Size limits of magnetic-domain engineering in continuous in-plane exchange-bias prototype films

• Alexander Gaul,
• Daniel Emmrich,
• Timo Ueltzhöffer,
• Henning Huckfeldt,
• Hatice Doğanay,
• Johanna Hackl,
• Muhammad Imtiaz Khan,
• Daniel M. Gottlob,
• Gregor Hartmann,
• André Beyer,
• Dennis Holzinger,
• Slavomír Nemšák,
• Claus M. Schneider,
• Armin Gölzhäuser,
• Günter Reiss and
• Arno Ehresmann

Beilstein J. Nanotechnol. 2018, 9, 2968–2979, doi:10.3762/bjnano.9.276

• the domain wall width has been investigated as a function of the angle between unidirectional anisotropy and domain wall. By shrinking the domain size of periodic domain stripes, we analyzed the influence of domain wall overlap on the domain stability. Finally, by changing the geometry of artificial

• engineering in an in-plane exchange-bias thin film as a prototypical system. For two-dimensional domains the limit depends on the domain geometry. The relative orientation between domain wall and anisotropy axes is a crucial parameter and therefore influences the achievable minimum domain size dramatically

• ) width, varying with material-specific magnetic parameters, but could not be tested yet. For exchange-bias material systems with in-plane anisotropy, typical DW widths are of the order of several hundreds of nanometers [16] to some micrometers [31]. A patterning method with lateral resolution

The effect of flexible joint-like elements on the adhesive performance of nature-inspired bent mushroom-like fibers

• Elliot Geikowsky,
• Serdar Gorumlu and
• Burak Aksak

Beilstein J. Nanotechnol. 2018, 9, 2893–2905, doi:10.3762/bjnano.9.268

• performance both theoretically and experimentally [13][14][15][16][17][18][19][20][21][22]. Murphy et al. [16] obtained a similar anisotropy ratio in shear to the gecko setae and observed adhesive engagement only when the fibers were moved in the same direction as the tilt angle. They observed that the angle

• aspect of natural curved/tilted fibers is the directional dependence of adhesion and shear. Similar anisotropy can be observed for the samples tested in this work as well (see Figure 6). All the samples exhibit higher shear forces in the gripping than in the releasing direction, the discrepancy being

• magnitude of the response in shear of soft joint fibers suggests that shear force in the gripping direction is approximately twice as high in the releasing direction, providing an anisotropy ratio of 2:1 at the highest applied preload. This ratio is marginally higher for very soft joint fibers. The highest

Magnetic and luminescent coordination networks based on imidazolium salts and lanthanides for sensitive ratiometric thermometry

• Pierre Farger,
• Cédric Leuvrey,
• Mathieu Gallart,
• Pierre Gilliot,
• Guillaume Rogez,
• João Rocha,
• Duarte Ananias,
• Pierre Rabu and
• Emilie Delahaye

Beilstein J. Nanotechnol. 2018, 9, 2775–2787, doi:10.3762/bjnano.9.259

• networks, the luminescent properties can be used to synthesize temperature probes with possible applications in the aerospace area, safety and health [17][18]. Beside luminescent properties, lanthanide ions exhibit large magnetic moment and strong magnetic anisotropy, which might have potential

Oriented zinc oxide nanorods: A novel saturable absorber for lasers in the near-infrared

• Pavel Loiko,
• Tanujjal Bora,
• Josep Maria Serres,
• Haohai Yu,
• Magdalena Aguiló,
• Francesc Díaz,
• Uwe Griebner,
• Valentin Petrov,
• Xavier Mateos and
• Joydeep Dutta

Beilstein J. Nanotechnol. 2018, 9, 2730–2740, doi:10.3762/bjnano.9.255

• a fiber-coupled laser diode (an InGaAs one, emitting at ≈0.978 µm, for the Yb laser, and an AlGaAs one, emitting at ≈0.802 µm, for the Tm laser). The polarization of the laser emission was linear, E || Nm, naturally selected by the anisotropy of the gain. More details about the laser set-up can be

Size-selected Fe₃O₄–Au hybrid nanoparticles for improved magnetism-based theranostics

• Maria V. Efremova,
• Yulia A. Nalench,
• Eirini Myrovali,
• Anastasiia S. Garanina,
• Ivan S. Grebennikov,
• Polina K. Gifer,
• Maxim A. Abakumov,
• Marina Spasova,
• Makis Angelakeris,
• Alexander G. Savchenko,
• Michael Farle,
• Natalia L. Klyachko,
• Alexander G. Majouga and
• Ulf Wiedwald

Beilstein J. Nanotechnol. 2018, 9, 2684–2699, doi:10.3762/bjnano.9.251

• -crystalline anisotropy and the saturation magnetization MS as well as on the shape and morphology [37][38][39]. We thus expect that except for sample MNP-44 all magnetite hybrid samples are single domain. The MS (Table 3) is measured at large fields by extrapolation of a linear fit to the ordinate. The MS

• (Table 2). The temperature dependence of the coercive field HC(T) allows us to estimate the effective magnetic anisotropy energy density Keff (Table 3) by using Sharrock’s equation for single domain, randomly oriented, non-interacting NPs [47][48][49]: Random orientation and single domain properties are

• Keff values while the uncertainty intervals have been estimated based on the volume distributions. We obtain 11 ± 7 kJ·m−3 and 10 ± 6 kJ·m−3 for MNP-15 and MNP-25, respectively. These values are in reasonable agreement with the first order anisotropy constant of bulk Fe3O4 K1 = 13 kJ·m−3 [37]. For MNP

Characterization of the microscopic tribological properties of sandfish (Scincus scincus) scales by atomic force microscopy

• Weibin Wu,
• Christian Lutz,
• Simon Mersch,
• Richard Thelen,
• Christian Greiner,
• Guillaume Gomard and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2018, 9, 2618–2627, doi:10.3762/bjnano.9.243

• corresponding averaged friction. In this way, we average between forward and backward friction and neglect the anisotropy of friction due to the comb-like structure [24]. Three different positons on each sample were recorded and the averaged frictional force (data points in Figure 6) and the corresponding

Friction reduction through biologically inspired scale-like laser surface textures

• Johannes Schneider,
• Vergil Djamiykov and
• Christian Greiner

Beilstein J. Nanotechnol. 2018, 9, 2561–2572, doi:10.3762/bjnano.9.238

• convincingly demonstrated frictional anisotropy and a maximum friction reduction of about 50% with biologically inspired surfaces [22]. These investigations relied on a two-step moulding technique for manufacturing scale-like structures and therefore focused on the frictional properties of polymeric samples

• , Supporting Information File 1 for an optical micrograph of a PEEK disc after a dry sliding experiment. As described above, only very limited wear was observed, even though not specifically quantified. When comparing with the literature, it becomes apparent that frictional anisotropy of the laser-generated

• scale-like surface textures needs to be tested in the future. Such effects were reported for a variety of biological systems [55][56] and polymeric [21][22] as well as metallic [24] surface morphologies inspired by snake skin. Modelling efforts revealed that anisotropy is a function of the counter

High-temperature magnetism and microstructure of a semiconducting ferromagnetic (GaSb)_1−x(MnSb)_x alloy

• Leonid N. Oveshnikov,
• Elena I. Nekhaeva,
• Alexey V. Kochura,
• Alexander B. Davydov,
• Mikhail A. Shakhov,
• Sergey F. Marenkin,
• Oleg A. Novodvorskii,
• Alexander P. Kuzmenko,
• Alexander L. Vasiliev,
• Boris A. Aronzon and
• Erkki Lahderanta

Beilstein J. Nanotechnol. 2018, 9, 2457–2465, doi:10.3762/bjnano.9.230

• in Table 1 and the parameters obtained from the Rxy(H) curves is related to a substantial magnetic anisotropy of the samples under study (see Figure 1). The observation of the anomalous Hall effect (AHE) clearly suggests that delocalized holes interact with the magnetic subsystem, i.e., that there

Evidence of friction reduction in laterally graded materials

• Roberto Guarino,
• Gianluca Costagliola,
• Federico Bosia and
• Nicola Maria Pugno

Beilstein J. Nanotechnol. 2018, 9, 2443–2456, doi:10.3762/bjnano.9.229

• produces a nonlinear reduction of static friction with the grading. A quasi-linear decrease can be obtained in the case of a triangular grading, which is symmetric with respect to the two edges, so that the anisotropy of the vertical stress distribution is less influential. In particular, this outcome can

Magnetism and magnetoresistance of single Ni–Cu alloy nanowires

• Andreea Costas,
• Camelia Florica,
• Elena Matei,
• Maria Eugenia Toimil-Molares,
• Ionel Stavarache,
• Andrei Kuncser,
• Victor Kuncser and
• Ionut Enculescu

Beilstein J. Nanotechnol. 2018, 9, 2345–2355, doi:10.3762/bjnano.9.219

• systems, the nanowires exhibit an additional degree of freedom associated to their inherent shape anisotropy, depending on the aspect ratio (the ratio between the length of the wire and its diameter). Both the aspect ratio and the wire diameter influence the magnetic domain structure of the wire, which is

• also related to an exchange length parameter, λex = π√(A/K), where A is the exchange stiffness and K is the anisotropy constant, respectively. Even for single-component metallic nanowires (e.g., Ni) of high aspect ratio, different magnetization reversal mechanisms might be in work (from the simplest

• electrons can be easily tuned via the nanowire composition. However, an anisotropy magneto-resistance (AMR) mechanism would be expected for such systems instead of GMR. As a direct consequence, this much weaker effect can no longer be detected in arrays of nanowires but only in single nanowires. Magneto

Lead-free hybrid perovskites for photovoltaics

• Oleksandr Stroyuk

Beilstein J. Nanotechnol. 2018, 9, 2209–2235, doi:10.3762/bjnano.9.207

• nanocrystals (NCs) [16][24][28][29][30][43][50][53][54][55][56]. Recently, broad recognition was gained by 1D and 2D layered hybrid perovskite materials with strong anisotropy of electron properties. Such materials are currently treated as very promising light harvesters with highly tunable optical and charge

Influence of the thickness of an antiferromagnetic IrMn layer on the static and dynamic magnetization of weakly coupled CoFeB/IrMn/CoFeB trilayers

• Deepika Jhajhria,
• Dinesh K. Pandya and
• Sujeet Chaudhary

Beilstein J. Nanotechnol. 2018, 9, 2198–2208, doi:10.3762/bjnano.9.206

• function of the angle θ. The two-fold symmetry for all samples clearly indicates the existence of the uniaxial magnetic anisotropy (UMA). This UMA results from the breakdown of the azimuthal symmetry in the deposited films, which is likely to be caused by the anisotropic stress in the films generated due

• proportional to the thickness of the CoFeB layers (up to 50 nm, data not shown), demonstrating that the UMA is a volume anisotropy rather than an interfacial anisotropy. From the fitting of the angular data, the individual values of uniaxial and cubic anisotropy field were calculated with the following

• equation [42]: Here, h is Planck’s constant, 4πMs is saturation magnetization, g is the Landé g-factor, Hk and Hcubic are the uniaxial and cubic anisotropy fields, respectively, and θk and θcubic are the angles between, respectively, uniaxial and cubic anisotropy easy axes and the observed easy axis (EA, θ

Recent highlights in nanoscale and mesoscale friction

• Andrea Vanossi,
• Dirk Dietzel,
• Andre Schirmeisen,
• Ernst Meyer,
• Rémy Pawlak,
• Thilo Glatzel,
• Marcin Kisiel,
• Shigeki Kawai and
• Nicola Manini

Beilstein J. Nanotechnol. 2018, 9, 1995–2014, doi:10.3762/bjnano.9.190

• able to synthesize smart lubricants that can change their lubrication properties on demand. By irradiation with the appropriate wavelength these novel materials might change from a high-friction to a low-friction state. Analogous concepts can be envisaged for friction anisotropy [180] and for adhesion

Synthesis of hafnium nanoparticles and hafnium nanoparticle films by gas condensation and energetic deposition

• Irini Michelakaki,
• Nikos Boukos,
• Dimitrios A. Dragatogiannis,
• Spyros Stathopoulos,
• Costas A. Charitidis and
• Dimitris Tsoukalas

Beilstein J. Nanotechnol. 2018, 9, 1868–1880, doi:10.3762/bjnano.9.179

• demonstrate high catalytic activity during hydrogenation of levulinic acid [17], nickel NPs, which find application as electrochemical sensor [18], and cobalt NPs, which exhibit high magnetic anisotropy [19]. Recently, we have reported that hcp hafnium nanoparticles fabricated by inert-gas condensation, when

Increasing the performance of a superconducting spin valve using a Heusler alloy

• Andrey A. Kamashev,
• Aidar A. Validov,
• Joachim Schumann,
• Vladislav Kataev,
• Bernd Büchner,
• Yakov V. Fominov and
• Ilgiz A. Garifullin

Beilstein J. Nanotechnol. 2018, 9, 1764–1769, doi:10.3762/bjnano.9.167

• samples [15]. Thus, the final design of the SSV structures was set as AFM/F1/N1/F2/N2/S. In this construction the Cu interlayer (N1) decouples magnetizations of the Fe1 (F1) and Fe2 (F2) layers and the antiferromagnetic (AFM) CoOx layer biases the magnetization of the Fe1 layer by anisotropy fields

Magnetic properties of Fe₃O₄ antidot arrays synthesized by AFIR: atomic layer deposition, focused ion beam and thermal reduction

• Juan L. Palma,
• Alejandro Pereira,
• Raquel Álvaro,
• José Miguel García-Martín and
• Juan Escrig

Beilstein J. Nanotechnol. 2018, 9, 1728–1734, doi:10.3762/bjnano.9.164

• of the holes has to be of the same order of magnitude as the domain wall width. Assuming Bloch-type domain walls, the width W is given by where A is the exchange constant and K is the magnetic anisotropy. Taking common values of A = 15.3 × 10−12 J/m [37] and K = 2.1 × 104 J/m3 [38], W = 84 nm is

Photoluminescence of CdSe/ZnS quantum dots in nematic liquid crystals in electric fields

• Margarita A. Kurochkina,
• Elena A. Konshina and
• Daria Khmelevskaia

Beilstein J. Nanotechnol. 2018, 9, 1544–1549, doi:10.3762/bjnano.9.145

• , Russia 10.3762/bjnano.9.145 Abstract We have experimentally investigated the effect of the reorientation of a nematic liquid crystal (LC) in an electric field on the photoluminescence (PL) of CdSe/ZnS semiconductor quantum dots (QDs). To the LC with positive dielectric anisotropy, 1 wt % QDs with a core

• spectral luminescence properties of the nematic LCs with a positive dielectric anisotropy doped with semiconductor CdSe/ZnS quantum dots [18][19][20]. The luminescence quenching of a planar oriented liquid crystal depended not only on the size but also on the concentration of QDs [18]. The PL intensity of

• the director field under the action of an electric field. We have used a nematic liquid crystal with positive dielectric anisotropy as the LC matrix. The liquid crystal doped with QDs was aligned in parallel (a vertical orientation) or perpendicular (a planar orientation) to the electric field vector

Optical near-field mapping of plasmonic nanostructures prepared by nanosphere lithography

• Gitanjali Kolhatkar,
• Alexandre Merlen,
• Jiawei Zhang,
• Chahinez Dab,
• Gregory Q. Wallace,
• François Lagugné-Labarthet and
• Andreas Ruediger

Beilstein J. Nanotechnol. 2018, 9, 1536–1543, doi:10.3762/bjnano.9.144

• periodicity of ≈3 µm−1 in the Fourier (2D reciprocal) space. The anisotropy of this pattern is also reflected in the 2D fast Fourier transform (FFT) of the optical image, presented in Figure 1c. In addition, those patterns vary with the polarization, and with the laser focus. Thus, these oscillation patterns

Robust midgap states in band-inverted junctions under electric and magnetic fields

• Álvaro Díaz-Fernández,
• Natalia del Valle and
• Francisco Domínguez-Adame

Beilstein J. Nanotechnol. 2018, 9, 1405–1413, doi:10.3762/bjnano.9.133

• , v is an interband matrix element having dimensions of velocity and it is assumed scalar, corresponding to isotropic bands around the L point. It is worth mentioning that the bands of IV–VI compounds around the L points are actually anisotropic. Nevertheless, this anisotropy can be absorbed in the

Interplay between pairing and correlations in spin-polarized bound states

• Szczepan Głodzik,
• Aksel Kobiałka,
• Anna Gorczyca-Goraj,
• Andrzej Ptok,
• Grzegorz Górski,
• Maciej M. Maśka and
• Tadeusz Domański

Beilstein J. Nanotechnol. 2018, 9, 1370–1380, doi:10.3762/bjnano.9.129

• angular anisotropy. Our results, presented in Figure 3, clearly indicate the spatial particle–hole oscillations of the YSR states (compare the blue and red lines). Such particle–hole oscillations decay exponentially with r in agreement with previous studies [11][37][38]. The dominant (particle or hole

Disorder-induced suppression of the zero-bias conductance peak splitting in topological superconducting nanowires

• Jun-Tong Ren,
• Hai-Feng Lü,
• Sha-Sha Ke,
• Yong Guo and
• Huai-Wu Zhang

Beilstein J. Nanotechnol. 2018, 9, 1358–1369, doi:10.3762/bjnano.9.128

• -binding model. We introduce three types of disorder into the system, including random fluctuations in the chemical potential, spatially changing in the superconducting pair potential, and the anisotropy of the nearest-neighbor hopping strength through lattice sites. We demonstrated that the disorder could

Formation and development of nanometer-sized cybotactic clusters in bent-core nematic liquid crystalline compounds

• Yuri P. Panarin,
• Sithara P. Sreenilayam,
• Jagdish K. Vij,
• Anne Lehmann and
• Carsten Tschierske

Beilstein J. Nanotechnol. 2018, 9, 1288–1296, doi:10.3762/bjnano.9.121

• . Depending on the frequency and the magnitude of the applied electric field, three types of electro-hydrodynamic instabilities have been observed in the BC nematics with negative dielectric and conductivity anisotropy [60][61]. During this exercise, we checked the effect of an external electric field on a

Field-controlled ultrafast magnetization dynamics in two-dimensional nanoscale ferromagnetic antidot arrays

• Anulekha De,
• Sucheta Mondal,
• Sourav Sahoo,
• Saswati Barman,
• Yoshichika Otani,
• Rajib Kumar Mitra and
• Anjan Barman

Beilstein J. Nanotechnol. 2018, 9, 1123–1134, doi:10.3762/bjnano.9.104

• can be varied to tune the magnonic spectra and magnetization dynamics in ferromagnetic antidot lattices. Several studies have been focused on the engineering of the coercive field, magnetoresistance and anisotropy properties on domain formation and the magnetization reversal mechanism with the change

• strength and orientation of the bias field [6][7][8][19][20][21][22][23][24][25][26]. Intrinsic configurational magnetic anisotropy arising due to the internal field variation can be tuned effectively by varying the antidot lattice symmetry [21][24]. The shape of the antidots is found to control the SW

• mode structures as well as the anisotropy in the frequency spectra [25]. Quantized SW modes have been found to be transformed to propagating ones and vice versa in rhombic antidot lattices with the variation of the in-plane orientation of the bias-magnetic field [26]. A particular study showed the

Magnetic characterization of cobalt nanowires and square nanorings fabricated by focused electron beam induced deposition

• Federico Venturi,
• Gian Carlo Gazzadi,
• Amir H. Tavabi,
• Alberto Rota,
• Rafal E. Dunin-Borkowski and
• Stefano Frabboni

Beilstein J. Nanotechnol. 2018, 9, 1040–1049, doi:10.3762/bjnano.9.97

• noted that Co carbonyl precursor was chosen here because it has been shown to provide high purity deposits with magnetic properties that are close to those of pure Co [13]. It is well known that shape anisotropy has a profound influence on the magnetic properties of nanostructured materials. The NW is a

• basic building block of magnetic nanodevices, as its high aspect ratio (length/width) often results in a single magnetic domain state due to shape anisotropy [14]. In detail, a NW has a stable magnetic state if its width is smaller than 7·Δd, where Δd is the dipolar exchange length [15], which is ca

• monodomain states, with their magnetization aligned along their long axes due to shape anisotropy [13]. Impurities are present on some samples (especially for the 20 s and 40 s depositions at 5 keV), resulting in flux-closure domain states, which deform the dipole-like phase structure locally. These

Effect of ferroelectric BaTiO₃ particles on the threshold voltage of a smectic A liquid crystal

• Abbas R. Imamaliyev,
• Mahammadali A. Ramazanov and
• Shirkhan A. Humbatov

Beilstein J. Nanotechnol. 2018, 9, 824–828, doi:10.3762/bjnano.9.76

• reduce the threshold voltage. The obtained result is explained by two factors: an increase of dielectric anisotropy of the liquid crystals and the formation of a strong electric field near polarized particles of BaTiO3. It was shown that the role of the second factor is dominant. The explanations of some

• ferroelectric BaTiO3 nanoparticles were found to exhibit a nonvolatile electromechanical memory effect in the isotropic phase [9]. Ferroelectric nanoparticles reduce the threshold voltage by enhancing the dielectric anisotropy of the nematic LC and the system becomes sensitive to the sign of the applied

• -decyloxybenzoate and 4-cyano-4′-pentylbiphenyl with a molar ratio of 1:1. The mixture is in the smectic A phase in the temperature range of 32.5–47.0 °C and has positive dielectric anisotropy. BaTiO3 is a ferroelectric material with high spontaneous polarization (0.26 C·m−2 at room temperature) [16][17]. In our