Ferroelectric properties and polarization fatigue of Bi-modified Pb(Zr,Ti)O₃ thin film

Abstract
Since many industrial applications of ferroelectric lead zirconium titanate [Pb(Zr,Ti)O₃ ; PZT] thin films are limited due to the problem of degradation, in this paper, it was investigated ferroelectric fatigue properties of Bi-modified PZT, (Pb_1-3/2xBi_x)(Zr_0.52Ti_0.48)O₃ (PBZT), and PBZT/PZT/PBZT thin films deposited onto platinized silicon wafers by means of sol-gel method. Ferroelectricity, confirmed by P-E hysteresis characteristics, was found below x=0.25 in both films. It was shown that the formation of Bi-modified structure be independent of Bi content, although the Bi content strongly affect P_r and E_c. The values of both dielectric constant and remnant polarization decrease monotonically with increasing the Bi contents, but the rate of polarization fatigue slightly increases. However, both films show good crystallinity and well saturated hysteresis curve at x=0.05, which is related to the rate slope of polarization fatigue. This paper describes how the presence of Bi affects the fatigue characteristics of PBZT thin films. Fatigue behavior of PBZT/PZT/PBZT multilayer was improved as compared to that of PBZT thin film.