Electron Magnetic Resonance of Eu2+ in SrCl2:Eu Single Crystal

The electron paramagnetic resonance (EPR) of the $Eu^{2+}$ ion in $SrCl_2$:Eu single crystal has been investigated using an X-band spectrometer. The angular dependence of magnetic resonance positions for the $Eu^{2+}$ impurity ion in the crystallographic aa-plane is analyzed with effective spin-Hamiltonian. The EPR spectra of the isolated $Eu^{2+}$ center merged to each other. The hyperfine splitting of the isolated $Eu^{2+}$ center due to the $^{151}Eu$ nucleus is approximately 35 G. Three kinds of $Eu^{2+}$ centers except the isolated $Eu^{2+}$ center, $Eu^{2+}$ pairs, $Eu^{2+}$ triples, and other $Eu^{2+}$ clusters, are split from the fitting of the integrated experimental spectrum with the Gaussian curve. The calculated spectroscopic splitting parameters of the $Eu^{2+}$ pairs, $Eu^{2+}$ triples, and other $Eu^{2+}$ clusters in $SrCl_2$:Eu crystal are $g_1$ = 2.06, $g_2$ = 1.94, and $g_3$ = 1.93, respectively.