The structural, magnetic and electrical properties of cobalt-doped SrRuO3

0≤x≤0.3) have been investigated. All the compounds have single phase with Pnma space group. The chemical homogeneity of synthesized samples are confirmed by scanning electron microscopy and energy-dispersive spectroscopy. The X-ray photoelectron spectra of Co and Ru reveal that both two transition metal elements exist in the mixed ionic pair, that is Co3+/ Co2+ and Ru5+/ Ru4+. With Co doping, the ferromagnetic transition temperatures Tc decreases moderately, but the magnetic moment drops substantially. The coercive field Hc is enhanced by the substitution of Co, which may originates from the high degree randomness of Co and Ru ions, as well as from the improved competition between ferromagnetic Ru4+-O-Ru4+ and antiferromagnetic Co2+-O-Ru5+ and/or Co3+-O-Co3+ iterations. Co substitution in SrRu1-xCoxO3 system weakens the itinerant properties of Ru 4d electrons and results in localization of mobile electrons, and thus gives rise to the metal-insulator transition at around x = 0.15.