MgTiO3 powders were prepared by the complex polymerization method and heat

treated at different temperatures for 2h. These powders were analyzed by X-ray

diffraction, Rietveld refinements, micro-Raman spectroscopy, X-ray absorption

near edge spectroscopy, ultraviolet–visible absorption spectroscopy and

photoluminescence measurements. The X-ray diffraction patterns and micro-

Raman spectra showed that the crystalline powders have a rhombohedral structure.

The X-ray absorption near edge spectra indicated that the local structure of

crystalline MgTiO3 powders was composed only by [TiO6] clusters, while the

disordered exhibit the simultaneous presence of both [TiO5] and [TiO6] complex

clusters into the lattice. The ultraviolet–visible spectra revealed different optical

band gap values as a function of heat treatment temperature. This result can be an

indicative of intermediary energy levels within the band gap of this material

because of structural defects into the perovskite-type structure. The

photoluminescence behaviour was attributed to the structural order–disorder and/or

distortions on the [TiO6]–[TiO6] complex clusters.

Photoluminescence Behaviour in MgTiO3 Powders with Vacancy/Distorted

Clusters and Octahedral Tilting. E.A.V.Ferri, J.C.Sczancoski, L.S.Cavalcante,

E.C.Paris, J.W.M.Espinosa, A.T.De Figueiredo, P.S.Pizani, V.R.Mastelaro,

J.A.Varela, E.Longo: Materials Chemistry and Physics, 2009, 117[1], 192-8