Synchrotron radiation X-ray diffraction evidence for nature of chemical bonds in Bi_4Ti_3O_(12) ceramic powders and grain-orientation mechanism of their films formed by aerosol deposition method

摘要

Structural characteristics of a bismuth titanate (Bi4Ti3O12, BiT) ceramic powder material and the polycrystalline film formed by the aerosol deposition (AD) method are investigated by synchrotron-radiation X-ray diffraction. The BiT powders without clear plate-like shapes are prepared as stating powders for the film deposition. The electron charge density analysis demonstrates that the particular BiT powders synthesized in this study have the same layered crystal structure as well-known BiT powder materials. Thec-oriented polycrystalline film is deposited at room temperature onto a glass substrate without any heat treatment by the AD method. The high orientation of the BiT as-deposited AD film is attributed to the layered crystal structure essentially originated from the anisotropic nature of chemical bonds in the BiT crystal rather than the shapes of particles of the starting powders.