Indications of phase separation in polycrystalline La1-xSrxMnO3 for x approximate to 0.5

We present systematic studies of polycrystalline La1-xSrxMnO3 where x is va ried from 0.46 to 0.53 at 0.01 intervals. We have measured the magnetic res onance, ac susceptibility, de magnetization, x-ray diffraction, four-probe resistivity, and optical reflectivity. The data seem to indicate that, at l ow T, the materials are intimate mixtures of ferromagnetic and antiferromag netic microregions. For x > 0.48 we observe anomalies pointing toward charg e ordering on lowering T. An effective-medium theory is presented, and an a ppropriate phase diagram is proposed.