The solgel process successfully prepared Nd<sub>2</sub>O<sub>3</sub> / SiO<sub>2</sub> nanocomposites. After drying in air at 85°C for three days, samples were heat treated, in air, at 750, 950, 1150 and 1250°C. Characterizations were made by, Infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Mechanisms of neodymium oxide nano clusters formation in the densified silica matrix with respect to thermal treatment are discussed. XRD profiles confirm the crystallinity of the nanoclusters. The size of the nanoclusters was found in the range 15-30nm.
In the present paper, using the hydrodynamic model of semiconductor plasmas and following the coupled mode
approach an analytical investigation of the stimulated Raman (SRS) and Brillouin (SBS) scatterings of the Stokes mode
is undertaken in magnetoactive doped III-V semiconductors. These phenomena have been studied considering that the
second-order forces responsible for them are different, viz., the finite differential polarizability gives rise to SRS, while
the material properties like piezoelectricity and electrostrictive strain produces SBS in the medium. Gain coefficients,
threshold pump intensities, and optimum pulse durations for the onset of SRS and SBS are estimated. The qualitative
behavior of transient gain coefficients is found to be in agreement with the experimental and other theoretical
observations. The proper selection of doping concentration and an externally applied magnetic field substantially
enhances the gain coefficients of SBS and SRS processes. The ratio between the two gain constants indicates that for the
same pump field SBS exhibits higher gain than SRS by two orders of magnitudes. The analysis explains satisfactorily the
competition between stimulated Raman and Brillouin processes in the short- and long-pulse duration regimes. Numerical
estimates have been made for n-type doped InSb crystal at 77K duly irradiated by 10.6&mgr;m CO<sub>2</sub> laser.