Abstract:
The results of electron paramagnetic resonance (EPR) studies of Dy$^{3+}$ ions in lead thiogallate PbGa$_2$S$_4$ single crystals have been presented. It has been shown that the ground state of these ions corresponds to the lowest Stark sublevel $\Gamma_6$ of the term $^6H_{15/2}$. The spectra are well described by the axially symmetric spin Hamiltonian with the effective spin $S$ = 1/2 with the factors $g_\parallel$ = 15.06 and $g_\perp$ = 2.47. The Dy$^{3+}$ ions substitute Pb$^{2+}$ ions in the crystal lattice of PbGa$_2$S$_4$. The observed hyperfine structure has allowed to unambiguously interpret the EPR spectra. The hyperfine interaction constants of two odd isotopes of dysprosium in lead thiogallate single crystals have been found to be $A_\parallel$ = 675 $\times$ 10$^{-4}$ cm$^{-1}$ and $A_\perp$ = 111 $\times$ 10$^{-4}$ cm$^{-1}$ for $^{163}$Dy and $A_\parallel$ = 472 $\times$ 10$^{-4}$ cm$^{-1}$ and $A_\perp$ = 77 $\times$ 10$^{-4}$ cm$^{-1}$ for $^{161}$Dy.
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