Dielectric dispersion in Li₂Ge₇O₁₅

Abstract

The complex dielectric constant of Li₂Ge₇O₁₅ crystal has been measured at frequencies from 21 MHz to 7 GHz around the Curie temperature Tc. The dielectric dispersion of the Debye type has been found. A critical slowing-down of dielectric response has been observed, and the relaxation frequency decreases to about 1 GHz at Tc. The origin of the Debye dispersion observed in the vicinity of Tc is discussed in connection with the resonant type dispersion of soft optical phonon mode.

Key Words:

• dielectric constant
• dielectric dispersion
• critical slowing-down
• Curie temperature
• Li₂Ge₇O₁₅
• order-disorder type