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Microwave asssited hydrothermal synthesis as a rapid route toward manganites preparation
|Cristina Leonelli , Antonino Rizzuti , Anna Corradi|
Universita di Modena and Reggio Emilia, Modena, Italy
The manganites A1-xA'xMnO3 with A a rare-earth metal and A' an alkali-earth metal are materials of great importance owing to their magnetic and electronic properties, particularly the phenomenon of colossal magneto resistance, whereby a decrease in resistivity of several orders of magnitude is seen on application of magnetic field close to the Curie temperature of the material. The manganites have also been studied as oxidation catalysts and as cathodes in solid-oxide fuel cells, and their potential application in electronic devices are highly dependent upon their atomic structures.
The synthesis of these class of perovskites is a challenge since control of manganese oxidation state. Main preparation methods of these compounds consist on solid state reaction and also sol-gel route, which require drastic or complex conditions. Hydrothermal method in combination of microwave technology is a advantageous tool for the efficient obtainment of inorganic compounds like manganites.
In this work attempts to prepare strontium-doped lanthanum manganites La1-xSrxMnO3 using microwave-assisted hydrothermal synthesis are performed starting from a mixture of lanthanum nitrate, strontium nitrate, manganese(II)nitrate, potassium permanganate and potassium hydroxide as mineralizer. For x = 0.5 the relative perovskite is obtained not pure. While with x = 1 for the first time hexagonal strontium manganite is prepared as tablet shaped crystallites with narrow particle size distribution (ca. 6 mm) at 210°C in 1 hour treatment. Convetional hydrothermal synthetic routes required at least 24 hrs treatment time.
Presentation: Poster at E-MRS Fall Meeting 2006, Symposium C, by Cristina Leonelli
See On-line Journal of E-MRS Fall Meeting 2006
Submitted: 2006-05-14 16:59 Revised: 2009-06-07 00:44