Study of molecular spin-crossover complex Fe(phen)2(NCS)2 thin films

We report on the growth by evaporation under high vacuum of high-quality thin films of Fe(phen)2(NCS)2 (phen=1,10-phenanthroline) that maintain the expected electronic structure down to a thickness of 10 nm and that exhibit a temperature-driven spin transition. We have investigated the current-voltage characteristics of a device based on such films. From the space charge-limited current regime, we deduce a mobility of 6.5x10-6 cm2/V?s that is similar to the low-range mobility measured on the widely studied tris(8-hydroxyquinoline)aluminium organic semiconductor. This work paves the way for multifunctional molecular devices based on spin-crossover complexes

Magnetoresistance signature of resonant states in electromigrated Ni nanocontacts

Fundamental insight is reported into magnetoresistance properties of ballistic-type atomic size Ni nanojunctions obtained at low temperatures. Feedback-controlled electromigration was used to reveal the ballistic nature of the transport and stabilize samples of conductance values in the range of G(0) (G(0) = 2e(2)/h). Bias voltage dependent measurements identify a clear magnetoresistance fingerprint of resonant tunneling, revealing that localized states in the nanojunctions can be responsible for nonlinear behavior in the IV curves and the related magnetoresistance properties. (C) 2011 American Institute of Physics. [doi:10.1063/1.3576939

Magnetoresistance signature of resonant states in electromigrated Ni nanocontacts

Fundamental insight is reported into magnetoresistance properties of ballistic-type atomic size Ni nanojunctions obtained at low temperatures. Feedback-controlled electromigration was used to reveal the ballistic nature of the transport and stabilize samples of conductance values in the range of G 0 (G 0 =2e 2 /h). Bias voltage dependent measurements identify a clear magnetoresistance fingerprint of resonant tunneling, revealing that localized states in the nanojunctions can be responsible for nonlinear behavior in the IV curves and the related magnetoresistance properties. © 2011 American Institute of Physics

Co-tunneling Enhancement of the Electrical Response of Nanoparticle Networks

A co-tunneling charge-transfer process dominates the electrical properties of a nanometer-sized slice in a nanoparticle network, which results in universal scaling of the conductance with temperature and bias voltage, as well as enhanced spintronics properties. By designing two large (10 mu m) electrodes with short (60 nm) separation, access is obtained to transport dominated by charge transfer involving nanoslices made of three nanoparticles only. Magnetic iron oxide nanoparticle networks exhibit a magnetoresistance ratio that is not reachable by tunneling or hopping processes, thereby illustrating how such a size-matched planar device with dominant co-tunneling charge-transfer process is optimal for realizing multifunctional devices with enhanced change of conductance under external stimulus

Nutritional aspects of food extrusion: a review

Extrusion cooking, as a multi-step, multi-functional and thermal/mechanical process, has permitted a large number of food applications. Effects of extrusion cooking on nutritional quality are ambiguous. Beneficial effects include destruction of antinutritional factors, gelatinisation of starch, increased soluble dietary fibre and reduction of lipid oxidation. On the other hand, Maillard reactions between protein and sugars reduce the nutritional value of the protein, depending on the raw material types, their composition and process conditions. Heat-labile vitamins may be lost to varying extents. Changes in proteins and amino acid profile, carbohydrates, dietary fibre, vitamins, mineral content and some non-nutrient healthful components of food may be either beneficial or deleterious. The present paper reviews the mechanisms underlying these changes, as well as the influence of process variables and feed characteristics. Mild extrusion conditions (high moisture content, low residence time, low temperature) improve the nutritional quality, while high extrusion temperatures (200 &deg;C), low moisture contents (&lt;15%) and/or improper formulation (e.g. presence of high-reactive sugars) can impair nutritional quality adversely. To obtain a nutritionally balanced extruded product, careful control of process parameters is essential.<br /