Enhancement of Polarization Property of PZT Film by Ion-Substitution Using Rare-Earth Elements

概要

論文の詳細を見る
Rare-earth-substituted lead zirconate titanate thin films were synthesized to improve the ferroelectric properties of lead zirconate titanate through the enhancement of its crystal anisotropy. Thin films of Pb1.00-(3x/2)REx(Zr0.40Ti0.60)O3 [RE-PZT(A)] and Pb1.00REx(Zr0.40Ti0.60)1-(3x/4)O3 [RE-PZT(B)] with $\text{RE}=\text{La}$ or Dy were deposited on (111)Pt/Ti/SiO2/(100)Si substrates by chemical solution deposition (CSD). Rare-earth-substitution did not affect the crystal orientation of the PZT-based films where the PZT(111) plane was oriented along the surface-normal direction. Dy3+ substitution based on Dy-PZT(B) up to $x=0.02$ enhanced the crystal anisotropy ($c/a$) and remanent polarization ($P_{\text{r}}$) of PZT films simultaneously, while both $c/a$ and $P_{\text{r}}$ values of Dy-PZT(A) decreased as $x$ increased continuously. On the other hand, La3+ substitution degraded the ferroelectric properties gradually in both the case of La-PZT(A) and (B). The Dy3+ ion could be substituted for a B-site in a PZT crystal preferentially, and that promoted the crystal anisotropy and the ferroelectric properties of PZT films.
2005-09-15