Results 1 - 10 of 5660
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[en] Tunable bistable and multistable resistance switching in conducting polymer nanowires has been reported. These wires show reproducible switching transition under several READ-WRITE-ERASE cycles. The switching is observed at low temperature and the ON/OFF resistance ratio for the voltage biased switching transition was found to be more than 103. Current biased measurements show lower ON/OFF ratio and some of the nanowires exhibit a multistable switching transition in current biased measurements. The threshold voltage for switching and the ON/OFF resistance ratio can be tuned by changing doping concentration of the nanowires
[en] As far as the fabrication of ultradense crossbars is related to correspondingly dense wire arrays, the crossbar route to tera-scale integration depends on the availability of preparation techniques for wire arrays with density of 106 cm−1 or more. For a planar arrangement this density implies a pitch of 10 nm or less, beyond the current possibility and close to the theoretical limit, assuming for the cross-point a minimum area of 10 nm2. Further increase of density can only be achieved organizing the nanowires in a three-dimensional fashion. This paper describes a planar top–down process for the preparation of vertically arranged poly-silicon nanowires. The technique is expected to allow the production of wire arrays with linear density (projected on the surface) larger than those achievable with any other proposed top–down processes. Used for the fabrication of the bottom wire array of crossbars, this process should allow an eventual cross-point density of the order of 1012 cm−2, thus being a candidate technology for tera-scale integration
[en] We have carried out a systematic study on domain wall (DW) pinning at an anti-notch in a Ni80Fe20 nanowire. Micromagnetic studies reveal that the potential polarity experienced by the DW at the anti-notch is a function of both DW chirality and anti-notch geometry. A transition in the potential disruption experienced by the DW is observed when the anti-notch height-to-width ratio (HAN/WAN) is 2. This transition is due to the relative orientation of the spins in the anti-notch with respect to the transverse component of the DW. When the anti-notch acts as a potential barrier, the DW undergoes damped oscillations prior to coming to an equilibrium position. The equilibrium position is a strong function of the anti-notch dimensions when the HAN/WAN ratio <2 and is constant for HAN/WAN ≥ 2. The effect of the relative orientation between the spins in the anti-notch and the transverse component of the DW on the shape of the potential is discussed.
[en] In this communication we present our response to the recent comment of Engel regarding our paper on FIB-fabricated Nb nanowires (see Tettamanzi et al 2009 20 465302). After further analysis and additional experimental evidence, we conclude that our interpretation of the experimental results in light of QPS theory is still valid when compared with the alternative proximity-based model as proposed by Engel. (reply)
[en] The investigation of the role of interactions in magnetic wire arrays is complex and often involves substantial simplifications. In this paper analytical expressions taking into consideration the geometry of the wires and dipolar interactions between them have been obtained. An expansion of these terms, at first order, can be easily evaluated and shows a good agreement with the total expression for the energy. The extent of the interwire magnetostatic coupling has also been investigated, and it is shown that the number of wires required to reach a size independent magnetic state in the array strongly depends on the relative magnetic orientation of the wires
[en] A parallel array of isolated metal nanowires is expected to be hydrophilic. We show, however, that a clustering of such nanowires brought about by vacuum drying produces a 'dual-scale roughness' and confers a strongly hydrophobic property to the surface. The mean size of the nanowire clusters as well as the contact angle are both found to be related to the wire length, and the critical wire length above which the surface becomes hydrophobic is ∼10 μm. Surface roughness is generally known to enhance water-repellent properties, but this is the first report of roughness-induced hydrophobicity on a bare (uncoated) metallic surface
[en] This paper provides detailed simulation results and analysis of the prospective performance of hybrid CMOS/nanoelectronic processor systems based upon the field-programmable nanowire interconnect (FPNI) architecture. To evaluate this architecture, a complete design was developed for an FPNI implementation using 90 nm CMOS with 15 nm wide nanowire interconnects. Detailed simulations of this design illustrate that critical design choices and tradeoffs exist beyond those specified by the architecture. This includes the selection of the types of junction nanodevices, as well as the implementation of low-level circuits. In particular, the simulation results presented here show that only nanodevices with an 'on/off' current ratio of 200 or more are suitable to produce correct system-level behaviour. Furthermore, the design of the CMOS logic gates in the FPNI system must be customized to accommodate the resistances of both 'on'-state and 'off'-state nanodevices. Using these customized designs together with models of suitable nanodevices, additional simulations demonstrate that, relative to conventional 90 nm CMOS FPGA systems, performance gains can be obtained of up to 70% greater speed or up to a ninefold reduction in energy consumption.
[en] We study theoretically the minimal conductivity of monolayer graphene in the presence of Rashba spin–orbit coupling. The Rashba spin–orbit interaction causes the low-energy bands to undergo trigonal-warping deformation and for energies smaller than the Lifshitz energy, the Fermi circle breaks up into parts, forming four separate Dirac cones. We calculate the minimal conductivity for an ideal strip of length L and width W within the Landauer–Büttiker formalism in a continuum and in a tight binding model. We show that the minimal conductivity depends on the relative orientation of the sample and the probing electrodes due to the interference of states related to different Dirac cones. We also explore the effects of finite system size and find that the minimal conductivity can be lowered compared to that of an infinitely wide sample.
[en] We report the L3,2-edge whiteline anomaly observed in PtAu nanowire, PtAu and Pt nanoparticles deposited on Si nanowire, and their comparison with that of Pt metal. It is found that charge redistribution upon the formation of these materials can indeed be tracked with the L3,2 whiteline intensity. The implications of these findings are discussed.