Papers by Author: S. Chen

Abstract: Sm-doped bismuth titanate and random oriented Bi4-xCexTi3O12 (BCT) thin films were fabricated on Pt/Ti/SiO2/Si substrates rf magnetron sputtering technique. The structures and the ferroelectric properties of the films were investigated. Ce doping leads to a marked improvement in the remanent polarization (Pr) and the coercive field (Ec). At the applied electric field of 100 kV/cm, Pr and Ec of the BCT (x = 0.8) film annealed at 650 oC are 20.5 μC/cm2 and 60 KV/cm, respectively. However, after 3 × 1010 switching cycles, 20% degradation of 2Pr is observed in the film.

Abstract: Pr6O11-doped bismuth titanate and random oriented BixPryTi3O12 ( y = 0.3, 0.6, 0.9, 1.2) thin films were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well developed rod-like grains with random orientation. Pr doping into BIT caused a shift of the Curie temperature (TC) of the BIT from 675°C to 578 , 517, 398 , and 315oC for the films with y = 0.3, 0.6, 0.9, and 1.2, respectively. The experimental results indicated that Pr doping into BIT result in a remarkable improvement in dielectric properties. Raman analysis shows that Pr3+ and Pr4+ ions substitution only appears in A-sit.

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.