Pressure Effect on the Ferroelectric Phase Transition in Li₂Ge₇O₁₅

Abstract

The effect of hydrostatic pressure on the ferroelectric phase transition in Li₂Ge₇O₁₅ 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 (dT_c⁄dP=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.