Self-assembly mechanism of Ni nanowires prepared with an external magnetic field

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

Beilstein J. Nanotechnol. 2015, 6, 2123–2128, doi:10.3762/bjnano.6.217

• magnetic field. Keywords: chemical reduction; external magnetic field; Ni nanoparticles; Ni nanowires; self-assembly mechanism; Introduction For the past decades, ferromagnetic (e.g., Fe, Co, Ni) nanowires have raised considerable attention due to their application prospects in magnetic, optoelectronic

• as preparing and removing the templates are required for this method. Recently, a self-assembly method employing a magnetic field to prepare ferromagnetic nanowires has been extensively studied because of its simplicity and effectiveness. For example, Wang et al. [13][14] synthesized nickel and

Paramagnetism of cobalt-doped ZnO nanoparticles obtained by microwave solvothermal synthesis

• Jacek Wojnarowicz,
• Sylwia Kusnieruk,
• Tadeusz Chudoba,
• Stanislaw Gierlotka,
• Witold Lojkowski,
• Wojciech Knoff,
• Malgorzata I. Lukasiewicz,
• Bartlomiej S. Witkowski,
• Anna Wolska,
• Marcin T. Klepka,
• Tomasz Story and
• Marek Godlewski

Beilstein J. Nanotechnol. 2015, 6, 1957–1969, doi:10.3762/bjnano.6.200

• as-synthesized samples displayed paramagnetic properties with a contribution of anti-ferromagnetic coupling of Co–Co pairs. After annealing in synthetic air, the samples remained paramagnetic and samples annealed under nitrogen flow showed a magnetic response under the influences of a magnetic field

• wide application of Zn1−xCoxO in spintronics, a ferromagnetic response (FM) at room temperature (RT) is required. This was theoretically predicted [34][35] and there are claims of experimental confirmation of these predictions [40][41][42]. However, there were also a number of observations

• ferromagnetic and paramagnetic properties [46][47]. Using hydrothermal [32][48] and sol–gel [49][50] synthesis methods, Co-doped ZnO with both ferromagnetic and paramagnetic properties was obtained [39][41][42]. These observations questioned the possibility of producing powders with controllable properties

A facile method for the preparation of bifunctional Mn:ZnS/ZnS/Fe₃O₄ magnetic and fluorescent nanocrystals

• Houcine Labiadh,
• Tahar Ben Chaabane,
• Romain Sibille,
• Lavinia Balan and
• Raphaël Schneider

Beilstein J. Nanotechnol. 2015, 6, 1743–1751, doi:10.3762/bjnano.6.178

• could be related to the quantum confinement effects of nanocrystals and to the diamagnetic contribution of the ZnS core. At 2 K, all bifunctional nanoparticles exhibited hysteresis with remnance magnetization, MR, at 9 T and coercivity, HC, indicating a dominant ferromagnetic nature of the iron oxide

• blocking temperature (TB) of the sample. The result of the ZFC and FC measurements confirmed the superparamagnetic behavior of the nanocrystals [36]. Below the blocking temperature, the material is ferromagnetic, and above TB, it is superparamagnetic [33]. The values for the TB are given in Table 2. TB

Radiation losses in the microwave K_u band in magneto-electric nanocomposites

• Talwinder Kaur,
• Sachin Kumar,
• Jyoti Sharma and
• A. K. Srivastava

Beilstein J. Nanotechnol. 2015, 6, 1700–1707, doi:10.3762/bjnano.6.173

• interaction causes anti-ferromagnetic coupling at interstitial sites of Fe3+ cations in BaM. These cations then show ferromagnetic resonance, which causes symmetric resonance absorption with line width ∆H. Two peaks that are associated with Fe3+ ions at tetrahedral and octahedral positions of hexaferrite

• imaginary part of permeability contributes more to the losses because of the occurrence of ferromagnetic resonance. The higher permeability values cause a shift of the ferromagnetic resonance frequency [42][43]. The matrix of conducting polyaniline and hexaferrite contributes to the dielectric losses (ε

Structural and magnetic properties of iron nanowires and iron nanoparticles fabricated through a reduction reaction

• Marcin Krajewski,
• Wei Syuan Lin,
• Hong Ming Lin,
• Katarzyna Brzozka,
• Sabina Lewinska,
• Natalia Nedelko,
• Anna Slawska-Waniewska,
• Jolanta Borysiuk and
• Dariusz Wasik

Beilstein J. Nanotechnol. 2015, 6, 1652–1660, doi:10.3762/bjnano.6.167

• transformations of iron oxides have a greater impact on the decrease of magnetization in the case of iron nanoparticles. It is related to the fact that Fe NPs have a larger surface area exposed to the atmosphere than Fe NWs. The ferromagnetic–paramagnetic transition was not measured directly because the applied

• ][15] and have become paramagnetic at temperatures lower than ferromagnetic-paramagnetic transition of α-Fe. On the other hand, it is worth noting that the measurements of magnetization as a function of the temperature confirm that even though both fabricated nanomaterials change their structures

• temperature of bulk crystalline iron. This can be mainly related to the interactions between the iron cores and the paramagnetic iron oxide phases, which have been formed during the oxidation reaction and have become paramagnetic at temperatures lower than ferromagnetic–paramagnetic transition of pure iron

Formation of pure Cu nanocrystals upon post-growth annealing of Cu–C material obtained from focused electron beam induced deposition: comparison of different methods

• Aleksandra Szkudlarek,
• Alfredo Rodrigues Vaz,
• Yucheng Zhang,
• Andrzej Rudkowski,
• Czesław Kapusta,
• Rolf Erni,
• Stanislav Moshkalev and
• Ivo Utke

Beilstein J. Nanotechnol. 2015, 6, 1508–1517, doi:10.3762/bjnano.6.156

• ], thermal sensors [8], photodetectors [9], and mode stabilizers for vertical surface emitting lasers [10]. Other deposits were used as ferromagnetic wires [11][12], superconducting wires [13], plasmonic structures [14], or as electrode nanocontacts [15][16]. The feasibility of obtaining 3D nanostructures

Influence of the shape and surface oxidation in the magnetization reversal of thin iron nanowires grown by focused electron beam induced deposition

• Luis A. Rodríguez,
• Lorenz Deen,
• Rosa Córdoba,
• César Magén,
• Etienne Snoeck,
• Bert Koopmans and
• José M. De Teresa

Beilstein J. Nanotechnol. 2015, 6, 1319–1331, doi:10.3762/bjnano.6.136

• %, thus giving a high ferromagnetic signal. Magneto-optical Kerr characterization indicates that HC decreases for increasing thickness and width, providing a route to control the magnetization reversal field through the modification of the nanowire dimensions. Transmission electron microscopy experiments

• valve in the GIS and had to be optimized in order to obtain deposits exhibiting ferromagnetic properties with suitable shape anisotropy. In these experiments, the nominal turbopump speed is 260 L/s for nitrogen gas. When the leak valve is opened, the chamber pressure increases. The chamber pressure is

• oxidized surface is not ferromagnetic, which affects the overall magnetization reversal of the wires. The oxidized layer will have a strong impact on the thinner part of the wires, i.e., the tails and halo, which will be prone to lose the ferromagnetism. As a consequence, the effective ferromagnetic volume

Magnetic properties of iron cluster/chromium matrix nanocomposites

• Arne Fischer,
• Robert Kruk,
• Di Wang and
• Horst Hahn

Beilstein J. Nanotechnol. 2015, 6, 1158–1163, doi:10.3762/bjnano.6.117

• characterization of structure and magnetic performance. Relevant magnetic characteristics, reflecting the ferromagnetic/antiferromagnetic coupling between Fe clusters and the Cr matrix, i.e., blocking temperature, coercivity field, and exchange bias were measured and their dependence on cluster size and cluster

• experiments with Fe/Ag was to study the characteristics of the embedded Fe clusters. Since Ag is diamagnetic no noteworthy magnetic interaction takes place between matrix and the ferromagnetic clusters and it was possible to gain information about, e.g., the size of the embedded clusters via magnetic

• measurements. The intention of the present work is to go one step further to a more complex cluster/matrix system and to substitute the passive Ag matrix with a functional one, e.g., antiferromagnetic (AFM) Cr, leading to additional effects: At the interface between the ferromagnetic (FM) and the

Tunable magnetism on the lateral mesoscale by post-processing of Co/Pt heterostructures

• Oleksandr V. Dobrovolskiy,
• Maksym Kompaniiets,
• Roland Sachser,
• Fabrizio Porrati,
• Christian Gspan,
• Harald Plank and
• Michael Huth

Beilstein J. Nanotechnol. 2015, 6, 1082–1090, doi:10.3762/bjnano.6.109

• magnetic properties of Co to the hard ferromagnetic response of the CoPt L10 phase, whose presence has been revealed by transmission electron microscopy. Experimental Preparations and geometry Co and Pt growth, processing and imaging experiments were carried out in a dual-beam high-resolution scanning

• Hs amounts to 1.3 T. Even though samples B and C demonstrate a hysteresis loop, we note that it is not completely open and the overall behavior of the Hall voltage curves is suggestive of a superposition of a soft and hard ferromagnetic response. We attribute these contributions to different phases

• tuned from the soft-magnetic properties of Co to the hard ferromagnetic response of the CoPt L10 phase. The reported approach is relevant for basic research in micro-magnetism and spin-dependent transport, as well as for various applications. Preparation and post-processing of the samples investigated

Interaction of electromagnetic radiation in the 20–200 GHz frequency range with arrays of carbon nanotubes with ferromagnetic nanoparticles

• Agylych Atdayev,
• Alexander L. Danilyuk and
• Serghej L. Prischepa

Beilstein J. Nanotechnol. 2015, 6, 1056–1064, doi:10.3762/bjnano.6.106

• (CNT) is considered within the model of distributed random nanoparticles with a core–shell morphology. The approach is based on a system composed of a CNT conducting resistive matrix, ferromagnetic inductive nanoparticles and the capacitive interface between the CNT matrix and the nanoparticles, which

• and transmission of electromagnetic radiation. Keywords: carbon nanotubes; electromagnetic radiation; ferromagnetic nanoparticles; magnetic dipole; magnetic nanocomposite; resonance circuit; Introduction Magnetic nanocomposites consisting of ferromagnetic nanoparticles embedded into a matrix

• material are currently the subject of intensive study. The properties of such materials can be tuned by the external magnetic field, spin-polarized current or electromagnetic radiation. In conventional ferromagnetic materials, the magnetic properties are determined by the domain structure and domain walls

Magnetic properties of self-organized Co dimer nanolines on Si/Ag(110)

• Lisa Michez,
• Kai Chen,
• Fabien Cheynis,
• Frédéric Leroy,
• Alain Ranguis,
• Haik Jamgotchian,
• Margrit Hanbücken and
• Laurence Masson

Beilstein J. Nanotechnol. 2015, 6, 777–784, doi:10.3762/bjnano.6.80

• Co layer exhibits an enhanced magnetization, strongly suggesting a ferromagnetic ordering with an in-plane easy axis of magnetization, which is perpendicular to the Co nanolines. Keywords: nanomagnetism; one-dimensional nanostructures; scanning tunneling microscopy (STM); self-organization; X-ray

• magnetization, strongly suggesting a ferromagnetic ordering with an in-plane easy axis of magnetization, perpendicular to the Co nanolines. Results and Discussion Self-organized growth of Si nanoribbons on Ag(110) Depending on the temperature of the silver substrate (Tsub) during Si deposition, different

• in the first layer of the 2 MLCo film, the moments of the Co atoms in the second layer can be estimated as µS = 1.66 ∙ µB and µL = 0.20 ∙ µB. These values, which are close to those of the bulk material (µS = 1.55 ∙ µB and µL = 0.153 ∙ µB) [35], strongly suggest a ferromagnetic ordering. This

A scanning probe microscope for magnetoresistive cantilevers utilizing a nested scanner design for large-area scans

• Tobias Meier,
• Alexander Förste,
• Ali Tavassolizadeh,
• Karsten Rott,
• Dirk Meyners,
• Roland Gröger,
• Günter Reiss,
• Eckhard Quandt,
• Thomas Schimmel and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2015, 6, 451–461, doi:10.3762/bjnano.6.46

• junction consists of two ferromagnetic CoFeB-electrodes separated by a thin dielectric MgO layer, which acts like a spin-valve. The electrical conductance of the magnetic tunnel junction, therefore, strongly depends on the orientation of the magnetization of the electrodes towards each other. When

• applied stress. In this way the TMR sensor is sensitive to both compressive and tensile stress what is required for essentially all modes of AFM. Assuming single domain behavior of the two ferromagnetic layers, the conductance of the TMR junction is depending on the angle α between the magnetizations of

Multifunctional layered magnetic composites

• Maria Siglreitmeier,
• Baohu Wu,
• Tina Kollmann,
• Martin Neubauer,
• Gergely Nagy,
• Dietmar Schwahn,
• Vitaliy Pipich,
• Damien Faivre,
• Dirk Zahn,
• Andreas Fery and
• Helmut Cölfen

Beilstein J. Nanotechnol. 2015, 6, 134–148, doi:10.3762/bjnano.6.13

• and three protein contacts, whereby one carbonyl oxygen atom binds over 2.9 Å and two hydroxy oxygens over 3.1 Å. Force vs deformation characteristic of pure gelatin and gelatin with ferromagnetic particles. Introduction of nanoparticles leads to a significant increase of the stiffness of the material

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

• TbPc2/Co heterojunction was already proposed to serve as a model system for a SMM semiconducting layer on top of a ferromagnetic electrode for a future spintronic device. The chemical and magnetic properties of this interface were investigated by Klar et al. and it was found that the magnetic moment of

Quasi-1D physics in metal-organic frameworks: MIL-47(V) from first principles

• Danny E. P. Vanpoucke,
• Jan W. Jaeken,
• Stijn De Baerdemacker,
• Kurt Lejaeghere and
• Veronique Van Speybroeck

Beilstein J. Nanotechnol. 2014, 5, 1738–1748, doi:10.3762/bjnano.5.184

• pressure of the pressure-induced large-pore-to-narrow-pore phase transition is calculated to be 82 MPa and 124 MPa for systems with ferromagnetic and antiferromagnetic chains, respectively. For a mixed system, the transition pressure is found to be a weighted average of the ferromagnetic and

• metal centers, and found quasi-1D ferromagnetic behavior with quenched antiferromagnetic inter-chain interactions. Stroppa et al. [40] and Wang et al. [41] investigated Cu-based MOFs with an ABX3 perovskite architecture and found these to exhibit quasi-1D multiferroic behavior. In both cases, Jahn

• . This leads to 24 possible spin configurations of which five are inequivalent (cf. Figure 2): (FM) ferromagnetic for both inter- and intra-chain spin alignment; (SFM) semi-ferromagnetic, containing one ferromagnetic and one antiferromagnetic chain; (AF1) although globally antiferromagnetic, this system

On the structure of grain/interphase boundaries and interfaces

• K. Anantha Padmanabhan and
• Herbert Gleiter

Beilstein J. Nanotechnol. 2014, 5, 1603–1615, doi:10.3762/bjnano.5.172

• state. This point of view is also in agreement with the observation that the interfaces in certain nano-glasses (e.g., Fe90Sc10) are ferromagnetic, whereas the corresponding melt-quenched Fe90Sc10 glass is paramagnetic at the same temperatures. Moreover, radial distribution measurements have revealed

• -quenching temperatures. This can explain the lower density of the nano-glasses. In a recent study [16], it has been shown that lattice expansion or amorphization makes EuTiO3 ferromagnetic, although the stable phase of crystalline EuTiO3 is antiferromagnetic. Ferromagnetism increases with an increase in the

• lattice volume of EuTiO3. Amorphization also has a similar effect on ferromagnetism. This observation has been explained in terms of competition between ferromagnetic and antiferromagnetic interactions among the Eu2+ ions. Similar ideas could also be relevant in understanding the development of

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

• 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

• antiferromagnetic coupling between nanomagnets. Ferromagnetic coupling invariably leads to magnetization hysteresis profiles that depict parallel magnetizations of equal magnitude and direction for all the constituent nanomagnets. In artificial superlattice structures the thickness of the interlayer is manipulated

• –1.5 nm between CoFeB nanomagnets has the consequence of generating an antiferromagnetic coupling, whereas with a larger thickness ferromagnetic coupling will ensue [9]. We investigate the changes in the hysteresis profiles that become apparent in systems of antiferromagnetically coupled nanomagnets

Enhancement of photocatalytic H₂ evolution of eosin Y-sensitized reduced graphene oxide through a simple photoreaction

• Weiying Zhang,
• Yuexiang Li,
• Shaoqin Peng and
• Xiang Cai

Beilstein J. Nanotechnol. 2014, 5, 801–811, doi:10.3762/bjnano.5.92

• holes occur in the RGO24 sheet (Figure 9B), which is consistent with the model shown in Scheme 1. The model is similar to the one reported in [51]. The ferromagnetic properties [51] of RGO obtained by a photoreaction and its paramagnetic resonance (EPR) spectra [38] indicate that there are some radicals

Towards precise defect control in layered oxide structures by using oxide molecular beam epitaxy

• Federico Baiutti,
• Georg Christiani and
• Gennady Logvenov

Beilstein J. Nanotechnol. 2014, 5, 596–602, doi:10.3762/bjnano.5.70

• . Bhattacharya et al. to tailor the magnetic exchange interaction in LaMnO3–SrMnO3 [20], where magnetic properties of these superlattices were tuned between ferromagnetic and antiferromagnetic metallic states by inserting extra single-unit-cell layers of LaMnO3 and SrMnO3, respectively. The ALL-oxide MBE at the

Plasma-assisted synthesis and high-resolution characterization of anisotropic elemental and bimetallic core–shell magnetic nanoparticles

• M. Hennes,
• A. Lotnyk and
• S. G. Mayr

Beilstein J. Nanotechnol. 2014, 5, 466–475, doi:10.3762/bjnano.5.54

• [4]. Unfortunately, many ferromagnetic materials are prone to strong oxidation (thereby losing their magnetic properties over time) and turn out to be highly cytotoxic, a knock-out criterion for any application in life sciences. The synthesis of well designed nanoalloys [5], combining two and more

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

• be used as high surface area electrodes. Apart from this, the ‘bamboo’-like N-CNTs obtained here could provide a new opening in drug delivery systems due to their rigid ‘needle-like’ morphology. These N-CNTs with a high content of ferromagnetic nanoparticles could potentially serve as magnetically

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

• obtained by using ferromagnetic and normal-metal detectors, we discriminate charge and spin degrees of freedom. We observe spin injection and long-range transport of pure, chargeless spin currents in the regime of large Zeeman splitting. We elucidate charge and spin transport by comparison to theoretical

• measurement scheme. A central superconducting aluminum wire is contacted by several normal-metal (copper) or ferromagnetic (iron) electrodes attached via thin tunnel barriers. A dc bias voltage Vinj with a small superimposed low-frequency ac excitation is applied to one junction (injector), and the resulting

• different contact distances d, and different material combinations, for which both injector and detector could be either normal (N) or ferromagnetic (F). These configurations will be labeled by AISIB, where A and B denote the injector and detector contacts, respectively. Two examples (NISIN and NISIF) are

Photovoltaic properties of ZnO nanorods/p-type Si heterojunction structures

• Rafal Pietruszka,
• Bartlomiej S. Witkowski,
• Grzegorz Luka,
• Lukasz Wachnicki,
• Sylwia Gieraltowska,
• Krzysztof Kopalko,
• Eunika Zielony,
• Piotr Bieganski,
• Ewa Placzek-Popko and
• Marek Godlewski

Beilstein J. Nanotechnol. 2014, 5, 173–179, doi:10.3762/bjnano.5.17

• ][13][14]. ZnO has a 3.37 eV direct band gap at room temperature [15] and a high excitation binding energy of 60 meV. It is intensively studied for light emitters in the near-UV region of the spectrum [16][17], or for spintronic applications [18][19][20], since ferromagnetic thin films of ZnO can be

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

• and then increases sharply to reach a maximum of 33.00 cm3·K·mol−1 at 1.8 K, which may be because of an intramolecular ferromagnetic interaction. If the Fe–Fe (Fe(1)–Fe(2) and Fe(3)–Fe(4)) interaction is antiferromagnetic and the Fe–Dy exchange interaction is negligible, then the only ferromagnetic

Nanoglasses: a new kind of noncrystalline materials

• Herbert Gleiter

Beilstein J. Nanotechnol. 2013, 4, 517–533, doi:10.3762/bjnano.4.61

• . More recent examples are light weight metals (e.g., Al), semiconductors (e.g., Si), materials with high strength (e.g., steels), superconductors, ferroelectrics, special ferromagnetic materials etc. The main reason for the preference of crystalline materials is the fact that one can control their

• spectrum of the ribbon or of the isolated Fe90Sc10 nanometer-sized clusters and (2) a ferromagnetic component (six-line subspectrum: red curve in Figure 12). As the ferromagnetism at ambient temperature is observed only if the Fe90Sc10 nanospheres are compacted (Figure 12), one is led to conclude that it

• paramagnetic at this temperature, in agreement with the results reported in the literature [41][42]. In contrast, the magnetization curve of the Fe90Sc10 nanoglass indicates that it is ferromagnetic and it exhibits an average magnetization of about 1.05 μB per Fe atom. According to the Mössbauer spectrum of