Temperature sintering effects on the magnetic, electrical and transport properties of La0.67Sr0.33MnO3/Nd0.67Sr0.33MnO3 composites

The microstructure, magnetic and electrical transport properties of La0.67Sr0.33MnO3/Nd0.67Sr0.33MnO3 composites are studied as a function of sintering temperature. At 900 ◦C, the intergrain exchange couplings between the adjacent particles give rise to an increase in resistance. Raising the sintering temperature induces the formation of an interfacial phase near the La0.67Sr0.33MnO3 and Nd0.67Sr0.33MnO3 grain boundaries as indicated in the XRD pattern and SEM image. At 1100 ◦C, the formation of interfacial phases near the grain boundaries enhances the conductivity in the composite. Broad magnetoresistance across room temperature is observed in a composite sintered at 1300 ◦C. This observation may be ascribed to the coexistence of multiphase in the composite which leads to a decrease in resistance. The results suggest that sintering temperature has a prominent effect on the properties of the grain boundary, which plays an important role in determining the electrical transport behaviour of the composites.