample surface differs . For a

• the dielectric tensor using Equation 1: where i = x, y, z. From the anisotropy of the extinction coefficient k in the Q band region (1.6–2.0 eV), it is possible to estimate the molecular orientation [13][14]. According to the model described in [16] we assume that two electronic transition dipole

• spectral range of 0.7–5.0 eV with an energy step width of 0.02 eV. Three different angles of incidence (50°, 60° and 70°) were exploited for increased sensitivity of the optical anisotropy of the films. The initially linear polarized light becomes elliptically polarized light after reflection on the sample

Cathode lens spectromicroscopy: methodology and applications

• T. O. Menteş,
• G. Zamborlini,
• A. Sala and
• A. Locatelli

Beilstein J. Nanotechnol. 2014, 5, 1873–1886, doi:10.3762/bjnano.5.198

• shown that the addition of oxygen modifies the pattern anisotropy while preserving the periodic structure [69]. Moreover, the Pd–O bispecies layer is stable upon lowering the temperature from above 1000 K down to room temperature. The different adlayer patterns that can be obtained by varying the amount

• of oxygen on the surface are depicted in Figure 10a. The changes in the pattern anisotropy are driven by the magnitude and sign of stress variations on the surface, which are both dependent on the presence and amount of oxygen [69]. The stability of the Pd–O stripes on W(110) at lower temperatures

• map in Figure 10b (right panel). This is a surprising confirmation of the magnetocrystalline anisotropy strength dominating the shape anisotropy. Iron oxides find wide application in several fields of research, among others magnetism and heterogeneous catalysis. In both cases, the heteroepitaxial

Equilibrium states and stability of pre-tensioned adhesive tapes

• Carmine Putignano,
• Luciano Afferrante,
• Luigi Mangialardi and
• Giuseppe Carbone

Beilstein J. Nanotechnol. 2014, 5, 1725–1731, doi:10.3762/bjnano.5.182

• theoretical investigations about rough contact mechanics [25][26][27][28][29], the role of roughness in this kind of systems is not yet well understood. Furthermore, viscoelasticity, which entails prominent effects in terms of friction and contact anisotropy [30][31], has not yet been included in analytical

Probing the electronic transport on the reconstructed Au/Ge(001) surface

• Franciszek Krok,
• Mark R. Kaspers,
• Alexander M. Bernhart,
• Marek Nikiel,
• Benedykt R. Jany,
• Paulina Indyka,
• Mateusz Wojtaszek,
• Rolf Möller and
• Christian A. Bobisch

Beilstein J. Nanotechnol. 2014, 5, 1463–1471, doi:10.3762/bjnano.5.159

• two contacts leading to a current flow across the surface. Thus, if the main contribution of the total current is flowing through the Au reconstructed 1D domains, the impact of the predicted conductance anisotropy should be observed as a variation of the electrochemical potential in the vicinity of

Restructuring of an Ir(210) electrode surface by potential cycling

• Khaled A. Soliman,
• Dieter M. Kolb,
• Ludwig A. Kibler and
• Timo Jacob

Beilstein J. Nanotechnol. 2014, 5, 1349–1356, doi:10.3762/bjnano.5.148

• in- and outside a UHV chamber. It was found that the presence of oxygen is crucial for the faceting process on Ir(210) [21][22]. Theoretical calculations for the Ir(210) system, based on first principles, provided supportive information. It was shown that, due to the anisotropy in surface free energy

Self-organization of mesoscopic silver wires by electrochemical deposition

• Sheng Zhong,
• Thomas Koch,
• Stefan Walheim,
• Harald Rösner,
• Eberhard Nold,
• Aaron Kobler,
• Torsten Scherer,
• Di Wang,
• Christian Kübel,
• Mu Wang,
• Horst Hahn and
• Thomas Schimmel

Beilstein J. Nanotechnol. 2014, 5, 1285–1290, doi:10.3762/bjnano.5.142

• atomic scale. It is known, that the (112) surface energy is relatively high and that the growth speed of [112] is faster than that of other facets [35]. Hence elongated silver wires are generated due to the anisotropy in growth rate. However, anisotropy in growth rate cannot guarantee for the formation

• same crystallographic direction. These observations confirm our understanding of the silver wire growth and support the nutrient-supply-flux induced side branching mechanism in silver wire growth. This branching mechanism is valid when the wire growth has very strong anisotropy and the side faces of

Dry friction of microstructured polymer surfaces inspired by snake skin

• Martina J. Baum,
• Lars Heepe,
• Elena Fadeeva and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2014, 5, 1091–1103, doi:10.3762/bjnano.5.122

• in contact with a smooth glass ball by a microtribometer in two perpendicular directions. The SIMPS exhibited a considerable frictional anisotropy: Frictional coefficients measured along the microstructure were about 33% lower than those measured in the opposite direction. Frictional coefficients

• structural wavelength and the mean width of denticulations. The length of the denticulations on SIMPS is shorter than that of the snake surface, but the overall dimensions of the microstructures are comparable (Table 1). The geometrical anisotropy in form of slopes is present (Figure 2a). The angle in the

• coefficients on the smooth surface and the measurements against to the microstructure of the SIMPS and in the lateral directions (Figure 8). A statistically significant anisotropy was found between the measurement directions (i) “along” versus “against” the microstructure and (ii) “along” versus “lateral” to

Designing magnetic superlattices that are composed of single domain nanomagnets

• Derek M. Forrester,
• Feodor V. Kusmartsev and
• Endre Kovács

Beilstein J. Nanotechnol. 2014, 5, 956–963, doi:10.3762/bjnano.5.109

• parallel, anti-parallel and canting average magnetization states. Results: We give examples of the phase diagrams in terms of anisotropy and coupling strength for two, three and four magnetic layers. Each phase diagrams character is defined by the shape of the magnetic hysteresis profile for a system in an

• anisotropies [1]. A nanomagnet with high shape anisotropy must have some kind of modulation in order to reduce the height of the anisotropy energy barrier. This is typically done through doping in order to reduce the saturation magnetization of the nanomagnet. In recent years amorphous ferromagnetic materials

• have low random anisotropy. In this work we study the magnetic response of linear arrays of nanomagnets to an oscillating magnetic field that is applied at a slight angle from parallel to the longest axis of an individual nanomagnet. A small perturbing magnetic field is also introduced that enables the

En route to controlled catalytic CVD synthesis of densely packed and vertically aligned nitrogen-doped carbon nanotube arrays

• Slawomir Boncel,
• Sebastian W. Pattinson,
• Valérie Geiser,
• Milo S. P. Shaffer and
• Krzysztof K. K. Koziol

Beilstein J. Nanotechnol. 2014, 5, 219–233, doi:10.3762/bjnano.5.24

• ., for the reduction of nitrogen oxides (NxOy) emission in exhausts [15]. A high degree of vertical alignment in the nanotube films (also called ‘carpets’ or ‘forests’) is a key aspect in numerous applications that gain from anisotropy, i.e., supercapacitors [16], counter electrodes [17], structural

Charge and spin transport in mesoscopic superconductors

• M. J. Wolf,
• F. Hübler,
• S. Kolenda and
• D. Beckmann

Beilstein J. Nanotechnol. 2014, 5, 180–185, doi:10.3762/bjnano.5.18

• data by about a factor of two, both for gnl and (not shown). We attribute this discrepancy to the fact that at zero applied field, any small additional source of pair breaking, such as gap anisotropy, magnetic impurities, spatial profile of the gap due to quasiparticle injection, etc., may contribute

Friction behavior of a microstructured polymer surface inspired by snake skin

• Martina J. Baum,
• Lars Heepe and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2014, 5, 83–97, doi:10.3762/bjnano.5.8

• the skin scales, so called microornamentation [1][4][5][6][7][8][9][10][11][12][13], and specific adaptations of the material architecture of the skin, like highly ordered embedded fibers [14], which can potentially influence material properties [15][16], might contribute to the frictional anisotropy

• different sliding directions within each dimension of pitches, showed a strong frictional anisotropy and strong variation in the occurrence of stick-slip induced vibrations, especially at pitch dimensions of 5 µm and 25 µm. For the smallest dimension of PGMS, less vibrations and a lower frictional

• . In opposite direction, this coefficient was significantly higher (0.32 ± 0.01). Comparison of results obtained in these sliding directions to those obtained in the lateral direction demonstrated the pronounced frictional anisotropy (µ lateral: 0.36 ± 0.02). The occurrence of stick-slip behavior was

Spin relaxation in antiferromagnetic Fe–Fe dimers slowed down by anisotropic Dy^III ions

• Valeriu Mereacre,
• Frederik Klöwer,
• Yanhua Lan,
• Rodolphe Clérac,
• Juliusz A. Wolny,
• Volker Schünemann,
• Christopher E. Anson and
• Annie K. Powell

Beilstein J. Nanotechnol. 2013, 4, 807–814, doi:10.3762/bjnano.4.92

• Mössbauer spectroscopy in combination with susceptibility measurements it was possible to identify the supertransferred hyperfine field through the oxygen bridges between DyIII and FeIII in a {Fe4Dy2} coordination cluster. The presence of the dysprosium ions provides enough magnetic anisotropy to “block

• ” the hyperfine field that is experienced by the iron nuclei. This has resulted in magnetic spectra with internal hyperfine fields of the iron nuclei of about 23 T. The set of data permitted us to conclude that the direction of the anisotropy in lanthanide nanosize molecular clusters is associated with

• the single ion and crystal field contributions and 57Fe Mössbauer spectroscopy may be informative with regard to the the anisotropy not only of the studied isotope, but also of elements interacting with this isotope. Keywords: anisotropy; dysprosium; iron; Mössbauer spectroscopy; Introduction The

Magnetic anisotropy of graphene quantum dots decorated with a ruthenium adatom

• Igor Beljakov,
• Velimir Meded,
• Franz Symalla,
• Karin Fink,
• Sam Shallcross and
• Wolfgang Wenzel

Beilstein J. Nanotechnol. 2013, 4, 441–445, doi:10.3762/bjnano.4.51

• decoration of a graphene sheet by magnetic transition-metal adatoms, utilizing the high in-plane versus out-of-plane magnetic anisotropy energy (MAE), has recently been proposed. This concept is extended in our density-functional-based modeling study by incorporating the influence of the graphene edge on the

• close to the edge, while the opposite is true for the zigzag edge. Additionally, in-plane pinning of the magnetization direction perpendicular to the edge itself is observed for the first time. Keywords: adsorbate; grapheme; graphene quantum dot; magnetic anisotropy; transition metal; Introduction

• graphene with a certain periodic coverage of metal adatoms. A homogeneous distribution of adatoms on a graphene sheet may pose further experimental difficulties, due to the possibility of adatom clustering. The magnetic anisotropy energy (MAE) is known to be profoundly influenced by the symmetry of the

In situ monitoring magnetism and resistance of nanophase platinum upon electrochemical oxidation

• Eva-Maria Steyskal,
• Stefan Topolovec,
• Stephan Landgraf,
• Heinz Krenn and
• Roland Würschum

Beilstein J. Nanotechnol. 2013, 4, 394–399, doi:10.3762/bjnano.4.46

• coupling varies with an applied electric field E [21][22], this may give rise to an E-dependence of the magnetization, directly. In addition the Rashba effect is also associated with magnetic surface anisotropy [22]. The E-dependence of the latter may also cause variations of the magnetic moment in

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

• . On both substrates the TbPc2 molecules couple antiferromagnetically to the ferromagnetic films, which is possibly due to a superexchange interaction via the phthalocyanine ligand that contacts the magnetic surface. Keywords: magnetic anisotropy; magnetic coupling; single molecule magnets; X-ray

• (III) (TbPc2) has only one rare-earth ion, coordinated by two organic phthalocyanine ligands consisting of nitrogen, carbon and hydrogen atoms (Figure 1a). The SMM properties arise simply from the single ion anisotropy of the Tb ion exhibiting a total angular momentum of J = 6 [14]. The crucial point

• ][17] or antiparallel due to an interlayer of oxygen [18][19]. Recently, it was shown that TbPc2 molecules can be magnetically coupled to a ferromagnetic Ni substrate [20]. The magnetic anisotropy and field dependence were also studied for TbPc2 in a submonolayer on Cu(100) [21] and on

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

• = 0.31 and the experimental finding that vesicles are formed, which requires 0.5 < P < 1. Charge attraction/repulsion [30] apparently only plays a minor role, since the observed formation of liposomes does not strongly depend on the ionic strengths of the aqueous medium. The anisotropy of the negative

Hydrogen-plasma-induced magnetocrystalline anisotropy ordering in self-assembled magnetic nanoparticle monolayers

• Alexander Weddemann,
• Judith Meyer,
• Anna Regtmeier,
• Irina Janzen,
• Dieter Akemeier and
• Andreas Hütten

Beilstein J. Nanotechnol. 2013, 4, 164–172, doi:10.3762/bjnano.4.16

• ; magnetocrystalline anisotropy; monolayers; Introduction Due to their wide range of applications in physical, biological and medical fields, magnetic nanoparticles have been thoroughly studied during the past few decades [1][2]. In this regard, various manufacturing techniques to synthesize particles with distinct

• prerequisite for such an application is the high thermal stability of a magnetic state in order to maintain the magnetic configuration and not to lose the stored information. In the case of a single particle, materials with a strong uniaxial magnetocrystalline anisotropy, such as face-centered tetragonal L10

• components are aligned parallel to the magnetization directions of the magnetic equilibrium state of the system itself. If particles with low magnetocrystalline anisotropy are considered, the magnetic equilibrium state is mainly dominated by dipolar coupling. In this case, the magnetic-moment vectors do not

Functionalization of vertically aligned carbon nanotubes

• Eloise Van Hooijdonk,
• Carla Bittencourt,
• Rony Snyders and
• Jean-François Colomer

Beilstein J. Nanotechnol. 2013, 4, 129–152, doi:10.3762/bjnano.4.14

• shifted towards obtaining control in the engineering of organized architectures with determined orientations, such as vertically aligned carbon nanotubes (VA-CNTs). Because of the strong anisotropy of the CNT properties, the orientation of the longitudinal direction of the CNTs is often requested in many

Characterization and properties of micro- and nanowires of controlled size, composition, and geometry fabricated by electrodeposition and ion-track technology

• Maria Eugenia Toimil-Molares

Beilstein J. Nanotechnol. 2012, 3, 860–883, doi:10.3762/bjnano.3.97

• nanowires were successfully grown from nickel [57], cobalt [79], and iron [80]. The growth of Fe-based nanowires with controllable size, aspect ratio, and magnetic anisotropy in FeCl3 and FeCl2 solutions was investigated by Song et al. They employed FeCl3 and FeCl2 solutions, studied the nanowire growth

Highly ordered ultralong magnetic nanowires wrapped in stacked graphene layers

• Abdel-Aziz El Mel,
• Jean-Luc Duvail,
• Eric Gautron,
• Wei Xu,
• Chang-Hwan Choi,
• Benoit Angleraud,
• Agnès Granier and
• Pierre-Yves Tessier

Beilstein J. Nanotechnol. 2012, 3, 846–851, doi:10.3762/bjnano.3.95

• observed uniaxial magnetic anisotropy field oriented along the nanowire axis is an indication that the shape anisotropy dominates the dipolar coupling between the wires. We further show that the thermal treatment induces a decrease in the coercivity of the nanowire arrays. This reflects an enhancement of

• perpendicular configuration (roughly = 3100 Oe and Mr/Ms = 0.14), indicate that the nanowire array exhibits a preferential magnetic orientation along the wire axis (i.e., easy axis parallel to the nanowires). In the case of polycrystalline ferromagnetic nanowires, such uniaxial magnetic anisotropy originates

• from the shape anisotropy resulting from the very high aspect ratio of these nanostructures [7][35][36][37][38][39][40][41][42][43]. Concerning the coercive field, it is slightly higher ( = 32 Oe) when the external magnetic field is applied parallel to the nanowire array, than the one measured for the

Tuning the properties of magnetic thin films by interaction with periodic nanostructures

• Ulf Wiedwald,
• Felix Haering,
• Stefan Nau,
• Carsten Schulze,
• Herbert Schletter,
• Denys Makarov,
• Alfred Plettl,
• Karsten Kuepper,
• Manfred Albrecht,
• Johannes Boneberg and
• Paul Ziemann

Beilstein J. Nanotechnol. 2012, 3, 831–842, doi:10.3762/bjnano.3.93

• limit, below which stored information is lost due to thermal fluctuations of the magnetization. To some extent this problem can be circumvented by increasing magnetic anisotropy energy densities [2][3][4][5][6][7][8], but alternative approaches such as tilted magnetic recording [9], exchange-coupled

• of Co/Pt multilayers with out-of-plane anisotropy deposited on a more densely packed array of Au nanoparticles. Results and Discussion Preparation of percolated magnetic thin films Percolated magnetic thin films have been prepared by various techniques [15][16]. One necessary requirement is a

• nm the spherical shape is not maintained and rather semispheres are formed on the Si/SiO2 substrate [25]. A [Co(0.3 nm)/Pt(0.8 nm)]12 multilayer stack with an effective perpendicular magnetic anisotropy of 0.3 MJ/m3 [31] has been deposited by alternating evaporation from pure Co and Pt sources by e

Strong spin-filtering and spin-valve effects in a molecular V–C₆₀–V contact

• Mohammad Koleini and
• Mads Brandbyge

Beilstein J. Nanotechnol. 2012, 3, 589–596, doi:10.3762/bjnano.3.69

• bulk magnetic tip the magnetization of the tip will be determined by the intrinsic magnetic anisotropy of the crystalline magnetization, which fixes the magnetization axes. As the tip molecule approaches the adatom on the non-magnetic surface, its magnetization will be determined by the interaction

P-wave Cooper pair splitting

• Henning Soller and
• Andreas Komnik

Beilstein J. Nanotechnol. 2012, 3, 493–500, doi:10.3762/bjnano.3.56

• ) refers to the electron field operator of the superconductor introduced in Equation 5 in position space. Finally, we need a Hamiltonian approach [46] for spin-active scattering. There are manifold effects, such as spin–orbit coupling, magnetic anisotropy or spin relaxation, that give rise to spin-activity