La 1x Sr x MnO 3 nanoparticles were synthesized by precipitation from diethylene glycol solution. Features of synthesis were studied using 1 Н, 13 С, 139 La nuclear magnetic resonance (NMR) investigations. The obtained results showed that the complexation reaction between diethylene glycol and metal cations takes place during the synthesis. These complexes decomposed at 200 ℃ and an amorphous precursor (La,Sr)MnO 3 was formed. According to X-ray results, the crystallization of the perovskite structure began at 600 ℃ and finished at 800 ℃. Microstructural studies showed that obtained nanoparticles are weakly agglomerated and have small sizes. Based on these nanoparticles, magnetic fluid was prepared which was effectively heated under an alternating magnetic field.