The effects of electrical transport properties on microstructure of (Lai.xBix)o.7Ago.3Mn03 ceramics. / Siti Munirah Md Razak

A detailed investigation of electrical transport properties on monovalent atom of silver (Ag) and bismuth atoms (Bi) doped polycrystalline of (Lai.xBix)o.7Ago.3Mn03 pellets. The sample of (Lai.xBix)o.7Ago.3Mn03 known as colossal Magnetoresistance (CMR). The sample of (Lai.xBix)o.7Ag0.3Mn03 with composition of x = 0.00, 0.10, 0.15, 0.20 were prepared by conventional solid state reaction method. The scanning electron microscope (SEM) used to determine the surface morphologies for the samples, X-ray diffractometer (XRD) to analyze the structure of the samples and the resistivity and metal-insulator transition temperature (TMI) measurement was determined by using Standard four point probe. The grains sizes of the samples become larger and softer with increasing the Bi3+ doping of x. The samples also identified as a rhombohedral structure with space group R3c. For the electrical transport properties, the resistivity is increased while the TMI is decreased when the composition of x is increased. From the graph of intensity (a.u) versus 29 (deg) curves of (Lai.xBix)0.7Ago.3Mn03 with x=0.00,0.10, 0.10 and 0.20, the two peaks below and above the metal-insulator transition temperature were found. The peak below the TMi is the metallic region and double exchange (DE) mechanism plays on it while above TMI, it is known as insulator region and the Jahn Taller mechanism plays on it.