Reverse micellar synthesis and properties of nanocrystalline GMR materials (LaMnO3, La0·67Sr0·33MnO 3 and La0·67Ca0·33MnO 3): Ramifications of size considerations

Abstract

Nanoparticles of complex manganites (viz. LaMnO3, La 0·67Sr0·33MnO3 and La 0·67Ca0·33MnO3) have been synthesized using the reverse micellar route. These manganites are prepared at 800°C and the monophasic nature of all the oxides has been established by powder X-ray diffraction studies. TEM studies show an average grain size of 68, 80 and 50 nm for LaMnO3, La0·67Sr 0·33MnO3 and La0·67Ca 0·33MnO3) respectively. Ferromagnetic ordering is observed at around 250 K for LaMnO3, 350 K for La 0·67Sr0·33MnO3 and 200 K for La0·67Ca0·33MnO3. These Curie temperatures correspond well with those reported for bulk materials with similar composition. © Indian Academy of Sciences.