La0.7Sr0.3MnO3 Nanoparticles Synthesized via the (Pechini) Polymeric Precursor Method

In this paper, we report the preparation of La 0.7 Sr 0.3 MnO 3 colossal magnetoresistance nanoparticles by means of the polymeric precursor method, at a temperature of 650 °C. Rietveld refinement of the X-ray powder diffraction spectra shows that the chemically-synthesized manganite is single-phase with the space group R3C. By using the peak broadening technique and Scherrer’s formula, a grain size of ∼15 nm was estimated. The ferromagnetic to paramagnetic transition is sharp with a Curie temperature of T C ∼360 K. In spite of the low annealing temperature, the insulator-metal-like transition temperature ( T p ) is close to T C . Transport measurements on the prepared samples show a magnetoresistance change of ∼10 % at room temperature in a field of 2 T. This high-field MR is probably due to grain-boundary effects.