**5. Acknowledgments**

508 Advances in Crystallization Processes

route (Dhahri et al., 2010). The present observation of a reduction in the particle size of the Nd0.8Sr0.2(Mn1-xCox)O3 phases in one of the methods but not in the other would point towards the synthesis method as the responsible for this effect, rather than the amount of cobalt. In this case, however, the observed decrease of the grain size is less significant than

Fig. 11. Secondary electron SEM micrographs obtained for all Nd0.8Sr0.2(Mn1-xCox)O3 compositions prepared by (a) sol-gel (sg) and (b) freeze-drying (fd) methods.

Different synthetic methods were used to prepare several perovskite type compounds. Phase-pure perovskites were obtained in all cases, irrespective of the method of synthesis and even when more than one method was used. It is to note that no differences in the overall crystal structure were observed in any of the cases when the method was changed. Moreover, changes in the crystal structure of the compounds within each series could be perfectly explained considering only compositional (and resulting structural) variables such as the mean A-site ionic radius or the A-site disorder, none of them being influenced by the synthesis route. This is true for the Ln1−xAxFeO3−δ series where changes from orthorhombic to cubic are consistent with the change in the doping level x and also for the Ln0.5A0.5FeO3 where the change was observed from rhombohedral to cubic symmetry when the mean A-

At least in the present group of compounds this seems to indicate that, properly used, and with no other factors present (such as in the case of the growth of samples on crystallographycally oriented substrates), the structural characteristics can be studied and

It is no news that, compared with the solid state reaction, the glycine-nitrate route, sol-gel and freeze-drying techniques require lower calcination temperatures to yield pure crystals of perovskite phases, with the resulting energy saving (very important nowadays). The disadvantage is, however, the fact that they are more time consuming and require more controlled synthesis conditions. In the same way, it is clearly observed that the ceramic

properly addressed without having into account the synthesis method.

in previous studies.

**4. Conclusion** 

site radius, <rA>, was varied.

This work has been financially supported by the Ministerio de Ciencia e Innovación PSE-12000-2009-7 (MICINN) and MAT 2010-15375; Consejería de Industria, Innovación, Comercio y Turismo (SAIOTEK 2011) and by the Consejería de Educación, Universidades e Investigación (IT-177-07) of the Basque Goverment of Gobierno Vasco/Eusko Jaurlaritza. Technical and human support provided by SGIker (UPV/EHU, MICINN, GV, EJ, ESF) and Alternative Generation Systems Group of Technological Research Centre is gratefully acknowledged.
