Structural, magnetic, and electronic transport properties of (Sr_(0.9)Ca_(0.1))_3Ru_2O_7 single crystal

摘要

We have studied the structural, magnetic, and electronic transport properties of (Sr_(0.9)Ca_(0.1))_3Ru_2O_7 using single crystals grown by a floating-zone technique. The structure analysis by Rietveld refinements reveals that the Ca substitution for Sr intensifies the structure distortion; the rotation angle of the RuO_6 octahedron increases. This structure change tunes magnetic and transport properties dramatically. The magnetic ground state switches from an itinerant metamagnetic state for Sr_3Ru_2O_7 to a nearly ferromagnetic state for (Sr_(0.9)Ca_(0.1))_3Ru_2O_7. The Fermi liquid behavior occurs in Sr_3Ru_2O_7, but is suppressed in (Sr_(0.9)Ca_(0.1))_3Ru_2O_7. These results strongly suggest that lattice, spin, and charge degrees of freedom are strongly coupled in this system. The band width narrowing caused by the structure distortion should be responsible for the enhancement of ferromagnetic correlations and the change of transport properties.