Remote control of magnetostriction-based nanocontacts at room temperature

The remote control of the electrical conductance through nanosized junctions at room temperature will play an important role in future nano-electromechanical systems and electronic devices. This can be achieved by exploiting the magnetostriction effects of ferromagnetic materials. Here we report on the electrical conductance of magnetic nanocontacts obtained from wires of the giant magnetostrictive compound Tb 0.3 Dy 0.7 Fe 1.95 as an active element in a mechanically controlled break-junction device. The nanocontacts are reproducibly switched at room temperature between "open" (zero conductance) and "closed" (nonzero conductance) states by variation of a magnetic field applied perpendicularly to the long wire axis. Conductance measurements in a magnetic field oriented parallel to the long wire axis exhibit a different behaviour where the conductance switches between both states only in a limited field range close to the coercive field. Investigating the conductance in the regime of electron tunneling by mechanical or magnetostrictive control of the electrode separation enables an estimation of the magnetostriction. The present results pave the way to utilize the material in devices based on nano-electromechanical systems operating at room temperature

Integrating Human-Centred Design Approach into Sustainable-Oriented 3D Printing Systems

Modern 3D printing systems have become pervasive and widely used both in professional and in informal contexts, including sustainable-oriented ones. However, the risk to create very effective but non-sustainable solutions is very high since 3D printing systems could potentially increase the environmental emergencies and the unsustainable growth. In the transition process toward sustainable ways of production and consumption, the so-called human factor still plays an important role in the achievement of sustainable-oriented actions; it drives the adoption of proper lifestyles that directly and indirectly influence the ways through which such technologies are used. Therefore, future Sustainable 3D Printing Systems should integrate the humans in the systems’ development. This study presents two important results: (a) it presents a set of interdisciplinary ‘Sustainable 3D Printing Systems’, which compose a promising sustainable-oriented scenario useful to support the transition processes toward sustainable designs and productions, and (b) it proposes a new strategy for the integration of human-centred aspects into Sustainable 3D Printing Systems, by combining insights from human-centred design approach

Genome-Wide and Phase-Specific DNA-Binding Rhythms of BMAL1 Control Circadian Output Functions in Mouse Liver

Temporal mapping during a circadian day of binding sites for the BMAL1 transcription factor in mouse liver reveals genome-wide daily rhythms in DNA binding and uncovers output functions that are controlled by the circadian oscillator

An entropy-based test for goodness of fit of the von mises distribution

The maximum entropy characterization of the von Mises distribution on the circle is exploited to derive a consistent goodness of fit test for the von Mises distribution. Monte Carlo simulation results are tabulated giving critical values of the test statistic for various sample sizes and values of the concentration parameter. A power analysis is presented for various alternative hypotheses, comparing this entropy statistic to two other competing goodness of fit statistics. The entropy statistic is shown to compare favorably and may be more attractive, especially considering its ease of computation

Magnetic field control of charge transport in solar cells and mechanically controlled break junction devices

Controlling the electronic transport through solid state devices has been of utmost importance to develop high efficient devices for practical applications like energy conversion, data storage, sensing applications etc. In this context, the charge transport can be broadly classified into two categories – (a) Diffusive and (b) Ballistic transport. In the Diffusive regime, electron mean free path is smaller than the length of the system and its width is larger than the Fermi wavelength (λF). In this case, electron transport is dominated by a series of scattering events which are mainly due to impurities and electron - phonon interactions. In the case of Ballistic regime, electron mean free path is greater than the length of the system and the width is comparable to λF. Ballistic transport theory describes the conduction through single atomic junctions. In this thesis, we have used the magnetic field as additional degree of freedom to control the transport phenomena in both diffusive and ballistic regimes. Essentially, magnetic field effect on (a) dye sensitized solar cells (Diffusive regime) and (b) mechanically controlled break junction devices (Ballistic regime) is explored

Effect of Low Substrate Temperature on the Magnetic Properties and Domain Structure of Fe₇₀Ga₃₀ Thin Films

We report on the effect of low substrate temperature on the correlation between structure, magnetic properties, and micromagnetic behavior of Fe70Ga30 thin films. The enhanced grain size and the decrease in the number of pinning centers are in correlation with the enhanced saturation magnetization and domain size (0.2- $0.5~\mu \text{m}$ ), respectively. Estimated effective magnetic anisotropy energy ( $K_{\mathrm {eff}}$ ) is found to increase with substrate temperature from $7.5 \times 10^{5}$ J/m3 (room temperature) to $13.6 \times 10^{5}$ J/m3 (350 °C). The coercivity variation from the object-oriented micromagnetic framework (OOMMF) simulation is in line with respect to experimental values. Spin structure from simulation also indicates multiple-domain configuration when there is a magnetization reversal. © 1965-2012 IEEE