Evidence from Raman Scattering for an Overdamped Soft Optic Mode in BaTiO3

Silent soft mode in hexagonal barium titanate observed by hyper-Raman scattering.

In a recent paper' Inoue et al. discussed a soft optical phonon that drives the second-order phase transition from hexagonal BaTi03, space group P63/mme (D6t, ), to a lower-symmetry structure at T, =222 K. The new phase is not ferroelectric and its structure is not known. The soft mode is Raman and infrared inactive and therefore is a so-called "silent" mode. Using hyper-Raman scattering, Inoue...

SOFT-MODE PHONONS in SrTiO3 THIN FILMS STUDIED by FAR-INFRARED ELLIPSOMETRY and RAMAN SCATTERING

We report the experimental studies of the vibrational spectra of SrTiO3 films with the thickness of 1 μm grown by pulsed laser deposition. Fourier-transform infrared ellipsometry between 30 and 700 cm and electric field-induced Raman scattering techniques have been utilized for investigation of the phonon behavior. These results can be used for comparison with the low-frequency measurements of ...

Stimulated Raman scattering in soft glass fluoride fibers

Collective spin fluctuation mode and Raman scattering in superconducting cuprates

Although the low-frequency electronic Raman response in the superconducting state of the cuprates can be largely understood in terms of a d-wave energy gap, a long-standing problem has been an explanation for the spectra observed in the A1g polarization orientations. We present calculations which suggest that the peak position of the observed A1g spectra is due to a collective spin fluctuation ...

development and implementation of an optimized control strategy for induction machine in an electric vehicle

in the area of automotive engineering there is a tendency to more electrification of power train. in this work control of an induction machine for the application of electric vehicle is investigated. through the changing operating point of the machine, adapting the rotor magnetization current seems to be useful to increase the machines efficiency. in the literature there are many approaches wh...