Exchange Bias Effect Concerned with Tunneling Magnetoresistance in ${\hbox {Sm}}_{0.35} {\hbox {Pr}}_{0.15}{\hbox {Sr}}_{0.5}{\hbox {MnO}}_3$ Phase Separated Manganites

In this paper, we report the exchange bias (EB) effect along with tunneling magnetoresistance (MR) in polycrystalline Sm_0.35Pr_0.15Sr_0.5MnO₃ manganite. Analogous to the shift in the magnetic hysteresis loop along the field (H)-axis, a shift is also observed in the MR-H curve when the sample is cooled in a static dc magnetic field at 5 K. The values of exchange fields (H_E), coercivity (H_C), remanence asymmetry (M_E) and magnetic coercivity (M_C) are found to strongly depend on cooling magnetic field and temperature. Magnetic training effect (T_E) is supportive experimental evidence which describes the decrease of exchange bias field when sample is successively field-cycled at a particular temperature. We have also observed T_E in the shift of the MR-H curve which has been interpreted by the spin relaxation model. We have observed the time dependent resistivity below the spin freezing temperature. The unusual MR behavior is interpreted in terms of the intragranular interface effect between short-range ferromagnetic clusters and spin-glass matrix giving rise to the EB effect, which is of special interest for potential application in multifunctional spintronic devices.