A MOSSBAUER EFFECT STUDY OF ELECTRONIC RELAXATION IN THE PARAMAGNETIC COMPOUND: NH4(FE,A1L)(SO4)2 . 12 H2O.
Abstract
The Mossbauer spectra of paramagnetic ferric compounds exhibit magnetic hyperfine splittings when the electronic relaxation rates of the ferric ions are made comparable to the precession frequency of the nucleus in the hyperfine field. This was observed in ferric ammonium alum diluted in aluminum ammonium alum NH4(Fe,Al)(SO4)2.12H2O), as a function of iron concentration, temperature, deuteration and external magnetic field. The effect was also observed in the corresponding potassium alums. The crystalline field levels of the ferric ion consists of three Kramers doublets and each doublet produces its own hyperfine pattern. In the absence of an external magnetic field, the spectrum due to the Sz = plus or minus 5/2 doublet was completely resolved, that due to the plus or minus 3/2 doublet partially resolved and that due to the plus or minus 1/2 doublet not resolved at all. Relaxation time estimates are made ranging from 4 x 10 to the -7th power sec to 6 x 10 to the -11th power sec depending on the concentration, the temperatures and the particular Kramers doublet under consideration. The magnetic field produced at the nucleus by the plus or minus 5/2 doublet was found to be -572 plus or minus 7 kgauss. The isomer shift is 0.53 plus or minus 0.1 mm/sec and the quadrupole interaction energy 1/4(E Sq)qQ=0.055 plus or minus 0.025 mm/sec. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1966
- Accession Number
- AD0646626
Entities
People
- Larry E. Campbell
Organizations
- Carnegie Institute of Technology