The primary objective of this study is the development of transparent thin film materials in the IR enabling strong infrared absorption of organic compounds in the vicinity of metal nanoparticles by the surface plasmon effect. For developing these optical micro-sensors, heterostructures combining gold nanoparticles and chalcogenide planar waveguides are fabricated and adequately characterized. Single As 2 S 3 and Ge 25 Sb 10 Se 65 amorphous chalcogenide thin films are prepared by radiofrequency magnetron sputtering. For the fabrication of gold nanoparticles on a chalcogenide planar waveguide, direct current sputtering is employed. Fabricated single layers or hetero-structures are characterized using various techniques to investigate the influence of deposition parameters. The nanoparticles of gold are functionalized by a self-assembled monolayer of 4-nitrothiophenol. Finally, the surface enhanced infrared absorption spectra of 4-nitrothiophenol self-assembled on fabricated Au/Ge-Sb-Se thin films hetero-structures are measured and analyzed. This optical component presents a ~24 enhancement factor for the detection of NO 2 symmetric stretching vibration band of 4-nitrothiophenol at 1336 cm −1 .

This article reports on the International Nanofluid Property Benchmark Exercise, or INPBE, in which the thermal conductivity of identical samples of colloidally stable dispersions of nanoparticles or "nanofluids," was measured by over 30 organizations worldwide, using a variety of experimental approaches, including the transient hot wire method, steady-state methods, and optical methods. The nanofluids tested in the exercise were comprised of aqueous and nonaqueous basefluids, metal and metal oxide particles, near-spherical and elongated particles, at low and high particle concentrations. The data analysis reveals that the data from most organizations lie within a relatively narrow band ͑Ϯ10% or less͒ about the sample average with only few outliers. The thermal conductivity of the nanofluids was found to increase with particle concentration and aspect ratio, as expected from classical theory. There are ͑small͒ systematic differences in the absolute values of the nanofluid thermal conductivity among the various experimental approaches; however, such differences tend to disappear when the data are normalized to the measured thermal conductivity of the basefluid. The effective medium theory developed for dispersed particles by Maxwell in 1881 and recently generalized by Nan et al. ͓J. Appl. Phys. 81, 6692 ͑1997͔͒, was found to be in good agreement with the experimental data, suggesting that no anomalous enhancement of thermal conductivity was achieved in the nanofluids tested in this exercise.

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The search for an ideal magnetic semiconductor with tunable ferromagnetic behaviour over a wide range of doping or by electrical gating is being actively pursued as a major step towards realizing spin electronics. A magnetic semiconductor having a high Curie temperature, capable of independently controlled carrier density and magnetic doping, is crucial for developing spin-based multifunctional devices. Cr-doped In(2)O(3) is such a unique system, where the electrical and magnetic behaviour-from ferromagnetic metal-like to ferromagnetic semiconducting to paramagnetic insulator-can be controllably tuned by the defect concentration. An explicit dependence of magnetic interaction leading to ferromagnetism on the carrier density is shown. A carrier-density-dependent high Curie temperature of 850-930 K has been measured, in addition to the observation of clear magnetic domain structures in these films. Being optically transparent with the above optimal properties, Cr-doped In(2)O(3) emerges as a viable candidate for the development of spin electronics.

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