Structure-property coupling in Sr3(Ru1-xMnx)2O7

Layered ruthenates are prototype materials for the study of structure-property correlations. We report the structural and physical properties of double-layered perovskite Sr-3(Ru1-xMnx)(2)O-7 single crystals with 0 <= x <= 0.7. Single-crystal x-ray diffraction refinements reveal that Mn doping on the Ru site leads to the shrinkage of unit-cell volume and the disappearance of (Ru/Mn)O-6 octahedron rotation when x > 0.16, but the crystal structure remains tetragonal. Upon doping, the electrical resistivity reveals a metallic character (d rho/dT > 0) at high temperatures but insulating behavior (d rho/dT < 0) below a characteristic temperature T-MIT. Interestingly, T-MIT is different from T-M, at which magnetic susceptibility reaches maximum. While T-MIT increases monotonically with increasing x, T-M displays a nonmonotonic dependence with x even though the effective spin increases from S similar to 1 (x = 0) to similar to 3/2 (x = 0.7). The phase diagram consists of three distinct magnetic ground states due to local structure change.