Structural and dielectric properties of Er substituted sol-gel fabricated PbTiO3 thin films

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].…”

“…Interestingly, they exhibit a rather large size effect in comparison to PT nanocrystals and thin films with same ratio of surface layers [11][12][13][14]. To understand it, the growth mechanism was investigated and the intermediate steps of the synthesizing process were traced.…”

“…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].…”