Effects of nonmagnetic silver Ag doping on the structural, magnetic and electric properties in La0.67Pb0.33MnO3 manganese oxides

Abstract The influence of the silver Ag-substitution for Pb ions in the mixed valence perovskites La 0.67 Pb 0.33− x Ag x MnO 3 (0≤ x ≤0.15) was investigated by X-ray magnetic and electric transport measurements. All compositions were synthesized using the sol–gel technique. X-ray diffraction and structure refinement show that they crystallize in the rhombohedral structure with the R3c space group. Upon Ag doping on Pb sites, the lattice parameters, unit cell volume, and the Mn–O–Mn bond angle are reduced. All the samples exhibit a ferromagnetic–paramagnetic transition and metallic-semi-conductor one with increasing temperature. The substitution of Pb by Ag has great influence on the magnetic and electrical transport properties of this family of compounds, decreasing continuously both the Curie temperature (from 361 to 290 K) and the resistivity transition temperature T p .