Study On Optical And Dielectrical Properties Of ABO₃ Oxide Materials

This article was divided into the following several parts to study about the optical and dielectric properties of the composite films doped with nanoparticles.We have obtained the composite films with metal particals on different substrates by pulsed laser deposition.Single-beam z-scan has also been used for investigating the nonlinear optical properties of the films.Distribution of the shape and size of the metal nanoparticles are achieved by using transmission electron microscopy.We also discussed the shape and position of the absorption peak induced by the surface plasma resonance.As for dielectric properties,we have also researched the relationship between the dielectric constant and frequency in different temperatures,and the relationship between dielectric loss and variable frequencies.The crystal internal structure was studied by impedance spectroscopy.More details are claimed as follows:?1?We fabricated the composite thin films by using nanometer-sized metal particles?Au,Ag,Fe,Co?embedded in dielectric matrices(SrTiO_3,TiO₂,Al₂O₃)by using pulsed laser deposition technique.A conclusion has been confirmed based on experimental plot and Mie theory after our study of the optical absorption properties of the composite thin films.The position of the resonance peak of the composite film will be influenced by the real part of the dielectric function of the embedded metal particle and the refractive index of the embedding matrix when the imaginary part of the dielectric function of a metal particle hardly changes.?2?Composite films?Au/SrTiO₃,Ni/SrTiO₃?formed by using pulsed laser deposition.And then we used a single-beam z-scan technique to study the nonlinear optical properties of the composite film.It turns out that the figure of merit of the two composite films are similar,indicating that Au or Ni metal particles had little effect on the improvement of the figure of merit.However,Au particles are more effective on the real part of the third-order nonlinear susceptibility than Ni particles,instead Ni particles have a greater effect on the imaginary part of the third-order nonlinear susceptibility.?3?We measured the dielectric loss of TbMnO₃ in different temperature and got the real part of the dielectric constant,and analyzed the relaxation mechanism.The effect of crystal grain and grain boundaries on dielectric relaxation was analyzed by impedance spectroscopy.