Abstract :
The effect of grain size on structural, magnetic and transport properties in electron-doped manganites La0.9Te0.1MnO3 has been investigated. All samples show a rhombohedral structure with the space group R 3 ¯ C at room temperature. The Mn–O–Mn bond angle decreases and the Mn–O bond length increases with the increase of grain size. All samples undergo paramagnetic (PM)-ferromagnetic (FM) phase transitions and the interesting phenomenon that both magnetization and the Curie temperature TC decrease with increasing grain size is observed, which is suggested to mainly originate from the increase of the Mn–O bond length dMn–O. Additionally, ρ obviously increases with decreasing grain size due to the increase of both the height and width of tunneling barriers with decreasing grain size. The results indicate that both the intrinsic colossal magnetoresistance and the extrinsic interfacial magnetoresistance can be effectively tuned in La0.9Te0.1MnO3 by changing grain size.
