Raman spectroscopic study of Na1/2Bi1/2TiO3-x%BaTiO3 single crystals as a function of temperature and composition

Abstract

Articles you may be interested inChemical and structural effects on the high-temperature mechanical behavior of (1−x)(Na1/2Bi1/2)TiO3-xBaTiO3 ceramics J. Appl. Phys. 117, 134110 (2015); 10.1063/1.4916784Anisotropy of ferroelectric behavior of (1 − x)Bi1/2Na1/2TiO3-xBaTiO3 single crystals across the morphotropic phase boundary J. Appl. Phys. 116, 044111 (2014) A Raman spectroscopic study of Na 1/2 Bi 1/2 TiO 3 -x%BaTiO 3 (NBT-x%BT) single crystals with x ¼ 0 and 5.6 has been performed as a function of temperature from 25 to 600 C. The general features of the Raman spectra for the various compositions were similar over the region of the phase diagram investigated, with only subtle changes between rhombohedral (R), tetragonal (T) and cubic phases. The peaks were broad, with no significant narrowing on cooling through a phase transition. We find evidence of an oxygen octahedral rotational mode in the paraelectric state. On cooling near and below the ferroelectric Curie temperature, a gradual change in intensity of the A-O and B-O peaks occurred with decreasing temperature. Evidence of a ferroelectric ! antiferroelectric transition was found near 200-250 C, consistent with the onset of dispersion in the dielectric constant. The phase transition mechanism was discussed. The findings indicate the presence of a broad distribution of quasistatic local structural distortions, which only have subtle differences in the various average structures.

Relaxor behaviour and phase transition of perovskite ferroelectrics-type complex oxides (1–x)Na0.5Bi0.5TiO3–xCaTiO3 system

“…The spectrum of NBT is in general very similar and in good agreement with the already published work [11,[76][77][78][79], where it was assigned a total of 13 Ramanactive modes (Γ R3c = 4A 1 + 9E) [78] that similar main regions in the spectrum can be detected [79]. It can be seen that all Raman bands are relatively broad which can be related to a possible disorder at A-site due to the random distribution of Na/Bi cations.…”

Evolution of phase structure and giant strain at low driving fields in Bi-based lead-free incipient piezoelectrics

“…4(a). Three main active modes were perceived in the pure BNBTNb-SZ ceramics from 100 to 700 cm −1 , which were identical to other BNT-based ceramics [49][50][51][52][53]. The Raman-active mode (A 1 ) observed around 150 cm −1 is related to the vibrations of an A-site perovskite structure which comprises of A-site cations Bi, Na, Ba, and Sr.…”

Structure and properties of Fe-modified Na0.5Bi0.5TiO3at ambient

“…15,[20][21][22][23][24] Due to challenges of intrinsic broadening and overlapping of phonon modes in the assignment of mode symmetries, structural analysis thus relies on analyzing soft-mode or hard-mode behavior as a function of composition, pressure or temperature. 15,[21][22][23][24] Other studies in NBT-BT 25 and NBT-SrTiO 3 24 generally confirmed that transitions involving the ferroelectric behavior are related to subtle local structural distortions and phase coexistence.…”