PACS 71.38.Ht, 76.30.Kg The electron spin resonance (ESR) method was used to investigate the internal spin dynamics of La 1-x Sr x CoO 3 (x = 0.1, 0.2, 0.3) compounds in the temperature range 170 to ~500 K. ESR spectra of the samples over the whole temperature range studied could be divided into three regions corresponding to different linewidths. This is due to the presence of an anisotropic field arising from ferromagnetic clusters. This is similar to manganite perovskites. The peak-to-peak ESR linewidth vs. temperature, ∆H pp (T), for the samples has a minimum value at a temperature T min (in this case T min ≈ 1.7T C , whereas T min ≈ 1.1T C for manganites). Asymmetric Lorentzian ESR spectra at temperatures T < T min become Gaussian at T > T min . ESR signals of La 1-x Sr x CoO 3 cobaltites are thermally damped out at ~460 K, this value being much lower than that for manganite compounds. The explanation of the experimental ∆H pp (T) data in the T > T min regime is based on the one-phonon process and adiabatic hopping motion of small polarons.

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