Effects of the Oxygen Nonstoichiometry on the Physical Properties of La0.7Sr0.3MnO3−δ□δ Manganites (0≤δ≤0.15)

✍ Scribed by N. Abdelmoula; K. Guidara; A. Cheikh–Rouhou; E. Dhahri; J.C. Joubert

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 162 KB
• Volume: 151
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2000.8636

✦ Synopsis

We present the oxygen de5ciency e4ects on the structural, magnetic, and electrical properties in La 0.7 Sr 0.3 MnO 3؊ ) solution where ) is a vacancy and 04 40.15. Polycrystalline samples La 0.7 Sr 0.3 MnO 3؊ ) were synthesized by a new method. In this series of manganites the Mn 3؉ content is systematically increased due to the increase in the nonstoichiometry . X-ray di4raction analysis shows a phase transition from a rhombohedral to an orthorhombic system at 0.0754 40.1. The material is ferromagnetic for 04 40.1 and antiferromagnetic for 0.1254 40.15. The Curie temperature T C and saturation magnetization M s decrease with increasing . Resistivity measurements as a function of temperature show a remarkable behavior for the La 0.7 Sr 0.3 MnO 2.9 compound; it is ferromagnetic metallic for 1154T4180 K and becomes ferromagnetic insulator below 115 K, where a charge ordering seems to appear. The di4erence in the hopping energies in our samples can be related to the existence of two crystallographic structures, one orthorhombic and the other rhombohedral.