Giant magnetoresistance at room temperature achieved in the ferromagnetic phase of powder La0.5Sr0.5MnO3

Strontium substituted lanthanum manganite La0.5Sr0.5MnO3, powder has been synthesized by solid state reaction method at 1673 K. X-ray diffraction shows that the material exists in a single phase having a perovskite-like structure. Some physical properties such as magnetization versus temperature and electrical transport measurements have been investigated. The material is ferromagnetic with Curie temperature T-c = 370 K. The zero-field resistivity has a semiconducting behavior in all the range 4-300 K according to Mott's law. We have explored the magnetoresistance effect at 40 and 300 K under a field up to 54 kOe.