scholarly journals Biologically encoded magnonics

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Benjamin W. Zingsem ◽  
Thomas Feggeler ◽  
Alexandra Terwey ◽  
Sara Ghaisari ◽  
Detlef Spoddig ◽  
...  
Keyword(s):  
Room Temperature ◽  
Logic Circuits ◽  
Band Gaps ◽  
Quantum Oscillations ◽  
Micromagnetic Simulations ◽  
Energy Demands ◽  
Local Arrangement ◽  
Generation Computing ◽  
Band Deformation ◽  
Nanoparticle Chains

Abstract Spin wave logic circuits using quantum oscillations of spins (magnons) as carriers of information have been proposed for next generation computing with reduced energy demands and the benefit of easy parallelization. Current realizations of magnonic devices have micrometer sized patterns. Here we demonstrate the feasibility of biogenic nanoparticle chains as the first step to truly nanoscale magnonics at room temperature. Our measurements on magnetosome chains (ca 12 magnetite crystals with 35 nm particle size each), combined with micromagnetic simulations, show that the topology of the magnon bands, namely anisotropy, band deformation, and band gaps are determined by local arrangement and orientation of particles, which in turn depends on the genotype of the bacteria. Our biomagnonic approach offers the exciting prospect of genetically engineering magnonic quantum states in nanoconfined geometries. By connecting mutants of magnetotactic bacteria with different arrangements of magnetite crystals, novel architectures for magnonic computing may be (self-) assembled.

scholarly journals Physical Simulations of High Speed and Low Power NanoMagnet Logic Circuits

2018 ◽  
Vol 8 (4) ◽  
pp. 37 ◽  
Author(s):  
Giovanna Turvani ◽  
Laura D’Alessandro ◽  
Marco Vacca
Keyword(s):  
High Speed ◽  
Logic Circuits ◽  
Micromagnetic Simulations ◽  
Electrical Fields ◽  
Nanomagnet Logic ◽  
Nanomagnetic Logic ◽  
Elastic Effect ◽  
Physical Simulations ◽  
A Chain ◽  
Beyond Cmos

Among all “beyond CMOS” solutions currently under investigation, nanomagnetic logic (NML) technology is considered to be one of the most promising. In this technology, nanoscale magnets are rectangularly shaped and are characterized by the intrinsic capability of enabling logic and memory functions in the same device. The design of logic architectures is accomplished by the use of a clocking mechanism that is needed to properly propagate information. Previous works demonstrated that the magneto-elastic effect can be exploited to implement the clocking mechanism by altering the magnetization of magnets. With this paper, we present a novel clocking mechanism enabling the independent control of each single nanodevice exploiting the magneto-elastic effect and enabling high-speed NML circuits. We prove the effectiveness of this approach by performing several micromagnetic simulations. We characterized a chain of nanomagnets in different conditions (e.g., different distance among cells, different electrical fields, and different magnet geometries). This solution improves NML, the reliability of circuits, the fabrication process, and the operating frequency of circuits while keeping the energy consumption at an extremely low level.

scholarly journals Synthesis and Characterisation of Novel Thiophene Based Azomethine Polymers and Study of Their Liquid Crystalline, Electrochemical and Optoelectronic Properties

2017 ◽  
Vol 25 (5) ◽  
pp. 345-362 ◽  
Author(s):  
Omer Yasin Al-Janabi ◽  
Peter J.S. Foot ◽  
Emaad Taha Al-Tikrity ◽  
Peter Spearman
Keyword(s):  
Cyclic Voltammetry ◽  
Liquid Crystalline ◽  
Room Temperature ◽  
Energy Levels ◽  
Band Gaps ◽  
Gas Liquid Chromatography ◽  
Lumo Energy ◽  
Chemical Structures ◽  
Homo And Lumo ◽  
Homo And Lumo Energy

This work reports the synthesis, structural characterisation, liquid crystallinity, luminescence and electroluminescence of novel thiophene azomethine polymers. The polymers under study were prepared via oxidative polymerisation of four novel monomers at room temperature using iron (III) chloride. The chemical structures of the prepared monomers and polymers were confirmed by infrared and 1H and 13CNMR spectroscopy. Molecular masses were determined for monomers and polymers by gas/liquid chromatography-mass spectrometry (GC/LC-MS) and by gel-permeation (size exclusion) chromatography (SEC), respectively. Thermal stability studies of the prepared materials were achieved by thermogravimetric analysis (TGA), and the onset of weight loss To and the endset Tmax were calculated from the thermograms. Liquid crystalline mesophases and phase changes of the monomers and polymers were studied by differential scanning calorimetry (DSC) and polarised optical microscopy (POM), and the glass transition temperatures Tg of the polymers were determined from the DSC curves. The electrochemical band gaps, HOMO and LUMO energy levels were measured by cyclic voltammetry. UV-visible absorption-emission spectra (liquid and solid films) of the polymers were obtained at room temperature with different solvents. Optical band gaps were calculated from the absorption edges, and were in good agreement with those estimated from cyclic voltammetry. Mixing the polymers with lanthanide salts such as EuCl3 and YbCl3 gave modified fluorescence, and the light emitted was much more intense than that from the pure polymers. Polymer based light-emitting diodes (PLEDs) were fabricated by spin coating, and their current-voltage characteristics were measured. In preliminary work, the polymer devices were found to produce electroluminescent spectra similar to the PL spectra of the corresponding samples. Molecular modelling studies were performed both on polymer segments and monomer molecules; the absorption spectra of the prepared polymers, HOMO and LUMO energy levels were calculated with ZINDO using AMI geometry optimisation.

scholarly journals Effects of the Argon Pressure on the Optical Band Gap of Zinc Oxide Thin Films Grown by Nonreactive RF Sputtering

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
M. Acosta ◽  
I. Riech ◽  
E. Martín-Tovar
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Band Gap ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Rf Sputtering ◽  
Argon Pressure ◽  
Band Gaps ◽  
Zno Thin Films ◽  
Optical Band Gaps

Zinc oxide (ZnO) thin films were grown by nonreactive RF sputtering at room temperature under varying argon pressures (PAr). Their optical band gap was found to increase from 3.58 to 4.34 eV when the argon pressure increases from 2.67 to 10.66 Pa. After annealing at 200°C and 500°C, optical band gaps decrease considerably. The observed widening of the band gap with increasingPArcan be understood as being a consequence of the poorer crystallinity of films grown at higher pressures. Measurements of morphological and electrical properties of these films correlate well with this picture. Our main aim is to understand the effects ofPAron several physical properties of the films, and most importantly on its optical band gap.

Structure and phase transition of the Se-rich variety of antimonpearceite, [(Ag,Cu)6(Sb,As)2(S,Se)7][Ag9Cu(S,Se)2Se2]

2006 ◽  
Vol 62 (5) ◽  
pp. 768-774 ◽  
Author(s):  
Michel Evain ◽  
Luca Bindi ◽  
Silvio Menchetti
Keyword(s):  
Phase Transition ◽  
Room Temperature ◽  
Atomic Displacement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dimensional Diffusion ◽  
Ionic Conducting ◽  
Local Arrangement ◽  
Diffusion Paths ◽  
Linear Coordination

The crystal structure of a Se-rich antimonpearceite has been solved and refined by means of X-ray diffraction data collected at temperatures above (room temperature) and below (120 K) an ionic conductivity-induced phase transition. Both structure arrangements consist of the stacking of [(Ag,Cu)6(Sb,As)2(S,Se)7]2− A (A′) and [Ag9Cu(S,Se)2Se2]2+ B (B′) module layers in which Sb forms isolated SbS3 pyramids typically occurring in sulfosalts; copper links two S atoms in a linear coordination, and silver occupies sites with coordination ranging from quasi-linear to almost tetrahedral. In the ionic-conducting form, at room temperature, the silver d 10 ions are found in the B (B′) module layer along two-dimensional diffusion paths and their electron densities described by means of a combination of a Gram–Charlier development of the atomic displacement factors and a split-atom model. The structure resembles that of pearceite, except for the presence of both specific (Se) and mixed (S, Se) sites. In the low-temperature `ordered' phase at 120 K the silver d 10 ions of the B (B′) module layer are located in well defined sites with mixed S—Se coordination ranging from quasi-linear to almost tetrahedral. The structure is then similar to that of 222-pearceite but with major differences, specifically its cell metric, symmetry and local arrangement in the B (B′) module layer.

Optical Properties of Nd Doped Lead Borotellurite Glass

2016 ◽  
Vol 846 ◽  
pp. 193-198 ◽  
Author(s):  
Azman Kasim ◽  
H. Azhan ◽  
S. Akmal Syamsyir ◽  
Mardhiah Abdullah ◽  
M.R.S. Nasuha
Keyword(s):  
Optical Properties ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Band Gap Energy ◽  
Rare Earth Ions ◽  
Band Gaps ◽  
Refractive Indices ◽  
Excitation Wavelength ◽  
Gap Energy ◽  
Trivalent Rare Earth

Many trivalent rare earth ions such as Er3+, Tm3+, Ho3+, Pr3+ and Nd3+ were doped as absorption and emission centers in glass hosts. In this work, lead borotellurite (PBT) glass doped with neodymium ion (Nd3+) has been prepared and characterized by mean of their optical properties. The UV-Vis measurement has been carried out in order to determine the optical band gap energy, reflective indices and the polarizability. Optical absorption spectra of the glass samples are recorded in the range 400–900 nm at room temperature From the result, there are six significant absorption peaks that corresponds to 525 nm, 584 nm, 683 nm, 747 nm, 805 nm and 878 nm wavelength have been observed with the most predominant peak to be used as excitation wavelength is found centered at 584 nm. The energy band gaps as well as the refractive indices were found to vary from 2.50eV to 2.59eV and from 1.89 to 1.96 with mol% of Nd content respectively. Meanwhile, the polarizability shows a similar trend of results to refractive indices as it varies from 5.56 x 10-24 cm3 to 5.63 x 10-24 cm3. These results will be discussed further in details.

Size Effects in Bi-Sb Solid Solutions Thin Films

2011 ◽  
Vol 1314 ◽  
Author(s):  
Elena I. Rogacheva ◽  
Dar’ya S. Orlova ◽  
Mildred S. Dresselhaus ◽  
Shuang Tang
Keyword(s):  
Thin Films ◽  
Solid Solutions ◽  
Room Temperature ◽  
Thermal Evaporation ◽  
Theoretical Calculations ◽  
Thermoelectric Power Factor ◽  
Quantum Oscillations ◽  
Kinetic Coefficients ◽  
Temperature Dependences ◽  
Good Agreement

ABSTRACTThe room-temperature dependences of the electrical conductivity σ, Seebeck coefficient S, Hall coefficient RH, and the thermoelectric power factor P on the thickness (d=10–300 nm) of the thin films grown on mica substrates by thermal evaporation in vacuum of Bi-Sb solid solutions crystals with 4.5 at.% Sb were obtained. It was established that an increase in d up to ~ 200 nm leads to a change in kinetic coefficients and that in the thickness dependences of the thermoelectric properties, quantum oscillations were observed. It was shown that the monotonic component of the σ(T) dependence can be satisfactorily approximated by theoretical calculations based on the classical Fuchs - Sondheimer theory. The theoretically estimated period of oscillations is in a good agreement with the experimentally observed period.

scholarly journals Fan-out enabled spin wave majority gate

2021 ◽  
Author(s):  
Abdulqader Mahmoud ◽  
Frederic Vanderveken ◽  
Christoph Adelmann ◽  
Florin Ciubotaru ◽  
Said Hamdioui ◽  
...  
Keyword(s):  
Spin Wave ◽  
State Of The Art ◽  
Logic Gate ◽  
Logic Circuits ◽  
Boolean Logic ◽  
Function Evaluation ◽  
Majority Gate ◽  
Logic Function ◽  
Micromagnetic Simulations ◽  
Majority Logic

By its very nature, Spin Wave (SW) interference provides intrinsic support for Majority logic function evaluation. Due to this and the fact that the 3-input Majority (MAJ3) gate and the Inverter constitute a universal Boolean logic gate set, different MAJ3 gate implementations have been proposed. However, they cannot be directly utilized for the construction of larger SW logic circuits as they lack a key cascading mechanism, i.e., fan-out capability. In this paper, we introduce a novel ladder-shaped SW MAJ3 gate design able to provide a maximum fan-out of 2 (FO2). The proper gate functionality is validated by means of micromagnetic simulations, which also demonstrate that the amplitude mismatch between the two outputs is negligible proving that an FO2 is properly achieved. Additionally, we evaluate the gate area and compare it with SW state-of-the-art and 15nm CMOS counterparts working under the same conditions. Our results indicate that the proposed structure requires 12x less area than the 15 nm CMOS MAJ3 gate and that at the gate level the fan-out capability results in 16% area savings, when compared with the state-of-the-art SW majority gate counterparts.

Room-temperature quantum oscillations in Ge junctionless MOSFETs at the scaling limit

2013 ◽  
Author(s):  
H. Wu ◽  
J. Y. Zhang ◽  
J. J. Gu ◽  
L. Dong ◽  
N. J. Conrad ◽  
...  
Keyword(s):  
Room Temperature ◽  
Scaling Limit ◽  
Quantum Oscillations

scholarly journals Influence of Doping Concentration on Dielectric, Optical, and Morphological Properties of PMMA Thin Films

2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
Lyly Nyl Ismail ◽  
Habibah Zulkefle ◽  
Sukreen Hana Herman ◽  
Mohamad Rusop Mahmood
Keyword(s):  
Thin Films ◽  
Dielectric Loss ◽  
Room Temperature ◽  
Sol Gel ◽  
Wavelength Region ◽  
Band Gaps ◽  
Morphological Properties ◽  
Dielectric Characteristics ◽  
Coating Method ◽  
Pmma Powder

PMMA thin films were deposited by sol gel spin coating method on ITO substrates. Toluene was used as the solvent to dissolve the PMMA powder. The PMMA concentration was varied from 30 ~ 120 mg. The dielectric properties were measured at frequency of 0 ~ 100 kHz. The dielectric permittivity was in the range of 7.3 to 7.5 which decreased as the PMMA concentration increased. The dielectric loss is in the range of 0.01 ~ –0.01. All samples show dielectric characteristics which have dielectric loss is less than 0.05. The optical properties for thin films were measured at room temperature across 200 ~ 1000 nm wavelength region. All samples are highly transparent. The energy band gaps are in the range of 3.6 eV to 3.9 eV when the PMMA concentration increased. The morphologies of the samples show that all samples are uniform and the surface roughness increased as the concentration increased. From this study, it is known that, the dielectric, optical, and morphology properties were influenced by the amount of PMMA concentration in the solution.

Sign in / Sign up

Export Citation Format

Share Document