Structural, magnetic, and electrical properties of single-crystallineLa1−xSrxMnO3(0.4<x<0.85)

We report on structural, magnetic and electrical properties of Sr-doped\nLaMnO_3 single crystals for doping levels 0.4 < x < 0.85. The complex\nstructural and magnetic phase diagram can only be explained assuming\nsignificant contributions from the orbital degrees of freedom. Close to x = 0.6\na ferromagnetic metal is followed by an antiferromagnetic metallic phase below\n200 K. This antiferromagnetic metallic phase exists in a monoclinic\ncrystallographic structure. Following theoretical predictions this metallic\nantiferromagnet is expected to reveal an (x^2-y^2)-type orbital order. For\nhigher Sr concentrations an antiferromagnetic insulator is established below\nroom temperature.\n