  The evolution between Fermi liquid and non-Fermi-liquid states in correlated
electron systems has been a central subject in condensed matter physics because
of the coupled intriguing magnetic and electronic states. An effective pathway
to explore the nature of non-Fermi liquid behavior is to approach its phase
boundary. Here we report a crossover from non-Fermi liquid to Fermi-liquid
state in metallic CaRuO3 through ionic liquid gating induced protonation with
electric field. This electronic transition subsequently triggers a reversible
magnetic transition with the emergence of an exotic ferromagnetic state from
this paramagnetic compound. Our theoretical analysis reveals that hydrogen
incorporation plays a critical role in both the electronic and magnetic phase
transitions via structural distortion and electron doping. These observations
not only help understand the correlated magnetic and electronic transitions in
perovskite ruthenate systems, but also provide novel pathways to design
electronic phases in correlated materials.
