PARAMAGNETIC RELAXATION IN DILUTE POTASSIUM FERRICYANIDE
Abstract
Paramagnetic relaxation times for the ground state Kramers doublet of iron present as a dilute substitutional impurity in potassium cobalticyanide was measured for iron concentrations from 0.24% to 3.5%, over the temperature range 1.25 to 4.5 K. Measurements were performed at 1.8 and 8.5 Gc/s. A review of relevant crystal field theory is given and includes calculation of energy levels for 3 lowest Kramers doublets. Spin-lattice relaxation theory is reviewed and compared with experimental findings. At low iron concentration spin lattice times measured at 1.8 Gc/s are found to display a 9th-power temperature variation over 5 decades of time, in agreement with the theory of the Raman process. No change in the Raman rate is observed between 1.8 and 8.5 Gc/s. At 8.5 Gc/s the linear temperature dependence for the direct relaxation process is also verified. At higher concentrations, added relaxation mechanisms appear. At highest concentrations a competing fast process is also observed, but is not fully understood.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1962
- Accession Number
- AD0296786
Entities
People
- Andreas Rannestad
Organizations
- Johns Hopkins University