Kazuyuki Hino

Formation and magnetic characteristics of cobalt–carbon nanocluster magnets embedded in amorphous carbon matrices

Abstract Co–C 2 nanocluster magnets are formed in amorphous carbon by high pressure reaction of Co 4 (CO) 12 and CH 2 Cl 2 . The average size of the clusters is 12 nm. Structural characteristics are investigated by transmission electron microscope (TEM), electron energy loss spectroscopy (EELS), extended X-ray absorption fine structure (EXAFS) analyses, and infrared spectroscopy suggesting that the clusters are (CoC 2 ) n with π bonds in C 2 2− . The magnetization decreases with decreasing temperatures from room temperature to 20 K, while 10 Oe field-cooling (FC) results in increasing magnetization at lower temperatures.

Electric-Field-Induced Changes in Absorption and Fluorescence of the Green Fluorescent Protein Chromophore in a PMMA Film

External electric field effects on absorption, fluorescence, and fluorescence decay of p-HBDI that is a model compound of the chromophore of GFP have been examined in a poly(methyl methacrylate) film. The electroabsorption spectrum is similar in shape to the first derivative of the absorption spectrum, which results from the difference in molecular polarizability between the ground state and the Franck-Condon excited state. The electrophotoluminescence spectrum is dominated by the corresponding fluorescence spectrum, indicating the enhancement of the fluorescence intensity in the presence of external electric fields. The direct measurements of the electric field effect on the fluorescence decay profile suggest that the field-induced deceleration of the nonradiative process contributes to the increase in the fluorescence intensity in the presence of electric fields.