Investigation of structural and electrical properties of La0.7(Ba1-x Ca x )0.3MnO3 compounds by sol-gel method

In this paper, we explored structural and electrical properties of La0.7(Ba1-xCax)0.3MnO3 (x = 0; 0.03; and 0.05)compounds. The general structure of perovskite manganites is AMnO3 (A= trivalent rare earth with divalent ion-doped).Average A-site cation size, external pressure, and the variance of the cation size 􀉐􀬶 are one of many factors that affectedto magneto-transport properties of manganites as reported by others. In this work we focus only on the electricalproperties in La0.7Ba0.3MnO3 Ca-doped compound which may influence crystal structure resulting resistivity phenomenaunder magnetic field influence. All samples were synthesized by sol-gel method from which fine powders were obtained.The X-ray powder diffraction pattern of powder materials shows that all samples are fully crystalline with arhombohedral structure. Rietveld refinement shows that the presence of calcium has changed some crystal structuralparameters such lattice parameter, Mn–O bond length, and Mn–O–Mn angles. The electrical resistivity of all synthesizedmaterials investigated by four point probe method using Cryogenic Magnet in the temperature range of 50-300 K underinfluence a magnetic field shows resistivity temperature dependent. In fact presence of calcium has reduced theresistivity. It might occure because it has made an enhancement in the mobility of hopping electrons. The magneticexternal field causes the resistivity decreased for all samples because host spin align by delocalizing the charge carries soelectron itinerant through the lattice suggested by other authors. Both calcium dopant concentration and the appliedexternal magnetic field shows strong correlation in reduction of resistivity AIP Conference Proceedings 1746, 020004 (2016); doi: 10.1063/1.4953929