X-ray photoelectron spectroscopic investigations on cubic BaTiO3, BaTi0.9fe0.1O3 and Ba0.9Nd0.1TiO3 systems

• Published in: Applied surface science 2008-08, Vol.254 (21), p.7074-7079
• Main Authors: JENA, Hrudananda, MITTAL, V. K, BERA, Santanu, NARASIMHAN, S. V, GOVINDAN KUTTY, K. V, KUTTY, T. R. N
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Physics
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2008.05.316

X-ray photoelectron spectroscopic (XPS) studies were carried out on wet-chemically synthesized cubic BaTiO3, Ba0.9Nd0.1TiO3 and BaTi0.9Fe0.1O3-delta powders. The compounds were prepared by hydrothermal and gel to crystallite conversion technique; and phases formed readily at 420 K. The phase purity of the powders was confirmed from X-ray diffractometry. Chemical state and chemical environment of the constituent elements in the compositions were examined by XPS. Ba2+ was found to exist in two different chemical environments in these titanates. The Ti 2p3/2 photoelectron peak in BaTi0.9Fe0.1O3-delta was found to be broadened after Fe3+ substitution. Any resolvable broadening was not observed distinctly in the Ti 2p peak for Ba0.9Nd0.1TiO3, unsintered BaTiO3 and BaTiO3 annealed in hydrogen (8% H2 + Ar) at 1000 K. The prevalence of mixed-valent titanium and iron in BaTi0.9Fe0.1O3-delta composition was evident from the XPS results and was further supported by the enhanced electrical conductivity at 298-550 K for BaTi0.9Fe0.1O3-delta in comparison to BaTiO3 and Ba0.9Nd0.1TiO3. Hydroxyl incorporation was facilitated by substituting Nd3+ in Ba-sublattice. The presence of hydroxyls was observed from the broadening of the O 1s peak in XPS studies of the compounds.