A Powder Neutron Diffraction Study of Structure and Magnetism in NiCr2S4

✍ Scribed by Anthony V. Powell; Douglas C. Colgan; Clemens Ritter

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 419 KB
• Volume: 134
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1997.7549

✦ Synopsis

Powder neutron diffraction data for NiCr 2 S 4 have been collected over the temperature range 1.84 4T4 4286 K. The Cr 3 S 4 structure (space group I2/m) is adopted at all temperatures. Refinement of 286 K data (a ‫؍‬ 5.8954(14) A s , b ‫؍‬ 3.4066(8) A s , c ‫؍‬ 11.0589(22) A s , ‫؍‬ 91.362(4)°°) demonstrates that the distribution of nickel and chromium cations between sites in a fully occupied metal layer and sites in an ordered vacancy layer is close to that expected for the normal structure type. Data collected at 1.8 K (a ‫؍‬ 5.8621(5) A s , b ‫؍‬ 3.4051(2) A s , c ‫؍‬ 11.0297(9) A s , ‫؍‬ 91.607(6)°°) reveal the presence of long-range magnetic order, involving a doubling of the unit cell in both the a and c directions. Cations in the fully occupied metal layer possess an ordered magnetic moment of 1.57(6) B which is directed parallel to the cation layers. Cations in the vacancy layer have a moment of 1.36(8) B which is directed toward the anion layers. The magnetic ordering temperature was determined as 180(5) K. These results are correlated with magnetic susceptibility and electrical conductivity data.