Facile synthesis of Ca-doped manganite nanoparticles by a nonaqueous sol–gel method and their magnetic properties

Perovskite manganite La1−xCaxMnO3 (image, 1/2 and 2/3) nanoparticles with the average particle size of about 20 nm have been synthesized by a facile nonaqueous sol–gel method using methanol as a solvent and characterized by X-ray diffraction, transmission electron microscopy and superconducting quantum interference device magnetometer. Magnetic measurements reveal that although their bulk counterparts have quite different magnetic ground states, the three-nanosized samples exhibit similar ferromagnetic behaviors below about 270 K. This result implies that with the particle size reduced to nanoscale, the ferromagnetism for image is weaken, while it is enhanced, accompanied by the suppression of the charge ordering, for image and 2/3. Moreover, the exchange bias phenomena are observed in the two latter nanoparticles, which is of special interest for potential applications.