Synthesis of lead magnesium niobate and La-modified lead magnesium niobate using different Mg precursors

Author： Ianculescu A. Brăileanu A. Pasuk I. Popescu C.

ISSN： 1388-6150

Source： Journal of Thermal Analysis and Calorimetry, Vol.80, Iss.3, 2005-06, pp. : 663-670

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Abstract

In the present study, the effect of the partial replacement of Pb²⁺ by La³⁺ in the lead magnesium niobate Pb(Mg_1/3Nb_2/3)O₃ (PMN) perovskite structure was examined, taking into account the Mg-source. Pure lead magnesium niobate (PMN) and lanthanum-modified lead magnesium niobate (PLMN) having composition (Pb_1-xLa_x) (Mg_1+x/3Nb_2-x/3)O₃ with x=0.2 were elaborated. The phase formation was investigated by DTA/TG methods correlated with X-ray diffraction, performed on materials obtained in non-isothermal conditions. The diffraction data for the ceramics obtained by isothermal treatments emphasized the influence of the lanthanum on the crystal structure, inducing the doubling of the unit cell parameter. SEM investigations pointed out the lanthanum inhibitor effect on the grain growth process, leading to an uniform grain distribution.