The effects of oxygen deficiency on the structural, magnetic and electrical properties in Perovskite manganites

Author.The effects of oxygen deficiency on structural magnetic and electrical properties of La0.7Sr0.3MnO3-δ□δ where □is a vacancy and 0 ≤ δ ≤ 0.15, has been investigated. We present a new method of creating vacancies in the oxygen sites achieved at atmospheric pressure. X-ray diffraction patterns reveal that these materials have a rhombohedral structure ∫ or δ ≤ 0.075 and orthorhombic when δ ≥ 0.1. The magnetization and resistivity measurements as a function of temperature show a ferromagnetic metallic behavior for δ ≤ 0.075 at low temperatures and paramagnetic semiconductor above the Curie temperature Tc. The magnitude of the saturation magnetization Ms and the ferromagnetic phase are reduced with increasing δ. A ferromagnetic insulating state below 115K is observed for δ = 0.1 sample. It seems to be due to an ordering of Mn3+ and Mn4+ species on the manganese lattice