Paramagnetic defects in ZnWO4 single crystals induced by electron irradiation at room temperature

Intrinsic paramagnetic defects in undoped zinc tungstate single crystals have been observed by ESR after electron irradiation at room temperature. The only observed hole-type defect is attributed to a hole trapped at an O2- ion near a zinc vacancy. Two electron-excess centers are each due to a single electron trapped at an oxygen vacancy, where the defects differ in the oxygen vacancy positions. All of the defects exhibit superhyperfine interactions with neighbouring 183W nuclei. Spin-Hamiltonian parameters are reported and discussed. (author)