SYNTHESIS AND CRYSTALLOCHEMICAL PROPERTIES OF Ce-SUBSTITUTED NANOPARTICLES OF MANGANITE (La,Sr)MnO3

Abstract

Serious of Ce-substituted lanthanum-strontium man-ganites La0.7–xSr0.3CexMnO3 (x = 0–0.2) nanoparticles were synthesized by sol-gel method with further heat treatment of precursors at 800 °C. Crystallographic properties of obtained nanoparticles were investiga-ted by X-ray diffraction method. According to XRD data, it was established that the substitution of lan-thanum ions by cerium in the crystalline structure and formation of single-phased nanoparticles occurs only up to 5 % mol. of Ce regardless of the heating temperature. Linear decreasing the cell volume of nanoparticles in this concentration range of Ce satis-fies the Vegard law and indicates on the formation of a continuous series of solid solutions with the dis-torted perovskite up to 5 % of Ce. At higher concen-trations of Ce there are additional peaks on the XRD patterns, which point on the formation of an addi-tional phase of CeO2. According to TEM studies, it was calculated that the average size of was 30–40 nm. To estimate heating efficiency of synthesized nanoparticles in the alternating magnetic field, mag-netic fluids based on the synthesized nanoparticles and aqueous dextran solution were prepared. It was shown that they effectively heated up to controlled temperatures in an alternating magnetic field, and their heating efficiency was directly proportional to the increase of the concentration of cerium. Accor-ding to the results of the complex studies, it was shown the possibility to synthesize single-phase Ce-substituted nanoparticles of manganite with a pe-rovskite structure. It was established that cerium does not significantly influence on the change of magnetic properties of such nanoparticles and they are promising for further investigations as the in-ducers of magnetic hyperthermia, as well as for the biological tests.