Wide-band EPR spectroscopy and relaxation study of Tm3+ ions in PbGa2S4 crystal

The PbGa2S4: Tm3+ crystal was investigated by tunable high-frequency EPR spectroscopy. Two thulium centers located in positions with different local symmetry were observed in the frequency range of 9.8–170 GHz. Both spectra with the resolved hyperfine structure correspond to the transition between sublevels of the main quasi-doublet Tm3+ with crystal field splitting of 6.93 GHz and 1.42 GHz. The times of phase memory and spin-lattice relaxation of thulium ions were measured by the spin-echo method for various values of the magnetic field. •Lead thiogallate has many positions where an impurity ion can embeded.•Investigation of non-Kramers ions by high-frequency magnetic resonance spectroscopy.•Rare-earth ion energy levels for quantum optics applications.•Phase memory time measured by the spin echo method.