Structural, magnetic and electrical properties of single crystalline   La_(1-x)Sr_xMnO_3 for 0.4 < x < 0.85
  We report on structural, magnetic and electrical properties of Sr-doped LaMnO_3 single crystals for doping levels 0.4 < x < 0.85. The complex structural and magnetic phase diagram can only be explained assuming significant contributions from the orbital degrees of freedom. Close to x = 0.6 a ferromagnetic metal is followed by an antiferromagnetic metallic phase below 200 K. This antiferromagnetic metallic phase exists in a monoclinic crystallographic structure. Following theoretical predictions this metallic antiferromagnet is expected to reveal an (x^2-y^2)-type orbital order. For higher Sr concentrations an antiferromagnetic insulator is established below room temperature. 
J. Hemberger, A. Krimmel, T. Kurz, H.-A. Krug von Nidda, V.Yu. Ivanov,   A.A. Mukhin, A.M. Balbashov, and A. Loidl