Ferroelectric properties of sandwich structured (Bi,La)4Ti3O12/Pb(Zr,Ti)O3/(Bi,La)4Ti3O12 thin films on Pt/Ti/SiO2/Si substrates

Sandwich structured (Bi, La)(4)Ti3O12/Pb(Zr, Ti)O-3/(Bi, La)(4)Ti3O12 thin films were fabricated on Pt/Ti/SiO2/Si substrates, with the intention of simultaneously utilizing the advantages of both (Bi, La)(4)Ti3O12 (BLT) and Pb(Zr, Ti)O-3 (PZT) thin films such as non-fatigue behaviours of BLT and good ferroelectric properties of PZT. Both BLT and PZT layers were prepared by a chemical solution deposition technique. The experiments demonstrated that the sandwich structure showed fatigue-free characteristics at least up to 10(10) switching bipolar pulse cycles under 8 V and excellent retention properties. The sandwich structured thin films also exhibited well-defined hysteresis loops with a remanent polarization (2P(r)) of 8.8 muC cm(-2) and a coercive field (E-c) of 47 kV cm(-1). The room-temperature dielectric constant and dissipation factor were 210 and 0.031, respectively, at a frequency of 100 kHz. These results suggest that this sandwich structure is a promising material combination for ferroelectric memory applications.