Phase competition driven temperature broadening of colossal magnetoresistance in La0.815Sr0.185MnO3

It is shown that the temperature dependence of the magnetoresistance (MR) in manganites can be appreciably broadened by enhancing phase competition. By substituting Mn4+ with small amounts of Ti4+, the ferromagnetic metallic La0.815Sr0.185MnO3 is pushed closer to the ferromagnetic metallic (FMM)/ferromagnetic insulating (FMI) phase boundary. Ti4+ substitution significantly reduces the ferromagnetic and insulator–metal transition temperatures and broadens their evolution. This results in weak temperature dependence of the MR across the M–I transition with a variation of only about 0.5%. Thus, the route adopted is well suited for overcoming one of the major limitations of using colossal magnetoresistive manganites as magnetosensitive devices.