Influence of Na-doping in La0.67Pb0.33-xNaxMnO3 (0 ≤ x ≤ 0.15) on its structural, magnetic and magneto-electrical properties

• The samples exhibit PM-FM phase transition.
• The electrical transport is investigated.
• Low temperature minimum resistivity is observed.
• The electrical resistivity in the entire temperature range fit well with the phenomenological percolation model.

We have studied the effect of Na substitution on structural, magnetic and electrical properties in La0.67Pb0.33-xNaxMnO3 (0 ≤ x ≤ 0.15). All compositions were synthesized using the sol–gel technique. X-ray diffraction and structure refinement show that they crystallize in the rhombohedra structure with the R − 3c space group. All the samples exhibit a paramagnetic (PM)-ferromagnetic (FM) phase transition (TC) at 363, 328, 305 and 285 K for x = 0, x = 0.05, x = 0.1 and x = 0.15 respectively. The replacement of Pb ion by Na results in a decrease of the metal-semiconductor transition temperature TM-Sc and the magnetoresistance (MR) as well as the resistivity are found to increase. The electrical resistivity in the entire temperature range fit well with the phenomenological percolation theory based on the phase segregation mechanism.

Temperature dependence of MR under several magnetic applied field values for the samples La0.67Pb0.18-xNa0.15MnO3.Figure optionsDownload as PowerPoint slide