Influence of Ag Substitution on Structural, Physical and Electrical Properties of Ndmno3

Pure and Ag-doped NdMnO3 were synthesized using the conventional solid-state reaction route to investigate the structural, physical, and electrical properties of both samples. The crystal structural, morphological, and optical properties of both samples were determined using X-ray diffraction (XRD), scanning electron microscopy (SEM), Ultraviolet-Visible spectroscopy (UV-VIS) and four-point probe. The Rietveld refinement showed that the compounds crystallized in orthorhombic structure, with the decrease in volume from 233.50 (x = 0) to 231.03 (x = 0.3) with the increase of lattice parameter b from 5.56 to 5.69, respectively. SEM exhibited both homogenous compounds. The optical properties of the samples were assumed to be an indirect bandgap and were obtained 4.60 eV and 4.82 eV for samples (x = 0, and x = 0.3), respectively. The resistivity curve shows a decrease when Ag was doped into the sample. Under the external magnetic field of 0.8 T, the value of resistivity of undoped sample decreases, while the value of resistivity of doped sample remains unchanged. The insulator region of the resistivity curves fitted well using variable range hopping (VRH) and small polaron hopping (SPH) models. The hopping distance, R h and energy hopping, E h at 150 K were decreased due to the distortion of the MnO6. Other than that, the values of activation energy, E a decreased as Ag was doped, and when external magnetic were applied, indicating that the delocalization of charge carrier was increased for this system.