Effects of Excess Bi2O3 on the Ferroelectric Behavior of Nd‐Doped Bi4Ti3O12 Thin Films

Abstract

Effects of excess Bi2O3 content on formation of (Bi3.15Nd0.85)Ti3O12 (BNT) films deposited by RF sputtering were investigated. The microstructures and electrical properties of BNT thin films are strongly dependent on the excess Bi2O3 content and post‐sputtering annealing temperature, as examined by XRD, SEM, and P–E hysteresis loops. A small amount of excess bismuth improves the crystallinity and therefore polarization of BNT films, while too much excess bismuth leads to a reduction in polarization and an increase in coercive field. P–E loops of well‐established squareness were observed for the BNT films derived from a moderate amount of Bi2O3 excess (5 mol%), where a remanent polarization 2Pr of 25.2 μC/cm2 and 2Ec of 161.5 kV/cm were shown. A similar change in dielectric constant with increasing excess Bi2O3 content was also observed, with the highest dielectric constant of 304.1 being measured for the BNT film derived from 5 mol% excess Bi2O3.