Effect of indium doping on structural, magnetic and transport properties of ordered Sr2FeMoO6 double perovskite

A series of Sr2Fe1−xInxMoO6 (x = 0, 0.1, 0.3 and 0.4 wt.%)(SFIMO) double perovskite oxide powders were prepared by sol–gel method. The materials were subjected to X-ray diffraction and found to crystallize in tetragonal structure with space group I4/mmm  . Lattice parameters and unit cell volume were calculated using X-ray diffraction data. It was found that the tetragonal distortion (c/a2) increases while the deviation of the tolerance factor from unity increases with increase of indium composition in SFIMO samples. Magnetization studies were carried out using vibrating sample magnetometer (VSM). It has been found that the saturation magnetization (Ms) and remanent magnetization (Mr) decreases while coercivity (Hc) increases with increase of indium composition in SFIMO samples. Electrical resistivity and magnetoresistance studies in the magnetic field range from −40 kOe to 40 kOe were carried out keeping the temperature constant at 5, 150 and 300 K using standard four-probe method. Resistivity studies were also performed in the temperature range from 5 to 300 K keeping magnetic field constant at 0, 10, 20 and 40 kOe. The resistivity studies showed that the magnitude of magneto resistance (MR%) decreases with increase of temperature from 5 to 300 K while the value of MR (%) is found to increase with increase of magnetic field. The MR (%) was found to decrease with increase of indium concentration in SFMIO compounds. The degree of ordering, Ms and MR (%) agreed well with each other.

Research highlights
► Indium doping reduces the ordering of Fe/Mo sites and introduces anti-site defects in Sr2Fe1−xInxMoO6 (SFIMO) materials.
► The tetragonal distortion and the deviation of tolerance factor from unity are found to increase with indium (In) composition in Sr2Fe1−xInxMoO6 materials suggesting addition of indium (In) reduces the symmetry of the lattice.
► The saturation magnetization (Ms) was found to decrease with the indium (In) concentration in SFIMO materials.
► MR (%) was found to increase with increase of applied field while the same was found to decrease with increase in temperature.
► Reduction in low field magneto resistance (LFMR) with indium (In) concentration has been observed in SFIMO materials.