Structure-properties phase diagram for La1-xSrxMnO3 (0.1 <= x <= 0.2)

By combining the results of magnetization, resistivity, and neutron powder- diffraction data for stoichiometric La1-xSrxMnO3, we have constructed a pha se diagram that describes the magnetic, transport, and structural propertie s and the relationships among them as a function of composition (0.1 less t han or equal to x less than or equal to 0.2) and temperature (10 - 340 K). We show that, with increasing Sr content, the Curie temperature increases l inearly, while the temperature of an orbital ordering transition to a state with a large coherent Jahn-Teller (JT) distortion decreases. These two pha se-transition lines cross at x = 0.145 and T = 210 K. When the transition t o the ferromagnetic state occurs in a phase that has a large coherent JT di stortion (x < 0.145), a strong magnetolattice coupling is observed; the coh erent JT distortion is dramatically reduced and the incoherent distortion i s enhanced in the ferromagnetic phase. For x > 0.145, where the coherent JT distortion is small above Curie temperature, magnetolattice coupling reduc es the incoherent distortion at T-C and strongly suppresses the transition to a phase with a large coherent JT distortion. These observations are cons istent with a competition between ferromagnetism and JT distortion that is mediated by a colossal spin-charge-lattice coupling. A metallic state occur s below the Curie temperature when both coherent and incoherent JT distorti ons are suppressed. [S0163-1829(99)14933-6].