Colossal electroresistance in Sm0.55Sr0.45MnO3

We report a colossal resistance drop around insulator–metal transition temperature (TMI) in Sm0.55Sr0.45MnO3 induced by direct current. Polycrystalline samples of Sm0.55Sr0.45MnO3 were synthesized through solid state reaction method. They have been investigated by X-ray diffraction for phase evaluation, scanning electron microscopy for grain morphology and dc resistivity measurement techniques for resistivity–temperature behavior. The resistivity–temperature behavior has been measured with different biasing currents (1 mA, 2.5 mA, 5 mA, 10 mA and 50 mA). With increasing biasing current, the resistivity of the samples decreased drastically. The change in the resistivity of the samples for bias currents 1 mA and 50 mA at TMI was found to be ∼2560%. This phenomenon of electroresistance is discussed in view of strong interaction between carrier spins and localized spins in Mn ions and percolative mechanism of phase-separation.

Research highlights▶ A colossal resistance drop around insulator-metal transition temperature (TMI) in polycrystalline samples of Sm0.55Sr0.45MnO3 has been observed by applying different direct currents in pulsed mode. ▶ The change in the resistivity of the samples for bias currents 1 mA and 50 mA at TMI was found to be ∼2560%. ▶ The observed phenomenon can be useful for the potential applications of the electroresistance (ER) such as nonvolatile memory elements.