Slight Co-doping tuned magnetic and electric properties on cubic BaFeO₃ single crystal

The single crystal of cubic perovskite BaFeO_3 shows multiple magnetic transitions and external stimulus sensitive magnetism. In this paper, a 5%-Co-doped BaFeO_3 (i.e. BaFe_0.95Co_0.05O_3) single crystal was grown by combining floating zone methods with high-pressure techniques. Such a slight Co doping has little effect on crystal structure, but significantly changes the magnetism from the parent antiferromagnetic ground state to a ferromagnetic one with the Curie temperature T_\rm C \approx 120 K. Compared with the parent BaFeO_3 at the induced ferromagnetic state, the saturated magnetic moment of the doped BaFe_0.95Co_0.05O_3 increases by about 10% and reaches 3.64 \mu_\rm B/f.u. Resistivity and specific heat measurements show that the ferromagnetic ordering favors metallic-like electrical transport behavior for BaFe_0.95Co_0.05O_3. The present work indicates that Co-doping is an effective method to tune the magnetic and electric properties for the cubic perovskite phase of BaFeO_3.