The Effect of Fuels on Structural, Magnetic, and Magnetoresistance Properties of Lanthanum Strontium Manganite Nanoparticles

In this research, lanthanum strontium manganite (LSMO) nanoparticles have been synthesized by combustion method using glycine, citric acid, and polyvinyl alcohol (PVA) fuels in stoichiometric state. Three samples were characterized by analyses of X-ray diffraction analyses (XRD), scanning electron microscope (SEM), Fourier transform-infrared (FTIR), vibrating sample magnetometer (VSM), and magnetoresistance (MR). The results show that samples have the rhombohedral perovskite structure (R-3c). The significant bond at 600 cm−1 in the FTIR spectra proved the existence of characteristic bond of LSMO samples. All samples have comparable sizes (≤ 100 nm). SEM images show that using the different fuels have a noticeable effect on the microstructure shape and porosity. The magnetization measurements done in the room temperature showed different saturation magnetization for each sample prepared by different fuels exhibited a superparamagnetic nature for all samples. Electrical resistivity analyses revealed that metal–insulator transition temperature (TMI) decreases by changing fuel types. The variation in the MR in the presence of 10 kG at low temperature in LSMO samples is due to inter-grain spin-polarized tunneling (SPT) and spin-dependent scattering (SDS) between the grain boundaries when external magnetic field is applied to the material.