Fabrication And Properties Of BiFeO₃ Film Using Pulsed Laser Deposition

As one of the minority perovskite structure materials that couple ferroelectricity and antiferromagnetism at room temperature, BiFeO3 has a promising application prospect in the fields of information storage, spintronic devices and sensors. In this thesis, the BiFeO3 thin films were grown on SrTiO3 substrates using pulsed laser deposition (PLD). The crystal structure, surface images, composition and ferroelectric properties were discussed. The main contents are listed as follows:(1) A review of basic structure and physical characteristic of BiFeO3 film was present, and the film-growth method was introduced.(2) Bi2O3(99.9%) and Fe2O3(99.9%) powders were mixed up in mol ratio of 1.1:1 to synthesize the single phase BiFeO3 ceramic target using conventional solid phase reaction method. The effects of sintering parameters on the structural properties of the targets were studied.(3) The BiFeO3 films have been fabricated on SrTiO3 substrates using PLD technique (KrF, 248nm, 25ns). The effects of some parameters such as substrate temperature on the crystallinity and structural properties of BiFeO3 films were discussed.(4) X-ray diffraction (XRD), Field-emission scanning electron microscopy (FSEM), Energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure, composition, and morphology properties of the BiFeO3 film.(5) The ferroelectric properties were measured using the RT-66 standardized test system and the saturated polarization hysteresis loop was observed at the room temperature. Also the effect of electrode was discussed.