The EPR susceptibility is calculated using a new method which unlike Anderson's random phase approximation, enables the calculation to be performed for the finite temperatures corresponding to current EPR practice. The dynamic susceptibility obtained is equivalent to the Bloch-Hasagawa equations designated 'case B', i.e. relaxation towards the instantaneous equilibrium, in agreement with the results for the s-d exchange model and an earlier RPA calculation. However, the interpretation of the parameters is different to that for the s-d exchange model (i) the effective s-d exchange contains contributions from covalent mixing, atomic exchange and the conduction electron-electron interaction responsible for conduction electron enhancement (ii) the impurity g factor becomes renormalized as compared with its bare or 'ionic' value (iii) the impurity-impurity spin interaction in the Anderson model contains direct covalent mixing contributions which do not occur in the s-d exchange model.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)
- Metals and Alloys