Ferrocholesteric–ferronematic transitions induced by shear flow and magnetic field

• Dmitriy V. Makarov,
• Alexander A. Novikov and
• Alexander N. Zakhlevnykh

Beilstein J. Nanotechnol. 2017, 8, 2552–2561, doi:10.3762/bjnano.8.255

• mechanism of interaction between the LC and an external magnetic field, the addition of magnetic particles into the LC leads to the appearance of an additional dipole mechanism of the influence on the system. Some types of synthesized ferroliquid crystals have ferromagnetic properties and are highly

• sensitive to an external magnetic field [11][12]. If the carrier medium in the ferroliquid crystal is a cholesteric liquid crystal (CLC), such a composite system is called ferrocholesteric (FC). A distinctive feature of a CLC is the presence of a supramolecular helical structure, which is very sensitive to

• structure with λ < 1. In Figure 3 we see that as λ decreases, the critical value of uc decreases and weakly depends on the orientation of the external magnetic field. Figure 4 and Figure 5 represent the diagrams of the ferrocholesteric–ferronematic phase transition in the plane u–h for the magnetic field

Alternating current magnetic susceptibility of a ferronematic

• Natália Tomašovičová,
• Jozef Kováč,
• Veronika Gdovinová,
• Nándor Éber,
• Tibor Tóth-Katona,
• Jan Jadżyn and
• Peter Kopčanský

Beilstein J. Nanotechnol. 2017, 8, 2515–2520, doi:10.3762/bjnano.8.251

• properties, such as the capability of these materials to respond to external magnetic field more efficiently, comes from the collective properties of the MNPs dispersed in the liquid crystal. In this respect, investigation of such colloidal LC systems opens up new perspectives even for applications. While

Dynamic behavior of a nematic liquid crystal mixed with CoFe₂O₄ ferromagnetic nanoparticles in a magnetic field

• Emil Petrescu,
• Cristina Cirtoaje and
• Cristina Stan

Beilstein J. Nanotechnol. 2017, 8, 2467–2473, doi:10.3762/bjnano.8.246

• magnetic field to reorient the LC molecules and faster decrease the transition threshold. A mixture of 1% CoFe2O4 and the nematic 4-cyano-4′-pentylbiphenyl (5CB, Aldrich) was used in a 180 micrometer thick planar cell subjected to an external magnetic field. Due to their magnetic properties, the

The interplay between spin densities and magnetic superexchange interactions: case studies of mono- and trinuclear bis(oxamato)-type complexes

• Azar Aliabadi,
• Bernd Büchner,
• Vladislav Kataev and
• Tobias Rüffer

Beilstein J. Nanotechnol. 2017, 8, 2245–2256, doi:10.3762/bjnano.8.224

• term represents the Zeeman interaction of an electron spin S with an external magnetic field B0, while g and μB stand for the g-tensor and the Bohr magneton, respectively. The hyperfine (HF) interaction between the electron spin S of Cu(II) and the 63Cu, 65Cu and 14N nuclear spins ICu and IN is

• described by the second and the third term, respectively. Here, ACu and AN are the on-site Cu and transferred N HF coupling tensors, respectively. The last term describes the nuclear Zeeman interaction of the 63Cu, 65Cu and 14N nuclear spins ICu and IN with the external magnetic field B0, which is not

• ENDOR spectra of 8@7 at (ν = 9.56 GHz, T = 20 K) at six different orientations of the single crystal in the external magnetic field. The 0° orientation corresponds to the direction of B0 along the -axis of the g-tensor, and the 90° orientation represents the perpendicular direction. Reproduced with

(Metallo)porphyrins for potential materials science applications

• Lars Smykalla,
• Carola Mende,
• Michael Fronk,
• Pablo F. Siles,
• Michael Hietschold,
• Georgeta Salvan,
• Dietrich R. T. Zahn,
• Oliver G. Schmidt,
• Tobias Rüffer and
• Heinrich Lang

Beilstein J. Nanotechnol. 2017, 8, 1786–1800, doi:10.3762/bjnano.8.180

• addition to what is easily readable in the UV–vis spectra [14]. The reason for the fine structure of the MCD spectra and hence for the higher sensitivity to the electronic properties lies in the Zeeman splitting of degenerate electronic levels induced by an external magnetic field. In addition to the

Synthesis and catalytic application of magnetic Co–Cu nanowires

• Lijuan Sun,
• Xiaoyu Li,
• Zhiqiang Xu,
• Kenan Xie and
• Li Liao

Beilstein J. Nanotechnol. 2017, 8, 1769–1773, doi:10.3762/bjnano.8.178

• replacement under an external magnetic field. The characterization results confirmed that the as-prepared product was bimetallic Co–Cu nanowires with a desirable linear structure. Additionally, the magnetic hysteresis loop showed that the bimetallic Co–Cu nanowires were paramagnetic, which meant they could be

• difference between the Co–Cu nanowire synthesis with and without application of an external magnetic field. It was very evident that the linear structure of the Co–Cu nanowires prepared without an external magnetic field was undesirable. Moreover, the Co–Cu nanowires prepared without an external magnetic

• emu·g−1, respectively. The appearance of a hysteresis loop demonstrated that the bimetallic Co–Cu nanowires possessed paramagnetism [12]. Therefore, the bimetallic Co–Cu nanowires could be easily separated from the solution by providing an external magnetic field. Figure 5b shows the plots of evolution

Near-infrared-responsive, superparamagnetic Au@Co nanochains

• Varadee Vittur,
• Arati G. Kolhatkar,
• Shreya Shah,
• Irene Rusakova,
• Dmitri Litvinov and
• T. Randall Lee

Beilstein J. Nanotechnol. 2017, 8, 1680–1687, doi:10.3762/bjnano.8.168

• (superparamagnetism) and provide a potentially useful new nanoarchitecture for biomedical or catalytic applications that can benefit from both activation by light and manipulation using an external magnetic field. Keywords: Au@Co; magneto-optical; nanochains; near-IR-active; superparamagnetic; Introduction The

• external magnetic field. Furthermore, the NIR-responsive capability (optical extinction maximum at ca. 900 nm) combined with their magnetic properties can plausibly be harnessed in nanotechnology-based biomedical applications, such as photo-thermally modulated drug delivery, photonic devices, and photo

• nanospheres in contrast to the chain-linked structures obtained using a magnetic stirrer. This control experiment indicates a likely interaction between the magnetic nanoparticles and the external magnetic field produced by the magnetic stirrer during the galvanic replacement reaction. We hypothesize that

Light-induced magnetoresistance in solution-processed planar hybrid devices measured under ambient conditions

• Sreetama Banerjee,
• Daniel Bülz,
• Danny Reuter,
• Karla Hiller,
• Dietrich R. T. Zahn and
• Georgeta Salvan

Beilstein J. Nanotechnol. 2017, 8, 1502–1507, doi:10.3762/bjnano.8.150

• ) designed and developed in this work. Negative magnetoresistance (positive magnetoconductance) was observed for both types of devices similar to the observations in [9]. Magnetoresistance is defined as the change in resistivity of a material/device due to application of an external magnetic field

• . Magnetoconductance (MC) is the change in conductivity of a material/device upon application of an external magnetic field. The magnetoresistance effect, however, was found to degrade over time significantly faster than the photocurrent. We suggest that this degradation is due to incorporation of water molecules from

Spin-chemistry concepts for spintronics scientists

• Konstantin L. Ivanov,
• Alexander Wagenpfahl,
• Carsten Deibel and
• Jörg Matysik

Beilstein J. Nanotechnol. 2017, 8, 1427–1445, doi:10.3762/bjnano.8.143

• a factor of three. In real cases, a quantum mechanical treatment should be used to calculate the conversion efficiency as a function of the external magnetic field strength. Thus, we obtain that the interconversion efficiency is sensitive to external magnetic fields, giving rise to MFEs on chemical

• experiment. For observing MFEs in steady-state experiments, it is necessary to have some “branching”, which makes the overall product yield dependent on the interconversion rate, i.e., on the external magnetic field strength. In the absence of such branching, all radical pairs would eventually recombine

• all field directions in space become completely equivalent. However, in solids the reaction yield and the MFE can depend on the direction of the external magnetic field [91][92][93]. RYDMR One more important member of the family of spin-chemistry techniques is RYDMR [94][95][96][97]. The idea of RYDMR

Characterization of ferrite nanoparticles for preparation of biocomposites

• Urszula Klekotka,
• Magdalena Rogowska,
• Dariusz Satuła and
• Beata Kalska-Szostko

Beilstein J. Nanotechnol. 2017, 8, 1257–1265, doi:10.3762/bjnano.8.127

• , interaction with living cells can be obtained. The use of an external magnetic field quite often helps in removing toxins from healthy cells [13][14] via modified nanoparticles having a sieve-like property. The main aim of this work is to study immobilization effects of biological particles to the selected

• external magnetic field while the size of the particles is a critical parameter. It was observed that superparamagnetic fluctuations are blocked (or not blocked) at RT for nanoparticles with a diameter smaller than the reference magnetite due to elemental substitution. Therefore, at any stage of the

Ultrasmall magnetic field-effect and sign reversal in transistors based on donor/acceptor systems

• Thomas Reichert and
• Tobat P. I. Saragi

Beilstein J. Nanotechnol. 2017, 8, 1104–1114, doi:10.3762/bjnano.8.112

• , which favours the formation of bipolarons. The formation process is spin-sensitive and the number of bipolarons is reduced for an increasing external magnetic field. At low drain voltage, a moderate number of bipolaron species is present and positive magnetoresistance is obtained. For larger Vd values

Tuning the spin coherence time of Cu(II)−(bis)oxamato and Cu(II)−(bis)oxamidato complexes by advanced ESR pulse protocols

• Ruslan Zaripov,
• Evgeniya Vavilova,
• Iskander Khairuzhdinov,
• Kev Salikhov,
• Violeta Voronkova,
• Mohammad A. Abdulmalic,
• Francois E. Meva,
• Saddam Weheabby,
• Tobias Rüffer,
• Bernd Büchner and
• Vladislav Kataev

Beilstein J. Nanotechnol. 2017, 8, 943–955, doi:10.3762/bjnano.8.96

• in fused quartz has been made. The shift of the ESR resonance frequency can be written in the form Δω = ∑AkMk, where Ak and Mk are the HF constant and the projection of the k-th nuclear spin on the direction of the external magnetic field. For a number of reasons the projection Mk can stochastically

Synthesis of graphene–transition metal oxide hybrid nanoparticles and their application in various fields

• Arpita Jana,
• Elke Scheer and
• Sebastian Polarz

Beilstein J. Nanotechnol. 2017, 8, 688–714, doi:10.3762/bjnano.8.74

Intercalation and structural aspects of macroRAFT agents into MgAl layered double hydroxides

• Dessislava Kostadinova,
• Ana Cenacchi Pereira,
• Muriel Lansalot,
• Franck D’Agosto,
• Elodie Bourgeat-Lami,
• Fabrice Leroux,
• Christine Taviot-Guého,
• Sylvian Cadars and
• Vanessa Prevot

Beilstein J. Nanotechnol. 2016, 7, 2000–2012, doi:10.3762/bjnano.7.191

• ., almost exclusively those of the LDH hydroxyl groups. In a last step, the obtained 1H magnetization is stored parallel to the external magnetic field axis for a time τM to allow this magnetization to diffuse among abundant 1H nuclei within both the LDH host and the (co)polymer guest. This process occurs

Ferromagnetic behaviour of ZnO: the role of grain boundaries

• Boris B. Straumal,
• Svetlana G. Protasova,
• Andrei A. Mazilkin,
• Eberhard Goering,
• Gisela Schütz,
• Petr B. Straumal and
• Brigitte Baretzky

Beilstein J. Nanotechnol. 2016, 7, 1936–1947, doi:10.3762/bjnano.7.185

• SQUID interferometer (Quantum Design MPMS-7 and MPMS-XL) in the external magnetic field applied parallel to the sample plane. The diamagnetic signal from a sample holder and a substrate was accurately subtracted from the magnetization curves. In Figure 3 the magnetization curves are plotted for pure ZnO

• method. Magnetization Js (in units of 10−3 µB/f.u.) as a function of the applied external magnetic field for pure zinc oxide films and zinc oxide films doped with 0.1 and 10 atom % Mn at room temperature. Reproduced with permission from [7], copyright 2009 American Physical Society. Dependence of

Thickness-modulated tungsten–carbon superconducting nanostructures grown by focused ion beam induced deposition for vortex pinning up to high magnetic fields

• Ismael García Serrano,
• Javier Sesé,
• Isabel Guillamón,
• Hermann Suderow,
• Sebastián Vieira,
• Manuel Ricardo Ibarra and
• José María De Teresa

Beilstein J. Nanotechnol. 2016, 7, 1698–1708, doi:10.3762/bjnano.7.162

• Physical Properties Measurement System (PPMS) from Quantum Design. In the following, it is assumed that in our range of measurements the magnetic induction inside the sample, B, is equal to μ0H, with μ0 being the vacuum permeability and H being the external magnetic field. At the magnetic fields and

Microwave synthesis of high-quality and uniform 4 nm ZnFe₂O₄ nanocrystals for application in energy storage and nanomagnetics

• Christian Suchomski,
• Ben Breitung,
• Ralf Witte,
• Michael Knapp,
• Sondes Bauer,
• Tilo Baumbach,
• Christian Reitz and
• Torsten Brezesinski

Beilstein J. Nanotechnol. 2016, 7, 1350–1360, doi:10.3762/bjnano.7.126

• and without an external magnetic field. Table 1 summarizes the fitted parameters, which agree with the ratio of tetrahedral to octahedral Fe in the partially inverted spinel structure from XPS. In addition, Figure 4 confirms that all Fe ions are in the Fe(III) state. This is also corroborated by the

Multiwalled carbon nanotube hybrids as MRI contrast agents

• Nikodem Kuźnik and
• Mateusz M. Tomczyk

Beilstein J. Nanotechnol. 2016, 7, 1086–1103, doi:10.3762/bjnano.7.102

• its abundance and very strong signals in NMR. For this reason, further consideration will focus on this nuclide. In a high external magnetic field B0 the nuclear spins orient along field lines. Slightly more than half of the vectors are directed along the field, while the rest are directed in the

Signal enhancement in cantilever magnetometry based on a co-resonantly coupled sensor

• Julia Körner,
• Christopher F. Reiche,
• Thomas Gemming,
• Bernd Büchner,
• Gerald Gerlach and
• Thomas Mühl

Beilstein J. Nanotechnol. 2016, 7, 1033–1043, doi:10.3762/bjnano.7.96

• external magnetic field is applied to the setup, the magnetic interaction of the sample with the field alters the resonance frequency of the cantilever by creating a torque [3]. The resulting frequency shift can be used as measurement signal to derive information on the properties of the sample. In most

• frequency of the cantilever. The magnetic interaction between sample and external magnetic field acts as the additional spring constant Δk, altering the resonance frequency of the cantilever. The frequency shift Δf induced by these interactions can be derived from Equation 1 as: In the case of cantilever

• magnetometry, Δk does not only depend on the interaction of the magnetic moment m of the sample with the external magnetic field H but also on the effective length of the cantilever Leff [6][7]. Furthermore, by assuming a simple Stoner–Wohlfarth single domain particle, the magnetic interaction is related to

Synthesis of cobalt nanowires in aqueous solution under an external magnetic field

• Xiaoyu Li,
• Lijuan Sun,
• Hu Wang,
• Kenan Xie,
• Qin Long,
• Xuefei Lai and
• Li Liao

Beilstein J. Nanotechnol. 2016, 7, 990–994, doi:10.3762/bjnano.7.91

• pressures, cobalt nanowires were synthesized by chemical reduction in aqueous solution with the assistance of polyvinylpyrrolidone (PVP) as surfactant under moderate conditions for the first time, while an external magnetic field of 40 mT was applied. Uniform linear cobalt nanowires with relatively smooth

• surfaces and firm structure were obtained and possessed an average diameter of about 100 nm with a coating layer of PVP. By comparison, the external magnetic field and PVP were proven to have a crucial influence on the morphology and the size of the synthesized cobalt nanowires. The prepared cobalt

• . Keywords: aqueous solution; cobalt nanowires; external magnetic field; magnetic properties; surfactant; Findings In recent years, cobalt nanowires, as a ferromagnetic material, have attracted considerable attention due to their outstanding magnetic properties and excellent performance in applications in

Thickness dependence of the triplet spin-valve effect in superconductor–ferromagnet–ferromagnet heterostructures

• Daniel Lenk,
• Vladimir I. Zdravkov,
• Jan-Michael Kehrle,
• Günter Obermeier,
• Aladin Ullrich,
• Roman Morari,
• Hans-Albrecht Krug von Nidda,
• Claus Müller,
• Mikhail Yu. Kupriyanov,
• Anatolie S. Sidorenko,
• Siegfried Horn,
• Rafael G. Deminov,
• Lenar R. Tagirov and
• Reinhard Tidecks

Beilstein J. Nanotechnol. 2016, 7, 957–969, doi:10.3762/bjnano.7.88

• applying an external magnetic field parallel to the layers of the heterostructure and exploiting the intrinsic perpendicular easy-axis of the magnetization of the Cu41Ni59 thin film in conjunction with the exchange bias between CoOx and Co. The magnetic configurations are confirmed by superconducting

• superconductor. We should remark, that strictly obeying the definition of Tc0, it can not be defined for the heterostructures of the present work, because magnetic material is present. Here it is used to identify the transition temperature in zero external magnetic field. For a two-dimensional and a three

• ) indicate the values of α for a two and a three-dimensional superconductor according to the GL-theory, respectively. Superconducting transition temperature, Tc0, in zero external magnetic field as a function of the F1 = Cu41Ni59 layer thickness dF1 = dCuNi. While the solid squares in (a) show experimental

Hemolysin coregulated protein 1 as a molecular gluing unit for the assembly of nanoparticle hybrid structures

• Tuan Anh Pham,
• Andreas Schreiber,
• Elena V. Sturm (née Rosseeva),
• Stefan Schiller and
• Helmut Cölfen

Beilstein J. Nanotechnol. 2016, 7, 351–363, doi:10.3762/bjnano.7.32

• conducted under an external magnetic field. After lyophilization of the reaction mixture, fiber-like structures in the micrometer range are obtained. The TEM investigation demonstrates networked structures of Fe3O4 and CoFe2O4 NPs. The magnetic measurements reveal a superparamagnetic character for the Fe3O4

• Information File 1. The water-dispersible, mercaptosuccinic acid stabilized Fe3O4 NP solution was aligned in an external magnetic field parallel to the sample. After the protein addition, Hcp1_cys3 interconnected the NPs, which results in a fibrous bio-hybrid structure. In Figure 8, SEM with EDX analysis and

• TEM images (Figure S5, Supporting Information File 1). These results indicate that the prealignment of Fe3O4 NPs in an external magnetic field is essential for the linear arrangement of the NPs chain formation. On the other hand, TEM investigations of the hybrid material show a network of magnetite

Simultaneous cancer control and diagnosis with magnetic nanohybrid materials

• Reza Saadat and
• Franz Renz

Beilstein J. Nanotechnol. 2016, 7, 121–125, doi:10.3762/bjnano.7.14

• -analogue Ga-DOTA (DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) complexes were synthesized and linked to Fe3O4 MNP. In this manner it is possible to transport the PET tracer with an external magnetic field right to the target location. The functionalized MNP are linked to each other via

Controlled graphene oxide assembly on silver nanocube monolayers for SERS detection: dependence on nanocube packing procedure

• Martina Banchelli,
• Bruno Tiribilli,
• Roberto Pini,
• Luigi Dei,
• Paolo Matteini and
• Gabriella Caminati

Beilstein J. Nanotechnol. 2016, 7, 9–21, doi:10.3762/bjnano.7.2

• [16] whereas more recently external magnetic field were employed to dynamically control the interparticle spacing of a nanoparticle monolayer at the hexane/water interface [17]; however, the fabrication of controllable hot spots still remains a remarkable challenge. The outstanding SERS capability of

Effects of spin–orbit coupling and many-body correlations in STM transport through copper phthalocyanine

• Benjamin Siegert,
• Andrea Donarini and
• Milena Grifoni

Beilstein J. Nanotechnol. 2015, 6, 2452–2462, doi:10.3762/bjnano.6.254

• the substrate). This quantum dot configuration should be favourable to experimentally probe SOI splittings and magnetic anisotropies when an external magnetic field is applied to the system, in analogy to the experiments in [6]. Indeed, we demonstrate that experimentally resolvable SOI splitting