We investigated the electronic structures of the 5d Ruddlesden-Popper series Sr n+1 Ir n O 3n+1 (n=1, 2, and ∞) using optical spectroscopy and first-principles calculations. As 5d orbitals are spatially more extended than 3d or 4d orbitals, it has been widely accepted that correlation effects are minimal in 5d compounds. However, we observed a bandwidth-controlled transition from a Mott insulator to a metal as we increased n. In addition, the artificially synthesized
( 1 − x ) Pb ( Zr 0.4 , Ti 0.6 ) O 3 – ( x ) Bi ( Zn 0.5 , Ti 0.5 ) O 3 (PZT-BZT) (x=0, 0.03, 0.05, 0.08, and 0.1) films were deposited on Pt(111)/Ti/SiO2/Si(100) substrates by chemical solution deposition using spin-coating. All samples showed highly (111) oriented perovskite phase and no other phase was observed. The ferroelectric properties of PZT-BZT films were systematically investigated as a function of the content x of the BZT solution. It is found that BZT doping in PZT films could greatly enhance the remnant polarization (Pr), as well as improve the fatigue property. In a 3 wt % BZT-doped PZT film, the 2Pr and the coercive field (Ec) are 90 μC/cm2 and 95 kV/cm at 10 kHz, respectively, at an electric field of 500 kV/cm, and the leakage current density is less than 1×10−7 A/cm2. The impact of BZT doping on the structure of PZT has been investigated by x-ray photoelectron spectroscopy.
Preparation of many amounts of thin film samples with different compositions takes long time. To confirm the possibility of brief and systematic preparation process of oxide films using a chemical solution deposition method, precursor solutions of PbTiO3 and PbZr03 are synthesized, and those solutions were mixed various volume rate to change the composition of Pb(Zr,Ti,,)O3 series samples from x=O. 1 to 0.9. PbTi03 and PbZr03 solutions were mixed just before the film deposition process. The dielectric and ferroelectric properties were evaluated systematically. The relative dielectric constant took a peak around x=0.5. On the other hand, well-saturated P-E hysteresis curves were observed for x=0.3 to 0.9. The remanent polarization and coercive field decreased with increasing Zr content x. These results are consistent with the ferroelectric properties of bulk and film PZT prepared conventional method. Therefore, mixed solution method results in reliable and brief process to discover new oxide materials.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.