Electrical properties of La0.7Ba0.297Ca0.003MnO3 obtained by low temperature sol-gel synthesis

Abstract

A compound of La0.7Ba0.297Ca0.003MnO3 was obtained by low temperature sol-gel synthesis. The structural and electrical properties of the material were systematically studied. La0.7Ba0.297Ca0.003MnO3 material is a member of mixed valence manganites which has a perovskite structure. The general structure is AMnO3 (A= trivalent rare earth with divalent ion-doped such as Sr2+, Ca2+, Ba2+, etc). The previous study proved that doped Ca2+ ion to the La0.7Ba0.3MnO3 material increased its CMR effect and MCE effect and decreased its Tc become near room temperature. CMR effect is change of resistivity due to external magnetic field in the perovskite-based material. Meanwhile, MCE (Magnetocaloric effect) is thermal response from material due to external magnetic field. In this work, we focus only on the electrical properties of La0.7Ba0.297Ca0.003MnO3 (low doped calcium content in the La0.7Ba0.3MnO3 material) obtained by low temperature sol-gel synthesis. The X-ray diffraction pattern shows that the material is fully crystalline with a rhombohedral structure and R-3c space group. Polycrystalline La0.7Ba0.297Ca0.003MnO3 has magnetic transition behavior from metallic-ferromagnetic behavior to the insulator-paramagnetic behavior with increasing temperature. This material also has magnetoresistance effect. Magnetoresistance value of the material is about 9% at 280 K under an external magnetic field of 1.5 T. In this case, extrinsic MR (extrinsic magnetoresistance) plays an important role since the material is polycrystalline. From this study, we conclude that with low temperature processing we obtained material that has CMR effect and magnetic transition phenomenon like material which prepared by high temperature processing.