"[A67BA5BEE52F]" . "infrared and terahertz spectroscopy; soft mode; incipient ferroelectrics"@en . "6"^^ . "US - Spojen\u00E9 st\u00E1ty americk\u00E9" . . . "P(GA202/09/0682), Z(AV0Z10100520)" . "Soft-mode behavior and incipient ferroelectricity in Na1/2Bi1/2Cu3Ti4O12." . "288236" . "000279090100001" . . "2"^^ . "Ferrarelli, M. C." . . . . "Soft-mode behavior and incipient ferroelectricity in Na1/2Bi1/2Cu3Ti4O12."@en . . . "Kamba, Stanislav" . . "RIV/68378271:_____/10:00347911" . "Nuzhnyy, Dmitry" . "RIV/68378271:_____/10:00347911!RIV11-GA0-68378271" . . . "Soft-mode behavior and incipient ferroelectricity in Na1/2Bi1/2Cu3Ti4O12."@en . "81" . . "Na1/2Bi1/2Cu3Ti4O12.(NBCTO) ceramics exhibit high intrinsic relative permittivity of 145 at 300 K that rises on cooling and levels off below 50 K with a value of 260 at 10 K without any signature of a structural transition. Such behavior is a typical feature of incipient ferroelectrics such as the perovskite CaTiO3. Infrared and terahertz spectroscopy on NBCTO ceramics are presented and reveal a room-temperature soft polar optic mode at 34 cm-1 that softens on cooling and is responsible for the temperature dependence of the relative permittivity. The temperature dependence of the soft-mode frequency obeys the Barrett formula with the onset of quantum fluctuations T1 occurring near 85 K and a hypothetical Curie temperature T0 of 155 K. A fitted vibrational zero-point energy (kBT1)/2 is in good agreement with the measured soft-mode frequency." . . . "Na1/2Bi1/2Cu3Ti4O12.(NBCTO) ceramics exhibit high intrinsic relative permittivity of 145 at 300 K that rises on cooling and levels off below 50 K with a value of 260 at 10 K without any signature of a structural transition. Such behavior is a typical feature of incipient ferroelectrics such as the perovskite CaTiO3. Infrared and terahertz spectroscopy on NBCTO ceramics are presented and reveal a room-temperature soft polar optic mode at 34 cm-1 that softens on cooling and is responsible for the temperature dependence of the relative permittivity. The temperature dependence of the soft-mode frequency obeys the Barrett formula with the onset of quantum fluctuations T1 occurring near 85 K and a hypothetical Curie temperature T0 of 155 K. A fitted vibrational zero-point energy (kBT1)/2 is in good agreement with the measured soft-mode frequency."@en . "Physical Review. B" . . . "Sinclair, D. C." . . "1098-0121" . "Soft-mode behavior and incipient ferroelectricity in Na1/2Bi1/2Cu3Ti4O12." . . "4"^^ . "22" .