Physical properties of La0.67Ca0.13Sr0.2Mn1−xFexO3 compounds doped Fe

Abstract

La0.67Ca0.13Sr0.2Mn1−xFexO3 (x = 0–0.1) compounds were synthesised by standard sol-gel reaction and characterised by X-ray diffraction at room temperature. X-ray diffraction and Rietveld refinement show that they crystallize in the rhombohedral structure with the R3‾c space group. The magnetic behavior (magnetization and Curie temperature TC) shows a large dependence on the fractional composition x. The Mössbauer results reveal the presence of iron ion at the trivalent state Fe3+ assigned by the same isomer shift δ value. Resistivity measurements, performed between 10 and 350 K, show a metal–insulator transition for 0.0 ≤ x < 0.1 and a pure insulator behavior for x = 0.1. The suppression of metallic behavior and ferromagnetism under the doping effects of Fe will be discussed in terms of doping disorder, Fe-Mn super-exchange interactions and a site percolation mechanism.