Pressure Effect on the Ferroelectric Phase Transiton in Li₂Ge₇O₁₅

Abstract

The effect of hydrostatic pressure on the ferroelectric phase transition in Li 2 Ge 7 O 15 has been investigatied by the dielectric and Raman scattering measurements. The phase transition point T c shows a linear dependence whose pressure derivative is positive (d T c /d P =1.46 K/kbar). In the ferroelectric phase a soft mode has been observed which evolves from underdamped to overdamped behavior as the pressure is reduced from high pressure side to 0.7 kbar at 291.5 K.