Magnetic resonance studies on~(207)Pb nuclei and paramagnetic impurities in PbWO_4:Eu, PbWO_4:Gd, and pure PbWO_4 single crystals

摘要

The electron paramagnetic resonance (EPR) of Eu~(2+) and Gd~(3+) ions in PbWO_4 crystals doped with paramagnetic impurities was investigated using an X-band spectrometer. It was found that during the growth of these crystals, Gd~(3+) ions substitute for the Pb~(2+) ions more effectively than Eu~(2+) ions. In addition, the relaxation rate 1/T_1 of the~(207)Pb nuclei in pure and doped PbWO_4 single crystals was studied using a nuclear magnetic resonance (NMR) spectrometer over a temperature range of 180-400 K. The relaxation mechanisms of the pure and doped crystals were Raman processes, resulting in relaxation rates that were proportional to the square of temperature.