| (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3（PMN-PT, PMNT） relaxor-basedferroelectric single crystals have excellent properties, such as dielectric, ferroelectric,piezoelectric, pyroelectric, electro-optical, and nonlinear optical properties, which haswidespread applications in the field of microwave tunable devices, nonvolatilememories, transducer, sensors, optical waveguide components. In order to implementthe minimization of devices and systems, it is significant to prepare PMN-PT thinfilms with excellent properties. However, there are many problems needed to beresolved for obtaining high quality thin films, such as reducing the preparationtemperature, optimizing quality of thin films, controlling crystallinity andpreferred-orientation, investigating the relations between microstructure and electricalproperties. In view of the above problems, preparing technologies, structures andelectric properties of PMN-PT ferroelectric monolayer and multilayer thin films werestudied in this thesis.The0.62Pb(Mg1/3Nb2/3)O3-0.38PbTiO3（PMN-0.38PT） thin films with pure-perovskite phase were prepared at a low temperature （550°C） by radio-frequencymagnetron sputtering （RF-magnetron sputtering）. The crystallinity, microstructure,and electrical properties of PMN-PT thin films were improved by using La1-xSrxCoO3（LSCO） buffer layers between PMN-PT films and Pt/Ti/SiO2/Si substrates.（110） and（100） preferred-oriented PMN-PT thin films been obtained on LSCO layers with thesame preferred-orientations, that attributed to co-contribution of the surface andlattice-match interface energy. The relationships between electrical properties andorientations were studied.Stable PMN-0.38PT solution was prepared successfully using Nb2O5byimproved Pechini method. The effect of substrates and annealing methods oncrystallinity, microstructure and electrical properties were investigated. The resultsshowed that the thin films on LaNiO3（LNO） treated with rapid thermal annealing（RTA） process had larger remanent polarization and higher dielectric constant thanthose treated with conventional furnance annealing （CFA） process. The effects of different annealing temperatures on the surface morphologies have been studied. Thegrains of thin films annealed at600°C and650°C were small and fluffy, while thegrains on thin films annealed at700°C were large and compact with cracks, whichcaused large leakage current.To optimize the electrical properties of the thin films, PMNT basedmultilayer films on LNO buffer layers were investigated, joining PbZr0.53Ti0.47O3（PZT） ferroelectric thin films. The multilayer thin films including PZT/PMNT，PMNT/PZT and PZT/PMNT/PZT. Results indicated that the multilayer films havelarger remanent polarization, smaller dielectric loss and leakage current, and thermalstablity between30to270°C than those in monolayer PMN-0.38PT film. Theinfluence of heterostructure interfaces on leakage current was investigated. |
