- Electron magnetic resonance (EMR) spectra were measured on different La 1−x Sr x MnO 3 manganites at the interval 100⩽T⩽420 K for studying an influence of the synthesis conditions on the magnetic homogeneity of the sample. The micron-sized crushed crystals La 0.833 Sr 0.126 MnO 3 and La 0.7 Sr 0.3 MnO 3 grown by fused-salt electrolysis and by floating zone melting with the Curie temperatures T C =320 K and 350 K, respectively, as well as nanosized sonochemically sinteredpowders La 0.7 Sr 0.3 MnO 3 (annealed, T C =340 K) were studied. The results obtained show that samples originated from bulk crystals are less homogeneous than the nanocrystalline one. Except for higher homogeneity, the nanosized sample demonstrates also a weaker magnetic anisotropy. As a result, strongly pronounced magnetic phase separation (revealed as coexisting ferromagnetic and paramagnetic signals in EMR spectra) is observed in crushed crystals.