Dielectric Relaxation of Gd Doped PbWO_4 Single Crystal

Dielectric responses of as-grown PbWO4 single crystal doped with Gd3+ ion were measured. Experimental results show that typical dielectric relaxation phenomena exist in the crystal. There is one Debye-type dielectric peak ( α ) in the heating cycle from 40 ℃ up to 600℃ , while another peak (β) in the cooling cycle. Activation energies of the two peaks( α and β) are 0.50±.01 eV and 0.51 ± 0.02 eV, with afrequency factor 1.44 × 109s-1 and 2.44 × 106s-1 respectively. Both peaks can be explained by the presence of dipole complexes formed by the doped Gd3+ ions coupled with Pb vacancies and interstitial oxysen respertively. The correlation between the dielectric and scintillation properties was discussed.