Li 2Ge 4O 9 is known to be a ferroelectric phase with Curie temperature at T c ∼ -93 C. In this study, we found both the lowest-frequency phonon and heat-capacity anomalies around 100 C in the Li 2Ge 4O 9 phase, demonstrating their presence in the structural phase-transition. The phase transition is probably triggered by regularization of distorted GeO 6 octahedra in the paraelectric phase, resulting in another phase consisting of the regular octahedral GeO 6 unit, which was supported by in situ measurement of emission of 2E → 4A 2 transition in the Mn 4-doped phase. It is deduced that the phase transition is more dynamic than ferroelectric phase-transition originating in ordering of the Li ions.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)