Ferroelectric properties of lithium heptagermanate crystal Li₂Ge₇O₁₅(LGO) in the vicinity of phase transition

Abstract

The crystals of lithium heptagermanate (Li₂Ge₇O₁₅) of high quality have been grown. The dielectric permeability of these crystals at Curie temperature (ε _m ) reaches 350. The temperature dependence of both dielectric constant and spontaneous polarization is nonclassical. In the vicinity of phase transition the critical exponents β and γ are the same as in Ising theory. The frequency dependence of ε _m in 10³-10⁶ Hz frequency range have been observed.

Key Words:

• Weak ferroelectric
• lithium heptagermanate
• phase transition
• permeability
• polarization