Long Range and Short Range Magnetic Order in Orthorhombic LiMnO2

✍ Scribed by J.E. Greedan; N.P. Raju; I.J. Davidson

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 279 KB
• Volume: 128
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1996.7189

✦ Synopsis

The magnetic properties of orthorhombic LiMnO 2 have been investigated in detail for the first time. The susceptibility data show several features including a Curie-Weiss regime from 600 to 800 K with p ‫؍‬ ؊1056(13) K and eff ‫؍‬ 4.82 B /Mn 3؉ , a broad maximum at 360 K, and a field-cooled (FC), zero field cooled (ZFC) divergence below 100 K. The broad maximum indicates two-dimensional rather than one-dimensional shortrange spin correlations. A Ne´el temperature for a transition to three-dimensional long-range order is seen at 261.5 K from both neutron diffraction and the magnetic heat capacity behavior as determined from the susceptibility data. The magnetic structure has been solved from neutron diffraction data and has a propagation vector of k"(1/2 1/2 1/2) and an ordered magnetic moment of 3.69(4) B /Mn 3؉ with a preferred direction parallel to the b axis. The neutron scattering data also provide evidence for two-dimensional short-range correlations above T c at 271 K in the form of a feature with a Warren line shape. The long-and short-range order are discussed in terms of the crystal structure which is of the ordered NaCl type distorted by the presence of the Jahn-Teller ion, Mn 3؉ .