  We report the nanoscale imaging of Ti-doped bilayer calcium ruthenates during
the Mott metal-insulator transition by microwave impedance microscopy.
Different from a typical first-order phase transition where coexistence of the
two terminal phases takes place, a new metallic stripe phase oriented along the
in-plane crystalline axes emerges inside both the G-type antiferromagnetic
insulating state and paramagnetic metallic state. The effect of this electronic
state can be observed in macroscopic measurements, allowing us to construct a
phase diagram that takes into account the energetically competing phases. Our
work provides a model approach to correlate the macroscopic properties and
mesoscopic phase separation in complex oxide materials.
