Otro
Luminescence in semi-crystalline zirconium titanate doped with lanthanum
Registro en:
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing. Lausanne: Elsevier B.V. Sa, v. 434, n. 1-2, p. 19-22, 2006.
0921-5093
10.1016/j.msea.2006.07.023
WOS:000240896400004
Autor
Freitas, G. F. G.
Nasar, R. S.
Cerqueira, M.
Melo, D. M. A.
Longo, Elson
Varela, José Arana
Resumen
This paper aims to describe the synthesis of the semi-crystalline and crystalline powder of lanthanum doped with zirconium titanate (65/35), LZT through Pechini method. The analysis done by Raman demonstrated that semi-crystalline phase at 550 degrees C and crystalline phase after 600 degrees C were formed. The XRD pattern shows the ZrTiO4 phase formation demonstrating that La substitutions into the lattice take place. The calcined powder at different temperatures shows a semi-crystalline phase presenting photoluminescence effect when processed at low temperatures. From 300 to 400 degrees C a broadband is observed at 563 nm and 568 nm, respectively. Defects creation such as: Zr3+ center dot Vo(center dot center dot) and Ti3+ - V-O(center dot center dot), Zr and Ti replaced by La with vacancy formation, impurities and imperfections contributed to the photoluminescence effect. However, the main emission is due to a reverse Ti4+ -> O2- or/and Zr4+ -> O2- transition that occur within a regular titanate or zirconate eight-fold coordination [BO8-delta], B = Zr4+, Ti4+. (c) 2006 Elsevier B.V. All rights reserved.