Ferroelectric properties of BaTiO<sub>3</sub> related thin film prepared by pulsed laser deposition method using Nd<sup>3+</sup>:YAG laser

Abstract

BaTi0.91(Hf0.5, Zr0.5)0.09O3 thin films were synthesized by pulsed laser deposition method using fourth harmonic generated Nd3+:YAG laser beam. The ferroelectric properties of BaTi0.91(Hf0.5, Zr0.5)0.09O3 thin films were investigated by electrical measurements. Using Debye model, the frequency dependence of dielectric constant for BaTi0.91(Hf0.5, Zr0.5)0.09O3 thin films was analyzed. The dielectric constant of multi-layerd film which was grown by BaxTi0.91(Hf0.5, Zr0.5)0.09O3 (x=1.0, 3.0) targets decreased significantly with increasing frequency. On the other hand, the BaTi0.91(Hf0.5, Zr0.5)0.09O3 thin film grown by BaxTi0.91(Hf0.5, Zr0.5)0.09O3 (x=1.5) target decreased weakly with increasing frequency. The dielectric constant, remanent polarization and coercive electric field were estimated to be 118 at 1kHz, 8.7μC/cm2 and 127kV/cm, respectively.BaTi0.91(Hf0.5, Zr0.5)0.09O3 thin film on Pt/SiO2/Si(100) substrate showed high Curie temperature than that of BaTi0.91(Hf0.5, Zr0.5)0.09O3 polycrystal. The RHEED intensity oscillation was observed during the deposition of SrTiO3 buffer layer and BaTi0.91(Hf0.5, Zr0.5)0.09O3 thin film on Nb:SrTiO3(100) substrate. The D-E hysteresis loop of BaTi0.91(Hf0.5, Zr0.5)0.09O3 thin film on Nb:SrTiO3(111) substrate was observed. The remanent polarization and coercive electric field were estimated to be 3.1μC/cm2 and 3.6kV/cm, respectively. Polarization fatigue measurements were carried out up to 1012 cycles.