| The La modified (Bi4-xLax)Ti3Oi2 (abbreviated as BLT) powders, ceramics, and films were prepared by using three kinds of Sol-Gel processing techniques with the initial materials of bismuth nitrate (Bi(NO3)3S^O), lanthanum nitrate (La(NO3)3 ?SFbO), and tetrabutyl titanate ((C^O^Ti). The BLT ferroelectric thin films were prepared on Si substrate by Sol-Gel method. The reaction mechanm of the Sol-Gel processing was investigated with IR spectroscopy, and with this understanding, the techniques of the Sol-Gel processing was optimized. By means of modem analyses techniques, such as DTA, laser diffraction particle size analyzer, XRD, SEM, TEM, EDAX, AFM, XPS etc., the reaction temperature, crystallized properties, particle size and distributing of BLT powders and the properties of physics/chemistry, dielectric properties of BLT ceramics were characterized; the thickness, microstructure, crystallized properties, chemical composition, bonding energy and chemical valence of elements in BLT thin films were investigated. The crystal structure of BLjTrjOrc, particularly, the structural influence of the substitution of Bi3+ with La3f in (Bi4.xLax)Ti3Oi2 thin films, and the behavior of La3+ in BLT thin films were studied thoroughly. The main conclusions obtained from above-mentioned works with innovation significance are as follows: 1. Adding quantitative acetic acid into the sol could c completely ontrol the speed ofthe hydrolysis and polymerization reaction, and the BLT powders with better physical and chemical properties could be obtained by using the Sol-Gel processing put forward in this paper.2. The particle size of the powders preheated at 450℃ is in the range of 30 to 100 nm, with the average of about 60 nm. The solid reaction of BLT powders occurs at 730 ℃ approximately resulting in the growth of BLT grain. The particle size of BLT grains is from 400 to 900 nm, with the average of about 450 nm when the powder was calcinated at 750℃ for 2 hours. The BLT powders heated under 730 ℃ were mixture with cubic (Bi.La^TiO^and monoclinic (BL^LaJTisOa, ^ut it converted to completely monoclinic (B^La^TiaOa when calcinated at 750℃.3. The BLT ceramics prepared from the powders prepared by Sol-Gel method were perovskite-like structure with better orientation and structure, and its density is decreasing following with increasing the amount of La. The polarization electric field of BLT ceramics is about 4.5kV/mm, and its dielectric properties were as following: ?425 (1kHz) and tg ?0.05 (1kHz). Additionally, the substitution of Bi3+ with La3+ in (Bl^yLa^Ti^O^ influenced the dielectric properties of BLT ceramics.4. SEM studies combined with other analysis techniques (such as AFM) of image were employed to examine the BLT thin films after annealing. The results indicated that the surface of BLT thin films is smooth and continuous. The Ra. and Rms. of the surface roughness of BLT thin films (the scanning area is 0.3 u m X 0.3 u m) are 33.01nm and 4.203nm, respectively. The thickness and refractive index of the BLT thin films are 400nm and 2.38, respectively. The extinction coefficient of the BLT thin films with x=0.2, 0.4, 0.6 are 0.0626, 0.0992, 0.101 respectively, which is increasing with increasing x values.5. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) studies were performed for determining the change of the crystal lattice constant, the chemical composition, and the chemical bonding energy of ferroelectric Lamodified (Bi4-xLaxTi3O12 (abbreviated as BLT) films prepared by Sol-Gel processing methods. It was found that BLT thin films have high c-axes orientation with monoclinic structure and the crystal lattice constant of BLT thin films changed. The a and b values were kept constant but the c value of the BLT thin films with x=0.2, 0.4, 0.6 are 32.8059nm, 32.7164nm, 32.5820nm, respectively, which is decreasing with increasing x values.6. XPS analyses were carried out for determining the composition and chemical states of the elements of the BLT materials. The chemic...
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