Influence of sintering temperature on microstructure and magnetotransport properties of La0.8Na0.2MnO3 ceramics

Polycrystalline La0.8Na0.2MnO3 prepared by sol–gel method, was sintered in the temperature range of 1050–1200 °C. The effects of sintering temperature on microstructure and magnetotransport properties are reported here. The results confirm the crucial role of sintering temperature on the magnetic and electrical transport properties. A reduction of the grain boundaries leads to the enhancement of the magnetization and the reduction of Tc. The resistivity is sensitivity to the higher temperature due to the appearance of excessive liquid. The MR effect may be weakened with the increase of sintering temperature and the liquid phase can also affect MR values in the lower temperature. In summary, it is important to adjust the sintering temperature to get appropriate properties for room temperature applications.