Synthesis of Pure and Doped LaMnO₃ Powders from Citrate Precursors

Abstract

In this work pure and doped LMO were prepared using modified Pechini method from lanthanum and manganese citrates. Lanthanum citrate was prepared starting from La2O3, while manganese citrate was prepared from Mn(NO3)2. Valence state of the manganese was controlled by adjusting pH value of the solution and confirmed by EPR and UV/VIS analysis. Thermal treatment conditions for preparation of LMO powders were determined from TG/DTA of dried precursors. XRD results confirmed that pure perovskite phase was successfully prepared in single LMO and Cadoped LMO. SEM and measurements of specific surface area of the powders showed the existence of large agglomerates consisting of submicronic primary particles.

Magnetic properties of pure and Ca and Sr doped LaMnO3prepared by polymerisable complex method

“…Molar ratio of CA/EG has a great impact on phase purity of synthesised manganites, and it was necessary to find out experimental conditions where neither phase separation nor formation of any precipitates occurs during the resin formation. 23 In our previous studies, 24 it was noticed that when smaller molar ratio of CA/EG is used (1 : 15), only LMO and LCMO powders can be obtained as a single phase. According to these results and results of some other authors, 23 the authors decided to use higher molar ratio of CA/EG in order to synthesise larger polymeric network to achieve better 1 Thermogravimety differential thermal analysis of a LMO and b LCMO homogeneity.…”

Sodium citrate dihydrate doped with Mn3+ions

“…Citric acid (2-hydroxypropane-1,2,3-tricarboxylic acid) belongs to the group of polycarboxylic acids present in biological fluids and playing very important roles in biochemical processes. Complexes of citric acid also attract considerable attention in the production of special materials, such as highconductive LaNiO 3 and LaMnO 3 (Počuča et al, 2007;Ðuriš et al, 2007), using a modification of Pechini's method (Pechini, 1967;Keishi & Toshio, 2005;Petrykin & Kakihana, 2005). In spite of this, not many citrate complexes have been structurally characterized.…”

Síntese e Caracterização do Composto SrTi1-xFexO3 Nanoestruturado

“…Nas últimas décadas, a utilização do método dos precursores poliméricos ou método Pechini 41 na síntese de diferentes óxidos policatiônicos na forma de pó ou filmes finos vem sendo realizada com grande sucesso [42][43][44][45][46][47] .…”