Magnetic and electrical properties induced by the silver in the lanthanum sites of La0.6Ca0.4MnO3 compound

• All samples crystallize in Pnma space group.
• Two metal–insulator transitions (Tρ1 and Tρ2) with Tρ2 = TCO.
• The electrical resistivity described by a percolation model.
• All samples exhibit a large MR value.

Structural, magnetic and electrical measurements were performed to examine the effect of the silver substitution in the lanthanum sites on the physical properties. X-ray diffraction data have been analyzed by Rietveld and show no structural changes induced by Ag doping. Magnetization versus temperature studies have shown that all samples exhibit a magnetic transition from ferromagnetic to paramagnetic phase when temperature is increased. Two transitions (Tρ1 and Tρ2) are observed in the electrical resistivity, the second transition in the resistivity can be attributed to an abnormality characteristic of charge ordering (CO) effect. The electrical resistivity was described by a phenomenological percolation model. The MR increases with increasing applied magnetic field and decreases with the Ag substitution. At room temperature, the magnetorresistance (MR) for lanthanum substitution is about 40% and 55% for the parent compound at a magnetic applied field of 8 T.

Figure optionsDownload as PowerPoint slide