Structural and magnetic aspects of the metal-insulator transition inCa2−xSrxRuO4

The phase diagram of ${\mathrm{Ca}}_{2-x}{\mathrm{Sr}}_x{\mathrm{RuO}}_4$ has been studied by neutron diffraction on powder and single-crystalline samples. The experiments reveal antiferromagnetic order and structural distortions characterized by tilts and rotations of the ${\mathrm{RuO}}_6$ octahedra. There is strong evidence that the structural details of the isovalent samples tune the magnetic as well as the electronic behavior. In particular we observe for low Sr concentration a metal-insulator transition associated with a structural change and magnetic ordering.