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

• nanorods; Q-switching; saturable absorption; solid-state lasers; zinc oxide; Introduction Zinc oxide (ZnO) is a well-known II–IV group wide-bandgap semiconductor (Eg = 3.37 eV), possessing a hexagonal wurtzite-type (sp. gr. P63mc) structure with unit cell parameters a = 3.25 Å, c = 5.20 Å. In recent years

• with picosecond pulses resulting in Isat = 16 kW/cm2, which is close to our observations. Passive Q-switching by ZnO nanorods The laser experiments were performed with the NRs grown for 5 h, because they exhibited minimum insertion loss. Stable Q-switching was also observed for the NRs grown for 10 h

• scaling of the laser in the PQS regime was limited by the Q-switching instabilities arising for Pabs > 3.2 W due to the heating of the SA by the residual (non-absorbed) pump [22]. The pulse duration Δτ, determined as full width at half maximum (FWHM) and the pulse repetition frequency (PRF) for the PQS

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

• magnetic heating contribution by using where C is the volumetric specific heat capacity of the sample, mf the dispersion mass, mMNPs is the iron mass diluted in the dispersion and ΔΤ/Δt is the maximal slope at initial time after switching on the heating AC field. In vitro experiments Cell culture. 4T1

Nanoantenna structures for the detection of phonons in nanocrystals

• Alexander G. Milekhin,
• Sergei A. Kuznetsov,
• Ilya A. Milekhin,
• Larisa L. Sveshnikova,
• Tatyana A. Duda,
• Ekaterina E. Rodyakina,
• Alexander V. Latyshev,
• Volodymyr M. Dzhagan and
• Dietrich R. T. Zahn

Beilstein J. Nanotechnol. 2018, 9, 2646–2656, doi:10.3762/bjnano.9.246

• obtained for three different angles of incidence θ = 0, 25, and 50°. Since the longitudinal LSPR mode can be excited either by TE- (E0 II X) or TM-polarized (H0 II Y) waves, both geometries are considered in the simulations. Note that switching to the second derivative of d instead of the dipole moment

Effective sensor properties and sensitivity considerations of a dynamic co-resonantly coupled cantilever sensor

• Julia Körner

Beilstein J. Nanotechnol. 2018, 9, 2546–2560, doi:10.3762/bjnano.9.237

• magnetic properties. This led to the first time observation of magnetic switching of these individual Heusler nanoparticles at room temperature and with a comparatively simple setup (laser-deflection detection) [16]. Other experiments in magnetic force microscopy showed a likewise increase in sensitivity

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

• coefficient of friction when switching from the 0° to the 90° direction, and this is evident especially for large values of Δ. The dependence of µs on the angle, instead, is more complex for Δ < 0.3, especially for the 3D FEM, where the interaction with the vertical stress distribution must also be taken into

Pinning of a ferroelectric Bloch wall at a paraelectric layer

• Vilgelmina Stepkova and
• Jiří Hlinka

Beilstein J. Nanotechnol. 2018, 9, 2356–2360, doi:10.3762/bjnano.9.220

• loop demonstrating switching of the Pt component of the Bloch wall located at a 1 nm thin SrTiO3 layer. The indicated value of the polarization Pt is averaged over the whole supercell shown in Figure 1b. Acknowledgements This work was supported by the Czech Science Foundation (project no. 15-04121S

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

• , the magnetization reversal canb be described using the Stoner–Wohlfarth model [29][30]. Thus, if the field is applied along the easy axis (EA), the magnetization changes steeply its orientation along the EA at a switching field proportional to the anisotropy constant and inversely proportional to the

• decrease of the magnetization from positive to negative saturation, with the saturation field equating the switching field in parallel geometry. If the current flows along the EA, the resistivity is above the saturation field (θ = 90°) and at zero field (where the magnetization lies along the EA, due to

• perpendicular to the easy axis. The saturation field (approaching the switching field in case of the S–W model) decreases very slowly with the Ni composition, contrary to what would be expected from the composition dependence of the saturation magnetization and inverse proportionality of the switching field

Intrinsic ultrasmall nanoscale silicon turns n-/p-type with SiO₂/Si₃N₄-coating

• Dirk König,
• Daniel Hiller,
• Noël Wilck,
• Birger Berghoff,
• Merlin Müller,
• Sangeeta Thakur,
• Giovanni Di Santo,
• Luca Petaccia,
• Joachim Mayer,
• Sean Smith and
• Joachim Knoch

Beilstein J. Nanotechnol. 2018, 9, 2255–2264, doi:10.3762/bjnano.9.210

• the electrostatic integrity of the devices causes conventional doping to fail. Metal–Si contacts formed by, e.g., silicide formation [36] result in rather high Schottky-barriers at the source/drain-channel interfaces that deteriorate the switching behaviour and on-state performance. h-DFT calculations

Optimization of the optical coupling in nanowire-based integrated photonic platforms by FDTD simulation

• Nan Guan,
• Andrey Babichev,
• Martin Foldyna,
• Dmitry Denisov,
• François H. Julien and
• Maria Tchernycheva

Beilstein J. Nanotechnol. 2018, 9, 2248–2254, doi:10.3762/bjnano.9.209

• between an LED and a photoconductive detector both based on GaN NWs [29]. The communication took place in free space. Using NWs located close to each other, the authors demonstrated a correlation between the LED on/off switching and the photodetector current variations. A waveguide for light channeling is

The role of adatoms in chloride-activated colloidal silver nanoparticles for surface-enhanced Raman scattering enhancement

• Nicolae Leopold,
• Andrei Stefancu,
• Krisztian Herman,
• István Sz. Tódor,
• Stefania D. Iancu,
• Vlad Moisoiu and
• Loredana F. Leopold

Beilstein J. Nanotechnol. 2018, 9, 2236–2247, doi:10.3762/bjnano.9.208

• addition of MgSO4 or Ca(NO3)2 in concentrations ranging from 10−4 –10−3 M to a cit-AgNP solution which already contains 1 mM NaCl, led to the switching on of the SERS effect and the recording of very intense SERS spectra of 10−9 M crystal violet. Accordingly, the intense SERS spectra of crystal violet

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

• lowering the spin torque critical current switching density [22][23]. For various other applications a fast relaxation is favored, e.g., in magnetoresistive heads [24][25]. The FM/AF exchange coupling is one of the approaches to tune the magnetization relaxation by enhancing the field linewidth ΔH and

High-throughput synthesis of modified Fresnel zone plate arrays via ion beam lithography

• Kahraman Keskinbora,
• Umut Tunca Sanli,
• Margarita Baluktsian,
• Corinne Grévent,
• Markus Weigand and
• Gisela Schütz

Beilstein J. Nanotechnol. 2018, 9, 2049–2056, doi:10.3762/bjnano.9.194

• redirected to higher orders including the 2nd and 3rd diffraction orders. 2nd order DE, which is almost 0 for a perfect 1:1 duty cycle (Supporting Information File 1, Figure S2), increases if the L:S ratio deviates from 1:1. The situation can be remedied relatively easily by switching to an SP-E process for

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

• process and the task of the related functional molecular groups. Then, the frictional properties of these films in the different conformations (e.g., trans and cis) will be intensively studied to understand how this conformation switching affects energy dissipation. Multiscale bridging The current

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

• embedded into a metal-oxide layer, result in a completely new behavior of resistive switching compared with pristine metal-oxide layers, which is important for operation and understanding of nonvolatile resistive random-access memory (ReRAM) [20]. Furthermore except of size, shape and structure of NPs, a

The role of the Ge mole fraction in improving the performance of a nanoscale junctionless tunneling FET: concept and scaling capability

• Hichem Ferhati,
• Fayçal Djeffal and
• Toufik Bentrcia

Beilstein J. Nanotechnol. 2018, 9, 1856–1862, doi:10.3762/bjnano.9.177

• investigated. Moreover, the impact of the Ge mole fraction in the proposed Si1−xGex source region on the electrical figures of merit (FoMs) of the transistor, including the swing factor and the ION/IOFF ratio is analyzed. It is found that the optimized design with 60 atom % of Ge offers improved switching

• , where the optimized design exhibits an improved switching behavior at the nanoscale level. These results make the optimized device suitable for designing digital circuit for high-performance nanoelectronic applications. Keywords: ambipolar conduction; heterojunctions; junctionless tunneling field

• structure demonstrates a superior switching behavior. This makes the optimized structure a potential alternative for providing energy-efficient transistors with suppressed ambipolar conduction for designing high-performance nanoelectronic circuits at low manufacturing cost. Numerical Simulations Figure 1

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

• polarization of the conduction band. The heterostructures demonstrate a significant superconducting spin-valve effect, i.e., a complete switching on and off of the superconducting current flowing through the system by manipulating the mutual orientations of the magnetization of the F1 and F2 layers. The

• magnitude of the effect is doubled in comparison with the previously studied analogous multilayers with the F2 layer made of the strong ferromagnet Fe. Theoretical analysis shows that a drastic enhancement of the switching effect is due to a smaller exchange field in the heterostructure coming from the

• Heusler film as compared to Fe. This enables to approach an almost ideal theoretical magnitude of the switching in the Heusler-based multilayer with a F2 layer thickness of ca. 1 nm. Keywords: ferromagnet; proximity effect; spin valve; superconductor; Introduction Historically, the first concept to

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

• presence of the ordered non-magnetic holes induces a demagnetization field distribution that changes the magnetization switching mechanisms [6], acting as pinning centers for domain walls [7], enhancing coercivity compared to that of the continuous film [8][9][10][11][12], and affecting the magnetic

Multimodal noncontact atomic force microscopy and Kelvin probe force microscopy investigations of organolead tribromide perovskite single crystals

• Yann Almadori,
• David Moerman,
• Jaume Llacer Martinez,
• Philippe Leclère and
• Benjamin Grévin

Beilstein J. Nanotechnol. 2018, 9, 1695–1704, doi:10.3762/bjnano.9.161

• form of a negative shift of ≈240 mV after switching the light pulse on. This fast change is followed by a slower evolution and a subsequent stabilization of the SP under illumination at a timescale of a few tens of seconds. The surface photovoltage (SPV) at equilibrium (or “stabilized SPV”, SPVStab) is

• therefore equal to the sum of a negative and a positive term, which will be referred to hereafter as “fast” and “slow” SPV components (SPVFast and SPVSlow, see Figure 2a) with regards to their different photoresponse dynamics. After switching the light off, the SP displays a fast positive shift followed by

• that the SP is slightly more positive than initially just after switching the light pulse off. This SP overshoot becomes much more pronounced at higher fluence (as shown in Figure 3c and Figure S3d in Supporting Information File 1). Our interpretation is that most of the photocarriers recombine quickly

Josephson effect in junctions of conventional and topological superconductors

• Alex Zazunov,
• Albert Iks,
• Miguel Alvarado,
• Alfredo Levy Yeyati and
• Reinhold Egger

Beilstein J. Nanotechnol. 2018, 9, 1659–1676, doi:10.3762/bjnano.9.158

• chosen in Figure 9, the ABSs provide the dominant contribution to the current in this regime. S–TS–S junctions: Switching the parity of a superconducting atomic contact Model We now proceed to the three-terminal S–TS–S setup shown in Figure 1b. The CPR found in the related TS–S–TS trijunction case has

• the odd parity sector of the SAC. For λ1 ≠ 0, the MBS-mediated switching between odd and even parity sectors will now be activated and thereby lift the supercurrent blockade. Conventional midgap level A similar behavior as predicted above for the MBS-induced parity switch between = ±1 sectors could

Solid-state Stern–Gerlach spin splitter for magnetic field sensing, spintronics, and quantum computing

• Kristofer Björnson and
• Annica M. Black-Schaffer

Beilstein J. Nanotechnol. 2018, 9, 1558–1563, doi:10.3762/bjnano.9.147

• sensitivity, or switching field, b, is related to the characteristic size of the device, r, through b = h/(2πqr2), with q being the unit of electric charge. Keywords: Aharanov–Bohm; quantum computing; spintronics; Stern–Gerlach; SU(2); topological insulator; Introduction Two famous examples of the

• “on” and “off” states for n even and odd, respectively, and we therefore define the magnetic switching quantum An alternative way to encode 1 and 0 is to use the currents of up- and down-spins, respectively. This requires normal leads through which both up- and down-spins can be transported. We

• and a NOT-gate, simply by changing B by the switching quantum in Equation 4. Quantum computer gate Having seen how a TI SG apparatus can be used to construct classical logic gates for spintronics, we finally turn to possible applications in quantum computing. It has been shown that a universal quantum

Cathodoluminescence as a probe of the optical properties of resonant apertures in a metallic film

• Kalpana Singh,
• Evgeniy Panchenko,
• Babak Nasr,
• Amelia Liu,
• Lukas Wesemann,
• Timothy J. Davis and
• Ann Roberts

Beilstein J. Nanotechnol. 2018, 9, 1491–1500, doi:10.3762/bjnano.9.140

• including the thickness of the metal film [13]. Other than the excitations discussed above, sharp Fano resonances arising from the interference of two modes [14] have promising applications in sensing, switching and lasing. These resonances have been investigated in various structures such as thin film

Electrostatically actuated encased cantilevers

• Benoit X. E. Desbiolles,
• Gabriela Furlan,
• Adam M. Schwartzberg,
• Paul D. Ashby and
• Dominik Ziegler

Beilstein J. Nanotechnol. 2018, 9, 1381–1389, doi:10.3762/bjnano.9.130

• an annealed ultra-flat gold surface. The surface is imaged in tapping mode using harmonic excitation with amplitude modulation feedback, a free amplitude of 1 nm and a set-point of 0.8 nm. In harmonic excitation, we observe that intentional switching of the applied Udc by a few volts would result in

Andreev spectrum and supercurrents in nanowire-based SNS junctions containing Majorana bound states

• Jorge Cayao,
• Annica M. Black-Schaffer,
• Elsa Prada and
• Ramón Aguado

Beilstein J. Nanotechnol. 2018, 9, 1339–1357, doi:10.3762/bjnano.9.127

• , transitions between the negative and positive energies are not allowed, because of an energy gap originating from Majorana overlaps. Strategies to detect the presence of MBSs beyond the equilibrium supercurrents described here include the ac Josephson effect, noise measurements, switching-current measurements

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

• -range translational order. The optical switching by rotation around the long molecular axes is much faster and easier than switching by rotation around the short axes. In 1970, Freiser predicted that the long and flat LC molecules could form a biaxial nematic phase (Nb), and furthermore, a second-order

• either a glass, a smectic and/or a crystal being formed. In spite of the several setbacks of not unambiguously obtaining a biaxial nematic LC, the subject continues to be of great scientific and technological interest [4] as it has the potential to obtain faster switching devices that incorporate such a

• molecules were aligned by surface treatment and one of the short axes was also aligned by the electric field. In more recent studies, the biaxiality of the sample studied was confirmed [3][4][5] by electro-optical switching [23], polarizing infrared spectroscopy (PIR) [24], polarizing optical microscopy

Artifacts in time-resolved Kelvin probe force microscopy

• Sascha Sadewasser,
• Nicoleta Nicoara and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2018, 9, 1272–1281, doi:10.3762/bjnano.9.119

• difference between the CPD under illumination and in the dark – after switching on and off a laser light source. The CPD change resulting from the separation of the excited charge carriers was monitored in real time over the course of several minutes. Similar experiments were also performed using