Electronic structure of the Ln sub(2)Ti sub(2)O sub(7) oxides with pyrochlore type structure

• Published in: Ferroelectrics Vol. 223; no. 1-4; pp. 91 - 98
• Main Authors: Bondarenko, T N, Borisenko, S V, Uvarov, V N, Teterin, Yu A, Yaresko, A N, Dzeganovski, V P, Sych, A M, Titov, Yu A, Senkevich, A I
• Format: Journal Article
• Language: English
• Published: 01-03-1999
• ISSN: 0015-0193

The objects of investigation were pyrochlore type Ln sub(2)Ti sub(2)O sub(7) oxides (Ln identical with Sm - Lu) and ferroelectric La sub(2)Ti sub(2)O sub(7) with layered perovskite-like structure. X-ray OK alpha , TiK beta sub(5), K alpha sub(1,2), L alpha -emission spectra and X-ray photoelectron spectra of the valence and core states were obtained for pyrochlore oxides. For Ln sub(2)Ti sub(2)O sub(7) X-ray photoelectron spectra have been measured. The cluster (X alpha -Scattering Waves) and band structure calculations (LMTO-ASA) have been carried out to study valence band structure and the charge states of atoms. As a result the valence band (VB) parameters of the Ln sub(2)Ti sub(2)O sub(7) series were defined. The Ln atomic number (Z sub(Ln)) influence on the Ln sub(2)Ti sub(2)O sub(7) (Ln identical with La; Sm-Lu) electronic structure was disclosed. The atomic charge states and their dependence on Z sub(Ln) have been determined in mentioned oxides. The Ln sub(2)Ti sub(2)O sub(7) electronic structure genesis has been defined.