Diluted magnetic interactions in an oxygen-deficient perovskite cobaltite: magnetoresistance in the series SrCo1−xScxO3−δ (0<x⩽0.5)

A series of the oxygen-deficient perovskite SrCo{sub 1-x}Sc{sub x}O{sub 3-{delta}} has been successfully prepared by using close ampoules for compositions in the range 0.05=ionic radius than those of the Co{sup 3+}/Co{sup 4+} cations. At 300K, resistivity ({rho}) values of about {approx}10{sup -2}{omega}cm are measured for both x=0.05 and 0.10, but for larger x values {rho} increases, reaching {rho}{sub 300K}=10{sup 2}{omega}cm for x=0.5. For the former, the lower resistivity values result from their weak ferromagnetic behavior characterized by a Curie temperature T{sub C} of {approx}60K. Interestingly, these oxides exhibit similar negative magnetoresistance values, reaching 12% in 7T at 5K, to those reported for the SrFe{sub 1-x}Co{sub x}O{sub 3-{delta}} samples. It is concluded that the simultaneous presence of non-magnetic (3d{sup 0}) Sc{sup 3+} species, substituted for cobalt, and of oxygen vacancies induce magnetic disordering, exemplified by the spin-glass like behavior of SrCo{sub 0.5}Sc{sub 0.5}O{sub 3-{delta}}, which favors the existence of magnetoresistance.