Magnetic phase separation in double layer ruthenates Ca3(Ru1-xTix)2O7

A phase transition from metallic AFM-b antiferromagnetic state to Mott insulating G-type antiferromagnetic (G-AFM) state was found in Ca-3(Ru1-xTix)(2)O-7 at about x = 0.03 in our previous work. In the present, we focused on the study of the magnetic transition near the critical composition through detailed magnetization measurements. There is no intermediate magnetic phases between the AFM-b and G-AFM states, which is in contrasted to manganites where a similar magnetic phase transition takes place through the presence of several intermediate magnetic phases. The AFM-b-to-G-AFM transition in Ca-3(Ru1-xTix)(2)O-7 happens through a phase separation process in the 2-5% Ti range, whereas similar magnetic transitions in manganites are tuned by 50-70% chemical substitutions. We discussed the possible origin of such an unusual magnetic transition and compared with that in manganites.