Structural and phonon characteristics of PbxLa1−xTiO3 nanocrystals prepared by hydrothermal technique

Phase transition and phonon characteristics of PbTiO3 single-crystal nanorods prepared in NaCl flux

“…Earlier investigations on doped PT have discovered that the impurities can also cause the decreasing of tetragonality, accompanying with broadening and weakening of Raman lines [12,14]. However, in the doped PT the frequency shifting of B 1 +E was distinctly observed, since the impurities change the valence state of oxygen [12,14,24,25]. As known, for PT the size effect does not affect the frequency of B 1 +E [11,18].…”

“…The stiffening of the mode B 1 +E can reflect the rigidity of the oxygen octahedral in the lattice of PT nanorods [11,18,20,23], ensuring that there is little distortion happened to the octahedral structure. Earlier investigations on doped PT have discovered that the impurities can also cause the decreasing of tetragonality, accompanying with broadening and weakening of Raman lines [12,14]. However, in the doped PT the frequency shifting of B 1 +E was distinctly observed, since the impurities change the valence state of oxygen [12,14,24,25].…”

“…It's known that the softening of mode E(1TO) drives a ferroelectric-to-paraelectric (tetragonal-to-cubic) phase transition [11,18,23] [11]. The reduction of tetragonality in the PT nanorods should be responsible for it, which also leads to weakening of ferroelectricity [11,12,18,23]. Fig.…”

“…As an important perovskite oxide of excellent ferroelectric and optoelectronic characters, PT has been studied theoretically and experimentally in the past decades. Among these pioneer works, many efforts were focused on the size effect of PT nanocrystals and thin films [11][12][13][14]. The phase transition driven by the soft mode E(1TO) and the mode soften behaviors have been extensively investigated, proving that the Raman scattering is a very sensitive and effective method for size effect related researches [11][12][13][14][15][16][17][18][19].…”

“…Among these pioneer works, many efforts were focused on the size effect of PT nanocrystals and thin films [11][12][13][14]. The phase transition driven by the soft mode E(1TO) and the mode soften behaviors have been extensively investigated, proving that the Raman scattering is a very sensitive and effective method for size effect related researches [11][12][13][14][15][16][17][18][19]. Subsequently, series of theoretical and empirical equations have been established to describe the detailed relationships between their size and characters [11,13,[15][16][17].…”