The magnetoresistance (MR) properties of a heterostructure fabricated by depositing a La0.5Sr0.5CoO3-sigma film on an n-type Si substrate have been studied. The heterostructure exhibits a good rectifying behavior. A negative MR at T=210 K and a positive MR at T=300 K are observed for all bias currents whereas; for temperatures ranging from 240 to 280 K the MR changes from being positive to negative with the increase of the bias current. The observed behavior of the MR effect is discussed in terms of current-induced ferromagnetic spin order. (C) 2012 Elsevier B.V. All rights reserved.