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 Sr3(Ru1 xMnx )2O7 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)O6 octahedron rotation when x > 0.16, but the crystal structure remains tetragonal. Upon doping, the electrical resistivity reveals a metallic character (d /dT > 0) at high temperatures but insulating behavior (d /dT < 0) below a characteristic temperature TMIT. Interestingly, TMIT is different from TM, at which magnetic susceptibility reaches maximum. While TMIT increases monotonically with increasing x,TM displays a nonmonotonic dependence with x even though the effective spin increases from S 1 (x = 0) to 3/2 (x = 0.7). The phase diagram consists of three distinct magnetic ground states due to local structure change.