Ferroelectric properties of ion-cosubstituted BIT thin films, (Bi 4.00-yLny)4-δ (Ti3.00-xX x)3O12 (BLnTX), with various lanthanoid (Ln: e.g., La3+, Nd3+, Pr3+, Sm3+) and higher-valent ions (X: e.g., V5+, Nb5+, Ta5+, W6+) were investigated to determine the optimum condition of the ion-cosubstitution. Ion-substituted BIT films were fabricated on (111)Pt/Ti/SiO2/(100)Si substrates using a chemical solution deposition (CSD) technique. In the case of Bi-site substitution, Pr 3+, Nd3+ and Sm3+-substituted BIT films (BPT, BNT and BST) had larger remanent polarization (Pr) values than that of conventional La3+-substituted BIT film (BLT). Especially, P r and Ec values of (Bi3.50Nd 0.50)Ti3.00O12 film were measured to be 32 μC/cm2 and 126 kV/cm, respectively. On the other hand, Ti-site substitution by higher-valent cations degraded the large leakage current density of the BIT film from ∼10-6 down to ∼10-7 A/cm2. V-substituted (Bi3.50Nd0.50)Ti 3.00O12 films, i.e., Nd3+/V5+- cosubstituted BIT films (BNTV), had larger Pr values than that of non-substituted (Bi3.50Nd0.50)Ti3.00O 12 film. (Bi3.49Nd0.50)(Ti2.97V 0.03)O12 film possessed Pr and Ec values of 37 μC/cm2 and 119 kV/cm respectively, which were comparable with those of conventional Pb-based ferroelectric thin films like lead zirconate titanate, Pb(Zr,Ti)O3.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Control and Systems Engineering
- Ceramics and Composites
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry