Magnetic Properties of La2NiO4.16and La2−xPrxNiO4+δ

✍ Scribed by N.J. Poirot; Ch. Allançon; P. Odier; P. Simon; J.M. Bassat; J.P. Loup

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 311 KB
• Volume: 138
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1998.7781

✦ Synopsis

Magnetic properties of La 2 NiO 4.16 and La 2؊x Pr x NiO 4؉ are studied by dc susceptibility in a wide temperature range, i.e., 4-1200 K. The principal aim is to investigate the modifications of magnetic interactions in the NiO 2 plane by inserting a magnetic ion in the LaO layer. Magnetic properties are considerably different with and without praseodymium. When 0(x42 the solid solution follows the Curie-Weiss law and the Curie constant varies linearly with x. For x ‫؍‬ 0, the susceptibility is smaller and another contribution appears above 200 K that is treated as the result of clusters of AF-coupled spins of two-dimensional character. Our model fits very well the data from 4 to 1000 K. Comparing the Curie-Weiss temperature with and without Pr suggests that small Pr quantities modify the in-plane Ni-O-Ni magnetic interactions and, thus, decrease the Curie-Weiss temperature. We think this is not a structural effect; it might correlate with an increased resistivity when Pr is substituted. For larger substitution, i.e., x'0.5, a single Pr 3؉ effect might dominate.