Phase separation in La0.5Ca0.5MnO3 controlled trough thermal treatments

A study of phase separation effects in polycrystalline La 0.5 Ca 0.5 MnO 3 in samples with average grain size ranging from 200 to 1300 nm is reported. Magnetic and electrical measurements show that the fraction of the ferromagnetic metallic phase gradually decreases as the grain size increase. The defective structure at the grain surface could explain the local inhibition of the COAFM phase, an effect that is gradually removed by grain size increase. Besides, this effect is also found to be highly dependent on the oxygen content and its spatial distribution.