Microscopic state of low doped manganites La1-xSrxMnO3 probed by ESR

The electron spin resonance (ESR) measurements were performed in single crystals of La1-xSrxMnO3 (0.05 less than or equal to x less than or equal to 0.125) in order to study the interplay of crystal field, Dzyaloshinsky-Moriya interaction, Jahn-Teller (JT) effect, and orbital order. The angular dependence of the ESR linewidth of an untwinned La0.95Sr0.05MnO3 single crystal has been analyzed in the high-temperature approximation, which takes into account the microscopic geometry of the four nonequivalent Mn positions in the orthorhombic unit cell. A strong mixing of the \3z(2) - r(2)) and \x(2) - y(2)) states for the real orbital configuration was found. Magnetic inhomogeneities observed in the ESR spectra across the composition range 0.075 less than or equal to x less than or equal to 0.125 can be attributed to the presence of ferromagnetic clusters (magnetic spin polarons) in the paramagnetic state. New polaronic models are proposed.