Electron paramagnetic resonance of radiation defects in LiYF4 crystal

Electron paramagnetic resonance (EPR) spectra of a nominally pure LiYF4 crystal were investigated after X-ray irradiation at room temperature (RT). The obtained results have shown the presence of a radiation-induced defect which is stable at RT. The broad EPR band of this defect in the X-microwave range is found to be structureless at RT. Based on the estimated g-values, the authors have suggested that the EPR spectra of the observed radiation defect could belong to an electron trap centre. The structure of the spectrum could be resolved by measurements at 77 K. The spectra exhibit the angular dependence, which has been explained by the g-anisotropy and hyperfine interaction of the unpaired electron spin with two neighbouring fluorine nuclei. (Authors)