Room temperature magnetoresistance in La0.67Sr0.33Mn1-xCoxO3

The substitution of Co for Mn in La0.67Sr0.33Mn1-xCoxO3 lowers the Curie temperature T-C and the metal-insulator transition temperature T-MI, accompanying the increase of the resistivity due to the weakening of the double-exchange interaction. The difference value between the T-C and the T-MI increases with Co substitution which may be attributed to local inhomogeneities in magnetic and electronic transport properties within the doped sample. There is an enhancement of the room temperature magnetoresistance DeltaR/R-0 induced by the substitution of Co for Mn in La0.67Sr0.33Mn1-xCoxO3, which may be connected with the shift of the Curie temperature T-C and metal-insulator transition temperature T-MI to the near room temperature through the substitution. Values of the room temperature magnetoresistance DeltaR/R-0 for La0.67Sr0.33Mn1-xCoxO3 depend not only on the T-C but also on the T-MI. (C) 2002 American Institute of Physics.