[8p-F212-1~14] 9.1 Dielectrics, ferroelectrics

2:00 PM - 2:15 PM JST(5:00 AM - 5:15 AM UTC)Presentation by Applicant for JSAP Young Scientists Presentation Award

[8p-F212-3] Phase Transition Mechanism in Titanite Studied by Raman Spectroscopy

〇(M1)Masayuki Hiromasu¹, Nobuo Nakajima¹, Toshiya Uohashi², Hiroki Taniguchi², Takumi Hasagawa¹ (1.Grad. Sch. of Adv. Sci. & Eng., Hiroshima Univ., 2.Grad. Sch. of Sci., Nagoya Univ.)

Keywords:

Titanite,Raman spectroscopy,Phase transition

Temperature-dependent lattice vibrations across the antiferroelectric phase transition of titanite (CaTiSiO₅) at T_a = 200 ℃ were examined by Raman spectroscopy. Because the reduction in Ti off-center displacement above T_a was smaller than expected, additional contributions from the lattice vibrations of the SiO₄ tetrahedra and Ca ions are suggested to play in the phase transition. Raman spectra revealed that a vibrational mode of Ca exhibits marked changes above T_a, whereas those of the SiO₄ tetrahedra show only minor variations. These results indicate that Ca-related lattice dynamics are correlated with the antiferroelectric order.