X- and Q-band magnetic resonance study of iridium-doped silver chloride microcrystals

Irradiation at low temperature (T < 120 K) of iridium-doped AgCl microcryst als with x-rays leads to the formation of a single Ir2+ complex. The compar ison between X- and Q-band EPR (electron paramagnetic resonance) spectra re veals that the defect has a small orthorhombic distortion. Pulse annealing to temperatures higher than 170 K converts the complex into a second Ir2+ c omplex with axial symmetry. This conversion is monitored with X-band ENDOR (electron-nuclear double resonance), allowing a consistent spectrum decompo sition and interpretation. For each defect a model is proposed.