Electronic structure of some oxide ferroelectrics and similar to them materials: Ultrasoft X-ray spectroscopy study

Abstract

The investigated objects were AT_iO₃, ALn₂Ti₄O₁₂ (A = Ca, Sr, Ba, Cd, Pb; Mg, Fe), ZrTiO₄, HfTiO₄ and also some oxides used for these compounds synthesis. There were well-known ferroelectrics in the row.

Ti-contained compounds crystal structure had different type, but in all cases structure possessed of Ti-containing oxygen octahedrons. X-ray TiLα-and O Kα-emission spectra, characterized valence band structure, were obtained. The composition and crystal structure influence on spectra (and objects electron distribution) was examined. A principal similarity of the Ti 3d-states distribution was found for all Ti-contained compounds. This caused the electronic structure common features. O2p-distribution in titanates included main features of TiO₂ and oxides AO-and AO₂-type. Dependence of spectra fine structure (and band structure) on A-components in the isostructural compounds groups were showed. First and second coordinate polyhedrons influence on spectra was analyzed. Titanates electron structure features were determined. The compounds band structure genesis was shown by comparison titanates and TiO₂, ZrO₂ and AO-oxides spectra. The ALn2Ti₄O₁₂ electron structure prognosis was done.

Key Words:

• ferroelectric
• dielectric
• titanates
• X-ray spectroscopy
• electronic structure
• crystal structure