EPR power pattern analysis for cubic sites of Fe3+ in MgO

A complete electron paramagnetic resonance power pattern characterization of Fe3+ in cubic sites in presented. A one-to-one correspondence among the peaks appearing in the powder pattern and the outer fine-structure transitions (Mnot = 1/2 ) observed in the single crystal along the <100>, <111>, and <110> directions is shown. It is shown that the process of mechanically grinding the single crystal to a powder (particle size approx.1--10 μ) does not remove the cubic symmetry sites. No axial or lower symmetry sites which may be induced by lattice distortion of the crystallites due to strain have been observed