Brillouin and Raman scattering in [N(CH3)4]2ZnCl4

The normal-incommensurate-commensurate phase transitions of [N(CH3)4]2ZnCl4 have been extensively studied through Brillouin and Raman scattering. Frequency dispersion of sound velocity of the [001] LA-mode has been confirmed in a frequency range of between 1 GHz and 10 GHz in the incommensurate phase. The relaxation time is characterized by [image omitted] and we obtain τ0 = 0.74 × 10-12 sec for T1 = 296 K.Low frequency light scattering spectra below 240 cm-1 have been carefully examined by Brillouin and Raman scattering. Neither soft mode nor critical relaxation mode has been observed in the light scattering spectra in the incommensurate phase.

Keywords:

• Brillouin and Raman Scattering
• [N(CH₃)₄]₂ZnCl₄