Enhanced Magnetoresistance Effect and Magnetic Properties of Double Perovskite La2−xSrxMnRuO6 (0 ≤ x ≤ 1.0)

Double perovskite La2−xSrxMnRuO6 (x = 0, 0.3, 0.5, 0.8, 1.0) samples were synthesized by the standard solid-state reaction method. The compounds can be well indexed as an orthorhombic structure with the space group of Pnma at room temperature. The Sr-doped samples exhibit a stronger ferromagnetic behavior than the undoped sample, which is responsible for the ferromagnetic super-exchange interaction of Mn3+-O2−-Ru4+. The Curie temperature of all samples increases with the increasing Sr2+ concentration. All the samples show a semiconducting-like behavior, and the nature of electrical conduction can be well described by Mott’s three-dimensional variable range hopping model. The appropriate Sr2+ substitution can effectively enhance the magnetoresistance effect. An enhanced negative magnetoresistance effect (~ 49%) in the La1.5Sr0.5MnRuO6 sample was observed at 25 K and 7 T.