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In order to assess the magnetic ordering process in Fe2VAl and the related material Fe2VGa, we have carried out nuclear magnetic resonance (NMR) and Mössbauer studies.27 Al NMR relaxation measurements covered the temperature range 4 -500 K in Fe2+xV1−xAl samples. We found a peak in the NMR spin-lattice relaxation rate, 27 (T −1 1 ), corresponding to the magnetic transitions in each of these samples. These peaks appear at 125 K, 17 K, and 165 K for x = 0.10, 0, and -0.05 respectively, and we connect these features with critical slowing down of the localized antisite defects. Mössbauer measurements for Fe2VAl and Fe2VGa showed lines with no hyperfine splitting, and isomer shifts nearly identical to those of the corresponding sites in Fe3Al and Fe3Ga, respectively. We show that a model in which local band filling leads to magnetic regions in the samples, in addition to the localized antisite defects, can account for the observed magnetic ordering behavior.

Electric field-modulated amplified spontaneous emission in waveguides based on poly [2-methoxy-5-( 2 ′ethylhexyloxy)-1, 4-phenylene vinylene] Appl.Poly͑p-phenylene vinylene͒ mulilayers have been prepared from its cationic precursor via the layer-by-layer deposition. The photoluminescence ͑PL͒ and film thickness of the multilayers have been examined via fluorimetry and atomic force microscopy. The PL of the multilayers has been observed that is consistent with the literature results. When phosphomolybdate PMo 12 is incorporated into the multilayer structure, PL quenching is detected that is proportional to the amount of PMo 12 used. The quenching is interpreted as exciton diffusion through the polymer multilayers, followed by exciton dissociation at the polymer/PMo 12 interface. We show that the modeling used for calculating the PL intensities derived from inorganic semiconductors is also applicable to conjugated polymers. According to the model, an exciton diffusion length is found to be 11.5± 0.4 nm.

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