Electrical Properties of La_(0.67)Sr_(0.33)Mn_(0.8)Ni_(0.2)O3 Synthesized by Sol Gel Method

摘要

The previous study of lanthanum manganites showed that physical properties of LaMnO3 compound has changed when Sr doped the La site. La_(0.67)Sr_(0.33)MnO3 compound give the highest Tc = 370 K and showed metal insulator transition. It happens as a result of changed in Mn~(3+)/Mn~(4+) ratio. Its indicated that Mn has the most important rule to the physical properties changed. In order to shift Tc of the compound to the near room temperature, Ni doped was given to Mn site of LSMO. In this paper, 20% Mn site was doped by Ni. La_(0.67)Sr_(0.33)Mn_(0.8)Ni_(0.2)O3 compound synthesized by sol gel method and characterized using XRD. Then, single phase compound resisitivity was measured to see the electrical properties this compound. The XRD result showed that sample have single phase with rhombohedral structure and R-3c space group. Resistivity as a temperature function graph does not show resistivity peak and metal insulator transition. The resistivity measurement showed that below 300 K, resistivity inscreased with decreased of temperature that indicates insulator behavior. It caused by decreased of double exchange interaction and increase of superexchange interaction. From this result, we can conclude that Ni doped decreased electrical properties of the sample.