TY - JOUR
T1 - Soft-phonon mode observation in Li 2Ge 4O 9 phase above room temperature
AU - Takahashi, Yoshihiro
AU - Kunitomo, Jun
AU - Nakamura, Kensaku
AU - Osada, Minoru
AU - Fujiwara, Takumi
N1 - Funding Information:
This work was supported by the Ministry of Education, Culture, Sports, Science and Technology of the Japanese Government and the Nippon Sheet Glass Foundation for Materials Science and Engineering. The authors would like to thank Professor Yuzuru Miyazaki and Mr. Eisuke Aikawa of Tohoku University, and Dr. Kiyotaka Iijima of NIMS-MANA for significant contributions to this study.
PY - 2012/2/27
Y1 - 2012/2/27
N2 - 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.
AB - 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.
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U2 - 10.1063/1.3688603
DO - 10.1063/1.3688603
M3 - Article
AN - SCOPUS:84857936680
SN - 0003-6951
VL - 100
JO - Applied Physics Letters
JF - Applied Physics Letters
IS - 9
M1 - 091902
ER -