Silva, I. P.Simoes, A. Z.Filho, F. M.Longo, Elson [UNESP]Varela, José Arana [UNESP]Perazolli, L.2014-05-202014-05-202007-04-01Materials Letters. Amsterdam: Elsevier B.V., v. 61, n. 10, p. 2121-2125, 2007.0167-577Xhttp://hdl.handle.net/11449/32291The effects of La2O3 on the properties of (Zn, Co, Ta) doped SnO2 varistors were investigated in this study. The samples with different La2O3 concentrations were sintered at 1400 degrees C for 2 h and their properties were characterized by XRD, SEM, I-V and impedance spectroscopy. The grain size was found to decrease from 13 pm to 9 gm with increasing La2O3 content. The addition of rare earth element leads to increase the nonlinear coefficient and the breakdown voltage. The enhancement was expected to arise from the possible segregation of lanthanide ion due to its larger ionic radius to the grain boundaries, thereby modifying its electrical characteristics. Furthermore, the dopants such as La may help in the adsorption of O' to O '' at the grain boundaries characteristics. (c) 2006 Elsevier B.V. All rights reserved.2121-2125engvaristorstin oxidelanthanidesnonlinear electrical behaviourArtigo10.1016/j.matlet.2006.08.025WOS:000245760900042Acesso restrito