  Sr1-xMnxTiO3 (where x = 0.03, 0.05, 0.07 and 0.09) was synthesized via
different routes that include solid-state, oxalate precipitation and freeze
drying. In oxalate precipitation technique, compositions corresponding to 3 and
5 mol % doping of Mn were monophasic whereas the higher compositions revealed
the presence of the secondary phases such as MnO, Mn3O4 etc., as confirmed by
high resolution X-ray diffraction (XRD) studies. The decomposition behavior of
the precursors prepared using oxalate precipitation method corresponding to the
above mentioned compositions was studied. Nanopowders of compositions
pertaining to 5 to 9 mol % of Mn doping were obtained using freeze-drying
technique. The average crystallite size of these nanopowders was found to be in
the 35 to 65 nm range. The microstructural studies carried out on the sintered
ceramics, fabricated using powders synthesized by different routes established
the fine grained nature (< 1 microm) of the one obtained by freeze drying
method. Raman scattering studies were carried out in order to complement the
observations made from XRD regarding the phase purity. The dielectric
properties of the ceramics obtained by different synthesis routes were studied
in the 80 - 300 K temperature range at 100 kHz and the effect of grain size has
been discussed.
