Mossbauer and Magnetic Studies of a Mixed-Valence Ferrimagnet, Fe2F5.2H2O.
Abstract
The red, crystalline mixed-valence compound pentafluorodiiron(II,III)dihydrate, Fe2F5.2H2O, has been examined using Mossbauer spectroscopy and magnetic susceptibilities. At 48K the material orders ferrimagnetically as the result of spin compensation of iron (III) by iron(II). Above this critical temperature, the observation of distinct quadrupole-split Mossbauer absorptions for iron(II) and iron(III) sites demonstrates the non-equivalence of oxidation states and established Fe2F5.2H2O as a Class II mixed-valence compound. In the temperature range 49=300 K, the magnetic susceptibility may be explained using the molecular field theory of ferrimagnetism. Long range order is observed below 48K. This order is demonstrated magnetically through the observation of spontaneous magnetization, field-dependent susceptibilities, and a saturation moment corresponding to a formula unit spin of S=1/2. Mossbauer spectra below the critical temperature exhibit magnetic hyperfine structure consistent with the ferrimagnetic ordering. Hysteresis in the magnetic behavior suggests the possibility of a low-temperature magnetic phase change. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 06, 1977
- Accession Number
- ADA040318
Entities
People
- D. B. Brown
- E. G. Walton
- Hiu Yung Wong
- W. M. Reiff
Organizations
- University of Vermont