Synthesis, Microstructure and EPR of CaMnO3 and EuxCa1-xMnO3 Manganite, Obtained by Coprecipitation

The synthesis of CaMnO3 and EuxCa1-xMnO3 obtained by coprecipitation method is showed. The synthesized samples were characterized by X-ray diffraction (XRD) and scanning electronic microscopy (SEM), the powders showed orthorhombic structure and pnma space group. When it was doped with Europium, their morphologytendency was spherical. Measurements were carried out on electron paramagnetic resonance (EPR) with constant frequency = 9.4 GHz (band X) and dc magnetic field (Hdc) 0-0.8 T, measurements were at 300 K and 77 K. EPR spectra showed significant differences between both samples, indicating that the substitution of divalent alkaline earth cations by trivalent rare earth ions, allowing the formation of a mixed valence state of manganese, Mn3+ and Mn4+. A 77 K, the manganite of concentration x = 0.30 had a magnetic ordering, noted by the presence of hysteresis.