Magnetic properties of pure and Ca and Sr doped LaMnO ₃ prepared by polymerisable complex method

In this work, pure and Ca2+ and Sr2+ doped LaMnO3 powders were obtained using polymerisable complex method from citrate precursors. La2O3, Mn(NO3)2 and citric acid were used for citrate formation, and ethylene glycol was later added as polymerisation agent. For the preparation of doped samples, solutions of Ca(CH3COO)2 and Sr(NO3)2 were used. Calcination was performed at 800°C for 6 h in oxygen atmosphere. X-ray diffraction analysis showed that single phase LaMnO3, La0·7Ca0·3MnO3, La0·7Sr0·3MnO3 and La0·7Ca0·15Sr0·15MnO3 powders were obtained. Morphology of prepared samples was analysed using SEM analysis. Field cooled and zero field cooled magnetisations versus temperature and hysteresis loops of powders and sintered samples were analysed. Curie temperatures were in the range from 170 to 370 K, depending on composition. Measured magnetisations even reached 85 emu g–1. The influence of dopants on magnetisation, Curie temperature and hysteresis loops were quantified and discussed.