NANNI , Paolo

The evolution with temperature of the Raman activity in the (1−x)Pb(Fe2∕3W1∕3)O3-xPbTiO3 solid solution with various compositions x∊(0, 1) was investigated. By increasing x, a general evolution of the system from disordered relaxor to ordered ferroelectric state with typical lines also observed in other Pb-based relaxors were found. The Raman...

A cobalt cementation process in ethanol-water solvent at different temperatures is presented. A new model is proposed which takes into account the depletion of the less electropositive metal by a shrinking core technique. The model comprises a system of two ordinary differential equations whose dependent variables are the concentration of the...

The bulk and surface structure of two BaTiO3 powders has been investigated by FT-IR and FT-Raman spectroscopies. A high-area sample (39 m2/g), produced by a hydrothermal method, cubic to XRD, appears to have lower symmetry to Raman spectroscopy, with unit-cell distortions similar to those of tetragonal ferroelectric BaTiO3. It contains BaCO3...

The transition relaxor-paraelectric in Pb(Fe2/3W1/3)O3 ceramics was studied by x-ray diffraction and Raman scattering at temperatures in the range of 85–800 K. For high diffraction angles (160° and 162°), a slight difference between the two phases was found. Raman spectra show an evolution with temperature with anomalies of bands of 848 cm−1...

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