Structural and electrical properties of gadolinium-substituted La0.6-xGdxSr0.4MnO3 (x=0-0.3)

In recent decades, manganites have received much attention due to their various compositions and applications in various fields. This study investigated manganite's structural and electrical properties with the chemical formula La0.6-xGdxSr0.4MnO3 (x = 0, 0.25, 0.05, 0.1, and 0.3). All samples were synthesized using the nitrate-complex auto-ignition technique. Structural analysis showed that the crystal structure of these samples is rhombohedral with an R-3c space group at room temperature. The XRD and FESEM image analysis investigated the samples' crystallite and grain size. Measurement of the specific electrical resistance of the samples in the temperature range of 10-350 K and the magnetic fields of 0-9 T showed that the increase in temperature of the electrical resistance first increases and then decreases. All samples' insulation-metal transition temperature (TM-I) moves to lower temperatures with an increasing Gd3+ substitution and moves to higher temperatures as the magnetic field increases. In addition to increasing substitution, the electrical resistance also increases due to changes in spin irregularity at the grain boundary and, consequently, the difficulty of the double exchange mechanism. The electrical resistance decreases with increasing magnetic field, followed by the magnetic order created in the samples and the changes in the spin angle between the charge carriers. Finally, the bolometric application and magnetoresistivity of the samples are examined.