Emergent electronic and magnetic state in Ca₃Ru ₂O₇ induced by Ti doping

We report an emergent electronic and magnetic state in the bilayer ruthenate Ca₃Ru₂O₇ upon doping with a small concentration of Ti on the Ru sites. In contrast to a quasi-two-dimensional metallic state in Ca₃Ru₂O₇, which has an antiferromagnetic (AF) state formed by ferromagnetic (F) bilayers stacked antiferromagnetically along the c-axis, we find an insulating ground state with a "G"-type nearest-neighbor AF order in Ca₃(Ru _1-xTi_x)₂O₇ for x 0.03. The close proximity of these two distinct electronic and magnetic states demonstrates unique competing magnetic interactions in Ca₃Ru₂O ₇, which provides a rare opportunity to investigate the interplay between correlated metal physics and Mott physics.