Papers by Author: X.B. Liu

Abstract: The electrical properties of Gd-doped bismuth titanates (Bi3.25Gd0.75Ti3O12, BGT) prepared by a conventional ceramic technique have been investigated. At applied d.c. field below 200V/mm, the current-voltage curve of the BGT ceramic exhibits a negative differential resistance behavior. The impedance spectrum indicates that the sample consists of semiconducting grain and moderately insulating grain boundary regions. XRD, SEM and EPMA analyses reveal crystalline phase characterized by a Bi-layered perovskite structure of Bi4Ti3O12 (BIT) and the distribution of every element is uniform. The BGT sample exhibits randomly oriented and plate-like morphology.

Abstract: Nd-doped bismuth titanate Bi4-xNdxTi3O12 (BNT) thin films were fabricated on Pt/Ti/SiO2/Si substrates by sol-gel method and spin-coating technique. The structures and the ferroelectric properties of the films were investigated. Nd doping leads to a marked improvement in the remanent polarization (Pr) and the coercive field (Ec). At the applied electric field of 260 kV/cm, Pr and Ec of the BNT film with x=0.5 annealed at 650oC are 19 μC/cm2 and 135 kV/cm, respectively. Moreover, the BNT film with x=0.5 showed a fatiguefree behavior up to 3×1010 read/write cycles.