Evidence of low‐temperature phase transition in BaTiO₃‐modified NaNbO₃: Raman spectroscopy study

Abstract

The solid solution of NaNbO 3 modified by 5% BaTiO 3 (NNBT05) is investigated by Raman spectroscopic technique as a function of temperature from 83 to 298 K. Detailed mode analysis revealed that the Raman bands at~112.8 and 277.1 cm −1 (at 298 K) disappear due to change in the symmetry of the structure at low temperature of 83 K. Further, rapid changes in the position of the Raman bands at 58.7 and 606.4 cm −1 (at 298 K) as a function of temperature provide evidence for the structural phase transition. These changes in the Raman spectra occur at different temperatures in the cooling and heating cycles as in a hysteresis loop, which provide evidence of the first-order nature of the phase transition at low temperature.

NaNbO3‐(Bi0.5Li0.5)TiO3 Lead‐Free Relaxor Ferroelectric Capacitors with Superior Energy‐Storage Performances via Multiple Synergistic Design

“…[52] However, the number of Raman peaks that can be observed in the experimental spectra is generally less than the expected number as a result of the weak intensity and very small frequency difference between some modes. [52,53] To better probe the variation of all Raman bands, the observable Raman vibrations can be divided into the independent translational vibration modes of the A-site cations and the internal oxygen octahedral modes (υ l , υ 2 , υ 3 , υ 4 , υ 5 , and υ 6 ). [52,53] In the low wave number region of <150 cm -1 , the modes are associated with the vibration of Bi, Li, and Na cations at the A-site of the perovskite lattice.…”

“…[52,53] To better probe the variation of all Raman bands, the observable Raman vibrations can be divided into the independent translational vibration modes of the A-site cations and the internal oxygen octahedral modes (υ l , υ 2 , υ 3 , υ 4 , υ 5 , and υ 6 ). [52,53] In the low wave number region of <150 cm -1 , the modes are associated with the vibration of Bi, Li, and Na cations at the A-site of the perovskite lattice. According to the difference in the atomic mass at the A-site, the three modes near 47, 72, and 99 cm -1 correspond to the BiO, NaO, and LiO vibrations, respectively.…”

High-Pressure Vibrational and Structural Studies of the Chemically Engineered Ferroelectric Phase of Sodium Niobate

“…We reported an orthorhombic antiferroelectric phase (space group: Pbcm) for x < 0.02, an orthorhombic ferroelectric phase (space group: Pmc2 1 ) for 0.02 < x < 0.10, and an orthorhombic ferroelectric phase (space group: Amm2) for x ≥ 0.10. We also reported the phase transitions as a function of temperature for NNBT03 and 05 using powder X-ray and neutron diffraction studies in conjunction with dielectric and Raman scattering measurements [30,31,35,36]. Apart from this, we provided evidence of the existence of a functional monoclinic phase at low temperatures.…”

“…For example, when doping the BaTiO 3 in the NaNbO 3 matrix, there is a significant enhancement in the dielectric and piezoelectric response of the material [30][31][32][33][34]. The structural, dielectric, ferroelectric and piezoelectric properties of NNBTx [(1 − x) NaNbO 3 − xBaTiO 3 ] ceramics have been investigated by various researchers [10,16,30,31,[33][34][35][36]. This solid solution is similar to K x Na 1−x NbO 3 (KNN), except that the KNbO 3 has been replaced by BaTiO 3 .…”

Recent advances in linear and nonlinear Raman spectroscopy. Part XIV

“…They found a new peak at 22 cm −1 at low temperatures and the temperature dependence of this peak made possible to assign it to the magnon mode at k = 0. Jauhari et al [ 182 ] provided evidence of a low‐temperature phase transition in BaTiO 3 ‐modified NaNbO 3 by Raman spectroscopy. Malfait et al [ 183 ] studied the capabilities of low‐wavenumber Raman spectroscopy to analyze the mechanism of devitrification of molecular glasses.…”